[kotlin][client] fix temp file name and remove old deprecated jvm-okhttp3 (#19064)

* [kotlin][client] fix temp file name and remove old deprecated jvm-okhttp3

* [kotlin][client] fix temp file name and remove old deprecated jvm-okhttp3

* [kotlin][client] fix temp file name and remove old deprecated jvm-okhttp3

modules/openapi-generator/src/main/resources/kotlin-client/build.gradle.mustache

@@ -155,9 +155,6 @@ dependencies {
     implementation "io.ktor:ktor-serialization-jackson:$ktor_version"
     {{/jackson}}
     {{/jvm-ktor}}
-    {{#jvm-okhttp3}}
-    implementation "com.squareup.okhttp3:okhttp:3.14.9"
-    {{/jvm-okhttp3}}
     {{#jvm-okhttp4}}
     implementation "com.squareup.okhttp3:okhttp:4.12.0"
     {{/jvm-okhttp4}}

modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-okhttp/api.mustache

@@ -243,6 +243,6 @@ import {{packageName}}.infrastructure.toMultiValue
     {{/operation}}
 
     private fun encodeURIComponent(uriComponent: kotlin.String): kotlin.String =
-        HttpUrl.Builder().scheme("http").host("localhost").addPathSegment(uriComponent).build().encodedPathSegments{{#jvm-okhttp3}}(){{/jvm-okhttp3}}[0]
+        HttpUrl.Builder().scheme("http").host("localhost").addPathSegment(uriComponent).build().encodedPathSegments[0]
 }
 {{/operations}}

modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-okhttp/infrastructure/ApiClient.kt.mustache

@@ -5,36 +5,19 @@ import android.os.Build
 {{/supportAndroidApiLevel25AndBelow}}
 import okhttp3.OkHttpClient
 import okhttp3.RequestBody
-{{#jvm-okhttp3}}
-import okhttp3.MediaType
-{{/jvm-okhttp3}}
-{{#jvm-okhttp4}}
 import okhttp3.RequestBody.Companion.asRequestBody
 import okhttp3.RequestBody.Companion.toRequestBody
-{{/jvm-okhttp4}}
 import okhttp3.FormBody
-{{#jvm-okhttp3}}
-import okhttp3.HttpUrl
-{{/jvm-okhttp3}}
-{{#jvm-okhttp4}}
 import okhttp3.HttpUrl.Companion.toHttpUrlOrNull
-{{/jvm-okhttp4}}
 import okhttp3.ResponseBody
-{{#jvm-okhttp4}}
 import okhttp3.MediaType.Companion.toMediaTypeOrNull
-{{/jvm-okhttp4}}
 import okhttp3.Request
 import okhttp3.Headers
-{{#jvm-okhttp4}}
 import okhttp3.Headers.Companion.toHeaders
-{{/jvm-okhttp4}}
 import okhttp3.MultipartBody
 import okhttp3.Call
 import okhttp3.Callback
 import okhttp3.Response
-{{#jvm-okhttp3}}
-import okhttp3.internal.Util.EMPTY_REQUEST
-{{/jvm-okhttp3}}
 import java.io.BufferedWriter
 import java.io.File
 import java.io.FileWriter
@@ -48,6 +31,7 @@ import java.time.OffsetDateTime
 import java.time.OffsetTime
 {{/threetenbp}}
 import java.util.Locale
+import java.util.regex.Pattern
 {{#useCoroutines}}
 import kotlin.coroutines.resume
 import kotlin.coroutines.resumeWithException
@@ -74,9 +58,7 @@ import com.fasterxml.jackson.core.type.TypeReference
 import com.squareup.moshi.adapter
 {{/moshi}}
 
-{{#jvm-okhttp4}}
 {{#nonPublicApi}}internal {{/nonPublicApi}}val EMPTY_REQUEST: RequestBody = ByteArray(0).toRequestBody()
-{{/jvm-okhttp4}}
 
 {{#nonPublicApi}}internal {{/nonPublicApi}}open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClient) {
     {{#nonPublicApi}}internal {{/nonPublicApi}}companion object {
@@ -118,12 +100,7 @@ import com.squareup.moshi.adapter
 
     protected inline fun <reified T> requestBody(content: T, mediaType: String?): RequestBody =
         when {
-            {{#jvm-okhttp3}}
-            content is File -> RequestBody.create(MediaType.parse(mediaType ?: guessContentTypeFromFile(content)), content)
-            {{/jvm-okhttp3}}
-            {{#jvm-okhttp4}}
             content is File -> content.asRequestBody((mediaType ?: guessContentTypeFromFile(content)).toMediaTypeOrNull())
-            {{/jvm-okhttp4}}
             mediaType == FormDataMediaType ->
                 MultipartBody.Builder()
                     .setType(MultipartBody.FORM)
@@ -134,35 +111,18 @@ import com.squareup.moshi.adapter
                             if (part.body is File) {
                                 val partHeaders = part.headers.toMutableMap() +
                                     ("Content-Disposition" to "form-data; name=\"$name\"; filename=\"${part.body.name}\"")
-                                {{#jvm-okhttp3}}
-                                val fileMediaType = MediaType.parse(guessContentTypeFromFile(part.body))
-                                addPart(
-                                    Headers.of(partHeaders),
-                                    RequestBody.create(fileMediaType, part.body)
-                                )
-                                {{/jvm-okhttp3}}
-                                {{#jvm-okhttp4}}
                                 val fileMediaType = guessContentTypeFromFile(part.body).toMediaTypeOrNull()
                                 addPart(
                                     partHeaders.toHeaders(),
                                     part.body.asRequestBody(fileMediaType)
                                 )
-                                {{/jvm-okhttp4}}
                             } else {
                                 val partHeaders = part.headers.toMutableMap() +
                                     ("Content-Disposition" to "form-data; name=\"$name\"")
-                                {{#jvm-okhttp3}}
-                                addPart(
-                                    Headers.of(partHeaders),
-                                    RequestBody.create(null, parameterToString(part.body))
-                                )
-                                {{/jvm-okhttp3}}
-                                {{#jvm-okhttp4}}
                                 addPart(
                                     partHeaders.toHeaders(),
                                     parameterToString(part.body).toRequestBody(null)
                                 )
-                                {{/jvm-okhttp4}}
                             }
                         }
                     }.build()
@@ -176,27 +136,6 @@ import com.squareup.moshi.adapter
                 }.build()
             }
             mediaType == null || mediaType.startsWith("application/") && mediaType.endsWith("json") ->
-            {{#jvm-okhttp3}}
-                if (content == null) {
-                    EMPTY_REQUEST
-                } else {
-                    RequestBody.create(
-                        {{#moshi}}
-                        MediaType.parse(mediaType ?: JsonMediaType), Serializer.moshi.adapter(T::class.java).toJson(content)
-                        {{/moshi}}
-                        {{#gson}}
-                        MediaType.parse(mediaType ?: JsonMediaType), Serializer.gson.toJson(content, T::class.java)
-                        {{/gson}}
-                        {{#jackson}}
-                        MediaType.parse(mediaType ?: JsonMediaType), Serializer.jacksonObjectMapper.writeValueAsString(content)
-                        {{/jackson}}
-                        {{#kotlinx_serialization}}
-                        MediaType.parse(mediaType ?: JsonMediaType), Serializer.kotlinxSerializationJson.encodeToString(content)
-                        {{/kotlinx_serialization}}
-                    )
-                }
-            {{/jvm-okhttp3}}
-            {{#jvm-okhttp4}}
                 if (content == null) {
                     EMPTY_REQUEST
                 } else {
@@ -214,15 +153,9 @@ import com.squareup.moshi.adapter
                     {{/kotlinx_serialization}}
                         .toRequestBody((mediaType ?: JsonMediaType).toMediaTypeOrNull())
                 }
-            {{/jvm-okhttp4}}
             mediaType == XmlMediaType -> throw UnsupportedOperationException("xml not currently supported.")
             mediaType == OctetMediaType && content is ByteArray ->
-            {{#jvm-okhttp3}}
-                RequestBody.create(MediaType.parse(OctetMediaType), content)
-            {{/jvm-okhttp3}}
-            {{#jvm-okhttp4}}
                 content.toRequestBody(OctetMediaType.toMediaTypeOrNull())
-            {{/jvm-okhttp4}}
             // TODO: this should be extended with other serializers
             else -> throw UnsupportedOperationException("requestBody currently only supports JSON body, byte body and File body.")
         }
@@ -230,22 +163,60 @@ import com.squareup.moshi.adapter
     {{#moshi}}
     @OptIn(ExperimentalStdlibApi::class)
     {{/moshi}}
-    protected inline fun <reified T: Any?> responseBody(body: ResponseBody?, mediaType: String? = JsonMediaType): T? {
+    protected inline fun <reified T: Any?> responseBody(response: Response, mediaType: String? = JsonMediaType): T? {
+        val body = response.body
         if(body == null) {
             return null
         }
         if (T::class.java == File::class.java) {
             // return tempFile
+            val contentDisposition = response.header("Content-Disposition")
+
+            val fileName = if (contentDisposition != null) {
+                // Get filename from the Content-Disposition header.
+                val pattern = Pattern.compile("filename=['\"]?([^'\"\\s]+)['\"]?")
+                val matcher = pattern.matcher(contentDisposition)
+                if (matcher.find()) {
+                    matcher.group(1)
+                        ?.replace(".*[/\\\\]", "")
+                        ?.replace(";", "")
+                } else {
+                    null
+                }
+            } else {
+                null
+            }
+
+            var prefix: String?
+            val suffix: String?
+            if (fileName == null) {
+                prefix = "download"
+                suffix = ""
+            } else {
+                val pos = fileName.lastIndexOf(".")
+                if (pos == -1) {
+                    prefix = fileName
+                    suffix = null
+                } else {
+                    prefix = fileName.substring(0, pos)
+                    suffix = fileName.substring(pos)
+                }
+                // Files.createTempFile requires the prefix to be at least three characters long
+                if (prefix.length < 3) {
+                    prefix = "download"
+                }
+            }
+
             {{^supportAndroidApiLevel25AndBelow}}
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val tempFile = java.nio.file.Files.createTempFile("tmp.{{packageName}}", null).toFile()
+            val tempFile = java.nio.file.Files.createTempFile(prefix, suffix).toFile()
             {{/supportAndroidApiLevel25AndBelow}}
             {{#supportAndroidApiLevel25AndBelow}}
             val tempFile = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
-                java.nio.file.Files.createTempFile("tmp.net.medicineone.teleconsultationandroid.openapi.openapicommon", null).toFile()
+                java.nio.file.Files.createTempFile(prefix, suffix).toFile()
             } else {
                 @Suppress("DEPRECATION")
-                createTempFile("tmp.net.medicineone.teleconsultationandroid.openapi.openapicommon", null)
+                createTempFile(prefix, suffix)
             }
             {{/supportAndroidApiLevel25AndBelow}}
             tempFile.deleteOnExit()
@@ -337,12 +308,7 @@ import com.squareup.moshi.adapter
     {{/hasAuthMethods}}
 
     protected {{#useCoroutines}}suspend {{/useCoroutines}}inline fun <reified I, reified T: Any?> request(requestConfig: RequestConfig<I>): ApiResponse<T?> {
-        {{#jvm-okhttp3}}
-        val httpUrl = HttpUrl.parse(baseUrl) ?: throw IllegalStateException("baseUrl is invalid.")
-        {{/jvm-okhttp3}}
-        {{#jvm-okhttp4}}
         val httpUrl = baseUrl.toHttpUrlOrNull() ?: throw IllegalStateException("baseUrl is invalid.")
-        {{/jvm-okhttp4}}
         {{#hasAuthMethods}}
 
         // take authMethod from operation
@@ -416,30 +382,30 @@ import com.squareup.moshi.adapter
         return response.use {
             when {
                 it.isRedirect -> Redirection(
-                    it.code{{#jvm-okhttp3}}(){{/jvm-okhttp3}},
+                    it.code,
-                    it.headers{{#jvm-okhttp3}}(){{/jvm-okhttp3}}.toMultimap()
+                    it.headers.toMultimap()
                 )
                 it.isInformational -> Informational(
-                    it.message{{#jvm-okhttp3}}(){{/jvm-okhttp3}},
+                    it.message,
-                    it.code{{#jvm-okhttp3}}(){{/jvm-okhttp3}},
+                    it.code,
-                    it.headers{{#jvm-okhttp3}}(){{/jvm-okhttp3}}.toMultimap()
+                    it.headers.toMultimap()
                 )
                 it.isSuccessful -> Success(
-                    responseBody(it.body{{#jvm-okhttp3}}(){{/jvm-okhttp3}}, accept),
+                    responseBody(it, accept),
-                    it.code{{#jvm-okhttp3}}(){{/jvm-okhttp3}},
+                    it.code,
-                    it.headers{{#jvm-okhttp3}}(){{/jvm-okhttp3}}.toMultimap()
+                    it.headers.toMultimap()
                 )
                 it.isClientError -> ClientError(
-                    it.message{{#jvm-okhttp3}}(){{/jvm-okhttp3}},
+                    it.message,
-                    it.body{{#jvm-okhttp3}}(){{/jvm-okhttp3}}?.string(),
+                    it.body?.string(),
-                    it.code{{#jvm-okhttp3}}(){{/jvm-okhttp3}},
+                    it.code,
-                    it.headers{{#jvm-okhttp3}}(){{/jvm-okhttp3}}.toMultimap()
+                    it.headers.toMultimap()
                 )
                 else -> ServerError(
-                    it.message{{#jvm-okhttp3}}(){{/jvm-okhttp3}},
+                    it.message,
-                    it.body{{#jvm-okhttp3}}(){{/jvm-okhttp3}}?.string(),
+                    it.body?.string(),
-                    it.code{{#jvm-okhttp3}}(){{/jvm-okhttp3}},
+                    it.code,
-                    it.headers{{#jvm-okhttp3}}(){{/jvm-okhttp3}}.toMultimap()
+                    it.headers.toMultimap()
                 )
             }
         }

modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-okhttp/infrastructure/ResponseExtensions.kt.mustache

@@ -5,20 +5,20 @@ import okhttp3.Response
 /**
  * Provides an extension to evaluation whether the response is a 1xx code
  */
-{{#nonPublicApi}}internal {{/nonPublicApi}}val Response.isInformational : Boolean get() = this.code{{#jvm-okhttp3}}(){{/jvm-okhttp3}} in 100..199
+{{#nonPublicApi}}internal {{/nonPublicApi}}val Response.isInformational : Boolean get() = this.code in 100..199
 
 /**
  * Provides an extension to evaluation whether the response is a 3xx code
  */
 @Suppress("EXTENSION_SHADOWED_BY_MEMBER")
-{{#nonPublicApi}}internal {{/nonPublicApi}}val Response.isRedirect : Boolean get() = this.code{{#jvm-okhttp3}}(){{/jvm-okhttp3}} in 300..399
+{{#nonPublicApi}}internal {{/nonPublicApi}}val Response.isRedirect : Boolean get() = this.code in 300..399
 
 /**
  * Provides an extension to evaluation whether the response is a 4xx code
  */
-{{#nonPublicApi}}internal {{/nonPublicApi}}val Response.isClientError : Boolean get() = this.code{{#jvm-okhttp3}}(){{/jvm-okhttp3}} in 400..499
+{{#nonPublicApi}}internal {{/nonPublicApi}}val Response.isClientError : Boolean get() = this.code in 400..499
 
 /**
  * Provides an extension to evaluation whether the response is a 5xx (Standard) through 999 (non-standard) code
  */
-{{#nonPublicApi}}internal {{/nonPublicApi}}val Response.isServerError : Boolean get() = this.code{{#jvm-okhttp3}}(){{/jvm-okhttp3}} in 500..999
+{{#nonPublicApi}}internal {{/nonPublicApi}}val Response.isServerError : Boolean get() = this.code in 500..999

samples/client/others/kotlin-jvm-okhttp-parameter-tests/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt

@@ -26,6 +26,7 @@ import java.time.LocalTime
 import java.time.OffsetDateTime
 import java.time.OffsetTime
 import java.util.Locale
+import java.util.regex.Pattern
 import com.squareup.moshi.adapter
 
 val EMPTY_REQUEST: RequestBody = ByteArray(0).toRequestBody()
@@ -120,14 +121,52 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
         }
 
     @OptIn(ExperimentalStdlibApi::class)
-    protected inline fun <reified T: Any?> responseBody(body: ResponseBody?, mediaType: String? = JsonMediaType): T? {
+    protected inline fun <reified T: Any?> responseBody(response: Response, mediaType: String? = JsonMediaType): T? {
+        val body = response.body
         if(body == null) {
             return null
         }
         if (T::class.java == File::class.java) {
             // return tempFile
+            val contentDisposition = response.header("Content-Disposition")
+
+            val fileName = if (contentDisposition != null) {
+                // Get filename from the Content-Disposition header.
+                val pattern = Pattern.compile("filename=['\"]?([^'\"\\s]+)['\"]?")
+                val matcher = pattern.matcher(contentDisposition)
+                if (matcher.find()) {
+                    matcher.group(1)
+                        ?.replace(".*[/\\\\]", "")
+                        ?.replace(";", "")
+                } else {
+                    null
+                }
+            } else {
+                null
+            }
+
+            var prefix: String?
+            val suffix: String?
+            if (fileName == null) {
+                prefix = "download"
+                suffix = ""
+            } else {
+                val pos = fileName.lastIndexOf(".")
+                if (pos == -1) {
+                    prefix = fileName
+                    suffix = null
+                } else {
+                    prefix = fileName.substring(0, pos)
+                    suffix = fileName.substring(pos)
+                }
+                // Files.createTempFile requires the prefix to be at least three characters long
+                if (prefix.length < 3) {
+                    prefix = "download"
+                }
+            }
+
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            val tempFile = java.nio.file.Files.createTempFile(prefix, suffix).toFile()
             tempFile.deleteOnExit()
             body.byteStream().use { inputStream ->
                 tempFile.outputStream().use { tempFileOutputStream ->
@@ -214,7 +253,7 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
                     it.headers.toMultimap()
                 )
                 it.isSuccessful -> Success(
-                    responseBody(it.body, accept),
+                    responseBody(it, accept),
                     it.code,
                     it.headers.toMultimap()
                 )

samples/client/petstore/kotlin-allOff-discriminator/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt

@@ -26,6 +26,7 @@ import java.time.LocalTime
 import java.time.OffsetDateTime
 import java.time.OffsetTime
 import java.util.Locale
+import java.util.regex.Pattern
 import com.squareup.moshi.adapter
 
 val EMPTY_REQUEST: RequestBody = ByteArray(0).toRequestBody()
@@ -120,14 +121,52 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
         }
 
     @OptIn(ExperimentalStdlibApi::class)
-    protected inline fun <reified T: Any?> responseBody(body: ResponseBody?, mediaType: String? = JsonMediaType): T? {
+    protected inline fun <reified T: Any?> responseBody(response: Response, mediaType: String? = JsonMediaType): T? {
+        val body = response.body
         if(body == null) {
             return null
         }
         if (T::class.java == File::class.java) {
             // return tempFile
+            val contentDisposition = response.header("Content-Disposition")
+
+            val fileName = if (contentDisposition != null) {
+                // Get filename from the Content-Disposition header.
+                val pattern = Pattern.compile("filename=['\"]?([^'\"\\s]+)['\"]?")
+                val matcher = pattern.matcher(contentDisposition)
+                if (matcher.find()) {
+                    matcher.group(1)
+                        ?.replace(".*[/\\\\]", "")
+                        ?.replace(";", "")
+                } else {
+                    null
+                }
+            } else {
+                null
+            }
+
+            var prefix: String?
+            val suffix: String?
+            if (fileName == null) {
+                prefix = "download"
+                suffix = ""
+            } else {
+                val pos = fileName.lastIndexOf(".")
+                if (pos == -1) {
+                    prefix = fileName
+                    suffix = null
+                } else {
+                    prefix = fileName.substring(0, pos)
+                    suffix = fileName.substring(pos)
+                }
+                // Files.createTempFile requires the prefix to be at least three characters long
+                if (prefix.length < 3) {
+                    prefix = "download"
+                }
+            }
+
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            val tempFile = java.nio.file.Files.createTempFile(prefix, suffix).toFile()
             tempFile.deleteOnExit()
             body.byteStream().use { inputStream ->
                 tempFile.outputStream().use { tempFileOutputStream ->
@@ -214,7 +253,7 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
                     it.headers.toMultimap()
                 )
                 it.isSuccessful -> Success(
-                    responseBody(it.body, accept),
+                    responseBody(it, accept),
                     it.code,
                     it.headers.toMultimap()
                 )

samples/client/petstore/kotlin-array-simple-string-jvm-okhttp4/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt

@@ -26,6 +26,7 @@ import java.time.LocalTime
 import java.time.OffsetDateTime
 import java.time.OffsetTime
 import java.util.Locale
+import java.util.regex.Pattern
 import com.squareup.moshi.adapter
 
 val EMPTY_REQUEST: RequestBody = ByteArray(0).toRequestBody()
@@ -120,14 +121,52 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
         }
 
     @OptIn(ExperimentalStdlibApi::class)
-    protected inline fun <reified T: Any?> responseBody(body: ResponseBody?, mediaType: String? = JsonMediaType): T? {
+    protected inline fun <reified T: Any?> responseBody(response: Response, mediaType: String? = JsonMediaType): T? {
+        val body = response.body
         if(body == null) {
             return null
         }
         if (T::class.java == File::class.java) {
             // return tempFile
+            val contentDisposition = response.header("Content-Disposition")
+
+            val fileName = if (contentDisposition != null) {
+                // Get filename from the Content-Disposition header.
+                val pattern = Pattern.compile("filename=['\"]?([^'\"\\s]+)['\"]?")
+                val matcher = pattern.matcher(contentDisposition)
+                if (matcher.find()) {
+                    matcher.group(1)
+                        ?.replace(".*[/\\\\]", "")
+                        ?.replace(";", "")
+                } else {
+                    null
+                }
+            } else {
+                null
+            }
+
+            var prefix: String?
+            val suffix: String?
+            if (fileName == null) {
+                prefix = "download"
+                suffix = ""
+            } else {
+                val pos = fileName.lastIndexOf(".")
+                if (pos == -1) {
+                    prefix = fileName
+                    suffix = null
+                } else {
+                    prefix = fileName.substring(0, pos)
+                    suffix = fileName.substring(pos)
+                }
+                // Files.createTempFile requires the prefix to be at least three characters long
+                if (prefix.length < 3) {
+                    prefix = "download"
+                }
+            }
+
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            val tempFile = java.nio.file.Files.createTempFile(prefix, suffix).toFile()
             tempFile.deleteOnExit()
             body.byteStream().use { inputStream ->
                 tempFile.outputStream().use { tempFileOutputStream ->
@@ -214,7 +253,7 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
                     it.headers.toMultimap()
                 )
                 it.isSuccessful -> Success(
-                    responseBody(it.body, accept),
+                    responseBody(it, accept),
                     it.code,
                     it.headers.toMultimap()
                 )

samples/client/petstore/kotlin-bigdecimal-default-okhttp4/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt

@@ -26,6 +26,7 @@ import java.time.LocalTime
 import java.time.OffsetDateTime
 import java.time.OffsetTime
 import java.util.Locale
+import java.util.regex.Pattern
 import com.squareup.moshi.adapter
 
 val EMPTY_REQUEST: RequestBody = ByteArray(0).toRequestBody()
@@ -120,14 +121,52 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
         }
 
     @OptIn(ExperimentalStdlibApi::class)
-    protected inline fun <reified T: Any?> responseBody(body: ResponseBody?, mediaType: String? = JsonMediaType): T? {
+    protected inline fun <reified T: Any?> responseBody(response: Response, mediaType: String? = JsonMediaType): T? {
+        val body = response.body
         if(body == null) {
             return null
         }
         if (T::class.java == File::class.java) {
             // return tempFile
+            val contentDisposition = response.header("Content-Disposition")
+
+            val fileName = if (contentDisposition != null) {
+                // Get filename from the Content-Disposition header.
+                val pattern = Pattern.compile("filename=['\"]?([^'\"\\s]+)['\"]?")
+                val matcher = pattern.matcher(contentDisposition)
+                if (matcher.find()) {
+                    matcher.group(1)
+                        ?.replace(".*[/\\\\]", "")
+                        ?.replace(";", "")
+                } else {
+                    null
+                }
+            } else {
+                null
+            }
+
+            var prefix: String?
+            val suffix: String?
+            if (fileName == null) {
+                prefix = "download"
+                suffix = ""
+            } else {
+                val pos = fileName.lastIndexOf(".")
+                if (pos == -1) {
+                    prefix = fileName
+                    suffix = null
+                } else {
+                    prefix = fileName.substring(0, pos)
+                    suffix = fileName.substring(pos)
+                }
+                // Files.createTempFile requires the prefix to be at least three characters long
+                if (prefix.length < 3) {
+                    prefix = "download"
+                }
+            }
+
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            val tempFile = java.nio.file.Files.createTempFile(prefix, suffix).toFile()
             tempFile.deleteOnExit()
             body.byteStream().use { inputStream ->
                 tempFile.outputStream().use { tempFileOutputStream ->
@@ -214,7 +253,7 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
                     it.headers.toMultimap()
                 )
                 it.isSuccessful -> Success(
-                    responseBody(it.body, accept),
+                    responseBody(it, accept),
                     it.code,
                     it.headers.toMultimap()
                 )

samples/client/petstore/kotlin-default-values-jvm-okhttp4/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt

@@ -26,6 +26,7 @@ import java.time.LocalTime
 import java.time.OffsetDateTime
 import java.time.OffsetTime
 import java.util.Locale
+import java.util.regex.Pattern
 import com.squareup.moshi.adapter
 
 val EMPTY_REQUEST: RequestBody = ByteArray(0).toRequestBody()
@@ -120,14 +121,52 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
         }
 
     @OptIn(ExperimentalStdlibApi::class)
-    protected inline fun <reified T: Any?> responseBody(body: ResponseBody?, mediaType: String? = JsonMediaType): T? {
+    protected inline fun <reified T: Any?> responseBody(response: Response, mediaType: String? = JsonMediaType): T? {
+        val body = response.body
         if(body == null) {
             return null
         }
         if (T::class.java == File::class.java) {
             // return tempFile
+            val contentDisposition = response.header("Content-Disposition")
+
+            val fileName = if (contentDisposition != null) {
+                // Get filename from the Content-Disposition header.
+                val pattern = Pattern.compile("filename=['\"]?([^'\"\\s]+)['\"]?")
+                val matcher = pattern.matcher(contentDisposition)
+                if (matcher.find()) {
+                    matcher.group(1)
+                        ?.replace(".*[/\\\\]", "")
+                        ?.replace(";", "")
+                } else {
+                    null
+                }
+            } else {
+                null
+            }
+
+            var prefix: String?
+            val suffix: String?
+            if (fileName == null) {
+                prefix = "download"
+                suffix = ""
+            } else {
+                val pos = fileName.lastIndexOf(".")
+                if (pos == -1) {
+                    prefix = fileName
+                    suffix = null
+                } else {
+                    prefix = fileName.substring(0, pos)
+                    suffix = fileName.substring(pos)
+                }
+                // Files.createTempFile requires the prefix to be at least three characters long
+                if (prefix.length < 3) {
+                    prefix = "download"
+                }
+            }
+
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            val tempFile = java.nio.file.Files.createTempFile(prefix, suffix).toFile()
             tempFile.deleteOnExit()
             body.byteStream().use { inputStream ->
                 tempFile.outputStream().use { tempFileOutputStream ->
@@ -214,7 +253,7 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
                     it.headers.toMultimap()
                 )
                 it.isSuccessful -> Success(
-                    responseBody(it.body, accept),
+                    responseBody(it, accept),
                     it.code,
                     it.headers.toMultimap()
                 )

samples/client/petstore/kotlin-enum-default-value/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt

@@ -26,6 +26,7 @@ import java.time.LocalTime
 import java.time.OffsetDateTime
 import java.time.OffsetTime
 import java.util.Locale
+import java.util.regex.Pattern
 import com.squareup.moshi.adapter
 
 val EMPTY_REQUEST: RequestBody = ByteArray(0).toRequestBody()
@@ -120,14 +121,52 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
         }
 
     @OptIn(ExperimentalStdlibApi::class)
-    protected inline fun <reified T: Any?> responseBody(body: ResponseBody?, mediaType: String? = JsonMediaType): T? {
+    protected inline fun <reified T: Any?> responseBody(response: Response, mediaType: String? = JsonMediaType): T? {
+        val body = response.body
         if(body == null) {
             return null
         }
         if (T::class.java == File::class.java) {
             // return tempFile
+            val contentDisposition = response.header("Content-Disposition")
+
+            val fileName = if (contentDisposition != null) {
+                // Get filename from the Content-Disposition header.
+                val pattern = Pattern.compile("filename=['\"]?([^'\"\\s]+)['\"]?")
+                val matcher = pattern.matcher(contentDisposition)
+                if (matcher.find()) {
+                    matcher.group(1)
+                        ?.replace(".*[/\\\\]", "")
+                        ?.replace(";", "")
+                } else {
+                    null
+                }
+            } else {
+                null
+            }
+
+            var prefix: String?
+            val suffix: String?
+            if (fileName == null) {
+                prefix = "download"
+                suffix = ""
+            } else {
+                val pos = fileName.lastIndexOf(".")
+                if (pos == -1) {
+                    prefix = fileName
+                    suffix = null
+                } else {
+                    prefix = fileName.substring(0, pos)
+                    suffix = fileName.substring(pos)
+                }
+                // Files.createTempFile requires the prefix to be at least three characters long
+                if (prefix.length < 3) {
+                    prefix = "download"
+                }
+            }
+
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            val tempFile = java.nio.file.Files.createTempFile(prefix, suffix).toFile()
             tempFile.deleteOnExit()
             body.byteStream().use { inputStream ->
                 tempFile.outputStream().use { tempFileOutputStream ->
@@ -214,7 +253,7 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
                     it.headers.toMultimap()
                 )
                 it.isSuccessful -> Success(
-                    responseBody(it.body, accept),
+                    responseBody(it, accept),
                     it.code,
                     it.headers.toMultimap()
                 )

samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt

@@ -26,6 +26,7 @@ import java.time.LocalTime
 import java.time.OffsetDateTime
 import java.time.OffsetTime
 import java.util.Locale
+import java.util.regex.Pattern
 import com.google.gson.reflect.TypeToken
 
 val EMPTY_REQUEST: RequestBody = ByteArray(0).toRequestBody()
@@ -119,14 +120,52 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
             else -> throw UnsupportedOperationException("requestBody currently only supports JSON body, byte body and File body.")
         }
 
-    protected inline fun <reified T: Any?> responseBody(body: ResponseBody?, mediaType: String? = JsonMediaType): T? {
+    protected inline fun <reified T: Any?> responseBody(response: Response, mediaType: String? = JsonMediaType): T? {
+        val body = response.body
         if(body == null) {
             return null
         }
         if (T::class.java == File::class.java) {
             // return tempFile
+            val contentDisposition = response.header("Content-Disposition")
+
+            val fileName = if (contentDisposition != null) {
+                // Get filename from the Content-Disposition header.
+                val pattern = Pattern.compile("filename=['\"]?([^'\"\\s]+)['\"]?")
+                val matcher = pattern.matcher(contentDisposition)
+                if (matcher.find()) {
+                    matcher.group(1)
+                        ?.replace(".*[/\\\\]", "")
+                        ?.replace(";", "")
+                } else {
+                    null
+                }
+            } else {
+                null
+            }
+
+            var prefix: String?
+            val suffix: String?
+            if (fileName == null) {
+                prefix = "download"
+                suffix = ""
+            } else {
+                val pos = fileName.lastIndexOf(".")
+                if (pos == -1) {
+                    prefix = fileName
+                    suffix = null
+                } else {
+                    prefix = fileName.substring(0, pos)
+                    suffix = fileName.substring(pos)
+                }
+                // Files.createTempFile requires the prefix to be at least three characters long
+                if (prefix.length < 3) {
+                    prefix = "download"
+                }
+            }
+
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            val tempFile = java.nio.file.Files.createTempFile(prefix, suffix).toFile()
             tempFile.deleteOnExit()
             body.byteStream().use { inputStream ->
                 tempFile.outputStream().use { tempFileOutputStream ->
@@ -232,7 +271,7 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
                     it.headers.toMultimap()
                 )
                 it.isSuccessful -> Success(
-                    responseBody(it.body, accept),
+                    responseBody(it, accept),
                     it.code,
                     it.headers.toMultimap()
                 )

samples/client/petstore/kotlin-jackson/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt

@@ -26,6 +26,7 @@ import java.time.LocalTime
 import java.time.OffsetDateTime
 import java.time.OffsetTime
 import java.util.Locale
+import java.util.regex.Pattern
 import com.fasterxml.jackson.core.type.TypeReference
 
 val EMPTY_REQUEST: RequestBody = ByteArray(0).toRequestBody()
@@ -119,14 +120,52 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
             else -> throw UnsupportedOperationException("requestBody currently only supports JSON body, byte body and File body.")
         }
 
-    protected inline fun <reified T: Any?> responseBody(body: ResponseBody?, mediaType: String? = JsonMediaType): T? {
+    protected inline fun <reified T: Any?> responseBody(response: Response, mediaType: String? = JsonMediaType): T? {
+        val body = response.body
         if(body == null) {
             return null
         }
         if (T::class.java == File::class.java) {
             // return tempFile
+            val contentDisposition = response.header("Content-Disposition")
+
+            val fileName = if (contentDisposition != null) {
+                // Get filename from the Content-Disposition header.
+                val pattern = Pattern.compile("filename=['\"]?([^'\"\\s]+)['\"]?")
+                val matcher = pattern.matcher(contentDisposition)
+                if (matcher.find()) {
+                    matcher.group(1)
+                        ?.replace(".*[/\\\\]", "")
+                        ?.replace(";", "")
+                } else {
+                    null
+                }
+            } else {
+                null
+            }
+
+            var prefix: String?
+            val suffix: String?
+            if (fileName == null) {
+                prefix = "download"
+                suffix = ""
+            } else {
+                val pos = fileName.lastIndexOf(".")
+                if (pos == -1) {
+                    prefix = fileName
+                    suffix = null
+                } else {
+                    prefix = fileName.substring(0, pos)
+                    suffix = fileName.substring(pos)
+                }
+                // Files.createTempFile requires the prefix to be at least three characters long
+                if (prefix.length < 3) {
+                    prefix = "download"
+                }
+            }
+
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            val tempFile = java.nio.file.Files.createTempFile(prefix, suffix).toFile()
             tempFile.deleteOnExit()
             body.byteStream().use { inputStream ->
                 tempFile.outputStream().use { tempFileOutputStream ->
@@ -232,7 +271,7 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
                     it.headers.toMultimap()
                 )
                 it.isSuccessful -> Success(
-                    responseBody(it.body, accept),
+                    responseBody(it, accept),
                     it.code,
                     it.headers.toMultimap()
                 )

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt

@@ -27,6 +27,7 @@ import java.time.LocalTime
 import java.time.OffsetDateTime
 import java.time.OffsetTime
 import java.util.Locale
+import java.util.regex.Pattern
 import kotlinx.serialization.decodeFromString
 import kotlinx.serialization.encodeToString
 
@@ -121,17 +122,55 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
             else -> throw UnsupportedOperationException("requestBody currently only supports JSON body, byte body and File body.")
         }
 
-    protected inline fun <reified T: Any?> responseBody(body: ResponseBody?, mediaType: String? = JsonMediaType): T? {
+    protected inline fun <reified T: Any?> responseBody(response: Response, mediaType: String? = JsonMediaType): T? {
+        val body = response.body
         if(body == null) {
             return null
         }
         if (T::class.java == File::class.java) {
             // return tempFile
+            val contentDisposition = response.header("Content-Disposition")
+
+            val fileName = if (contentDisposition != null) {
+                // Get filename from the Content-Disposition header.
+                val pattern = Pattern.compile("filename=['\"]?([^'\"\\s]+)['\"]?")
+                val matcher = pattern.matcher(contentDisposition)
+                if (matcher.find()) {
+                    matcher.group(1)
+                        ?.replace(".*[/\\\\]", "")
+                        ?.replace(";", "")
+                } else {
+                    null
+                }
+            } else {
+                null
+            }
+
+            var prefix: String?
+            val suffix: String?
+            if (fileName == null) {
+                prefix = "download"
+                suffix = ""
+            } else {
+                val pos = fileName.lastIndexOf(".")
+                if (pos == -1) {
+                    prefix = fileName
+                    suffix = null
+                } else {
+                    prefix = fileName.substring(0, pos)
+                    suffix = fileName.substring(pos)
+                }
+                // Files.createTempFile requires the prefix to be at least three characters long
+                if (prefix.length < 3) {
+                    prefix = "download"
+                }
+            }
+
             val tempFile = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
-                java.nio.file.Files.createTempFile("tmp.net.medicineone.teleconsultationandroid.openapi.openapicommon", null).toFile()
+                java.nio.file.Files.createTempFile(prefix, suffix).toFile()
             } else {
                 @Suppress("DEPRECATION")
-                createTempFile("tmp.net.medicineone.teleconsultationandroid.openapi.openapicommon", null)
+                createTempFile(prefix, suffix)
             }
             tempFile.deleteOnExit()
             body.byteStream().use { inputStream ->
@@ -238,7 +277,7 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
                     it.headers.toMultimap()
                 )
                 it.isSuccessful -> Success(
-                    responseBody(it.body, accept),
+                    responseBody(it, accept),
                     it.code,
                     it.headers.toMultimap()
                 )

samples/client/petstore/kotlin-jvm-okhttp4-coroutines/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt

@@ -26,6 +26,7 @@ import java.time.LocalTime
 import java.time.OffsetDateTime
 import java.time.OffsetTime
 import java.util.Locale
+import java.util.regex.Pattern
 import kotlin.coroutines.resume
 import kotlin.coroutines.resumeWithException
 import kotlinx.coroutines.suspendCancellableCoroutine
@@ -122,14 +123,52 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
             else -> throw UnsupportedOperationException("requestBody currently only supports JSON body, byte body and File body.")
         }
 
-    protected inline fun <reified T: Any?> responseBody(body: ResponseBody?, mediaType: String? = JsonMediaType): T? {
+    protected inline fun <reified T: Any?> responseBody(response: Response, mediaType: String? = JsonMediaType): T? {
+        val body = response.body
         if(body == null) {
             return null
         }
         if (T::class.java == File::class.java) {
             // return tempFile
+            val contentDisposition = response.header("Content-Disposition")
+
+            val fileName = if (contentDisposition != null) {
+                // Get filename from the Content-Disposition header.
+                val pattern = Pattern.compile("filename=['\"]?([^'\"\\s]+)['\"]?")
+                val matcher = pattern.matcher(contentDisposition)
+                if (matcher.find()) {
+                    matcher.group(1)
+                        ?.replace(".*[/\\\\]", "")
+                        ?.replace(";", "")
+                } else {
+                    null
+                }
+            } else {
+                null
+            }
+
+            var prefix: String?
+            val suffix: String?
+            if (fileName == null) {
+                prefix = "download"
+                suffix = ""
+            } else {
+                val pos = fileName.lastIndexOf(".")
+                if (pos == -1) {
+                    prefix = fileName
+                    suffix = null
+                } else {
+                    prefix = fileName.substring(0, pos)
+                    suffix = fileName.substring(pos)
+                }
+                // Files.createTempFile requires the prefix to be at least three characters long
+                if (prefix.length < 3) {
+                    prefix = "download"
+                }
+            }
+
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            val tempFile = java.nio.file.Files.createTempFile(prefix, suffix).toFile()
             tempFile.deleteOnExit()
             body.byteStream().use { inputStream ->
                 tempFile.outputStream().use { tempFileOutputStream ->
@@ -246,7 +285,7 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
                     it.headers.toMultimap()
                 )
                 it.isSuccessful -> Success(
-                    responseBody(it.body, accept),
+                    responseBody(it, accept),
                     it.code,
                     it.headers.toMultimap()
                 )

samples/client/petstore/kotlin-kotlinx-datetime/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt

@@ -26,6 +26,7 @@ import java.time.LocalTime
 import java.time.OffsetDateTime
 import java.time.OffsetTime
 import java.util.Locale
+import java.util.regex.Pattern
 import com.squareup.moshi.adapter
 
 val EMPTY_REQUEST: RequestBody = ByteArray(0).toRequestBody()
@@ -120,14 +121,52 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
         }
 
     @OptIn(ExperimentalStdlibApi::class)
-    protected inline fun <reified T: Any?> responseBody(body: ResponseBody?, mediaType: String? = JsonMediaType): T? {
+    protected inline fun <reified T: Any?> responseBody(response: Response, mediaType: String? = JsonMediaType): T? {
+        val body = response.body
         if(body == null) {
             return null
         }
         if (T::class.java == File::class.java) {
             // return tempFile
+            val contentDisposition = response.header("Content-Disposition")
+
+            val fileName = if (contentDisposition != null) {
+                // Get filename from the Content-Disposition header.
+                val pattern = Pattern.compile("filename=['\"]?([^'\"\\s]+)['\"]?")
+                val matcher = pattern.matcher(contentDisposition)
+                if (matcher.find()) {
+                    matcher.group(1)
+                        ?.replace(".*[/\\\\]", "")
+                        ?.replace(";", "")
+                } else {
+                    null
+                }
+            } else {
+                null
+            }
+
+            var prefix: String?
+            val suffix: String?
+            if (fileName == null) {
+                prefix = "download"
+                suffix = ""
+            } else {
+                val pos = fileName.lastIndexOf(".")
+                if (pos == -1) {
+                    prefix = fileName
+                    suffix = null
+                } else {
+                    prefix = fileName.substring(0, pos)
+                    suffix = fileName.substring(pos)
+                }
+                // Files.createTempFile requires the prefix to be at least three characters long
+                if (prefix.length < 3) {
+                    prefix = "download"
+                }
+            }
+
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            val tempFile = java.nio.file.Files.createTempFile(prefix, suffix).toFile()
             tempFile.deleteOnExit()
             body.byteStream().use { inputStream ->
                 tempFile.outputStream().use { tempFileOutputStream ->
@@ -233,7 +272,7 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
                     it.headers.toMultimap()
                 )
                 it.isSuccessful -> Success(
-                    responseBody(it.body, accept),
+                    responseBody(it, accept),
                     it.code,
                     it.headers.toMultimap()
                 )

samples/client/petstore/kotlin-modelMutable/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt

@@ -26,6 +26,7 @@ import java.time.LocalTime
 import java.time.OffsetDateTime
 import java.time.OffsetTime
 import java.util.Locale
+import java.util.regex.Pattern
 import com.squareup.moshi.adapter
 
 val EMPTY_REQUEST: RequestBody = ByteArray(0).toRequestBody()
@@ -120,14 +121,52 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
         }
 
     @OptIn(ExperimentalStdlibApi::class)
-    protected inline fun <reified T: Any?> responseBody(body: ResponseBody?, mediaType: String? = JsonMediaType): T? {
+    protected inline fun <reified T: Any?> responseBody(response: Response, mediaType: String? = JsonMediaType): T? {
+        val body = response.body
         if(body == null) {
             return null
         }
         if (T::class.java == File::class.java) {
             // return tempFile
+            val contentDisposition = response.header("Content-Disposition")
+
+            val fileName = if (contentDisposition != null) {
+                // Get filename from the Content-Disposition header.
+                val pattern = Pattern.compile("filename=['\"]?([^'\"\\s]+)['\"]?")
+                val matcher = pattern.matcher(contentDisposition)
+                if (matcher.find()) {
+                    matcher.group(1)
+                        ?.replace(".*[/\\\\]", "")
+                        ?.replace(";", "")
+                } else {
+                    null
+                }
+            } else {
+                null
+            }
+
+            var prefix: String?
+            val suffix: String?
+            if (fileName == null) {
+                prefix = "download"
+                suffix = ""
+            } else {
+                val pos = fileName.lastIndexOf(".")
+                if (pos == -1) {
+                    prefix = fileName
+                    suffix = null
+                } else {
+                    prefix = fileName.substring(0, pos)
+                    suffix = fileName.substring(pos)
+                }
+                // Files.createTempFile requires the prefix to be at least three characters long
+                if (prefix.length < 3) {
+                    prefix = "download"
+                }
+            }
+
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            val tempFile = java.nio.file.Files.createTempFile(prefix, suffix).toFile()
             tempFile.deleteOnExit()
             body.byteStream().use { inputStream ->
                 tempFile.outputStream().use { tempFileOutputStream ->
@@ -233,7 +272,7 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
                     it.headers.toMultimap()
                 )
                 it.isSuccessful -> Success(
-                    responseBody(it.body, accept),
+                    responseBody(it, accept),
                     it.code,
                     it.headers.toMultimap()
                 )

samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt

@@ -26,6 +26,7 @@ import java.time.LocalTime
 import java.time.OffsetDateTime
 import java.time.OffsetTime
 import java.util.Locale
+import java.util.regex.Pattern
 import com.squareup.moshi.adapter
 
 val EMPTY_REQUEST: RequestBody = ByteArray(0).toRequestBody()
@@ -120,14 +121,52 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
         }
 
     @OptIn(ExperimentalStdlibApi::class)
-    protected inline fun <reified T: Any?> responseBody(body: ResponseBody?, mediaType: String? = JsonMediaType): T? {
+    protected inline fun <reified T: Any?> responseBody(response: Response, mediaType: String? = JsonMediaType): T? {
+        val body = response.body
         if(body == null) {
             return null
         }
         if (T::class.java == File::class.java) {
             // return tempFile
+            val contentDisposition = response.header("Content-Disposition")
+
+            val fileName = if (contentDisposition != null) {
+                // Get filename from the Content-Disposition header.
+                val pattern = Pattern.compile("filename=['\"]?([^'\"\\s]+)['\"]?")
+                val matcher = pattern.matcher(contentDisposition)
+                if (matcher.find()) {
+                    matcher.group(1)
+                        ?.replace(".*[/\\\\]", "")
+                        ?.replace(";", "")
+                } else {
+                    null
+                }
+            } else {
+                null
+            }
+
+            var prefix: String?
+            val suffix: String?
+            if (fileName == null) {
+                prefix = "download"
+                suffix = ""
+            } else {
+                val pos = fileName.lastIndexOf(".")
+                if (pos == -1) {
+                    prefix = fileName
+                    suffix = null
+                } else {
+                    prefix = fileName.substring(0, pos)
+                    suffix = fileName.substring(pos)
+                }
+                // Files.createTempFile requires the prefix to be at least three characters long
+                if (prefix.length < 3) {
+                    prefix = "download"
+                }
+            }
+
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            val tempFile = java.nio.file.Files.createTempFile(prefix, suffix).toFile()
             tempFile.deleteOnExit()
             body.byteStream().use { inputStream ->
                 tempFile.outputStream().use { tempFileOutputStream ->
@@ -233,7 +272,7 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
                     it.headers.toMultimap()
                 )
                 it.isSuccessful -> Success(
-                    responseBody(it.body, accept),
+                    responseBody(it, accept),
                     it.code,
                     it.headers.toMultimap()
                 )

samples/client/petstore/kotlin-name-parameter-mappings/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt

@@ -26,6 +26,7 @@ import java.time.LocalTime
 import java.time.OffsetDateTime
 import java.time.OffsetTime
 import java.util.Locale
+import java.util.regex.Pattern
 import com.squareup.moshi.adapter
 
 val EMPTY_REQUEST: RequestBody = ByteArray(0).toRequestBody()
@@ -120,14 +121,52 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
         }
 
     @OptIn(ExperimentalStdlibApi::class)
-    protected inline fun <reified T: Any?> responseBody(body: ResponseBody?, mediaType: String? = JsonMediaType): T? {
+    protected inline fun <reified T: Any?> responseBody(response: Response, mediaType: String? = JsonMediaType): T? {
+        val body = response.body
         if(body == null) {
             return null
         }
         if (T::class.java == File::class.java) {
             // return tempFile
+            val contentDisposition = response.header("Content-Disposition")
+
+            val fileName = if (contentDisposition != null) {
+                // Get filename from the Content-Disposition header.
+                val pattern = Pattern.compile("filename=['\"]?([^'\"\\s]+)['\"]?")
+                val matcher = pattern.matcher(contentDisposition)
+                if (matcher.find()) {
+                    matcher.group(1)
+                        ?.replace(".*[/\\\\]", "")
+                        ?.replace(";", "")
+                } else {
+                    null
+                }
+            } else {
+                null
+            }
+
+            var prefix: String?
+            val suffix: String?
+            if (fileName == null) {
+                prefix = "download"
+                suffix = ""
+            } else {
+                val pos = fileName.lastIndexOf(".")
+                if (pos == -1) {
+                    prefix = fileName
+                    suffix = null
+                } else {
+                    prefix = fileName.substring(0, pos)
+                    suffix = fileName.substring(pos)
+                }
+                // Files.createTempFile requires the prefix to be at least three characters long
+                if (prefix.length < 3) {
+                    prefix = "download"
+                }
+            }
+
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            val tempFile = java.nio.file.Files.createTempFile(prefix, suffix).toFile()
             tempFile.deleteOnExit()
             body.byteStream().use { inputStream ->
                 tempFile.outputStream().use { tempFileOutputStream ->
@@ -214,7 +253,7 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
                     it.headers.toMultimap()
                 )
                 it.isSuccessful -> Success(
-                    responseBody(it.body, accept),
+                    responseBody(it, accept),
                     it.code,
                     it.headers.toMultimap()
                 )

samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt

@@ -26,6 +26,7 @@ import java.time.LocalTime
 import java.time.OffsetDateTime
 import java.time.OffsetTime
 import java.util.Locale
+import java.util.regex.Pattern
 import com.squareup.moshi.adapter
 
 internal val EMPTY_REQUEST: RequestBody = ByteArray(0).toRequestBody()
@@ -120,14 +121,52 @@ internal open class ApiClient(val baseUrl: String, val client: OkHttpClient = de
         }
 
     @OptIn(ExperimentalStdlibApi::class)
-    protected inline fun <reified T: Any?> responseBody(body: ResponseBody?, mediaType: String? = JsonMediaType): T? {
+    protected inline fun <reified T: Any?> responseBody(response: Response, mediaType: String? = JsonMediaType): T? {
+        val body = response.body
         if(body == null) {
             return null
         }
         if (T::class.java == File::class.java) {
             // return tempFile
+            val contentDisposition = response.header("Content-Disposition")
+
+            val fileName = if (contentDisposition != null) {
+                // Get filename from the Content-Disposition header.
+                val pattern = Pattern.compile("filename=['\"]?([^'\"\\s]+)['\"]?")
+                val matcher = pattern.matcher(contentDisposition)
+                if (matcher.find()) {
+                    matcher.group(1)
+                        ?.replace(".*[/\\\\]", "")
+                        ?.replace(";", "")
+                } else {
+                    null
+                }
+            } else {
+                null
+            }
+
+            var prefix: String?
+            val suffix: String?
+            if (fileName == null) {
+                prefix = "download"
+                suffix = ""
+            } else {
+                val pos = fileName.lastIndexOf(".")
+                if (pos == -1) {
+                    prefix = fileName
+                    suffix = null
+                } else {
+                    prefix = fileName.substring(0, pos)
+                    suffix = fileName.substring(pos)
+                }
+                // Files.createTempFile requires the prefix to be at least three characters long
+                if (prefix.length < 3) {
+                    prefix = "download"
+                }
+            }
+
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            val tempFile = java.nio.file.Files.createTempFile(prefix, suffix).toFile()
             tempFile.deleteOnExit()
             body.byteStream().use { inputStream ->
                 tempFile.outputStream().use { tempFileOutputStream ->
@@ -233,7 +272,7 @@ internal open class ApiClient(val baseUrl: String, val client: OkHttpClient = de
                     it.headers.toMultimap()
                 )
                 it.isSuccessful -> Success(
-                    responseBody(it.body, accept),
+                    responseBody(it, accept),
                     it.code,
                     it.headers.toMultimap()
                 )

samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt

@@ -26,6 +26,7 @@ import java.time.LocalTime
 import java.time.OffsetDateTime
 import java.time.OffsetTime
 import java.util.Locale
+import java.util.regex.Pattern
 import com.squareup.moshi.adapter
 
 val EMPTY_REQUEST: RequestBody = ByteArray(0).toRequestBody()
@@ -120,14 +121,52 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
         }
 
     @OptIn(ExperimentalStdlibApi::class)
-    protected inline fun <reified T: Any?> responseBody(body: ResponseBody?, mediaType: String? = JsonMediaType): T? {
+    protected inline fun <reified T: Any?> responseBody(response: Response, mediaType: String? = JsonMediaType): T? {
+        val body = response.body
         if(body == null) {
             return null
         }
         if (T::class.java == File::class.java) {
             // return tempFile
+            val contentDisposition = response.header("Content-Disposition")
+
+            val fileName = if (contentDisposition != null) {
+                // Get filename from the Content-Disposition header.
+                val pattern = Pattern.compile("filename=['\"]?([^'\"\\s]+)['\"]?")
+                val matcher = pattern.matcher(contentDisposition)
+                if (matcher.find()) {
+                    matcher.group(1)
+                        ?.replace(".*[/\\\\]", "")
+                        ?.replace(";", "")
+                } else {
+                    null
+                }
+            } else {
+                null
+            }
+
+            var prefix: String?
+            val suffix: String?
+            if (fileName == null) {
+                prefix = "download"
+                suffix = ""
+            } else {
+                val pos = fileName.lastIndexOf(".")
+                if (pos == -1) {
+                    prefix = fileName
+                    suffix = null
+                } else {
+                    prefix = fileName.substring(0, pos)
+                    suffix = fileName.substring(pos)
+                }
+                // Files.createTempFile requires the prefix to be at least three characters long
+                if (prefix.length < 3) {
+                    prefix = "download"
+                }
+            }
+
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            val tempFile = java.nio.file.Files.createTempFile(prefix, suffix).toFile()
             tempFile.deleteOnExit()
             body.byteStream().use { inputStream ->
                 tempFile.outputStream().use { tempFileOutputStream ->
@@ -233,7 +272,7 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
                     it.headers.toMultimap()
                 )
                 it.isSuccessful -> Success(
-                    responseBody(it.body, accept),
+                    responseBody(it, accept),
                     it.code,
                     it.headers.toMultimap()
                 )

samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/infrastructure/SerializerHelper.kt

@@ -1,14 +0,0 @@
-package org.openapitools.client.infrastructure
-
-import com.squareup.moshi.Moshi
-import com.squareup.moshi.adapters.EnumJsonAdapter
-
-object SerializerHelper {
-    fun addEnumUnknownDefaultCase(moshiBuilder: Moshi.Builder): Moshi.Builder {
-        return moshiBuilder
-            .add(org.openapitools.client.models.Order.Status::class.java, EnumJsonAdapter.create(org.openapitools.client.models.Order.Status::class.java)
-                .withUnknownFallback(org.openapitools.client.models.Order.Status.unknown_default_open_api))
-            .add(org.openapitools.client.models.Pet.Status::class.java, EnumJsonAdapter.create(org.openapitools.client.models.Pet.Status::class.java)
-                .withUnknownFallback(org.openapitools.client.models.Pet.Status.unknown_default_open_api))
-    }
-}

samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/models/Order.kt

@@ -1,70 +0,0 @@
-/**
- *
- * Please note:
- * This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
- * Do not edit this file manually.
- *
- */
-
-@file:Suppress(
-    "ArrayInDataClass",
-    "EnumEntryName",
-    "RemoveRedundantQualifierName",
-    "UnusedImport"
-)
-
-package org.openapitools.client.models
-
-
-import com.squareup.moshi.Json
-import com.squareup.moshi.JsonClass
-
-/**
- * An order for a pets from the pet store
- *
- * @param id 
- * @param petId 
- * @param quantity 
- * @param shipDate 
- * @param status Order Status
- * @param complete 
- */
-
-
-data class Order (
-
-    @Json(name = "id")
-    val id: kotlin.Long? = null,
-
-    @Json(name = "petId")
-    val petId: kotlin.Long? = null,
-
-    @Json(name = "quantity")
-    val quantity: kotlin.Int? = null,
-
-    @Json(name = "shipDate")
-    val shipDate: java.time.OffsetDateTime? = null,
-
-    /* Order Status */
-    @Json(name = "status")
-    val status: Order.Status? = null,
-
-    @Json(name = "complete")
-    val complete: kotlin.Boolean? = false
-
-) {
-
-    /**
-     * Order Status
-     *
-     * Values: placed,approved,delivered,unknown_default_open_api
-     */
-    @JsonClass(generateAdapter = false)
-    enum class Status(val value: kotlin.String) {
-        @Json(name = "placed") placed("placed"),
-        @Json(name = "approved") approved("approved"),
-        @Json(name = "delivered") delivered("delivered"),
-        @Json(name = "unknown_default_open_api") unknown_default_open_api("unknown_default_open_api");
-    }
-}
-

samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt

@@ -26,6 +26,7 @@ import java.time.LocalTime
 import java.time.OffsetDateTime
 import java.time.OffsetTime
 import java.util.Locale
+import java.util.regex.Pattern
 import com.squareup.moshi.adapter
 
 val EMPTY_REQUEST: RequestBody = ByteArray(0).toRequestBody()
@@ -120,14 +121,52 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
         }
 
     @OptIn(ExperimentalStdlibApi::class)
-    protected inline fun <reified T: Any?> responseBody(body: ResponseBody?, mediaType: String? = JsonMediaType): T? {
+    protected inline fun <reified T: Any?> responseBody(response: Response, mediaType: String? = JsonMediaType): T? {
+        val body = response.body
         if(body == null) {
             return null
         }
         if (T::class.java == File::class.java) {
             // return tempFile
+            val contentDisposition = response.header("Content-Disposition")
+
+            val fileName = if (contentDisposition != null) {
+                // Get filename from the Content-Disposition header.
+                val pattern = Pattern.compile("filename=['\"]?([^'\"\\s]+)['\"]?")
+                val matcher = pattern.matcher(contentDisposition)
+                if (matcher.find()) {
+                    matcher.group(1)
+                        ?.replace(".*[/\\\\]", "")
+                        ?.replace(";", "")
+                } else {
+                    null
+                }
+            } else {
+                null
+            }
+
+            var prefix: String?
+            val suffix: String?
+            if (fileName == null) {
+                prefix = "download"
+                suffix = ""
+            } else {
+                val pos = fileName.lastIndexOf(".")
+                if (pos == -1) {
+                    prefix = fileName
+                    suffix = null
+                } else {
+                    prefix = fileName.substring(0, pos)
+                    suffix = fileName.substring(pos)
+                }
+                // Files.createTempFile requires the prefix to be at least three characters long
+                if (prefix.length < 3) {
+                    prefix = "download"
+                }
+            }
+
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            val tempFile = java.nio.file.Files.createTempFile(prefix, suffix).toFile()
             tempFile.deleteOnExit()
             body.byteStream().use { inputStream ->
                 tempFile.outputStream().use { tempFileOutputStream ->
@@ -233,7 +272,7 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
                     it.headers.toMultimap()
                 )
                 it.isSuccessful -> Success(
-                    responseBody(it.body, accept),
+                    responseBody(it, accept),
                     it.code,
                     it.headers.toMultimap()
                 )

samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt

@@ -21,6 +21,7 @@ import java.io.FileWriter
 import java.io.IOException
 import java.net.URLConnection
 import java.util.Locale
+import java.util.regex.Pattern
 import org.threeten.bp.LocalDate
 import org.threeten.bp.LocalDateTime
 import org.threeten.bp.LocalTime
@@ -120,14 +121,52 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
         }
 
     @OptIn(ExperimentalStdlibApi::class)
-    protected inline fun <reified T: Any?> responseBody(body: ResponseBody?, mediaType: String? = JsonMediaType): T? {
+    protected inline fun <reified T: Any?> responseBody(response: Response, mediaType: String? = JsonMediaType): T? {
+        val body = response.body
         if(body == null) {
             return null
         }
         if (T::class.java == File::class.java) {
             // return tempFile
+            val contentDisposition = response.header("Content-Disposition")
+
+            val fileName = if (contentDisposition != null) {
+                // Get filename from the Content-Disposition header.
+                val pattern = Pattern.compile("filename=['\"]?([^'\"\\s]+)['\"]?")
+                val matcher = pattern.matcher(contentDisposition)
+                if (matcher.find()) {
+                    matcher.group(1)
+                        ?.replace(".*[/\\\\]", "")
+                        ?.replace(";", "")
+                } else {
+                    null
+                }
+            } else {
+                null
+            }
+
+            var prefix: String?
+            val suffix: String?
+            if (fileName == null) {
+                prefix = "download"
+                suffix = ""
+            } else {
+                val pos = fileName.lastIndexOf(".")
+                if (pos == -1) {
+                    prefix = fileName
+                    suffix = null
+                } else {
+                    prefix = fileName.substring(0, pos)
+                    suffix = fileName.substring(pos)
+                }
+                // Files.createTempFile requires the prefix to be at least three characters long
+                if (prefix.length < 3) {
+                    prefix = "download"
+                }
+            }
+
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            val tempFile = java.nio.file.Files.createTempFile(prefix, suffix).toFile()
             tempFile.deleteOnExit()
             body.byteStream().use { inputStream ->
                 tempFile.outputStream().use { tempFileOutputStream ->
@@ -233,7 +272,7 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
                     it.headers.toMultimap()
                 )
                 it.isSuccessful -> Success(
-                    responseBody(it.body, accept),
+                    responseBody(it, accept),
                     it.code,
                     it.headers.toMultimap()
                 )

samples/client/petstore/kotlin-uppercase-enum/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt

@@ -26,6 +26,7 @@ import java.time.LocalTime
 import java.time.OffsetDateTime
 import java.time.OffsetTime
 import java.util.Locale
+import java.util.regex.Pattern
 import kotlinx.serialization.decodeFromString
 import kotlinx.serialization.encodeToString
 
@@ -120,14 +121,52 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
             else -> throw UnsupportedOperationException("requestBody currently only supports JSON body, byte body and File body.")
         }
 
-    protected inline fun <reified T: Any?> responseBody(body: ResponseBody?, mediaType: String? = JsonMediaType): T? {
+    protected inline fun <reified T: Any?> responseBody(response: Response, mediaType: String? = JsonMediaType): T? {
+        val body = response.body
         if(body == null) {
             return null
         }
         if (T::class.java == File::class.java) {
             // return tempFile
+            val contentDisposition = response.header("Content-Disposition")
+
+            val fileName = if (contentDisposition != null) {
+                // Get filename from the Content-Disposition header.
+                val pattern = Pattern.compile("filename=['\"]?([^'\"\\s]+)['\"]?")
+                val matcher = pattern.matcher(contentDisposition)
+                if (matcher.find()) {
+                    matcher.group(1)
+                        ?.replace(".*[/\\\\]", "")
+                        ?.replace(";", "")
+                } else {
+                    null
+                }
+            } else {
+                null
+            }
+
+            var prefix: String?
+            val suffix: String?
+            if (fileName == null) {
+                prefix = "download"
+                suffix = ""
+            } else {
+                val pos = fileName.lastIndexOf(".")
+                if (pos == -1) {
+                    prefix = fileName
+                    suffix = null
+                } else {
+                    prefix = fileName.substring(0, pos)
+                    suffix = fileName.substring(pos)
+                }
+                // Files.createTempFile requires the prefix to be at least three characters long
+                if (prefix.length < 3) {
+                    prefix = "download"
+                }
+            }
+
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            val tempFile = java.nio.file.Files.createTempFile(prefix, suffix).toFile()
             tempFile.deleteOnExit()
             body.byteStream().use { inputStream ->
                 tempFile.outputStream().use { tempFileOutputStream ->
@@ -214,7 +253,7 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
                     it.headers.toMultimap()
                 )
                 it.isSuccessful -> Success(
-                    responseBody(it.body, accept),
+                    responseBody(it, accept),
                     it.code,
                     it.headers.toMultimap()
                 )

samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt

@@ -26,6 +26,7 @@ import java.time.LocalTime
 import java.time.OffsetDateTime
 import java.time.OffsetTime
 import java.util.Locale
+import java.util.regex.Pattern
 import com.squareup.moshi.adapter
 
 val EMPTY_REQUEST: RequestBody = ByteArray(0).toRequestBody()
@@ -120,14 +121,52 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
         }
 
     @OptIn(ExperimentalStdlibApi::class)
-    protected inline fun <reified T: Any?> responseBody(body: ResponseBody?, mediaType: String? = JsonMediaType): T? {
+    protected inline fun <reified T: Any?> responseBody(response: Response, mediaType: String? = JsonMediaType): T? {
+        val body = response.body
         if(body == null) {
             return null
         }
         if (T::class.java == File::class.java) {
             // return tempFile
+            val contentDisposition = response.header("Content-Disposition")
+
+            val fileName = if (contentDisposition != null) {
+                // Get filename from the Content-Disposition header.
+                val pattern = Pattern.compile("filename=['\"]?([^'\"\\s]+)['\"]?")
+                val matcher = pattern.matcher(contentDisposition)
+                if (matcher.find()) {
+                    matcher.group(1)
+                        ?.replace(".*[/\\\\]", "")
+                        ?.replace(";", "")
+                } else {
+                    null
+                }
+            } else {
+                null
+            }
+
+            var prefix: String?
+            val suffix: String?
+            if (fileName == null) {
+                prefix = "download"
+                suffix = ""
+            } else {
+                val pos = fileName.lastIndexOf(".")
+                if (pos == -1) {
+                    prefix = fileName
+                    suffix = null
+                } else {
+                    prefix = fileName.substring(0, pos)
+                    suffix = fileName.substring(pos)
+                }
+                // Files.createTempFile requires the prefix to be at least three characters long
+                if (prefix.length < 3) {
+                    prefix = "download"
+                }
+            }
+
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            val tempFile = java.nio.file.Files.createTempFile(prefix, suffix).toFile()
             tempFile.deleteOnExit()
             body.byteStream().use { inputStream ->
                 tempFile.outputStream().use { tempFileOutputStream ->
@@ -233,7 +272,7 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
                     it.headers.toMultimap()
                 )
                 it.isSuccessful -> Success(
-                    responseBody(it.body, accept),
+                    responseBody(it, accept),
                     it.code,
                     it.headers.toMultimap()
                 )