Apply style and explode values from encoding for form-encoded request body parameters (#12162)

modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java

@@ -1932,16 +1932,49 @@ public class DefaultCodegen implements CodegenConfig {
     }
 
     /**
-     * Sets the content type of the parameter based on the encoding specified in the request body.
+     * Sets the content type, style, and explode of the parameter based on the encoding specified
+     * in the request body.
      *
      * @param codegenParameter Codegen parameter
      * @param mediaType        MediaType from the request body
      */
-    public void setParameterContentType(CodegenParameter codegenParameter, MediaType mediaType) {
+    public void setParameterEncodingValues(CodegenParameter codegenParameter, MediaType mediaType) {
         if (mediaType != null && mediaType.getEncoding() != null) {
             Encoding encoding = mediaType.getEncoding().get(codegenParameter.baseName);
             if (encoding != null) {
+                boolean styleGiven = true;
+                Encoding.StyleEnum style = encoding.getStyle();
+                if(style == null || style == Encoding.StyleEnum.FORM) {
+                    // (Unfortunately, swagger-parser-v3 will always provide 'form'
+                    // when style is not specified, so we can't detect that)
+                    style = Encoding.StyleEnum.FORM;
+                    styleGiven = false;
+                }
+                boolean explodeGiven = true;
+                Boolean explode = encoding.getExplode();
+                if(explode == null) {
+                    explode = style == Encoding.StyleEnum.FORM; // Default to True when form, False otherwise
+                    explodeGiven = false;
+                }
+
+                if(!styleGiven && !explodeGiven) {
+                    // Ignore contentType if style or explode are specified.
                     codegenParameter.contentType = encoding.getContentType();
+                }
+
+                codegenParameter.style = style.toString();
+                codegenParameter.isDeepObject = Encoding.StyleEnum.DEEP_OBJECT == style;
+
+                if(codegenParameter.isContainer) {
+                    codegenParameter.isExplode = explode;
+                    String collectionFormat = getCollectionFormat(codegenParameter);
+                    codegenParameter.collectionFormat = StringUtils.isEmpty(collectionFormat) ? "csv" : collectionFormat;
+                    codegenParameter.isCollectionFormatMulti = "multi".equals(collectionFormat);
+                } else {
+                    codegenParameter.isExplode = false;
+                    codegenParameter.collectionFormat = null;
+                    codegenParameter.isCollectionFormatMulti = false;
+                }
             } else {
                 LOGGER.debug("encoding not specified for {}", codegenParameter.baseName);
             }
@@ -4087,7 +4120,7 @@ public class DefaultCodegen implements CodegenConfig {
                 formParams = fromRequestBodyToFormParameters(requestBody, imports);
                 op.isMultipart = contentType.startsWith("multipart");
                 for (CodegenParameter cp : formParams) {
-                    setParameterContentType(cp, requestBody.getContent().get(contentType));
+                    setParameterEncodingValues(cp, requestBody.getContent().get(contentType));
                     postProcessParameter(cp);
                 }
                 // add form parameters to the beginning of all parameter list
@@ -6398,11 +6431,12 @@ public class DefaultCodegen implements CodegenConfig {
                 LOGGER.warn("Could not compute datatypeWithEnum from {}, {}", arrayInnerProperty.baseType, arrayInnerProperty.enumName);
             }
             // end of hoisting
-            //TODO fix collectionFormat for form parameters
+
-            //collectionFormat = getCollectionFormat(s);
+            // collectionFormat for form parameter does not consider
+            // style and explode from encoding at this point
             String collectionFormat = getCollectionFormat(codegenParameter);
-            // default to csv:
             codegenParameter.collectionFormat = StringUtils.isEmpty(collectionFormat) ? "csv" : collectionFormat;
+            codegenParameter.isCollectionFormatMulti = "multi".equals(collectionFormat);
 
             // recursively add import
             while (arrayInnerProperty != null) {
@@ -6444,8 +6478,6 @@ public class DefaultCodegen implements CodegenConfig {
         // set nullable
         setParameterNullable(codegenParameter, codegenProperty);
 
-        //TODO collectionFormat for form parameter not yet supported
-        //codegenParameter.collectionFormat = getCollectionFormat(propertySchema);
         return codegenParameter;
     }
 
@@ -7367,15 +7399,31 @@ public class DefaultCodegen implements CodegenConfig {
     }
 
     /**
-     * Returns null by default but can be overwritten to return a valid collectionFormat
+     * Builds OAPI 2.0 collectionFormat value based on style and explode values
      * for the {@link CodegenParameter}.
      *
      * @param codegenParameter parameter
      * @return string for a collectionFormat.
      */
     protected String getCollectionFormat(CodegenParameter codegenParameter) {
+        if ("form".equals(codegenParameter.style)) {
+            // Ref: https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.1.md#style-values
+            if (codegenParameter.isExplode) {
+                return "multi";
+            } else {
+                return "csv";
+            }
+        } else if ("simple".equals(codegenParameter.style)) {
+            return "csv";
+        } else if ("pipeDelimited".equals(codegenParameter.style)) {
+            return "pipes";
+        } else if ("spaceDelimited".equals(codegenParameter.style)) {
+            return "ssv";
+        } else {
+            // Doesn't map to any of the collectionFormat strings
             return null;
         }
+    }
 
     private CodegenComposedSchemas getComposedSchemas(Schema schema) {
         if (!(schema instanceof ComposedSchema) && schema.getNot()==null) {

modules/openapi-generator/src/test/java/org/openapitools/codegen/DefaultCodegenTest.java

@@ -4064,6 +4064,44 @@ public class DefaultCodegenTest {
         cp = mt.getSchema();
         assertEquals(cp.baseName, "SchemaForRequestBodyTextPlain");
         assertTrue(cp.isString);
+
+        path = "/requestBodyWithEncodingTypes";
+        co = codegen.fromOperation(path, "POST", openAPI.getPaths().get(path).getPost(), null);
+        List<CodegenParameter> formParams = co.formParams;
+
+        assertEquals(formParams.get(0).paramName, "intParam");
+        assertFalse(formParams.get(0).isContainer);
+        assertFalse(formParams.get(0).isExplode); // Should not be true for non-container
+
+        assertEquals(formParams.get(1).paramName, "explodeTrue");
+        assertTrue(formParams.get(1).isContainer);
+        assertEquals(formParams.get(1).style, Encoding.StyleEnum.FORM.toString());
+        assertTrue(formParams.get(1).isExplode);
+        assertNull(formParams.get(1).contentType);
+
+        assertEquals(formParams.get(2).paramName, "explodeFalse");
+        assertTrue(formParams.get(2).isContainer);
+        assertEquals(formParams.get(2).style, Encoding.StyleEnum.FORM.toString());
+        assertFalse(formParams.get(2).isExplode);
+        assertNull(formParams.get(2).contentType);
+
+        assertEquals(formParams.get(3).paramName, "noStyleNoExplode");
+        assertTrue(formParams.get(3).isContainer);
+        assertEquals(formParams.get(3).style, Encoding.StyleEnum.FORM.toString());
+        assertTrue(formParams.get(3).isExplode); // Defaults to true for style == FORM
+        assertEquals(formParams.get(3).contentType, "text/plain");
+
+        assertEquals(formParams.get(4).paramName, "styleSpecified");
+        assertTrue(formParams.get(4).isContainer);
+        assertEquals(formParams.get(4).style, Encoding.StyleEnum.SPACE_DELIMITED.toString());
+        assertFalse(formParams.get(4).isExplode);
+        assertNull(formParams.get(4).contentType);
+
+        assertEquals(formParams.get(5).paramName, "styleSpecifiedNoExplode");
+        assertTrue(formParams.get(5).isContainer);
+        assertEquals(formParams.get(5).style, Encoding.StyleEnum.SPACE_DELIMITED.toString());
+        assertFalse(formParams.get(5).isExplode); // Defaults to false for style other than FORM
+        assertNull(formParams.get(5).contentType);
     }
 
     @Test

modules/openapi-generator/src/test/resources/3_0/content-data.yaml

@@ -98,6 +98,57 @@ paths:
       responses:
         200:
           description: OK
+  /requestBodyWithEncodingTypes:
+    post:
+      requestBody:
+        content:
+          application/x-www-form-urlencoded:
+            schema:
+              type: object
+              properties:
+                int-param:
+                  type: integer
+                explode-true:
+                  type: array
+                  items:
+                    type: string
+                explode-false:
+                  type: array
+                  items:
+                    type: string
+                no-style-no-explode:
+                  type: array
+                  items:
+                    type: string
+                style-specified:
+                  type: array
+                  items:
+                    type: string
+                style-specified-no-explode:
+                  type: array
+                  items:
+                    type: string
+            encoding:
+              int-param:
+                explode: true            # should be disregarded for non-container
+              explode-true:
+                contentType: text/plain  # should be disregarded
+                explode: true
+              explode-false:
+                contentType: text/plain  # should be disregarded
+                explode: false
+              no-style-no-explode:
+                contentType: text/plain
+              style-specified:
+                contentType: text/plain  # should be disregarded
+                style: spaceDelimited
+                explode: false
+              style-specified-no-explode:
+                contentType: text/plain  # should be disregarded
+                style: spaceDelimited
+      responses:
+        200:
+          description: OK
 components:
   headers:
     X-Rate-Limit: