diff --git a/modules/swagger-codegen/src/main/resources/swift3/AlamofireImplementations.mustache b/modules/swagger-codegen/src/main/resources/swift3/AlamofireImplementations.mustache
index 03e421b7f10..2857c85889d 100644
--- a/modules/swagger-codegen/src/main/resources/swift3/AlamofireImplementations.mustache
+++ b/modules/swagger-codegen/src/main/resources/swift3/AlamofireImplementations.mustache
@@ -30,6 +30,25 @@ open class AlamofireRequestBuilder<T>: RequestBuilder<T> {
         return Alamofire.SessionManager(configuration: configuration)
     }
 
+    /**
+     May be overridden by a subclass if you want to control the Content-Type
+     that is given to an uploaded form part.
+
+     Return nil to use the default behavior (inferring the Content-Type from
+     the file extension).  Return the desired Content-Type otherwise.
+     */
+    open func contentTypeForFormPart(fileURL: URL) -> String? {
+        return nil
+    }
+
+    /**
+     May be overridden by a subclass if you want to control the request
+     configuration (e.g. to override the cache policy).
+     */
+    open func makeRequest(manager: SessionManager, method: HTTPMethod, encoding: ParameterEncoding) -> DataRequest {
+        return manager.request(URLString, method: method, parameters: parameters, encoding: encoding)
+    }
+
     override open func execute(_ completion: @escaping (_ response: Response<T>?, _ error: Error?) -> Void) {
         let managerId:String = UUID().uuidString
         // Create a new manager for each request to customize its request header
@@ -47,7 +66,12 @@ open class AlamofireRequestBuilder<T>: RequestBuilder<T> {
                 for (k, v) in self.parameters! {
                     switch v {
                     case let fileURL as URL:
-                        mpForm.append(fileURL, withName: k)
+                        if let mimeType = self.contentTypeForFormPart(fileURL: fileURL) {
+                            mpForm.append(fileURL, withName: k, fileName: fileURL.lastPathComponent, mimeType: mimeType)
+                        }
+                        else {
+                            mpForm.append(fileURL, withName: k)
+                        }
                         break
                     case let string as String:
                         mpForm.append(string.data(using: String.Encoding.utf8)!, withName: k)
@@ -72,7 +96,7 @@ open class AlamofireRequestBuilder<T>: RequestBuilder<T> {
                 }
             })
         } else {
-            let request = manager.request(URLString, method: xMethod!, parameters: parameters, encoding: encoding)
+            let request = makeRequest(manager: manager, method: xMethod!, encoding: encoding)
             if let onProgressReady = self.onProgressReady {
                 onProgressReady(request.progress)
             }
diff --git a/samples/client/petstore/swift3/default/PetstoreClient/Classes/Swaggers/AlamofireImplementations.swift b/samples/client/petstore/swift3/default/PetstoreClient/Classes/Swaggers/AlamofireImplementations.swift
index 03e421b7f10..2857c85889d 100644
--- a/samples/client/petstore/swift3/default/PetstoreClient/Classes/Swaggers/AlamofireImplementations.swift
+++ b/samples/client/petstore/swift3/default/PetstoreClient/Classes/Swaggers/AlamofireImplementations.swift
@@ -30,6 +30,25 @@ open class AlamofireRequestBuilder<T>: RequestBuilder<T> {
         return Alamofire.SessionManager(configuration: configuration)
     }
 
+    /**
+     May be overridden by a subclass if you want to control the Content-Type
+     that is given to an uploaded form part.
+
+     Return nil to use the default behavior (inferring the Content-Type from
+     the file extension).  Return the desired Content-Type otherwise.
+     */
+    open func contentTypeForFormPart(fileURL: URL) -> String? {
+        return nil
+    }
+
+    /**
+     May be overridden by a subclass if you want to control the request
+     configuration (e.g. to override the cache policy).
+     */
+    open func makeRequest(manager: SessionManager, method: HTTPMethod, encoding: ParameterEncoding) -> DataRequest {
+        return manager.request(URLString, method: method, parameters: parameters, encoding: encoding)
+    }
+
     override open func execute(_ completion: @escaping (_ response: Response<T>?, _ error: Error?) -> Void) {
         let managerId:String = UUID().uuidString
         // Create a new manager for each request to customize its request header
@@ -47,7 +66,12 @@ open class AlamofireRequestBuilder<T>: RequestBuilder<T> {
                 for (k, v) in self.parameters! {
                     switch v {
                     case let fileURL as URL:
-                        mpForm.append(fileURL, withName: k)
+                        if let mimeType = self.contentTypeForFormPart(fileURL: fileURL) {
+                            mpForm.append(fileURL, withName: k, fileName: fileURL.lastPathComponent, mimeType: mimeType)
+                        }
+                        else {
+                            mpForm.append(fileURL, withName: k)
+                        }
                         break
                     case let string as String:
                         mpForm.append(string.data(using: String.Encoding.utf8)!, withName: k)
@@ -72,7 +96,7 @@ open class AlamofireRequestBuilder<T>: RequestBuilder<T> {
                 }
             })
         } else {
-            let request = manager.request(URLString, method: xMethod!, parameters: parameters, encoding: encoding)
+            let request = makeRequest(manager: manager, method: xMethod!, encoding: encoding)
             if let onProgressReady = self.onProgressReady {
                 onProgressReady(request.progress)
             }
diff --git a/samples/client/petstore/swift3/promisekit/PetstoreClient/Classes/Swaggers/AlamofireImplementations.swift b/samples/client/petstore/swift3/promisekit/PetstoreClient/Classes/Swaggers/AlamofireImplementations.swift
index 03e421b7f10..2857c85889d 100644
--- a/samples/client/petstore/swift3/promisekit/PetstoreClient/Classes/Swaggers/AlamofireImplementations.swift
+++ b/samples/client/petstore/swift3/promisekit/PetstoreClient/Classes/Swaggers/AlamofireImplementations.swift
@@ -30,6 +30,25 @@ open class AlamofireRequestBuilder<T>: RequestBuilder<T> {
         return Alamofire.SessionManager(configuration: configuration)
     }
 
+    /**
+     May be overridden by a subclass if you want to control the Content-Type
+     that is given to an uploaded form part.
+
+     Return nil to use the default behavior (inferring the Content-Type from
+     the file extension).  Return the desired Content-Type otherwise.
+     */
+    open func contentTypeForFormPart(fileURL: URL) -> String? {
+        return nil
+    }
+
+    /**
+     May be overridden by a subclass if you want to control the request
+     configuration (e.g. to override the cache policy).
+     */
+    open func makeRequest(manager: SessionManager, method: HTTPMethod, encoding: ParameterEncoding) -> DataRequest {
+        return manager.request(URLString, method: method, parameters: parameters, encoding: encoding)
+    }
+
     override open func execute(_ completion: @escaping (_ response: Response<T>?, _ error: Error?) -> Void) {
         let managerId:String = UUID().uuidString
         // Create a new manager for each request to customize its request header
@@ -47,7 +66,12 @@ open class AlamofireRequestBuilder<T>: RequestBuilder<T> {
                 for (k, v) in self.parameters! {
                     switch v {
                     case let fileURL as URL:
-                        mpForm.append(fileURL, withName: k)
+                        if let mimeType = self.contentTypeForFormPart(fileURL: fileURL) {
+                            mpForm.append(fileURL, withName: k, fileName: fileURL.lastPathComponent, mimeType: mimeType)
+                        }
+                        else {
+                            mpForm.append(fileURL, withName: k)
+                        }
                         break
                     case let string as String:
                         mpForm.append(string.data(using: String.Encoding.utf8)!, withName: k)
@@ -72,7 +96,7 @@ open class AlamofireRequestBuilder<T>: RequestBuilder<T> {
                 }
             })
         } else {
-            let request = manager.request(URLString, method: xMethod!, parameters: parameters, encoding: encoding)
+            let request = makeRequest(manager: manager, method: xMethod!, encoding: encoding)
             if let onProgressReady = self.onProgressReady {
                 onProgressReady(request.progress)
             }
diff --git a/samples/client/petstore/swift3/rxswift/PetstoreClient/Classes/Swaggers/AlamofireImplementations.swift b/samples/client/petstore/swift3/rxswift/PetstoreClient/Classes/Swaggers/AlamofireImplementations.swift
index 03e421b7f10..2857c85889d 100644
--- a/samples/client/petstore/swift3/rxswift/PetstoreClient/Classes/Swaggers/AlamofireImplementations.swift
+++ b/samples/client/petstore/swift3/rxswift/PetstoreClient/Classes/Swaggers/AlamofireImplementations.swift
@@ -30,6 +30,25 @@ open class AlamofireRequestBuilder<T>: RequestBuilder<T> {
         return Alamofire.SessionManager(configuration: configuration)
     }
 
+    /**
+     May be overridden by a subclass if you want to control the Content-Type
+     that is given to an uploaded form part.
+
+     Return nil to use the default behavior (inferring the Content-Type from
+     the file extension).  Return the desired Content-Type otherwise.
+     */
+    open func contentTypeForFormPart(fileURL: URL) -> String? {
+        return nil
+    }
+
+    /**
+     May be overridden by a subclass if you want to control the request
+     configuration (e.g. to override the cache policy).
+     */
+    open func makeRequest(manager: SessionManager, method: HTTPMethod, encoding: ParameterEncoding) -> DataRequest {
+        return manager.request(URLString, method: method, parameters: parameters, encoding: encoding)
+    }
+
     override open func execute(_ completion: @escaping (_ response: Response<T>?, _ error: Error?) -> Void) {
         let managerId:String = UUID().uuidString
         // Create a new manager for each request to customize its request header
@@ -47,7 +66,12 @@ open class AlamofireRequestBuilder<T>: RequestBuilder<T> {
                 for (k, v) in self.parameters! {
                     switch v {
                     case let fileURL as URL:
-                        mpForm.append(fileURL, withName: k)
+                        if let mimeType = self.contentTypeForFormPart(fileURL: fileURL) {
+                            mpForm.append(fileURL, withName: k, fileName: fileURL.lastPathComponent, mimeType: mimeType)
+                        }
+                        else {
+                            mpForm.append(fileURL, withName: k)
+                        }
                         break
                     case let string as String:
                         mpForm.append(string.data(using: String.Encoding.utf8)!, withName: k)
@@ -72,7 +96,7 @@ open class AlamofireRequestBuilder<T>: RequestBuilder<T> {
                 }
             })
         } else {
-            let request = manager.request(URLString, method: xMethod!, parameters: parameters, encoding: encoding)
+            let request = makeRequest(manager: manager, method: xMethod!, encoding: encoding)
             if let onProgressReady = self.onProgressReady {
                 onProgressReady(request.progress)
             }