Handling Mocking media types

development/testing/manifests/api.yaml

@@ -212,6 +212,18 @@ spec:
                       completed: true
                       order: 13
                       url: "http://mockedURL.com"
+                text/plain:
+                  example: |
+                    title: "Mocked title with text example
+                    completed: true
+                    order: 13
+                    url: "http://mockedURL.com"
+                application/xml:
+                  example:
+                    title: "Mocked title with XML example"
+                    completed: true
+                    order: 13
+                    url: "http://mockedURL.com"
             '400':
               description: Client error
               content:
@@ -265,7 +277,19 @@ spec:
                       - url
                   # This example is the must for the response body mocking
                   example:
-                    title: "Mocked title"
+                    title: "Mocked JSON title"
+                    completed: true
+                    order: 13
+                    url: "http://mockedURL.com"
+                application/xml:
+                  example:
+                    title: "Mocked XML title"
+                    completed: true
+                    order: 13
+                    url: "http://mockedURL.com"
+                text/plain:
+                  example: |
+                    title: "Mocked Text title"
                     completed: true
                     order: 13
                     url: "http://mockedURL.com"

development/testing/postman/api.postman_collection.json

@@ -790,7 +790,7 @@
 									"    pm.expect(jsonData).to.be.an(\"object\");",
 									"    pm.expect(pm.response.headers.get('content-type')).to.eql('application/json');",
 									"    pm.expect(pm.response.headers.get('x-kusk-mocked')).to.eql('true');",
-									"    pm.expect(jsonData.title).to.eql(\"Mocked title\");",
+									"    pm.expect(jsonData.title).to.eql(\"Mocked JSON title\");",
 									"    pm.expect(jsonData.order).to.eql(13);",
 									"    pm.expect(jsonData.completed).to.eql(true);",
 									"}",
@@ -1036,4 +1036,4 @@
 			"type": "string"
 		}
 	]
-}
+}

docs/extension.md

@@ -271,6 +271,7 @@ The validation objects contains the following properties to configure automatic
 | validation.request.enabled | boolean flag to enable request validation |
 
 #### strict validation of request bodies
+
 Strict validation means that the request body must conform exactly to the schema specified in your openapi spec.
 Any fields not in schema will cause the validation to fail the request/response.
 To enable this, please add the following field to your schema block if the request body is of type `object`
@@ -353,21 +354,33 @@ Note: currently `mocking` is incompatible with the `validation` option, the conf
                       - url
                   # Singular example has the priority over other examples.
                   example:
-                    title: "Mocked title"
+                    title: "Mocked JSON title"
                     completed: true
                     order: 13
                     url: "http://mockedURL.com"
                   examples:
                     first:
-                      title: "Mocked title #1"
+                      title: "Mocked JSON title #1"
                       completed: true
                       order: 12
                       url: "http://mockedURL.com"
                     second:
-                      title: "Mocked title #2"
+                      title: "Mocked JSON title #2"
                       completed: true
                       order: 13
                       url: "http://mockedURL.com"
+                application/xml:
+                  example:
+                    title: "Mocked XML title"
+                    completed: true
+                    order: 13
+                    url: "http://mockedURL.com"
+                text/plain:
+                  example: |
+                    title: "Mocked Text title"
+                    completed: true
+                    order: 13
+                    url: "http://mockedURL.com"
         patch:
           # Disable for patch
           x-kusk:
@@ -376,18 +389,57 @@ Note: currently `mocking` is incompatible with the `validation` option, the conf
         ...
 ```
 
-With the example above the response to GET request will be:
-
-```shell
-< HTTP/1.1 200 OK
-< content-type: application/json
-< x-kusk-mocked: true
-< date: Mon, 21 Feb 2022 14:36:52 GMT
-< content-length: 81
-< x-envoy-upstream-service-time: 0
-< server: envoy
-< 
-{"completed":true,"order":13,"title":"Mocked title","url":"http://mockedURL.com"}
-```
-
-The response includes the `x-kusk-mocked: true` header indicating mocking.
+With the example above, the response to GET request will be different depending on the client's preferred media type when using the `Accept` header.
+
+Below we're using the example.com setup from the development/testing directory.
+
+1. Curl call without specifying the Accept header. From the list of specified media types (application/json, plain/text, application/xml) - uses our default Mocking media type - application/json:
+
+    ```shell
+    curl -v -H "Host: example.com" http://192.168.49.3/testing/mocked/multiple/1
+
+    < HTTP/1.1 200 OK
+    < content-type: application/json
+    < x-kusk-mocked: true
+    < date: Mon, 21 Feb 2022 14:36:52 GMT
+    < content-length: 81
+    < x-envoy-upstream-service-time: 0
+    < server: envoy
+    < 
+    {"completed":true,"order":13,"title":"Mocked JSON title","url":"http://mockedURL.com"}
+    ```
+
+    The response includes the `x-kusk-mocked: true` header indicating mocking.
+
+2. With the Accept header, that has application/xml as the preffered type:
+
+    ```shell
+    curl -v -H "Host: example.com" -H "Accept: application/xml"  http://192.168.49.3/testing/mocked/1
+    < HTTP/1.1 200 OK
+    < content-type: application/xml
+    < x-kusk-mocked: true
+    < date: Mon, 28 Feb 2022 08:56:46 GMT
+    < content-length: 117
+    < x-envoy-upstream-service-time: 0
+    < server: envoy
+
+    <doc><completed>true</completed><order>13</order><title>Mocked XML title</title><url>http://mockedURL.com</url></doc>
+    ```
+
+3. With the Accept header specifying multiple weighted preffered media types, text/plain with more weight.
+
+    ```shell
+    curl -v -H "Host: example.com" -H "Accept: application/json;q=0.8,text/plain;q=0.9"  http://192.168.49.3/testing/mocked/1
+    < content-type: text/plain
+    < x-kusk-mocked: true
+    < date: Mon, 28 Feb 2022 08:56:00 GMT
+    < content-length: 81
+    < x-envoy-upstream-service-time: 0
+    < server: envoy
+    < 
+    title: "Mocked Text title"
+    completed: true
+    order: 13
+    url: "http://mockedURL.com"
+
+    ```

go.mod

@@ -38,6 +38,7 @@ require (
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/census-instrumentation/opencensus-proto v0.2.1 // indirect
 	github.com/cespare/xxhash/v2 v2.1.1 // indirect
+	github.com/clbanning/mxj v1.8.4
 	github.com/cncf/xds/go v0.0.0-20211011173535-cb28da3451f1 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/envoyproxy/protoc-gen-validate v0.1.0 // indirect

go.sum

@@ -96,6 +96,8 @@ github.com/cespare/xxhash/v2 v2.1.1/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XL
 github.com/chzyer/logex v1.1.10/go.mod h1:+Ywpsq7O8HXn0nuIou7OrIPyXbp3wmkHB+jjWRnGsAI=
 github.com/chzyer/readline v0.0.0-20180603132655-2972be24d48e/go.mod h1:nSuG5e5PlCu98SY8svDHJxuZscDgtXS6KTTbou5AhLI=
 github.com/chzyer/test v0.0.0-20180213035817-a1ea475d72b1/go.mod h1:Q3SI9o4m/ZMnBNeIyt5eFwwo7qiLfzFZmjNmxjkiQlU=
+github.com/clbanning/mxj v1.8.4 h1:HuhwZtbyvyOw+3Z1AowPkU87JkJUSv751ELWaiTpj8I=
+github.com/clbanning/mxj v1.8.4/go.mod h1:BVjHeAH+rl9rs6f+QIpeRl0tfu10SXn1pUSa5PVGJng=
 github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDkc90ppPyw=
 github.com/cncf/udpa/go v0.0.0-20191209042840-269d4d468f6f/go.mod h1:M8M6+tZqaGXZJjfX53e64911xZQV5JYwmTeXPW+k8Sc=
 github.com/cncf/udpa/go v0.0.0-20200629203442-efcf912fb354/go.mod h1:WmhPx2Nbnhtbo57+VJT5O0JRkEi1Wbu0z5j0R8u5Hbk=

internal/agent/httpserver/handlers.go

@@ -48,16 +48,41 @@ func (h *mainHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 
 	// Add Mocked header to show that we mocked the response
 	w.Header().Set(HeaderMockResponseInsert, "true")
-	// TODO: detect content type for the user using its request Accept Header
-	mediaType := "application/json"
-	data, ok := mockResponse.MediaTypeData[mediaType]
 	// If no media type data (example) found - this is the simple http code in the response, write it and return
-	if !ok {
+	if len(mockResponse.MediaTypeData) == 0 {
 		w.WriteHeader(mockResponse.StatusCode)
 		return
 	}
-	// otherwise, set Content-Type and write the body
-	w.Header().Set("Content-Type", mediaType)
+	mediaTypes := getMediaTypes(mockResponse.MediaTypeData)
+	defaultMediaType := getDefaultMediaType(mediaTypes)
+	// Get media type from the request Accept header parsing and matching to the existing media content type.
+	// If missing or not matched - use the first entry in the media content map.
+	chosenMediaType := NegotiateContentType(r, mediaTypes, defaultMediaType)
+	data := mockResponse.MediaTypeData[chosenMediaType]
+	w.Header().Set("Content-Type", chosenMediaType)
 	w.WriteHeader(mockResponse.StatusCode)
 	w.Write(data)
 }
+
+func getMediaTypes(mediaTypesData map[string][]byte) []string {
+	mediaTypes := make([]string, 0, len(mediaTypesData))
+	for contentType := range mediaTypesData {
+		mediaTypes = append(mediaTypes, contentType)
+	}
+
+	return mediaTypes
+}
+
+func getDefaultMediaType(mediaTypes []string) string {
+	if len(mediaTypes) == 1 {
+		return mediaTypes[0]
+	}
+	// Return any json-based mediaType as default
+	for _, mediaType := range mediaTypes {
+		if mocking.JsonMediaTypePattern.Match([]byte(mediaType)) {
+			return mediaType
+		}
+	}
+	// Otherwise return the first found
+	return mediaTypes[0]
+}