improve buffer options

CHANGELOG.md

@@ -11,6 +11,7 @@ Unreleased changes are available as `avenga/couper:edge` container.
 
 * **Changed**
   * More specific error log messages for [`oauth2`](https://docs.couper.io/configuration/block/oauth2) and [`beta_token_request`](https://docs.couper.io/configuration/block/token_request) token request errors ([#755](https://github.com/avenga/couper/pull/755))
+  * In addition to having an appropriate JSON media type in the `Content-Type` header field, (backend) requests or backend responses for an endpoint are only JSON-parsed if indicated by a [`.json_body` reference](https://docs.couper.io/configuration/variables) in the endpoint configuration ([#749](https://github.com/avenga/couper/pull/749))
 
 * **Fixed**
   * Erroneously sending an empty [`Server-Timing` header](https://docs.couper.io/configuration/command-line#oberservation-options) ([#700](https://github.com/avenga/couper/pull/700))

eval/buffer.go

@@ -15,14 +15,32 @@ import (
 type BufferOption uint8
 
 const (
-	BufferNone BufferOption = iota
-	BufferRequest
-	BufferResponse
+	BufferNone        BufferOption = 0
+	BufferRequest     BufferOption = 1
+	BufferResponse    BufferOption = 2
+	JSONParseRequest  BufferOption = 4
+	JSONParseResponse BufferOption = 8
 )
 
+func (i BufferOption) Request() bool {
+	return i&BufferRequest == BufferRequest
+}
+
+func (i BufferOption) JSONRequest() bool {
+	return i&JSONParseRequest == JSONParseRequest
+}
+
+func (i BufferOption) Response() bool {
+	return i&BufferResponse == BufferResponse
+}
+
+func (i BufferOption) JSONResponse() bool {
+	return i&JSONParseResponse == JSONParseResponse
+}
+
 func (i BufferOption) GoString() string {
 	var result []string
-	for _, o := range []BufferOption{BufferRequest, BufferResponse} {
+	for _, o := range []BufferOption{BufferRequest, BufferResponse, JSONParseRequest, JSONParseResponse} {
 		if (i & o) == o {
 			result = append(result, o.String())
 		}
@@ -33,10 +51,6 @@ func (i BufferOption) GoString() string {
 	return strings.Join(result, "|")
 }
 
-func (i BufferOption) Response() bool {
-	return i&BufferResponse == BufferResponse
-}
-
 // MustBuffer determines if any of the hcl.bodies makes use of 'body', 'form_body' or 'json_body' or
 // of known attributes and variables which require a parsed client-request or backend-response body.
 func MustBuffer(bodies ...hcl.Body) BufferOption {
@@ -70,7 +84,7 @@ func MustBuffer(bodies ...hcl.Body) BufferOption {
 			rootName := traversal.RootName()
 
 			if len(traversal) == 1 {
-				if rootName == ClientRequest || rootName == BackendRequest {
+				if rootName == ClientRequest || rootName == BackendRequests || rootName == BackendRequest {
 					result |= BufferRequest
 				}
 				if rootName == BackendResponses || rootName == BackendResponse {
@@ -79,7 +93,7 @@ func MustBuffer(bodies ...hcl.Body) BufferOption {
 				continue
 			}
 
-			if rootName != ClientRequest && rootName != BackendRequest && rootName != BackendResponses && rootName != BackendResponse {
+			if rootName != ClientRequest && rootName != BackendRequests && rootName != BackendRequest && rootName != BackendResponses && rootName != BackendResponse {
 				continue
 			}
 
@@ -92,6 +106,8 @@ func MustBuffer(bodies ...hcl.Body) BufferOption {
 					case ClientRequest:
 						fallthrough
 					case BackendRequest:
+						fallthrough
+					case BackendRequests:
 						result |= BufferRequest
 
 					case BackendResponse:
@@ -100,31 +116,38 @@ func MustBuffer(bodies ...hcl.Body) BufferOption {
 						result |= BufferResponse
 					}
 				case CTX: // e.g. jwt token (value) could be read from any (body) source
-					if rootName == ClientRequest || rootName == BackendRequest {
+					if rootName == ClientRequest || rootName == BackendRequests || rootName == BackendRequest {
 						result |= BufferRequest
 					}
 				case FormBody:
-					if rootName == ClientRequest || rootName == BackendRequest {
+					if rootName == ClientRequest || rootName == BackendRequests || rootName == BackendRequest {
 						result |= BufferRequest
 					}
 				case JSONBody:
 					switch rootName {
 					case ClientRequest:
 						fallthrough
 					case BackendRequest:
+						fallthrough
+					case BackendRequests:
 						result |= BufferRequest
+						result |= JSONParseRequest
 
 					case BackendResponse:
 						fallthrough
 					case BackendResponses:
 						result |= BufferResponse
+						result |= JSONParseResponse
 					}
 				default:
 					// e.g. backend_responses.default
 					if len(traversal) == 2 {
 						if rootName == BackendResponse || rootName == BackendResponses {
 							result |= BufferResponse
 						}
+						if rootName == BackendRequest || rootName == BackendRequests {
+							result |= BufferRequest
+						}
 					}
 				}
 			}

eval/buffer_test.go

@@ -20,14 +20,23 @@ func TestMustBuffer(t *testing.T) {
 		{"buffer request", `endpoint "/" { set_response_headers = { x = request } }`, BufferRequest},
 		{"buffer request body", `endpoint "/" { set_response_headers = { x = request.body } }`, BufferRequest},
 		{"buffer request form_body", `endpoint "/" { set_response_headers = { x = request.form_body } }`, BufferRequest},
-		{"buffer request json_body", `endpoint "/" { set_response_headers = { x = request.json_body } }`, BufferRequest},
+		{"buffer request json_body", `endpoint "/" { set_response_headers = { x = request.json_body } }`, BufferRequest | JSONParseRequest},
+		{"buffer backend_requests specific", `endpoint "/" { set_response_headers = { x = backend_requests.r } }`, BufferRequest},
+		{"buffer backend_requests body", `endpoint "/" { set_response_headers = { x = backend_requests.r.body } }`, BufferRequest},
+		{"buffer backend_requests form_body", `endpoint "/" { set_response_headers = { x = backend_requests.r.form_body } }`, BufferRequest},
+		{"buffer backend_requests json_body", `endpoint "/" { set_response_headers = { x = backend_requests.r.json_body } }`, BufferRequest | JSONParseRequest},
+		{"buffer backend_request body", `backend "b" { set_response_headers = { x = backend_request.body } }`, BufferRequest},
+		{"buffer backend_request form_body", `backend "b" { set_response_headers = { x = backend_request.form_body } }`, BufferRequest},
+		{"buffer backend_request json_body", `backend "b" { set_response_headers = { x = backend_request.json_body } }`, BufferRequest | JSONParseRequest},
 		{"buffer request add_form_params", `endpoint "/" { add_form_params = [] }`, BufferRequest},
 		{"buffer request set_form_params", `endpoint "/" { set_form_params = [] }`, BufferRequest},
 		{"buffer request remove_form_params", `endpoint "/" { remove_form_params = [] }`, BufferRequest},
-		{"buffer responses", `endpoint "/" { set_response_headers = { x = backend_responses } }`, BufferResponse},
-		{"buffer default response", `endpoint "/" { set_response_headers = { x = backend_responses.default } }`, BufferResponse},
-		{"buffer response body", `endpoint "/" { set_response_headers = { x = backend_responses.default.body } }`, BufferResponse},
-		{"buffer response json_body", `endpoint "/" { set_response_headers = { x = backend_responses.default.json_body } }`, BufferResponse},
+		{"buffer backend_responses", `endpoint "/" { set_response_headers = { x = backend_responses } }`, BufferResponse},
+		{"buffer backend_responses default", `endpoint "/" { set_response_headers = { x = backend_responses.default } }`, BufferResponse},
+		{"buffer backend_responses body", `endpoint "/" { set_response_headers = { x = backend_responses.default.body } }`, BufferResponse},
+		{"buffer backend_responses json_body", `endpoint "/" { set_response_headers = { x = backend_responses.default.json_body } }`, BufferResponse | JSONParseResponse},
+		{"buffer backend_response body", `backend "b" { set_response_headers = { x = backend_response.body } }`, BufferResponse},
+		{"buffer backend_response json_body", `backend "b" { set_response_headers = { x = backend_response.json_body } }`, BufferResponse | JSONParseResponse},
 		{"buffer request/response", `endpoint "/" {
 	set_response_headers = {
 	  x = request

eval/context.go

@@ -161,7 +161,12 @@ func (c *Context) WithClientRequest(req *http.Request) *Context {
 		}
 	}
 	port, _ := strconv.ParseInt(p, 10, 64)
-	body, jsonBody := parseReqBody(req)
+
+	var parseJSON bool
+	if opts, ok := ctx.Value(request.BufferOptions).(BufferOption); ok {
+		parseJSON = opts.JSONRequest()
+	}
+	body, jsonBody := parseReqBody(req, parseJSON)
 
 	origin := NewRawOrigin(req.URL)
 	ctx.eval.Variables[ClientRequest] = cty.ObjectVal(ctxMap.Merge(ContextMap{
@@ -254,7 +259,13 @@ func newBerespValues(ctx context.Context, readBody bool, beresp *http.Response)
 	}
 	port, _ := strconv.ParseInt(p, 10, 64)
 
-	body, jsonBody := parseReqBody(bereq)
+	bufferOption, bOk := bereq.Context().Value(request.BufferOptions).(BufferOption)
+
+	var body, jsonBody cty.Value
+	if bOk && bufferOption.Request() {
+		body, jsonBody = parseReqBody(bereq, bufferOption.JSONRequest())
+	}
+
 	bereqVal = cty.ObjectVal(ContextMap{
 		Method:   cty.StringVal(bereq.Method),
 		URL:      cty.StringVal(bereq.URL.String()),
@@ -269,14 +280,12 @@ func newBerespValues(ctx context.Context, readBody bool, beresp *http.Response)
 		FormBody: seetie.ValuesMapToValue(parseForm(bereq).PostForm),
 	}.Merge(newVariable(ctx, bereq.Cookies(), bereq.Header)))
 
-	bufferOption, bOk := bereq.Context().Value(request.BufferOptions).(BufferOption)
-
 	var respBody, respJSONBody cty.Value
 	if readBody && !IsUpgradeResponse(bereq, beresp) {
-		if bOk && (bufferOption&BufferResponse) == BufferResponse {
-			respBody, respJSONBody = parseRespBody(beresp)
+		if bOk && bufferOption.Response() {
+			respBody, respJSONBody = parseRespBody(beresp, bufferOption.JSONResponse())
 		}
-	} else if bOk && (bufferOption&BufferResponse) != BufferResponse {
+	} else if bOk && !bufferOption.Response() {
 		hasBlock, _ := bereq.Context().Value(request.ResponseBlock).(bool)
 		ws, _ := bereq.Context().Value(request.WebsocketsAllowed).(bool)
 		if name != "default" || (name == "default" && hasBlock) {
@@ -467,7 +476,7 @@ func mergeBackendVariables(etx *hcl.EvalContext, key string, cmap ContextMap) {
 const defaultMaxMemory = 32 << 20 // 32 MB
 
 // parseForm populates the request PostForm field.
-// As Proxy we should not consume the request body.
+// As Proxy, we should not consume the request body.
 // Rewind body via GetBody method.
 func parseForm(r *http.Request) *http.Request {
 	if r.GetBody == nil || r.Form != nil {
@@ -487,7 +496,7 @@ func isJSONMediaType(contentType string) bool {
 	return len(mParts) == 2 && mParts[0] == "application" && (mParts[1] == "json" || strings.HasSuffix(mParts[1], "+json"))
 }
 
-func parseReqBody(req *http.Request) (cty.Value, cty.Value) {
+func parseReqBody(req *http.Request, parseJSON bool) (cty.Value, cty.Value) {
 	jsonBody := cty.EmptyObjectVal
 	if req == nil || req.GetBody == nil {
 		return cty.NilVal, jsonBody
@@ -499,21 +508,21 @@ func parseReqBody(req *http.Request) (cty.Value, cty.Value) {
 		return cty.NilVal, jsonBody
 	}
 
-	if isJSONMediaType(req.Header.Get("Content-Type")) {
+	if parseJSON && isJSONMediaType(req.Header.Get("Content-Type")) {
 		jsonBody = parseJSONBytes(b)
 	}
 	return cty.StringVal(string(b)), jsonBody
 }
 
-func parseRespBody(beresp *http.Response) (cty.Value, cty.Value) {
+func parseRespBody(beresp *http.Response, parseJSON bool) (cty.Value, cty.Value) {
 	jsonBody := cty.EmptyObjectVal
 
 	b := parseSetRespBody(beresp)
 	if b == nil {
 		return cty.NilVal, jsonBody
 	}
 
-	if isJSONMediaType(beresp.Header.Get("Content-Type")) {
+	if parseJSON && isJSONMediaType(beresp.Header.Get("Content-Type")) {
 		jsonBody = parseJSONBytes(b)
 	}
 	return cty.StringVal(string(b)), jsonBody