review feedback

proxy/common.go

@@ -50,10 +50,6 @@ func unmarshalRequestBody(r *http.Request, target interface{}) error {
 	}
 	r.Body = ioutil.NopCloser(bytes.NewReader(body))
 
-	if len(body) == 0 {
-		return nil
-	}
-
 	d := json.NewDecoder(bytes.NewReader(body))
 	d.UseNumber() // don't want large numbers in scientific format
 	return d.Decode(&target)
@@ -66,7 +62,6 @@ func marshalRequestBody(r *http.Request, body interface{}) error {
 	}
 	r.Body = ioutil.NopCloser(bytes.NewReader(newBody))
 	r.ContentLength = int64(len(newBody))
-	r.Header.Set("Content-Type", "application/json")
 	return nil
 }
 

proxy/proxy.go

@@ -396,6 +396,10 @@ func (proxy *Proxy) setWeaveDNS(hostConfig *docker.HostConfig, hostname, dnsDoma
 }
 
 func (proxy *Proxy) getDNSDomain() (domain string, running bool) {
+	if proxy.WithoutDNS {
+		return "", false
+	}
+
 	domain = nameserver.DefaultDomain
 	running = proxy.WithDNS
 	weaveContainer, err := proxy.client.InspectContainer("weave")

proxy/start_container_interceptor.go

@@ -14,11 +14,11 @@ type startContainerRequestBody struct {
 
 func (i *startContainerInterceptor) InterceptRequest(r *http.Request) error {
 	container, err := inspectContainerInPath(i.proxy.client, r.URL.Path)
-	if err != nil || !containerShouldAttach(container) {
+	if err != nil {
 		return err
 	}
 
-	if r.Header.Get("Content-Type") != "application/json" {
+	if !containerShouldAttach(container) || r.Header.Get("Content-Type") != "application/json" {
 		i.proxy.createWait(r, container.ID)
 		return nil
 	}
@@ -35,8 +35,11 @@ func (i *startContainerInterceptor) InterceptRequest(r *http.Request) error {
 		}
 	}
 
+	if err := marshalRequestBody(r, hostConfig); err != nil {
+		return err
+	}
 	i.proxy.createWait(r, container.ID)
-	return marshalRequestBody(r, hostConfig)
+	return nil
 }
 
 func (i *startContainerInterceptor) InterceptResponse(r *http.Response) error {