@@ -693,8 +693,11 @@ func postContainersStart(eng *engine.Engine, version version.Version, w http.Res

 	if vars == nil {

 		return fmt.Errorf("Missing parameter")

 	}

-	name := vars["name"]

-	job := eng.Job("start", name)

+	var (

+		name = vars["name"]

+		job  = eng.Job("start", name)

+	)

+

 	// allow a nil body for backwards compatibility

 	if r.Body != nil {

 		if api.MatchesContentType(r.Header.Get("Content-Type"), "application/json") {

@@ -704,6 +707,10 @@ func postContainersStart(eng *engine.Engine, version version.Version, w http.Res

 		}

 	}

 	if err := job.Run(); err != nil {

+		if err.Error() == "Container already started" {

+			w.WriteHeader(http.StatusNotModified)

+			return nil

+		}

 		return err

 	}

 	w.WriteHeader(http.StatusNoContent)

@@ -720,6 +727,10 @@ func postContainersStop(eng *engine.Engine, version version.Version, w http.Resp

 	job := eng.Job("stop", vars["name"])

 	job.Setenv("t", r.Form.Get("t"))

 	if err := job.Run(); err != nil {

+		if err.Error() == "Container already stopped" {

+			w.WriteHeader(http.StatusNotModified)

+			return nil

+		}

 		return err

 	}

 	w.WriteHeader(http.StatusNoContent)

@@ -21,7 +21,7 @@ page_keywords: API, Docker, rcli, REST, documentation

 The current version of the API is v1.13

 Calling `/images/<name>/insert` is the same as calling

-`/v1.12/images/<name>/insert`.

+`/v1.13/images/<name>/insert`.

 You can still call an old version of the API using

 `/v1.12/images/<name>/insert`.

@@ -38,6 +38,12 @@ You can still call an old version of the API using

 `Sockets` parameter added to the `/info` endpoint listing all the sockets the 

 daemon is configured to listen on.

+`POST /containers/(name)/start`

+`POST /containers/(name)/stop`

+

+**New!**

+`start` and `stop` will now return 304 if the container's status is not modified

+

 ## v1.12

 ### Full Documentation

@@ -429,6 +429,7 @@ Start the container `id`

     Status Codes:

     -   **204** – no error

+    -   **304** – container already started

     -   **404** – no such container

     -   **500** – server error

@@ -455,6 +456,7 @@ Stop the container `id`

     Status Codes:

     -   **204** – no error

+    -   **304** – container already stopped

     -   **404** – no such container

     -   **500** – server error

@@ -2046,6 +2046,11 @@ func (srv *Server) ContainerStart(job *engine.Job) engine.Status {

 	if container == nil {

 		return job.Errorf("No such container: %s", name)

 	}

+

+	if container.State.IsRunning() {

+		return job.Errorf("Container already started")

+	}

+

 	// If no environment was set, then no hostconfig was passed.

 	if len(job.Environ()) > 0 {

 		hostConfig := runconfig.ContainerHostConfigFromJob(job)

@@ -2099,6 +2104,9 @@ func (srv *Server) ContainerStop(job *engine.Job) engine.Status {

 		t = job.GetenvInt("t")

 	}

 	if container := srv.daemon.Get(name); container != nil {

+		if !container.State.IsRunning() {

+			return job.Errorf("Container already stopped")

+		}

 		if err := container.Stop(int(t)); err != nil {

 			return job.Errorf("Cannot stop container %s: %s\n", name, err)

 		}