commands: Use a flag to enable streaming channel output

commands/http/client.go

@@ -42,6 +42,9 @@ func (c *client) Send(req cmds.Request) (cmds.Response, error) {
 	// override with json to send to server
 	req.SetOption(cmds.EncShort, cmds.JSON)
 
+	// stream channel output
+	req.SetOption(cmds.ChanOpt, "true")
+
 	query, err := getQuery(req)
 	if err != nil {
 		return nil, err

commands/http/handler.go

@@ -84,13 +84,6 @@ func (i Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set(contentTypeHeader, mime)
 	}
 
-	// if the res output is a channel, set a custom header for it
-	isChan := false
-	if _, ok := res.Output().(chan interface{}); ok {
-		w.Header().Set(channelHeader, "1")
-		isChan = true
-	}
-
 	// if response contains an error, write an HTTP error status code
 	if e := res.Error(); e != nil {
 		if e.Code == cmds.ErrClient {
@@ -108,11 +101,14 @@ func (i Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	if isChan {
+	// if output is a channel and user requested streaming channels,
+	// use chunk copier for the output
+	_, isChan := res.Output().(chan interface{})
+	streamChans, _, _ := req.Option("stream-channels").Bool()
+	if isChan && streamChans {
 		err = copyChunks(w, out)
 		if err != nil {
 			log.Error(err)
-			fmt.Println(err)
 		}
 		return
 	}

commands/option.go

@@ -158,15 +158,18 @@ const (
 	EncLong  = "encoding"
 	RecShort = "r"
 	RecLong  = "recursive"
+	ChanOpt  = "stream-channels"
 )
 
 // options that are used by this package
 var OptionEncodingType = StringOption(EncShort, EncLong, "The encoding type the output should be encoded with (json, xml, or text)")
 var OptionRecursivePath = BoolOption(RecShort, RecLong, "Add directory paths recursively")
+var OptionStreamChannels = BoolOption(ChanOpt, "Stream channel output")
 
 // global options, added to every command
 var globalOptions = []Option{
 	OptionEncodingType,
+	OptionStreamChannels,
 }
 
 // the above array of Options, wrapped in a Command