response: option to disable output draining

This commit was moved from ipfs/go-ipfs-http-client@9f3d9635fa

client/httpapi/api.go

@@ -131,6 +131,7 @@ func (api *HttpApi) request(command string, args ...string) *RequestBuilder {
 		command: command,
 		args:    args,
 		shell:   api,
+		drainOut: true,
 	}
 }
 

client/httpapi/apifile.go

@@ -57,7 +57,7 @@ func (f *apiFile) reset() error {
 	if f.r != nil {
 		f.r.Close()
 	}
-	req := f.core.request("cat", f.path.String())
+	req := f.core.request("cat", f.path.String()).NoDrain()
 	if f.at != 0 {
 		req.Option("offset", f.at)
 	}

client/httpapi/pubsub.go

@@ -113,8 +113,8 @@ func (api *PubsubAPI) Subscribe(ctx context.Context, topic string, opts ...caopt
 	}
 
 	resp, err := api.core().request("pubsub/sub", topic).
-		Option("discover", options.Discover).
-		Send(ctx)
+		Option("discover", options.Discover).NoDrain().Send(ctx)
+
 	if err != nil {
 		return nil, err
 	}

client/httpapi/request.go

@@ -13,6 +13,7 @@ type Request struct {
 	Opts    map[string]string
 	Body    io.Reader
 	Headers map[string]string
+	DrainOut bool // if set, resp.Close will read all remaining data
 }
 
 func NewRequest(ctx context.Context, url, command string, args ...string) *Request {
@@ -30,5 +31,6 @@ func NewRequest(ctx context.Context, url, command string, args ...string) *Reque
 		Args:    args,
 		Opts:    opts,
 		Headers: make(map[string]string),
+		DrainOut: true,
 	}
 }

client/httpapi/requestbuilder.go

@@ -19,6 +19,7 @@ type RequestBuilder struct {
 	opts    map[string]string
 	headers map[string]string
 	body    io.Reader
+	drainOut bool
 
 	shell *HttpApi
 }
@@ -84,6 +85,12 @@ func (r *RequestBuilder) Header(name, value string) *RequestBuilder {
 	return r
 }
 
+// NoDrain disables output draining in response closer
+func (r *RequestBuilder) NoDrain() *RequestBuilder {
+	r.drainOut = false
+	return r
+}
+
 // Send sends the request and return the response.
 func (r *RequestBuilder) Send(ctx context.Context) (*Response, error) {
 	r.shell.applyGlobal(r)

client/httpapi/response.go

@@ -35,13 +35,18 @@ func (r *trailerReader) Close() error {
 type Response struct {
 	Output io.ReadCloser
 	Error  *Error
+
+	drainOutput bool
 }
 
 func (r *Response) Close() error {
 	if r.Output != nil {
 
-		// always drain output (response body) //TODO: make optional for things like cat
-		_, err1 := io.Copy(ioutil.Discard, r.Output)
+		// always drain output (response body)
+		var err1 error
+		if r.drainOutput {
+			_, err1 = io.Copy(ioutil.Discard, r.Output)
+		}
 		err2 := r.Output.Close()
 		if err1 != nil {
 			return err1
@@ -114,6 +119,7 @@ func (r *Request) Send(c *http.Client) (*Response, error) {
 
 	nresp := new(Response)
 
+	nresp.drainOutput = r.DrainOut
 	nresp.Output = &trailerReader{resp}
 	if resp.StatusCode >= http.StatusBadRequest {
 		e := &Error{