func getQuery(req cmds.Request) (string, error) {
query := url.Values{}
for k, v := range req.Options() {
str := fmt.Sprintf("%v", v)
query.Set(k, str)
}
args := req.Arguments()
argDefs := req.Command().Arguments
argDefIndex := 0
for _, arg := range args {
argDef := argDefs[argDefIndex]
// skip ArgFiles
for argDef.Type == cmds.ArgFile {
argDefIndex++
argDef = argDefs[argDefIndex]
}
query.Add("arg", arg)
if len(argDefs) > argDefIndex+1 {
argDefIndex++
}
}
return query.Encode(), nil
}
// read json objects off of the given stream, and write the objects out to
// the 'out' channel
func readStreamedJson(req cmds.Request, rr io.Reader, out chan<- interface{}) {
defer close(out)
dec := json.NewDecoder(rr)
outputType := reflect.TypeOf(req.Command().Type)
ctx := req.Context()
for {
v, err := decodeTypedVal(outputType, dec)
if err != nil {
if err != io.EOF {
// log.Error(err)
}
return
}
select {
case <-ctx.Done():
return
case out <- v:
}
}
}
func (c *client) Send(req cmds.Request) (cmds.Response, error) {
if req.Context() == nil {
// log.Warningf("no context set in request")
if err := req.SetRootContext(context.TODO()); err != nil {
return nil, err
}
}
// save user-provided encoding
previousUserProvidedEncoding, found, err := req.Option(cmds.EncShort).String()
if err != nil {
return nil, err
}
// 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
}
var fileReader *MultiFileReader
var reader io.Reader
if req.Files() != nil {
fileReader = NewMultiFileReader(req.Files(), true)
reader = fileReader
} else {
// if we have no file data, use an empty Reader
// (http.NewRequest panics when a nil Reader is used)
reader = strings.NewReader("")
}
path := strings.Join(req.Path(), "/")
url := fmt.Sprintf(ApiUrlFormat, c.serverAddress, ApiPath, path, query)
httpReq, err := http.NewRequest("POST", url, reader)
if err != nil {
return nil, err
}
// TODO extract string consts?
if fileReader != nil {
httpReq.Header.Set(contentTypeHeader, "multipart/form-data; boundary="+fileReader.Boundary())
httpReq.Header.Set(contentDispHeader, "form-data: name=\"files\"")
} else {
httpReq.Header.Set(contentTypeHeader, applicationOctetStream)
}
ec := make(chan error, 1)
rc := make(chan cmds.Response, 1)
dc := req.Context().Done()
go func() {
httpRes, err := c.httpClient.Do(httpReq)
if err != nil {
ec <- err
return
}
// using the overridden JSON encoding in request
res, err := getResponse(httpRes, req)
if err != nil {
ec <- err
return
}
rc <- res
}()
for {
select {
case <-dc:
// log.Debug("Context cancelled, cancelling HTTP request...")
tr := http.DefaultTransport.(*http.Transport)
tr.CancelRequest(httpReq)
dc = nil // Wait for ec or rc
case err := <-ec:
return nil, err
case res := <-rc:
if found && len(previousUserProvidedEncoding) > 0 {
// reset to user provided encoding after sending request
// NB: if user has provided an encoding but it is the empty string,
// still leave it as JSON.
req.SetOption(cmds.EncShort, previousUserProvidedEncoding)
}
return res, nil
}
}
}
// getResponse decodes a http.Response to create a cmds.Response
func getResponse(httpRes *http.Response, req cmds.Request) (cmds.Response, error) {
var err error
res := cmds.NewResponse(req)
contentType := httpRes.Header.Get(contentTypeHeader)
contentType = strings.Split(contentType, ";")[0]
lengthHeader := httpRes.Header.Get(contentLengthHeader)
if len(lengthHeader) > 0 {
length, err := strconv.ParseUint(lengthHeader, 10, 64)
if err != nil {
return nil, err
}
res.SetLength(length)
}
rr := &httpResponseReader{httpRes}
res.SetCloser(rr)
if contentType != applicationJson {
// for all non json output types, just stream back the output
res.SetOutput(rr)
return res, nil
} else if len(httpRes.Header.Get(channelHeader)) > 0 {
// if output is coming from a channel, decode each chunk
outChan := make(chan interface{})
go readStreamedJson(req, rr, outChan)
res.SetOutput((<-chan interface{})(outChan))
return res, nil
}
dec := json.NewDecoder(rr)
// If we ran into an error
if httpRes.StatusCode >= http.StatusBadRequest {
e := cmds.Error{}
switch {
case httpRes.StatusCode == http.StatusNotFound:
// handle 404s
e.Message = "Command not found."
e.Code = cmds.ErrClient
case contentType == plainText:
// handle non-marshalled errors
mes, err := ioutil.ReadAll(rr)
if err != nil {
return nil, err
}
e.Message = string(mes)
e.Code = cmds.ErrNormal
default:
// handle marshalled errors
err = dec.Decode(&e)
if err != nil {
return nil, err
}
}
res.SetError(e, e.Code)
return res, nil
}
outputType := reflect.TypeOf(req.Command().Type)
v, err := decodeTypedVal(outputType, dec)
if err != nil && err != io.EOF {
return nil, err
}
res.SetOutput(v)
return res, nil
}
func sendResponse(w http.ResponseWriter, r *http.Request, res cmds.Response, req cmds.Request) {
mime, err := guessMimeType(res)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
status := http.StatusOK
// if response contains an error, write an HTTP error status code
if e := res.Error(); e != nil {
if e.Code == cmds.ErrClient {
status = http.StatusBadRequest
} else {
status = http.StatusInternalServerError
}
// NOTE: The error will actually be written out by the reader below
}
out, err := res.Reader()
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
h := w.Header()
if res.Length() > 0 {
h.Set(contentLengthHeader, strconv.FormatUint(res.Length(), 10))
}
if _, ok := res.Output().(io.Reader); ok {
// we don't set the Content-Type for streams, so that browsers can MIME-sniff the type themselves
// we set this header so clients have a way to know this is an output stream
// (not marshalled command output)
mime = ""
h.Set(streamHeader, "1")
}
// if output is a channel and user requested streaming channels,
// use chunk copier for the output
_, isChan := res.Output().(chan interface{})
if !isChan {
_, isChan = res.Output().(<-chan interface{})
}
streamChans, _, _ := req.Option("stream-channels").Bool()
if isChan {
h.Set(channelHeader, "1")
if streamChans {
// streaming output from a channel will always be json objects
mime = applicationJson
}
}
if mime != "" {
h.Set(contentTypeHeader, mime)
}
h.Set(transferEncodingHeader, "chunked")
if r.Method == "HEAD" { // after all the headers.
return
}
if err := writeResponse(status, w, out); err != nil {
if strings.Contains(err.Error(), "broken pipe") {
// log.Info("client disconnect while writing stream ", err)
return
}
// log.Error("error while writing stream ", err)
}
}