github.com/goplusjs/gopherjs@v1.2.6-0.20211206034512-f187917453b8/compiler/natives/src/net/http/http.go (about)

     1  // +build js
     2  
     3  package http
     4  
     5  import (
     6  	"bufio"
     7  	"bytes"
     8  	"errors"
     9  	"io/ioutil"
    10  	"net/textproto"
    11  	"strconv"
    12  
    13  	"github.com/gopherjs/gopherjs/js"
    14  )
    15  
    16  var DefaultTransport = func() RoundTripper {
    17  	switch {
    18  	case js.Global.Get("fetch") != js.Undefined && js.Global.Get("ReadableStream") != js.Undefined: // ReadableStream is used as a check for support of streaming response bodies, see https://fetch.spec.whatwg.org/#streams.
    19  		return &fetchTransport{}
    20  	case js.Global.Get("XMLHttpRequest") != js.Undefined:
    21  		return &XHRTransport{}
    22  	default:
    23  		return noTransport{}
    24  	}
    25  }()
    26  
    27  // noTransport is used when neither Fetch API nor XMLHttpRequest API are available. It always fails.
    28  type noTransport struct{}
    29  
    30  func (noTransport) RoundTrip(req *Request) (*Response, error) {
    31  	return nil, errors.New("net/http: neither of Fetch nor XMLHttpRequest APIs is available")
    32  }
    33  
    34  type XHRTransport struct {
    35  	inflight map[*Request]*js.Object
    36  }
    37  
    38  func (t *XHRTransport) RoundTrip(req *Request) (*Response, error) {
    39  	xhr := js.Global.Get("XMLHttpRequest").New()
    40  
    41  	if t.inflight == nil {
    42  		t.inflight = map[*Request]*js.Object{}
    43  	}
    44  	t.inflight[req] = xhr
    45  	defer delete(t.inflight, req)
    46  
    47  	respCh := make(chan *Response)
    48  	errCh := make(chan error)
    49  
    50  	xhr.Set("onload", func() {
    51  		header, _ := textproto.NewReader(bufio.NewReader(bytes.NewReader([]byte(xhr.Call("getAllResponseHeaders").String() + "\n")))).ReadMIMEHeader()
    52  		body := js.Global.Get("Uint8Array").New(xhr.Get("response")).Interface().([]byte)
    53  
    54  		contentLength := int64(-1)
    55  		switch req.Method {
    56  		case "HEAD":
    57  			if l, err := strconv.ParseInt(header.Get("Content-Length"), 10, 64); err == nil {
    58  				contentLength = l
    59  			}
    60  		default:
    61  			contentLength = int64(len(body))
    62  		}
    63  
    64  		respCh <- &Response{
    65  			Status:        xhr.Get("status").String() + " " + xhr.Get("statusText").String(),
    66  			StatusCode:    xhr.Get("status").Int(),
    67  			Header:        Header(header),
    68  			ContentLength: contentLength,
    69  			Body:          ioutil.NopCloser(bytes.NewReader(body)),
    70  			Request:       req,
    71  		}
    72  	})
    73  
    74  	xhr.Set("onerror", func(e *js.Object) {
    75  		errCh <- errors.New("net/http: XMLHttpRequest failed")
    76  	})
    77  
    78  	xhr.Set("onabort", func(e *js.Object) {
    79  		errCh <- errors.New("net/http: request canceled")
    80  	})
    81  
    82  	xhr.Call("open", req.Method, req.URL.String())
    83  	xhr.Set("responseType", "arraybuffer") // has to be after "open" until https://bugzilla.mozilla.org/show_bug.cgi?id=1110761 is resolved
    84  	for key, values := range req.Header {
    85  		for _, value := range values {
    86  			xhr.Call("setRequestHeader", key, value)
    87  		}
    88  	}
    89  	if req.Body == nil {
    90  		xhr.Call("send")
    91  	} else {
    92  		body, err := ioutil.ReadAll(req.Body)
    93  		if err != nil {
    94  			req.Body.Close() // RoundTrip must always close the body, including on errors.
    95  			return nil, err
    96  		}
    97  		req.Body.Close()
    98  		xhr.Call("send", body)
    99  	}
   100  
   101  	select {
   102  	case resp := <-respCh:
   103  		return resp, nil
   104  	case err := <-errCh:
   105  		return nil, err
   106  	}
   107  }
   108  
   109  func (t *XHRTransport) CancelRequest(req *Request) {
   110  	if xhr, ok := t.inflight[req]; ok {
   111  		xhr.Call("abort")
   112  	}
   113  }