mirror of
https://github.com/taigrr/wasm-experiments
synced 2025-01-18 04:03:21 -08:00
Move Fetch Transport to separate repo
This commit is contained in:
Johan Brandhorst
parent
bf681695c7
commit
8725450750
@ -1,250 +0,0 @@
|
||||
// +build js,wasm
|
||||
|
||||
package fetch
|
||||
|
||||
//go:generate bash -c "GOROOT=$GOPATH/src/github.com/neelance/go/ GOOS=js GOARCH=wasm stringer -type Method"
|
||||
|
||||
import (
|
||||
"errors"
|
||||
"fmt"
|
||||
"io"
|
||||
"io/ioutil"
|
||||
"net/http"
|
||||
"strconv"
|
||||
"syscall/js"
|
||||
"syscall/js/callback"
|
||||
)
|
||||
|
||||
type Method int
|
||||
|
||||
// https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods
|
||||
const (
|
||||
GET Method = iota
|
||||
HEAD
|
||||
POST
|
||||
PUT
|
||||
DELETE
|
||||
CONNECT
|
||||
OPTIONS
|
||||
TRACE
|
||||
PATCH
|
||||
)
|
||||
|
||||
/*
|
||||
|
||||
type Request struct {
|
||||
Method Method
|
||||
URL *url.URL
|
||||
Headers http.Header
|
||||
Body io.Reader
|
||||
}
|
||||
|
||||
type Response struct {
|
||||
URL *url.URL
|
||||
Headers http.Header
|
||||
Body io.ReadCloser
|
||||
StatusCode int
|
||||
Ok bool
|
||||
}
|
||||
|
||||
func Fetch(ctx context.Context, req *Request) (*Response, error) {
|
||||
init := js.Global.Get("Object").New()
|
||||
init.Set("method", req.Method.String())
|
||||
if req.Body != nil {
|
||||
switch req.Method {
|
||||
case GET, HEAD:
|
||||
return nil, errors.New("cannot use body with GET or HEAD HTTP methods")
|
||||
}
|
||||
b, err := ioutil.ReadAll(req.Body)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
init.Set("body", b)
|
||||
}
|
||||
|
||||
headers := js.Global.Get("Headers").New()
|
||||
for header, values := range req.Headers {
|
||||
for _, value := range values {
|
||||
headers.Call("append", header, value)
|
||||
}
|
||||
}
|
||||
init.Set("headers", headers)
|
||||
|
||||
ac := js.Global.Get("AbortController").New()
|
||||
init.Set("signal", ac.Get("signal"))
|
||||
|
||||
promise := js.Global.Call("fetch", req.URL.String(), init)
|
||||
|
||||
wait := make(chan Response)
|
||||
errChan := make(chan error)
|
||||
cb := callback.New(func(args []js.Value) {
|
||||
jsResp := args[0]
|
||||
resp := Response{
|
||||
Headers: http.Header{},
|
||||
}
|
||||
u, err := url.Parse(jsResp.Get("url").String())
|
||||
if err != nil {
|
||||
errChan <- err
|
||||
}
|
||||
jsResp.Get("headers").Call("forEach", callback.New(func(args []js.Value) {
|
||||
key, val := args[0].String(), args[1].String()
|
||||
resp.Headers[key] = append(resp.Headers[key], val)
|
||||
}).Value)
|
||||
|
||||
|
||||
wait <- Response{
|
||||
Ok: jsResp.Get("ok").Bool(),
|
||||
URL: u,
|
||||
}
|
||||
})
|
||||
|
||||
promise.Call("then", cb.Value)
|
||||
|
||||
select {
|
||||
case <-ctx.Done():
|
||||
// Abort the Fetch request
|
||||
ac.Call("abort")
|
||||
return nil, ctx.Err()
|
||||
case resp := <-wait:
|
||||
return &resp, nil
|
||||
case err := <-errChan:
|
||||
return nil, err
|
||||
}
|
||||
}
|
||||
*/
|
||||
|
||||
// Adapted for syscall/js from
|
||||
// https://github.com/gopherjs/gopherjs/blob/8dffc02ea1cb8398bb73f30424697c60fcf8d4c5/compiler/natives/src/net/http/fetch.go
|
||||
|
||||
// streamReader implements an io.ReadCloser wrapper for ReadableStream of https://fetch.spec.whatwg.org/.
|
||||
type streamReader struct {
|
||||
pending []byte
|
||||
stream js.Value
|
||||
}
|
||||
|
||||
func (r *streamReader) Read(p []byte) (n int, err error) {
|
||||
if len(r.pending) == 0 {
|
||||
var (
|
||||
bCh = make(chan []byte)
|
||||
errCh = make(chan error)
|
||||
)
|
||||
r.stream.Call("read").Call("then",
|
||||
func(result js.Value) {
|
||||
if result.Get("done").Bool() {
|
||||
errCh <- io.EOF
|
||||
return
|
||||
}
|
||||
var value []byte
|
||||
// TODO: Any way to avoid this copying?
|
||||
result.Get("value").Call("forEach", callback.New(func(args []js.Value) {
|
||||
value = append(value, args[0].String()[0])
|
||||
}).Value)
|
||||
bCh <- value
|
||||
},
|
||||
func(reason js.Value) {
|
||||
// Assumes it's a DOMException.
|
||||
errCh <- errors.New(reason.Get("message").String())
|
||||
},
|
||||
)
|
||||
select {
|
||||
case b := <-bCh:
|
||||
r.pending = b
|
||||
case err := <-errCh:
|
||||
return 0, err
|
||||
}
|
||||
}
|
||||
n = copy(p, r.pending)
|
||||
r.pending = r.pending[n:]
|
||||
return n, nil
|
||||
}
|
||||
|
||||
func (r *streamReader) Close() error {
|
||||
// This ignores any error returned from cancel method. So far, I did not encounter any concrete
|
||||
// situation where reporting the error is meaningful. Most users ignore error from resp.Body.Close().
|
||||
// If there's a need to report error here, it can be implemented and tested when that need comes up.
|
||||
r.stream.Call("cancel")
|
||||
return nil
|
||||
}
|
||||
|
||||
// Transport is a RoundTripper that is implemented using Fetch API. It supports streaming
|
||||
// response bodies.
|
||||
type Transport struct{}
|
||||
|
||||
func (t *Transport) RoundTrip(req *http.Request) (*http.Response, error) {
|
||||
headers := js.Global.Get("Headers").New()
|
||||
for key, values := range req.Header {
|
||||
for _, value := range values {
|
||||
headers.Call("append", key, value)
|
||||
}
|
||||
}
|
||||
|
||||
ac := js.Global.Get("AbortController").New()
|
||||
|
||||
opt := js.Global.Get("Object").New()
|
||||
opt.Set("headers", headers)
|
||||
opt.Set("method", req.Method)
|
||||
opt.Set("credentials", "same-origin")
|
||||
opt.Set("signal", ac.Get("signal"))
|
||||
|
||||
if req.Body != nil {
|
||||
// TODO: Find out if request body can be streamed into the fetch request rather than in advance here.
|
||||
// See BufferSource at https://fetch.spec.whatwg.org/#body-mixin.
|
||||
body, err := ioutil.ReadAll(req.Body)
|
||||
if err != nil {
|
||||
_ = req.Body.Close() // RoundTrip must always close the body, including on errors.
|
||||
return nil, err
|
||||
}
|
||||
_ = req.Body.Close()
|
||||
opt.Set("body", body)
|
||||
}
|
||||
respPromise := js.Global.Call("fetch", req.URL.String(), opt)
|
||||
|
||||
var (
|
||||
respCh = make(chan *http.Response)
|
||||
errCh = make(chan error)
|
||||
)
|
||||
respPromise.Call("then",
|
||||
callback.New(func(args []js.Value) {
|
||||
result := args[0]
|
||||
header := http.Header{}
|
||||
result.Get("headers").Call("forEach", callback.New(func(args []js.Value) {
|
||||
key, value := args[0].String(), args[1].String()
|
||||
ck := http.CanonicalHeaderKey(key)
|
||||
header[ck] = append(header[ck], value)
|
||||
}).Value)
|
||||
|
||||
contentLength := int64(-1)
|
||||
if cl, err := strconv.ParseInt(header.Get("Content-Length"), 10, 64); err == nil {
|
||||
contentLength = cl
|
||||
}
|
||||
|
||||
select {
|
||||
case respCh <- &http.Response{
|
||||
Status: result.Get("status").String() + " " + http.StatusText(result.Get("status").Int()),
|
||||
StatusCode: result.Get("status").Int(),
|
||||
Header: header,
|
||||
ContentLength: contentLength,
|
||||
Body: &streamReader{stream: result.Get("body").Call("getReader")},
|
||||
Request: req,
|
||||
}:
|
||||
case <-req.Context().Done():
|
||||
}
|
||||
}).Value,
|
||||
callback.New(func(args []js.Value) {
|
||||
select {
|
||||
case errCh <- fmt.Errorf("net/http: fetch() failed: %s", args[0].String()):
|
||||
case <-req.Context().Done():
|
||||
}
|
||||
}).Value,
|
||||
)
|
||||
select {
|
||||
case <-req.Context().Done():
|
||||
// Abort the Fetch request
|
||||
ac.Call("abort")
|
||||
return nil, errors.New("net/http: request canceled")
|
||||
case resp := <-respCh:
|
||||
return resp, nil
|
||||
case err := <-errCh:
|
||||
return nil, err
|
||||
}
|
||||
}
|
||||
@ -1,16 +0,0 @@
|
||||
// Code generated by "stringer -type Method"; DO NOT EDIT.
|
||||
|
||||
package fetch
|
||||
|
||||
import "strconv"
|
||||
|
||||
const _Method_name = "GETHEADPOSTPUTDELETECONNECTOPTIONSTRACEPATCH"
|
||||
|
||||
var _Method_index = [...]uint8{0, 3, 7, 11, 14, 20, 27, 34, 39, 44}
|
||||
|
||||
func (i Method) String() string {
|
||||
if i < 0 || i >= Method(len(_Method_index)-1) {
|
||||
return "Method(" + strconv.FormatInt(int64(i), 10) + ")"
|
||||
}
|
||||
return _Method_name[_Method_index[i]:_Method_index[i+1]]
|
||||
}
|
||||
@ -4,14 +4,26 @@ package main
|
||||
|
||||
import (
|
||||
"fmt"
|
||||
"io/ioutil"
|
||||
"net/http"
|
||||
|
||||
"github.com/johanbrandhorst/wasm-experiments/fetch/fetch"
|
||||
"github.com/johanbrandhorst/fetch"
|
||||
)
|
||||
|
||||
func main() {
|
||||
c := http.Client{
|
||||
Transport: &fetch.Transport{},
|
||||
}
|
||||
fmt.Println(c.Get("https://api.github.com"))
|
||||
resp, err := c.Get("https://api.github.com")
|
||||
if err != nil {
|
||||
fmt.Println(err)
|
||||
return
|
||||
}
|
||||
defer resp.Body.Close()
|
||||
b, err := ioutil.ReadAll(resp.Body)
|
||||
if err != nil {
|
||||
fmt.Println(err)
|
||||
return
|
||||
}
|
||||
fmt.Println(string(b))
|
||||
}
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user