|
| 1 | +// Copyright 2018 The Go Authors. All rights reserved. |
| 2 | +// Use of this source code is governed by a BSD-style |
| 3 | +// license that can be found in the LICENSE file. |
| 4 | + |
| 5 | +// Code in this file is edited from go source code at net/http/roundtrip_js.go |
| 6 | + |
| 7 | +//go:build wasm |
| 8 | + |
| 9 | +package wasm |
| 10 | + |
| 11 | +import ( |
| 12 | + "errors" |
| 13 | + "fmt" |
| 14 | + "io" |
| 15 | + "net/http" |
| 16 | + "strconv" |
| 17 | + "syscall/js" |
| 18 | + |
| 19 | + _ "unsafe" |
| 20 | +) |
| 21 | + |
| 22 | +var uint8Array = js.Global().Get("Uint8Array") |
| 23 | + |
| 24 | +// jsFetchMode is a Request.Header map key that, if present, |
| 25 | +// signals that the map entry is actually an option to the Fetch API mode setting. |
| 26 | +// Valid values are: "cors", "no-cors", "same-origin", "navigate" |
| 27 | +// The default is "same-origin". |
| 28 | +// |
| 29 | +// Reference: https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/fetch#Parameters |
| 30 | +const jsFetchMode = "js.fetch:mode" |
| 31 | + |
| 32 | +// jsFetchCreds is a Request.Header map key that, if present, |
| 33 | +// signals that the map entry is actually an option to the Fetch API credentials setting. |
| 34 | +// Valid values are: "omit", "same-origin", "include" |
| 35 | +// The default is "same-origin". |
| 36 | +// |
| 37 | +// Reference: https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/fetch#Parameters |
| 38 | +const jsFetchCreds = "js.fetch:credentials" |
| 39 | + |
| 40 | +// jsFetchRedirect is a Request.Header map key that, if present, |
| 41 | +// signals that the map entry is actually an option to the Fetch API redirect setting. |
| 42 | +// Valid values are: "follow", "error", "manual" |
| 43 | +// The default is "follow". |
| 44 | +// |
| 45 | +// Reference: https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/fetch#Parameters |
| 46 | +const jsFetchRedirect = "js.fetch:redirect" |
| 47 | + |
| 48 | +var errClosed = errors.New("internal/wasm: reader is closed") |
| 49 | + |
| 50 | +// streamReader implements an io.ReadCloser wrapper for ReadableStream. |
| 51 | +// See https://fetch.spec.whatwg.org/#readablestream for more information. |
| 52 | +type streamReader struct { |
| 53 | + pending []byte |
| 54 | + stream js.Value |
| 55 | + err error // sticky read error |
| 56 | +} |
| 57 | + |
| 58 | +func (r *streamReader) Read(p []byte) (n int, err error) { |
| 59 | + if r.err != nil { |
| 60 | + return 0, r.err |
| 61 | + } |
| 62 | + if len(r.pending) == 0 { |
| 63 | + var ( |
| 64 | + bCh = make(chan []byte, 1) |
| 65 | + errCh = make(chan error, 1) |
| 66 | + ) |
| 67 | + success := js.FuncOf(func(this js.Value, args []js.Value) any { |
| 68 | + result := args[0] |
| 69 | + if result.Get("done").Bool() { |
| 70 | + errCh <- io.EOF |
| 71 | + return nil |
| 72 | + } |
| 73 | + value := make([]byte, result.Get("value").Get("byteLength").Int()) |
| 74 | + js.CopyBytesToGo(value, result.Get("value")) |
| 75 | + bCh <- value |
| 76 | + return nil |
| 77 | + }) |
| 78 | + defer success.Release() |
| 79 | + failure := js.FuncOf(func(this js.Value, args []js.Value) any { |
| 80 | + // Assumes it's a TypeError. See |
| 81 | + // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypeError |
| 82 | + // for more information on this type. See |
| 83 | + // https://streams.spec.whatwg.org/#byob-reader-read for the spec on |
| 84 | + // the read method. |
| 85 | + errCh <- errors.New(args[0].Get("message").String()) |
| 86 | + return nil |
| 87 | + }) |
| 88 | + defer failure.Release() |
| 89 | + r.stream.Call("read").Call("then", success, failure) |
| 90 | + select { |
| 91 | + case b := <-bCh: |
| 92 | + r.pending = b |
| 93 | + case err := <-errCh: |
| 94 | + r.err = err |
| 95 | + return 0, err |
| 96 | + } |
| 97 | + } |
| 98 | + n = copy(p, r.pending) |
| 99 | + r.pending = r.pending[n:] |
| 100 | + return n, nil |
| 101 | +} |
| 102 | + |
| 103 | +func (r *streamReader) Close() error { |
| 104 | + // This ignores any error returned from cancel method. So far, I did not encounter any concrete |
| 105 | + // situation where reporting the error is meaningful. Most users ignore error from resp.Body.Close(). |
| 106 | + // If there's a need to report error here, it can be implemented and tested when that need comes up. |
| 107 | + r.stream.Call("cancel") |
| 108 | + if r.err == nil { |
| 109 | + r.err = errClosed |
| 110 | + } |
| 111 | + return nil |
| 112 | +} |
| 113 | + |
| 114 | +// arrayReader implements an io.ReadCloser wrapper for ArrayBuffer. |
| 115 | +// https://developer.mozilla.org/en-US/docs/Web/API/Body/arrayBuffer. |
| 116 | +type arrayReader struct { |
| 117 | + arrayPromise js.Value |
| 118 | + pending []byte |
| 119 | + read bool |
| 120 | + err error // sticky read error |
| 121 | +} |
| 122 | + |
| 123 | +func (r *arrayReader) Read(p []byte) (n int, err error) { |
| 124 | + if r.err != nil { |
| 125 | + return 0, r.err |
| 126 | + } |
| 127 | + if !r.read { |
| 128 | + r.read = true |
| 129 | + var ( |
| 130 | + bCh = make(chan []byte, 1) |
| 131 | + errCh = make(chan error, 1) |
| 132 | + ) |
| 133 | + success := js.FuncOf(func(this js.Value, args []js.Value) any { |
| 134 | + // Wrap the input ArrayBuffer with a Uint8Array |
| 135 | + uint8arrayWrapper := uint8Array.New(args[0]) |
| 136 | + value := make([]byte, uint8arrayWrapper.Get("byteLength").Int()) |
| 137 | + js.CopyBytesToGo(value, uint8arrayWrapper) |
| 138 | + bCh <- value |
| 139 | + return nil |
| 140 | + }) |
| 141 | + defer success.Release() |
| 142 | + failure := js.FuncOf(func(this js.Value, args []js.Value) any { |
| 143 | + // Assumes it's a TypeError. See |
| 144 | + // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypeError |
| 145 | + // for more information on this type. |
| 146 | + // See https://fetch.spec.whatwg.org/#concept-body-consume-body for reasons this might error. |
| 147 | + errCh <- errors.New(args[0].Get("message").String()) |
| 148 | + return nil |
| 149 | + }) |
| 150 | + defer failure.Release() |
| 151 | + r.arrayPromise.Call("then", success, failure) |
| 152 | + select { |
| 153 | + case b := <-bCh: |
| 154 | + r.pending = b |
| 155 | + case err := <-errCh: |
| 156 | + return 0, err |
| 157 | + } |
| 158 | + } |
| 159 | + if len(r.pending) == 0 { |
| 160 | + return 0, io.EOF |
| 161 | + } |
| 162 | + n = copy(p, r.pending) |
| 163 | + r.pending = r.pending[n:] |
| 164 | + return n, nil |
| 165 | +} |
| 166 | + |
| 167 | +func (r *arrayReader) Close() error { |
| 168 | + if r.err == nil { |
| 169 | + r.err = errClosed |
| 170 | + } |
| 171 | + return nil |
| 172 | +} |
| 173 | + |
| 174 | +type Transport struct { |
| 175 | +} |
| 176 | + |
| 177 | +// RoundTrip implements the RoundTripper interface using the WHATWG Fetch API. |
| 178 | +func (t *Transport) RoundTrip(req *http.Request) (*http.Response, error) { |
| 179 | + |
| 180 | + ac := js.Global().Get("AbortController") |
| 181 | + if !ac.IsUndefined() { |
| 182 | + // Some browsers that support WASM don't necessarily support |
| 183 | + // the AbortController. See |
| 184 | + // https://developer.mozilla.org/en-US/docs/Web/API/AbortController#Browser_compatibility. |
| 185 | + ac = ac.New() |
| 186 | + } |
| 187 | + |
| 188 | + opt := js.Global().Get("Object").New() |
| 189 | + // See https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/fetch |
| 190 | + // for options available. |
| 191 | + opt.Set("method", req.Method) |
| 192 | + opt.Set("credentials", "same-origin") |
| 193 | + if h := req.Header.Get(jsFetchCreds); h != "" { |
| 194 | + opt.Set("credentials", h) |
| 195 | + req.Header.Del(jsFetchCreds) |
| 196 | + } |
| 197 | + if h := req.Header.Get(jsFetchMode); h != "" { |
| 198 | + opt.Set("mode", h) |
| 199 | + req.Header.Del(jsFetchMode) |
| 200 | + } |
| 201 | + if h := req.Header.Get(jsFetchRedirect); h != "" { |
| 202 | + opt.Set("redirect", h) |
| 203 | + req.Header.Del(jsFetchRedirect) |
| 204 | + } |
| 205 | + if !ac.IsUndefined() { |
| 206 | + opt.Set("signal", ac.Get("signal")) |
| 207 | + } |
| 208 | + headers := js.Global().Get("Headers").New() |
| 209 | + for key, values := range req.Header { |
| 210 | + for _, value := range values { |
| 211 | + headers.Call("append", key, value) |
| 212 | + } |
| 213 | + } |
| 214 | + opt.Set("headers", headers) |
| 215 | + |
| 216 | + if req.Body != nil { |
| 217 | + // TODO(johanbrandhorst): Stream request body when possible. |
| 218 | + // See https://bugs.chromium.org/p/chromium/issues/detail?id=688906 for Blink issue. |
| 219 | + // See https://bugzilla.mozilla.org/show_bug.cgi?id=1387483 for Firefox issue. |
| 220 | + // See https://github.com/web-platform-tests/wpt/issues/7693 for WHATWG tests issue. |
| 221 | + // See https://developer.mozilla.org/en-US/docs/Web/API/Streams_API for more details on the Streams API |
| 222 | + // and browser support. |
| 223 | + // NOTE(haruyama480): Ensure HTTP/1 fallback exists. |
| 224 | + // See https://go.dev/issue/61889 for discussion. |
| 225 | + body, err := io.ReadAll(req.Body) |
| 226 | + if err != nil { |
| 227 | + req.Body.Close() // RoundTrip must always close the body, including on errors. |
| 228 | + return nil, err |
| 229 | + } |
| 230 | + req.Body.Close() |
| 231 | + if len(body) != 0 { |
| 232 | + buf := uint8Array.New(len(body)) |
| 233 | + js.CopyBytesToJS(buf, body) |
| 234 | + opt.Set("body", buf) |
| 235 | + } |
| 236 | + } |
| 237 | + |
| 238 | + fetchPromise := js.Global().Call("fetch", req.URL.String(), opt) |
| 239 | + var ( |
| 240 | + respCh = make(chan *http.Response, 1) |
| 241 | + errCh = make(chan error, 1) |
| 242 | + success, failure js.Func |
| 243 | + ) |
| 244 | + success = js.FuncOf(func(this js.Value, args []js.Value) any { |
| 245 | + success.Release() |
| 246 | + failure.Release() |
| 247 | + |
| 248 | + result := args[0] |
| 249 | + header := http.Header{} |
| 250 | + // https://developer.mozilla.org/en-US/docs/Web/API/Headers/entries |
| 251 | + headersIt := result.Get("headers").Call("entries") |
| 252 | + for { |
| 253 | + n := headersIt.Call("next") |
| 254 | + if n.Get("done").Bool() { |
| 255 | + break |
| 256 | + } |
| 257 | + pair := n.Get("value") |
| 258 | + key, value := pair.Index(0).String(), pair.Index(1).String() |
| 259 | + ck := http.CanonicalHeaderKey(key) |
| 260 | + header[ck] = append(header[ck], value) |
| 261 | + } |
| 262 | + |
| 263 | + contentLength := int64(0) |
| 264 | + clHeader := header.Get("Content-Length") |
| 265 | + switch { |
| 266 | + case clHeader != "": |
| 267 | + cl, err := strconv.ParseInt(clHeader, 10, 64) |
| 268 | + if err != nil { |
| 269 | + errCh <- fmt.Errorf("net/http: ill-formed Content-Length header: %v", err) |
| 270 | + return nil |
| 271 | + } |
| 272 | + if cl < 0 { |
| 273 | + // Content-Length values less than 0 are invalid. |
| 274 | + // See: https://datatracker.ietf.org/doc/html/rfc2616/#section-14.13 |
| 275 | + errCh <- fmt.Errorf("net/http: invalid Content-Length header: %q", clHeader) |
| 276 | + return nil |
| 277 | + } |
| 278 | + contentLength = cl |
| 279 | + default: |
| 280 | + // If the response length is not declared, set it to -1. |
| 281 | + contentLength = -1 |
| 282 | + } |
| 283 | + |
| 284 | + b := result.Get("body") |
| 285 | + var body io.ReadCloser |
| 286 | + // The body is undefined when the browser does not support streaming response bodies (Firefox), |
| 287 | + // and null in certain error cases, i.e. when the request is blocked because of CORS settings. |
| 288 | + if !b.IsUndefined() && !b.IsNull() { |
| 289 | + body = &streamReader{stream: b.Call("getReader")} |
| 290 | + } else { |
| 291 | + // Fall back to using ArrayBuffer |
| 292 | + // https://developer.mozilla.org/en-US/docs/Web/API/Body/arrayBuffer |
| 293 | + body = &arrayReader{arrayPromise: result.Call("arrayBuffer")} |
| 294 | + } |
| 295 | + |
| 296 | + code := result.Get("status").Int() |
| 297 | + respCh <- &http.Response{ |
| 298 | + Status: fmt.Sprintf("%d %s", code, http.StatusText(code)), |
| 299 | + StatusCode: code, |
| 300 | + Header: header, |
| 301 | + ContentLength: contentLength, |
| 302 | + Body: body, |
| 303 | + Request: req, |
| 304 | + } |
| 305 | + |
| 306 | + return nil |
| 307 | + }) |
| 308 | + failure = js.FuncOf(func(this js.Value, args []js.Value) any { |
| 309 | + success.Release() |
| 310 | + failure.Release() |
| 311 | + |
| 312 | + err := args[0] |
| 313 | + // The error is a JS Error type |
| 314 | + // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error |
| 315 | + // We can use the toString() method to get a string representation of the error. |
| 316 | + errMsg := err.Call("toString").String() |
| 317 | + // Errors can optionally contain a cause. |
| 318 | + if cause := err.Get("cause"); !cause.IsUndefined() { |
| 319 | + // The exact type of the cause is not defined, |
| 320 | + // but if it's another error, we can call toString() on it too. |
| 321 | + if !cause.Get("toString").IsUndefined() { |
| 322 | + errMsg += ": " + cause.Call("toString").String() |
| 323 | + } else if cause.Type() == js.TypeString { |
| 324 | + errMsg += ": " + cause.String() |
| 325 | + } |
| 326 | + } |
| 327 | + errCh <- fmt.Errorf("net/http: fetch() failed: %s", errMsg) |
| 328 | + return nil |
| 329 | + }) |
| 330 | + |
| 331 | + fetchPromise.Call("then", success, failure) |
| 332 | + select { |
| 333 | + case <-req.Context().Done(): |
| 334 | + if !ac.IsUndefined() { |
| 335 | + // Abort the Fetch request. |
| 336 | + ac.Call("abort") |
| 337 | + } |
| 338 | + return nil, req.Context().Err() |
| 339 | + case resp := <-respCh: |
| 340 | + return resp, nil |
| 341 | + case err := <-errCh: |
| 342 | + return nil, err |
| 343 | + } |
| 344 | +} |
0 commit comments