Initial commit

.gitignore

@@ -0,0 +1 @@
+dist

LICENSE.md

@@ -0,0 +1,19 @@
+Copyright 2022-present [syumai](https://github.com/syumai/)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+

README.md

@@ -0,0 +1,47 @@
+# workers
+
+* `workers` is a package to run an HTTP server written in Go on [Cloudflare Workers](https://workers.cloudflare.com/).
+* This package can easily serve *http.Handler* on Cloudflare Workers.
+
+## Features
+
+* [x] serve http.Handler
+* [ ] environment variables (WIP)
+* [ ] KV (WIP)
+* [ ] R2 (WIP)
+
+## Installation
+
+```
+go get github.com/syumai/workers
+```
+
+## Usage
+
+implement your http.Handler and give it to `workers.Serve()`.
+
+```go
+func main() {
+	var handler http.HandlerFunc = func (w http.ResponseWriter, req *http.Request) { ... }
+    workers.Serve(handler)
+}
+```
+
+or just call `http.Handle` and `http.HandleFunc`, then invoke `workers.Serve()` with nil.
+
+```go
+func main() {
+	http.HandleFunc("/hello", func (w http.ResponseWriter, req *http.Request) { ... })
+	workers.Serve(nil) // if nil is given, http.DefaultMux is used.
+}
+```
+
+for concrete examples, see `examples` directory.
+
+## License
+
+MIT
+
+## Author
+
+syumai

examples/assets/polyfill_performance.js

@@ -0,0 +1,36 @@
+// @license http://opensource.org/licenses/MIT
+// copyright Paul Irish 2015
+
+
+// Date.now() is supported everywhere except IE8. For IE8 we use the Date.now polyfill
+//   github.com/Financial-Times/polyfill-service/blob/master/polyfills/Date.now/polyfill.js
+// as Safari 6 doesn't have support for NavigationTiming, we use a Date.now() timestamp for relative values
+
+// if you want values similar to what you'd get with real perf.now, place this towards the head of the page
+// but in reality, you're just getting the delta between now() calls, so it's not terribly important where it's placed
+
+
+(function(){
+
+  if ("performance" in globalThis == false) {
+      globalThis.performance = {};
+  }
+  
+  Date.now = (Date.now || function () {  // thanks IE8
+	  return new Date().getTime();
+  });
+
+  if ("now" in globalThis.performance == false){
+    
+    var nowOffset = Date.now();
+    
+    if (performance.timing && performance.timing.navigationStart){
+      nowOffset = performance.timing.navigationStart
+    }
+
+    globalThis.performance.now = function now(){
+      return Date.now() - nowOffset;
+    }
+  }
+
+})();

examples/assets/wasm_exec.js

@@ -0,0 +1,543 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+//
+// This file has been modified for use by the TinyGo compiler.
+
+(() => {
+	// Map multiple JavaScript environments to a single common API,
+	// preferring web standards over Node.js API.
+	//
+	// Environments considered:
+	// - Browsers
+	// - Node.js
+	// - Electron
+	// - Parcel
+
+	if (typeof global !== "undefined") {
+		// global already exists
+	} else if (typeof window !== "undefined") {
+		window.global = window;
+	} else if (typeof self !== "undefined") {
+		self.global = self;
+	} else {
+		throw new Error("cannot export Go (neither global, window nor self is defined)");
+	}
+
+	/*
+	if (!global.require && typeof require !== "undefined") {
+		global.require = require;
+	}
+	*/
+
+		/*
+	if (!global.fs && global.require) {
+		global.fs = require("fs");
+	}
+	*/
+
+	const enosys = () => {
+		const err = new Error("not implemented");
+		err.code = "ENOSYS";
+		return err;
+	};
+
+	if (!global.fs) {
+		let outputBuf = "";
+		global.fs = {
+			constants: { O_WRONLY: -1, O_RDWR: -1, O_CREAT: -1, O_TRUNC: -1, O_APPEND: -1, O_EXCL: -1 }, // unused
+			writeSync(fd, buf) {
+				outputBuf += decoder.decode(buf);
+				const nl = outputBuf.lastIndexOf("\n");
+				if (nl != -1) {
+					console.log(outputBuf.substr(0, nl));
+					outputBuf = outputBuf.substr(nl + 1);
+				}
+				return buf.length;
+			},
+			write(fd, buf, offset, length, position, callback) {
+				if (offset !== 0 || length !== buf.length || position !== null) {
+					callback(enosys());
+					return;
+				}
+				const n = this.writeSync(fd, buf);
+				callback(null, n);
+			},
+			chmod(path, mode, callback) { callback(enosys()); },
+			chown(path, uid, gid, callback) { callback(enosys()); },
+			close(fd, callback) { callback(enosys()); },
+			fchmod(fd, mode, callback) { callback(enosys()); },
+			fchown(fd, uid, gid, callback) { callback(enosys()); },
+			fstat(fd, callback) { callback(enosys()); },
+			fsync(fd, callback) { callback(null); },
+			ftruncate(fd, length, callback) { callback(enosys()); },
+			lchown(path, uid, gid, callback) { callback(enosys()); },
+			link(path, link, callback) { callback(enosys()); },
+			lstat(path, callback) { callback(enosys()); },
+			mkdir(path, perm, callback) { callback(enosys()); },
+			open(path, flags, mode, callback) { callback(enosys()); },
+			read(fd, buffer, offset, length, position, callback) { callback(enosys()); },
+			readdir(path, callback) { callback(enosys()); },
+			readlink(path, callback) { callback(enosys()); },
+			rename(from, to, callback) { callback(enosys()); },
+			rmdir(path, callback) { callback(enosys()); },
+			stat(path, callback) { callback(enosys()); },
+			symlink(path, link, callback) { callback(enosys()); },
+			truncate(path, length, callback) { callback(enosys()); },
+			unlink(path, callback) { callback(enosys()); },
+			utimes(path, atime, mtime, callback) { callback(enosys()); },
+		};
+	}
+
+	if (!global.process) {
+		global.process = {
+			getuid() { return -1; },
+			getgid() { return -1; },
+			geteuid() { return -1; },
+			getegid() { return -1; },
+			getgroups() { throw enosys(); },
+			pid: -1,
+			ppid: -1,
+			umask() { throw enosys(); },
+			cwd() { throw enosys(); },
+			chdir() { throw enosys(); },
+		}
+	}
+
+	/*
+	if (!global.crypto) {
+		const nodeCrypto = require("crypto");
+		global.crypto = {
+			getRandomValues(b) {
+				nodeCrypto.randomFillSync(b);
+			},
+		};
+	}
+	*/
+
+	if (!global.performance) {
+		global.performance = {
+			now() {
+				const [sec, nsec] = process.hrtime();
+				return sec * 1000 + nsec / 1000000;
+			},
+		};
+	}
+
+	/*
+	if (!global.TextEncoder) {
+		global.TextEncoder = require("util").TextEncoder;
+	}
+
+	if (!global.TextDecoder) {
+		global.TextDecoder = require("util").TextDecoder;
+	}
+	*/
+
+	// End of polyfills for common API.
+
+	const encoder = new TextEncoder("utf-8");
+	const decoder = new TextDecoder("utf-8");
+	var logLine = [];
+
+	global.Go = class {
+		constructor() {
+			this._callbackTimeouts = new Map();
+			this._nextCallbackTimeoutID = 1;
+
+			const mem = () => {
+				// The buffer may change when requesting more memory.
+				return new DataView(this._inst.exports.memory.buffer);
+			}
+
+			const setInt64 = (addr, v) => {
+				mem().setUint32(addr + 0, v, true);
+				mem().setUint32(addr + 4, Math.floor(v / 4294967296), true);
+			}
+
+			const getInt64 = (addr) => {
+				const low = mem().getUint32(addr + 0, true);
+				const high = mem().getInt32(addr + 4, true);
+				return low + high * 4294967296;
+			}
+
+			const loadValue = (addr) => {
+				const f = mem().getFloat64(addr, true);
+				if (f === 0) {
+					return undefined;
+				}
+				if (!isNaN(f)) {
+					return f;
+				}
+
+				const id = mem().getUint32(addr, true);
+				return this._values[id];
+			}
+
+			const storeValue = (addr, v) => {
+				const nanHead = 0x7FF80000;
+
+				if (typeof v === "number") {
+					if (isNaN(v)) {
+						mem().setUint32(addr + 4, nanHead, true);
+						mem().setUint32(addr, 0, true);
+						return;
+					}
+					if (v === 0) {
+						mem().setUint32(addr + 4, nanHead, true);
+						mem().setUint32(addr, 1, true);
+						return;
+					}
+					mem().setFloat64(addr, v, true);
+					return;
+				}
+
+				switch (v) {
+					case undefined:
+						mem().setFloat64(addr, 0, true);
+						return;
+					case null:
+						mem().setUint32(addr + 4, nanHead, true);
+						mem().setUint32(addr, 2, true);
+						return;
+					case true:
+						mem().setUint32(addr + 4, nanHead, true);
+						mem().setUint32(addr, 3, true);
+						return;
+					case false:
+						mem().setUint32(addr + 4, nanHead, true);
+						mem().setUint32(addr, 4, true);
+						return;
+				}
+
+				let id = this._ids.get(v);
+				if (id === undefined) {
+					id = this._idPool.pop();
+					if (id === undefined) {
+						id = this._values.length;
+					}
+					this._values[id] = v;
+					this._goRefCounts[id] = 0;
+					this._ids.set(v, id);
+				}
+				this._goRefCounts[id]++;
+				let typeFlag = 1;
+				switch (typeof v) {
+					case "string":
+						typeFlag = 2;
+						break;
+					case "symbol":
+						typeFlag = 3;
+						break;
+					case "function":
+						typeFlag = 4;
+						break;
+				}
+				mem().setUint32(addr + 4, nanHead | typeFlag, true);
+				mem().setUint32(addr, id, true);
+			}
+
+			const loadSlice = (array, len, cap) => {
+				return new Uint8Array(this._inst.exports.memory.buffer, array, len);
+			}
+
+			const loadSliceOfValues = (array, len, cap) => {
+				const a = new Array(len);
+				for (let i = 0; i < len; i++) {
+					a[i] = loadValue(array + i * 8);
+				}
+				return a;
+			}
+
+			const loadString = (ptr, len) => {
+				return decoder.decode(new DataView(this._inst.exports.memory.buffer, ptr, len));
+			}
+
+			const timeOrigin = Date.now() - performance.now();
+			this.importObject = {
+				wasi_snapshot_preview1: {
+					// https://github.com/WebAssembly/WASI/blob/main/phases/snapshot/docs.md#fd_write
+					fd_write: function(fd, iovs_ptr, iovs_len, nwritten_ptr) {
+						let nwritten = 0;
+						if (fd == 1) {
+							for (let iovs_i=0; iovs_i<iovs_len;iovs_i++) {
+								let iov_ptr = iovs_ptr+iovs_i*8; // assuming wasm32
+								let ptr = mem().getUint32(iov_ptr + 0, true);
+								let len = mem().getUint32(iov_ptr + 4, true);
+								nwritten += len;
+								for (let i=0; i<len; i++) {
+									let c = mem().getUint8(ptr+i);
+									if (c == 13) { // CR
+										// ignore
+									} else if (c == 10) { // LF
+										// write line
+										let line = decoder.decode(new Uint8Array(logLine));
+										logLine = [];
+										console.log(line);
+									} else {
+										logLine.push(c);
+									}
+								}
+							}
+						} else {
+							console.error('invalid file descriptor:', fd);
+						}
+						mem().setUint32(nwritten_ptr, nwritten, true);
+						return 0;
+					},
+					fd_close: () => 0,      // dummy
+					fd_fdstat_get: () => 0, // dummy
+					fd_seek: () => 0,       // dummy
+					"proc_exit": (code) => {
+						if (global.process) {
+							// Node.js
+							process.exit(code);
+						} else {
+							// Can't exit in a browser.
+							throw 'trying to exit with code ' + code;
+						}
+					},
+					random_get: (bufPtr, bufLen) => {
+						crypto.getRandomValues(loadSlice(bufPtr, bufLen));
+						return 0;
+					},
+				},
+				env: {
+					// func ticks() float64
+					"runtime.ticks": () => {
+						return timeOrigin + performance.now();
+					},
+
+					// func sleepTicks(timeout float64)
+					"runtime.sleepTicks": (timeout) => {
+						// Do not sleep, only reactivate scheduler after the given timeout.
+						setTimeout(this._inst.exports.go_scheduler, timeout);
+					},
+
+					// func finalizeRef(v ref)
+					"syscall/js.finalizeRef": (sp) => {
+						// Note: TinyGo does not support finalizers so this should never be
+						// called.
+						// console.error('syscall/js.finalizeRef not implemented');
+					},
+
+					// func stringVal(value string) ref
+					"syscall/js.stringVal": (ret_ptr, value_ptr, value_len) => {
+						const s = loadString(value_ptr, value_len);
+						storeValue(ret_ptr, s);
+					},
+
+					// func valueGet(v ref, p string) ref
+					"syscall/js.valueGet": (retval, v_addr, p_ptr, p_len) => {
+						let prop = loadString(p_ptr, p_len);
+						let value = loadValue(v_addr);
+						let result = Reflect.get(value, prop);
+						storeValue(retval, result);
+					},
+
+					// func valueSet(v ref, p string, x ref)
+					"syscall/js.valueSet": (v_addr, p_ptr, p_len, x_addr) => {
+						const v = loadValue(v_addr);
+						const p = loadString(p_ptr, p_len);
+						const x = loadValue(x_addr);
+						Reflect.set(v, p, x);
+					},
+
+					// func valueDelete(v ref, p string)
+					"syscall/js.valueDelete": (v_addr, p_ptr, p_len) => {
+						const v = loadValue(v_addr);
+						const p = loadString(p_ptr, p_len);
+						Reflect.deleteProperty(v, p);
+					},
+
+					// func valueIndex(v ref, i int) ref
+					"syscall/js.valueIndex": (ret_addr, v_addr, i) => {
+						storeValue(ret_addr, Reflect.get(loadValue(v_addr), i));
+					},
+
+					// valueSetIndex(v ref, i int, x ref)
+					"syscall/js.valueSetIndex": (v_addr, i, x_addr) => {
+						Reflect.set(loadValue(v_addr), i, loadValue(x_addr));
+					},
+
+					// func valueCall(v ref, m string, args []ref) (ref, bool)
+					"syscall/js.valueCall": (ret_addr, v_addr, m_ptr, m_len, args_ptr, args_len, args_cap) => {
+						const v = loadValue(v_addr);
+						const name = loadString(m_ptr, m_len);
+						const args = loadSliceOfValues(args_ptr, args_len, args_cap);
+						try {
+							const m = Reflect.get(v, name);
+							storeValue(ret_addr, Reflect.apply(m, v, args));
+							mem().setUint8(ret_addr + 8, 1);
+						} catch (err) {
+							storeValue(ret_addr, err);
+							mem().setUint8(ret_addr + 8, 0);
+						}
+					},
+
+					// func valueInvoke(v ref, args []ref) (ref, bool)
+					"syscall/js.valueInvoke": (ret_addr, v_addr, args_ptr, args_len, args_cap) => {
+						try {
+							const v = loadValue(v_addr);
+							const args = loadSliceOfValues(args_ptr, args_len, args_cap);
+							storeValue(ret_addr, Reflect.apply(v, undefined, args));
+							mem().setUint8(ret_addr + 8, 1);
+						} catch (err) {
+							storeValue(ret_addr, err);
+							mem().setUint8(ret_addr + 8, 0);
+						}
+					},
+
+					// func valueNew(v ref, args []ref) (ref, bool)
+					"syscall/js.valueNew": (ret_addr, v_addr, args_ptr, args_len, args_cap) => {
+						const v = loadValue(v_addr);
+						const args = loadSliceOfValues(args_ptr, args_len, args_cap);
+						try {
+							storeValue(ret_addr, Reflect.construct(v, args));
+							mem().setUint8(ret_addr + 8, 1);
+						} catch (err) {
+							storeValue(ret_addr, err);
+							mem().setUint8(ret_addr+ 8, 0);
+						}
+					},
+
+					// func valueLength(v ref) int
+					"syscall/js.valueLength": (v_addr) => {
+						return loadValue(v_addr).length;
+					},
+
+					// valuePrepareString(v ref) (ref, int)
+					"syscall/js.valuePrepareString": (ret_addr, v_addr) => {
+						const s = String(loadValue(v_addr));
+						const str = encoder.encode(s);
+						storeValue(ret_addr, str);
+						setInt64(ret_addr + 8, str.length);
+					},
+
+					// valueLoadString(v ref, b []byte)
+					"syscall/js.valueLoadString": (v_addr, slice_ptr, slice_len, slice_cap) => {
+						const str = loadValue(v_addr);
+						loadSlice(slice_ptr, slice_len, slice_cap).set(str);
+					},
+
+					// func valueInstanceOf(v ref, t ref) bool
+					"syscall/js.valueInstanceOf": (v_addr, t_addr) => {
+ 						return loadValue(v_addr) instanceof loadValue(t_addr);
+					},
+
+					// func copyBytesToGo(dst []byte, src ref) (int, bool)
+					"syscall/js.copyBytesToGo": (ret_addr, dest_addr, dest_len, dest_cap, source_addr) => {
+						let num_bytes_copied_addr = ret_addr;
+						let returned_status_addr = ret_addr + 4; // Address of returned boolean status variable
+
+						const dst = loadSlice(dest_addr, dest_len);
+						const src = loadValue(source_addr);
+						if (!(src instanceof Uint8Array || src instanceof Uint8ClampedArray)) {
+							mem().setUint8(returned_status_addr, 0); // Return "not ok" status
+							return;
+						}
+						const toCopy = src.subarray(0, dst.length);
+						dst.set(toCopy);
+						setInt64(num_bytes_copied_addr, toCopy.length);
+						mem().setUint8(returned_status_addr, 1); // Return "ok" status
+					},
+
+					// copyBytesToJS(dst ref, src []byte) (int, bool)
+					// Originally copied from upstream Go project, then modified:
+					//   https://github.com/golang/go/blob/3f995c3f3b43033013013e6c7ccc93a9b1411ca9/misc/wasm/wasm_exec.js#L404-L416
+					"syscall/js.copyBytesToJS": (ret_addr, dest_addr, source_addr, source_len, source_cap) => {
+						let num_bytes_copied_addr = ret_addr;
+						let returned_status_addr = ret_addr + 4; // Address of returned boolean status variable
+
+						const dst = loadValue(dest_addr);
+						const src = loadSlice(source_addr, source_len);
+						if (!(dst instanceof Uint8Array || dst instanceof Uint8ClampedArray)) {
+							mem().setUint8(returned_status_addr, 0); // Return "not ok" status
+							return;
+						}
+						const toCopy = src.subarray(0, dst.length);
+						dst.set(toCopy);
+						setInt64(num_bytes_copied_addr, toCopy.length);
+						mem().setUint8(returned_status_addr, 1); // Return "ok" status
+					},
+				}
+			};
+		}
+
+		async run(instance) {
+			this._inst = instance;
+			this._values = [ // JS values that Go currently has references to, indexed by reference id
+				NaN,
+				0,
+				null,
+				true,
+				false,
+				global,
+				this,
+			];
+			this._goRefCounts = []; // number of references that Go has to a JS value, indexed by reference id
+			this._ids = new Map();  // mapping from JS values to reference ids
+			this._idPool = [];      // unused ids that have been garbage collected
+			this.exited = false;    // whether the Go program has exited
+
+			const mem = new DataView(this._inst.exports.memory.buffer)
+
+			while (true) {
+				const callbackPromise = new Promise((resolve) => {
+					this._resolveCallbackPromise = () => {
+						if (this.exited) {
+							throw new Error("bad callback: Go program has already exited");
+						}
+						setTimeout(resolve, 0); // make sure it is asynchronous
+					};
+				});
+				this._inst.exports._start();
+				if (this.exited) {
+					break;
+				}
+				await callbackPromise;
+			}
+		}
+
+		_resume() {
+			if (this.exited) {
+				throw new Error("Go program has already exited");
+			}
+			this._inst.exports.resume();
+			if (this.exited) {
+				this._resolveExitPromise();
+			}
+		}
+
+		_makeFuncWrapper(id) {
+			const go = this;
+			return function () {
+				const event = { id: id, this: this, args: arguments };
+				go._pendingEvent = event;
+				go._resume();
+				return event.result;
+			};
+		}
+	}
+
+	if (
+		global.require &&
+		global.require.main === module &&
+		global.process &&
+		global.process.versions &&
+		!global.process.versions.electron
+	) {
+		if (process.argv.length != 3) {
+			console.error("usage: go_js_wasm_exec [wasm binary] [arguments]");
+			process.exit(1);
+		}
+
+		const go = new Go();
+		WebAssembly.instantiate(fs.readFileSync(process.argv[2]), go.importObject).then((result) => {
+			return go.run(result.instance);
+		}).catch((err) => {
+			console.error(err);
+			process.exit(1);
+		});
+	}
+})();

examples/simple-json-server/Makefile

@@ -0,0 +1,12 @@
+.PHONY: dev
+dev:
+	wrangler dev
+
+.PHONY: build
+build:
+	mkdir -p dist
+	tinygo build -o ./dist/app.wasm -target wasm ./main.go
+
+.PHONY: publish
+publish:
+	wrangler publish

examples/simple-json-server/README.md

@@ -0,0 +1,52 @@
+# simple-json-server
+
+* A simple HTTP JSON server implemented in Go and compiled with tinygo.
+
+## Example
+
+* https://simple-json-server.syumai.workers.dev
+
+### Request
+
+```
+curl --location --request POST 'https://simple-json-server.syumai.workers.dev/hello' \
+--header 'Content-Type: application/json' \
+--data-raw '{
+    "name": "syumai"
+}'
+```
+
+### Response
+
+```json
+{
+    "message": "Hello, syumai!"
+}
+```
+
+## Development
+
+### Requirements
+
+This project requires these tools to be installed globally.
+
+* wrangler
+* tinygo
+* [easyjson](https://github.com/mailru/easyjson)
+  - `go install github.com/mailru/easyjson/...@latest`
+
+### Commands
+
+```
+make dev     # run dev server
+make build   # build Go Wasm binary
+make publish # publish worker
+```
+
+## Author
+
+syumai
+
+## License
+
+MIT

examples/simple-json-server/app/app_easyjson.go

@@ -0,0 +1,152 @@
+// Code generated by easyjson for marshaling/unmarshaling. DO NOT EDIT.
+
+package app
+
+import (
+	json "encoding/json"
+
+	easyjson "github.com/mailru/easyjson"
+	jlexer "github.com/mailru/easyjson/jlexer"
+	jwriter "github.com/mailru/easyjson/jwriter"
+)
+
+// suppress unused package warning
+var (
+	_ *json.RawMessage
+	_ *jlexer.Lexer
+	_ *jwriter.Writer
+	_ easyjson.Marshaler
+)
+
+func easyjsonD2c14bDecodeGithubComSyumaiWorkersPlaygroundTinygoApp(in *jlexer.Lexer, out *HelloResponse) {
+	isTopLevel := in.IsStart()
+	if in.IsNull() {
+		if isTopLevel {
+			in.Consumed()
+		}
+		in.Skip()
+		return
+	}
+	in.Delim('{')
+	for !in.IsDelim('}') {
+		key := in.UnsafeFieldName(false)
+		in.WantColon()
+		if in.IsNull() {
+			in.Skip()
+			in.WantComma()
+			continue
+		}
+		switch key {
+		case "message":
+			out.Message = string(in.String())
+		default:
+			in.SkipRecursive()
+		}
+		in.WantComma()
+	}
+	in.Delim('}')
+	if isTopLevel {
+		in.Consumed()
+	}
+}
+func easyjsonD2c14bEncodeGithubComSyumaiWorkersPlaygroundTinygoApp(out *jwriter.Writer, in HelloResponse) {
+	out.RawByte('{')
+	first := true
+	_ = first
+	{
+		const prefix string = ",\"message\":"
+		out.RawString(prefix[1:])
+		out.String(string(in.Message))
+	}
+	out.RawByte('}')
+}
+
+// MarshalJSON supports json.Marshaler interface
+func (v HelloResponse) MarshalJSON() ([]byte, error) {
+	w := jwriter.Writer{}
+	easyjsonD2c14bEncodeGithubComSyumaiWorkersPlaygroundTinygoApp(&w, v)
+	return w.Buffer.BuildBytes(), w.Error
+}
+
+// MarshalEasyJSON supports easyjson.Marshaler interface
+func (v HelloResponse) MarshalEasyJSON(w *jwriter.Writer) {
+	easyjsonD2c14bEncodeGithubComSyumaiWorkersPlaygroundTinygoApp(w, v)
+}
+
+// UnmarshalJSON supports json.Unmarshaler interface
+func (v *HelloResponse) UnmarshalJSON(data []byte) error {
+	r := jlexer.Lexer{Data: data}
+	easyjsonD2c14bDecodeGithubComSyumaiWorkersPlaygroundTinygoApp(&r, v)
+	return r.Error()
+}
+
+// UnmarshalEasyJSON supports easyjson.Unmarshaler interface
+func (v *HelloResponse) UnmarshalEasyJSON(l *jlexer.Lexer) {
+	easyjsonD2c14bDecodeGithubComSyumaiWorkersPlaygroundTinygoApp(l, v)
+}
+func easyjsonD2c14bDecodeGithubComSyumaiWorkersPlaygroundTinygoApp1(in *jlexer.Lexer, out *HelloRequest) {
+	isTopLevel := in.IsStart()
+	if in.IsNull() {
+		if isTopLevel {
+			in.Consumed()
+		}
+		in.Skip()
+		return
+	}
+	in.Delim('{')
+	for !in.IsDelim('}') {
+		key := in.UnsafeFieldName(false)
+		in.WantColon()
+		if in.IsNull() {
+			in.Skip()
+			in.WantComma()
+			continue
+		}
+		switch key {
+		case "name":
+			out.Name = string(in.String())
+		default:
+			in.SkipRecursive()
+		}
+		in.WantComma()
+	}
+	in.Delim('}')
+	if isTopLevel {
+		in.Consumed()
+	}
+}
+func easyjsonD2c14bEncodeGithubComSyumaiWorkersPlaygroundTinygoApp1(out *jwriter.Writer, in HelloRequest) {
+	out.RawByte('{')
+	first := true
+	_ = first
+	{
+		const prefix string = ",\"name\":"
+		out.RawString(prefix[1:])
+		out.String(string(in.Name))
+	}
+	out.RawByte('}')
+}
+
+// MarshalJSON supports json.Marshaler interface
+func (v HelloRequest) MarshalJSON() ([]byte, error) {
+	w := jwriter.Writer{}
+	easyjsonD2c14bEncodeGithubComSyumaiWorkersPlaygroundTinygoApp1(&w, v)
+	return w.Buffer.BuildBytes(), w.Error
+}
+
+// MarshalEasyJSON supports easyjson.Marshaler interface
+func (v HelloRequest) MarshalEasyJSON(w *jwriter.Writer) {
+	easyjsonD2c14bEncodeGithubComSyumaiWorkersPlaygroundTinygoApp1(w, v)
+}
+
+// UnmarshalJSON supports json.Unmarshaler interface
+func (v *HelloRequest) UnmarshalJSON(data []byte) error {
+	r := jlexer.Lexer{Data: data}
+	easyjsonD2c14bDecodeGithubComSyumaiWorkersPlaygroundTinygoApp1(&r, v)
+	return r.Error()
+}
+
+// UnmarshalEasyJSON supports easyjson.Unmarshaler interface
+func (v *HelloRequest) UnmarshalEasyJSON(l *jlexer.Lexer) {
+	easyjsonD2c14bDecodeGithubComSyumaiWorkersPlaygroundTinygoApp1(l, v)
+}

examples/simple-json-server/app/hello.go

@@ -0,0 +1,38 @@
+//go:generate easyjson .
+package app
+
+import (
+	"fmt"
+	"net/http"
+	"os"
+
+	"github.com/mailru/easyjson"
+)
+
+//easyjson:json
+type HelloRequest struct {
+	Name string `json:"name"`
+}
+
+//easyjson:json
+type HelloResponse struct {
+	Message string `json:"message"`
+}
+
+func HelloHandler(w http.ResponseWriter, req *http.Request) {
+	var helloReq HelloRequest
+	if err := easyjson.UnmarshalFromReader(req.Body, &helloReq); err != nil {
+		w.WriteHeader(http.StatusBadRequest)
+		w.Header().Set("Content-Type", "text/plain")
+		w.Write([]byte("request format is invalid"))
+		return
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	msg := fmt.Sprintf("Hello, %s!", helloReq.Name)
+	helloRes := HelloResponse{Message: msg}
+
+	if _, err := easyjson.MarshalToWriter(&helloRes, w); err != nil {
+		fmt.Fprintf(os.Stderr, "failed to encode response: %w\n", err)
+	}
+}

examples/simple-json-server/go.mod

@@ -0,0 +1,12 @@
+module github.com/syumai/workers/examples/simple-json-server
+
+go 1.18
+
+require (
+	github.com/mailru/easyjson v0.7.7
+	github.com/syumai/workers v0.0.0-00010101000000-000000000000
+)
+
+replace github.com/syumai/workers => ../../
+
+require github.com/josharian/intern v1.0.0 // indirect

examples/simple-json-server/go.sum

@@ -0,0 +1,4 @@
+github.com/josharian/intern v1.0.0 h1:vlS4z54oSdjm0bgjRigI+G1HpF+tI+9rE5LLzOg8HmY=
+github.com/josharian/intern v1.0.0/go.mod h1:5DoeVV0s6jJacbCEi61lwdGj/aVlrQvzHFFd8Hwg//Y=
+github.com/mailru/easyjson v0.7.7 h1:UGYAvKxe3sBsEDzO8ZeWOSlIQfWFlxbzLZe7hwFURr0=
+github.com/mailru/easyjson v0.7.7/go.mod h1:xzfreul335JAWq5oZzymOObrkdz5UnU4kGfJJLY9Nlc=

examples/simple-json-server/main.go

@@ -0,0 +1,13 @@
+package main
+
+import (
+	"net/http"
+
+	"github.com/syumai/workers"
+	"github.com/syumai/workers/examples/simple-json-server/app"
+)
+
+func main() {
+	http.HandleFunc("/hello", app.HelloHandler)
+	workers.Serve(nil) // use http.DefaultServeMux
+}

examples/simple-json-server/worker.mjs

@@ -0,0 +1,17 @@
+import "../assets/polyfill_performance.js";
+import "../assets/wasm_exec.js";
+import mod from "./dist/app.wasm";
+
+const go = new Go();
+
+const load = WebAssembly.instantiate(mod, go.importObject).then((instance) => {
+  go.run(instance);
+  return instance;
+});
+
+export default {
+  async fetch(req) {
+    await load;
+    return handleRequest(req);
+  },
+};

examples/simple-json-server/wrangler.toml

@@ -0,0 +1,9 @@
+name = "simple-json-server"
+main = "./worker.mjs"
+compatibility_date = "2022-05-13"
+compatibility_flags = [
+    "streams_enable_constructors"
+]
+
+[build]
+command = "make build"

go.mod

@@ -0,0 +1,3 @@
+module github.com/syumai/workers
+
+go 1.18

handler.go

@@ -0,0 +1,67 @@
+package workers
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+	"syscall/js"
+)
+
+var httpHandler http.Handler
+
+func init() {
+	var handleRequestCallback js.Func
+	handleRequestCallback = js.FuncOf(func(this js.Value, args []js.Value) any {
+		if len(args) != 1 {
+			panic(fmt.Errorf("too many args given to handleRequest: %d", len(args)))
+		}
+		var cb js.Func
+		cb = js.FuncOf(func(_ js.Value, pArgs []js.Value) any {
+			defer cb.Release()
+			resolve := pArgs[0]
+			go func() {
+				res, err := handleRequest(args[0])
+				if err != nil {
+					panic(err)
+				}
+				resolve.Invoke(res)
+			}()
+			return js.Undefined()
+		})
+		return newPromise(cb)
+	})
+	global.Set("handleRequest", handleRequestCallback)
+}
+
+// handleRequest accepts a Request object and returns Response object.
+func handleRequest(reqObj js.Value) (js.Value, error) {
+	if httpHandler == nil {
+		return js.Value{}, fmt.Errorf("Serve must be called before handleRequest.")
+	}
+	req, err := toRequest(reqObj)
+	if err != nil {
+		panic(err)
+	}
+	reader, writer := io.Pipe()
+	w := &responseWriterBuffer{
+		header:     http.Header{},
+		statusCode: http.StatusOK,
+		PipeReader: reader,
+		PipeWriter: writer,
+	}
+	go func() {
+		defer writer.Close()
+		httpHandler.ServeHTTP(w, req)
+	}()
+	return w.toJSResponse()
+}
+
+// Server serves http.Handler on Cloudflare Workers.
+// if the given handler is nil, http.DefaultServeMux will be used.
+func Serve(handler http.Handler) {
+	if handler == nil {
+		handler = http.DefaultServeMux
+	}
+	httpHandler = handler
+	select {}
+}

jsutil.go

@@ -0,0 +1,32 @@
+package workers
+
+import "syscall/js"
+
+var (
+	global              = js.Global()
+	objectClass         = global.Get("Object")
+	promiseClass        = global.Get("Promise")
+	responseClass       = global.Get("Response")
+	headersClass        = global.Get("Headers")
+	arrayClass          = global.Get("Array")
+	uint8ArrayClass     = global.Get("Uint8Array")
+	errorClass          = global.Get("Error")
+	readableStreamClass = global.Get("ReadableStream")
+)
+
+func newObject() js.Value {
+	return objectClass.New()
+}
+
+func newUint8Array(size int) js.Value {
+	return uint8ArrayClass.New(size)
+}
+
+func newPromise(fn js.Func) js.Value {
+	return promiseClass.New(fn)
+}
+
+// arrayFrom calls Array.from to given argument and returns result Array.
+func arrayFrom(v js.Value) js.Value {
+	return arrayClass.Call("from", v)
+}

request.go

@@ -0,0 +1,57 @@
+package workers
+
+import (
+	"io"
+	"net/http"
+	"net/url"
+	"strconv"
+	"strings"
+	"syscall/js"
+)
+
+// toBody converts JavaScripts sides ReadableStream (can be null) to io.ReadCloser.
+// * ReadableStream: https://developer.mozilla.org/en-US/docs/Web/API/ReadableStream
+func toBody(streamOrNull js.Value) io.ReadCloser {
+	if streamOrNull.IsNull() {
+		return nil
+	}
+	sr := streamOrNull.Call("getReader")
+	return io.NopCloser(convertStreamReaderToReader(sr))
+}
+
+// toHeader converts JavaScript sides Headers to http.Header.
+// * Headers: https://developer.mozilla.org/ja/docs/Web/API/Headers
+func toHeader(headers js.Value) http.Header {
+	entries := arrayFrom(headers.Call("entries"))
+	headerLen := entries.Length()
+	h := http.Header{}
+	for i := 0; i < headerLen; i++ {
+		entry := entries.Index(i)
+		key := entry.Index(0).String()
+		value := entry.Index(1).String()
+		h[key] = strings.Split(value, ",")
+	}
+	return h
+}
+
+// toRequest converts JavaScript sides Request to *http.Request.
+// * Request: https://developer.mozilla.org/ja/docs/Web/API/Request
+func toRequest(req js.Value) (*http.Request, error) {
+	reqUrl, err := url.Parse(req.Get("url").String())
+	if err != nil {
+		return nil, err
+	}
+	header := toHeader(req.Get("headers"))
+
+	// ignore err
+	contentLength, _ := strconv.ParseInt(header.Get("Content-Length"), 10, 64)
+	return &http.Request{
+		Method:           req.Get("method").String(),
+		URL:              reqUrl,
+		Header:           header,
+		Body:             toBody(req.Get("body")),
+		ContentLength:    contentLength,
+		TransferEncoding: strings.Split(header.Get("Transfer-Encoding"), ","),
+		Host:             header.Get("Host"),
+	}, nil
+}

response.go

@@ -0,0 +1,29 @@
+package workers
+
+import (
+	"io"
+	"net/http"
+	"syscall/js"
+)
+
+func toJSHeader(header http.Header) js.Value {
+	h := headersClass.New()
+	for key, values := range header {
+		for _, value := range values {
+			h.Call("append", key, value)
+		}
+	}
+	return h
+}
+
+func toJSResponse(body io.ReadCloser, status int, header http.Header) (js.Value, error) {
+	if status == 0 {
+		status = http.StatusOK
+	}
+	respInit := newObject()
+	respInit.Set("status", status)
+	respInit.Set("statusText", http.StatusText(status))
+	respInit.Set("headers", toJSHeader(header))
+	readableStream := convertReaderToReadableStream(body)
+	return responseClass.New(readableStream, respInit), nil
+}

responsewriter.go

@@ -0,0 +1,28 @@
+package workers
+
+import (
+	"io"
+	"net/http"
+	"syscall/js"
+)
+
+type responseWriterBuffer struct {
+	header     http.Header
+	statusCode int
+	*io.PipeReader
+	*io.PipeWriter
+}
+
+var _ http.ResponseWriter = &responseWriterBuffer{}
+
+func (w responseWriterBuffer) Header() http.Header {
+	return w.header
+}
+
+func (w responseWriterBuffer) WriteHeader(statusCode int) {
+	w.statusCode = statusCode
+}
+
+func (w responseWriterBuffer) toJSResponse() (js.Value, error) {
+	return toJSResponse(w.PipeReader, w.statusCode, w.header)
+}

stream.go

@@ -0,0 +1,140 @@
+package workers
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"syscall/js"
+)
+
+// streamReaderToReader implements io.Reader sourced from ReadableStreamDefaultReader.
+// * ReadableStreamDefaultReader: https://developer.mozilla.org/en-US/docs/Web/API/ReadableStreamDefaultReader
+// * This implementation is based on: https://deno.land/std@0.139.0/streams/conversion.ts#L76
+type streamReaderToReader struct {
+	buf          bytes.Buffer
+	streamReader js.Value
+}
+
+// Read reads bytes from ReadableStreamDefaultReader.
+func (sr *streamReaderToReader) Read(p []byte) (n int, err error) {
+	if sr.buf.Len() == 0 {
+		promise := sr.streamReader.Call("read")
+		resultCh := make(chan js.Value)
+		errCh := make(chan error)
+		var then, catch js.Func
+		then = js.FuncOf(func(_ js.Value, args []js.Value) any {
+			defer then.Release()
+			result := args[0]
+			if result.Get("done").Bool() {
+				errCh <- io.EOF
+				return js.Undefined()
+			}
+			resultCh <- result.Get("value")
+			return js.Undefined()
+		})
+		catch = js.FuncOf(func(_ js.Value, args []js.Value) any {
+			defer catch.Release()
+			result := args[0]
+			errCh <- fmt.Errorf("JavaScript error on read: %s", result.Call("toString").String())
+			return js.Undefined()
+		})
+		promise.Call("then", then).Call("catch", catch)
+		select {
+		case result := <-resultCh:
+			chunk := make([]byte, result.Get("byteLength").Int())
+			_ = js.CopyBytesToGo(chunk, result)
+			// The length written is always the same as the length of chunk, so it can be discarded.
+			// - https://pkg.go.dev/bytes#Buffer.Write
+			_, err := sr.buf.Write(chunk)
+			if err != nil {
+				return 0, err
+			}
+		case err := <-errCh:
+			return 0, err
+		}
+	}
+	return sr.buf.Read(p)
+}
+
+// convertStreamReaderToReader converts ReadableStreamDefaultReader to io.Reader.
+func convertStreamReaderToReader(sr js.Value) io.Reader {
+	return &streamReaderToReader{
+		streamReader: sr,
+	}
+}
+
+// readerToReadableStream implements ReadableStream sourced from io.ReadCloser.
+// * ReadableStream: https://developer.mozilla.org/docs/Web/API/ReadableStream
+// * This implementation is based on: https://deno.land/std@0.139.0/streams/conversion.ts#L230
+type readerToReadableStream struct {
+	reader   io.ReadCloser
+	chunkBuf []byte
+}
+
+// Pull implements ReadableStream's pull method.
+// * https://developer.mozilla.org/en-US/docs/Web/API/ReadableStream/ReadableStream#pull
+func (rs *readerToReadableStream) Pull(controller js.Value) error {
+	n, err := rs.reader.Read(rs.chunkBuf)
+	if err == io.EOF {
+		if err := rs.reader.Close(); err != nil {
+			return err
+		}
+		controller.Call("close")
+		return nil
+	}
+	if err != nil {
+		jsErr := errorClass.New(err.Error())
+		controller.Call("error", jsErr)
+		if err := rs.reader.Close(); err != nil {
+			return err
+		}
+		return err
+	}
+	ua := newUint8Array(n)
+	_ = js.CopyBytesToJS(ua, rs.chunkBuf[:n])
+	controller.Call("enqueue", ua)
+	return nil
+}
+
+// Cancel implements ReadableStream's cancel method.
+// * https://developer.mozilla.org/en-US/docs/Web/API/ReadableStream/ReadableStream#cancel
+func (rs *readerToReadableStream) Cancel() error {
+	return rs.reader.Close()
+}
+
+// https://deno.land/std@0.139.0/streams/conversion.ts#L5
+const defaultChunkSize = 16_640
+
+// convertReaderToReadableStream converts io.ReadCloser to ReadableStream.
+func convertReaderToReadableStream(reader io.ReadCloser) js.Value {
+	stream := &readerToReadableStream{
+		reader:   reader,
+		chunkBuf: make([]byte, defaultChunkSize),
+	}
+	rsInit := newObject()
+	rsInit.Set("pull", js.FuncOf(func(_ js.Value, args []js.Value) any {
+		var cb js.Func
+		cb = js.FuncOf(func(this js.Value, pArgs []js.Value) any {
+			defer cb.Release()
+			resolve := pArgs[0]
+			reject := pArgs[1]
+			controller := args[0]
+			err := stream.Pull(controller)
+			if err != nil {
+				reject.Invoke(errorClass.New(err.Error()))
+				return js.Undefined()
+			}
+			resolve.Invoke()
+			return js.Undefined()
+		})
+		return newPromise(cb)
+	}))
+	rsInit.Set("cancel", js.FuncOf(func(js.Value, []js.Value) any {
+		err := stream.Cancel()
+		if err != nil {
+			panic(err)
+		}
+		return js.Undefined()
+	}))
+	return readableStreamClass.New(rsInit)
+}