feat: 更新WebSocket 优化逻辑

Signed-off-by: MiaoWoo <admin@yumc.pw>

packages/websocket/src/engine.io-parser/commons.ts

@@ -0,0 +1,21 @@
+const PACKET_TYPES = Object.create(null) // no Map = no polyfill
+PACKET_TYPES["open"] = "0"
+PACKET_TYPES["close"] = "1"
+PACKET_TYPES["ping"] = "2"
+PACKET_TYPES["pong"] = "3"
+PACKET_TYPES["message"] = "4"
+PACKET_TYPES["upgrade"] = "5"
+PACKET_TYPES["noop"] = "6"
+
+const PACKET_TYPES_REVERSE = Object.create(null)
+Object.keys(PACKET_TYPES).forEach(key => {
+    PACKET_TYPES_REVERSE[PACKET_TYPES[key]] = key
+})
+
+const ERROR_PACKET = { type: "error", data: "parser error" }
+
+export = {
+    PACKET_TYPES,
+    PACKET_TYPES_REVERSE,
+    ERROR_PACKET
+}

packages/websocket/src/engine.io-parser/decodePacket.ts

@@ -0,0 +1,48 @@
+const { PACKET_TYPES_REVERSE, ERROR_PACKET } = require("./commons")
+
+export const decodePacket = (encodedPacket, binaryType) => {
+    if (typeof encodedPacket !== "string") {
+        return {
+            type: "message",
+            data: mapBinary(encodedPacket, binaryType)
+        }
+    }
+    const type = encodedPacket.charAt(0)
+    if (type === "b") {
+        const buffer = Buffer.from(encodedPacket.substring(1), "base64")
+        return {
+            type: "message",
+            data: mapBinary(buffer, binaryType)
+        }
+    }
+    if (!PACKET_TYPES_REVERSE[type]) {
+        return ERROR_PACKET
+    }
+    return encodedPacket.length > 1
+        ? {
+            type: PACKET_TYPES_REVERSE[type],
+            data: encodedPacket.substring(1)
+        }
+        : {
+            type: PACKET_TYPES_REVERSE[type]
+        }
+}
+
+const mapBinary = (data, binaryType) => {
+    switch (binaryType) {
+        case "arraybuffer":
+            return Buffer.isBuffer(data) ? toArrayBuffer(data) : data
+        case "nodebuffer":
+        default:
+            return data // assuming the data is already a Buffer
+    }
+}
+
+const toArrayBuffer = buffer => {
+    const arrayBuffer = new ArrayBuffer(buffer.length)
+    const view = new Uint8Array(arrayBuffer)
+    for (let i = 0; i < buffer.length; i++) {
+        view[i] = buffer[i]
+    }
+    return arrayBuffer
+}

packages/websocket/src/engine.io-parser/encodePacket.ts

@@ -0,0 +1,26 @@
+const { PACKET_TYPES } = require("./commons")
+
+export const encodePacket = ({ type, data }, supportsBinary, callback) => {
+    console.trace('encodePacket', type, JSON.stringify(data))
+    if (data instanceof ArrayBuffer || ArrayBuffer.isView(data)) {
+        const buffer = toBuffer(data)
+        return callback(encodeBuffer(buffer, supportsBinary))
+    }
+    // plain string
+    return callback(PACKET_TYPES[type] + (data || ""))
+}
+
+const toBuffer = data => {
+    if (Buffer.isBuffer(data)) {
+        return data
+    } else if (data instanceof ArrayBuffer) {
+        return Buffer.from(data)
+    } else {
+        return Buffer.from(data.buffer, data.byteOffset, data.byteLength)
+    }
+}
+
+// only 'message' packets can contain binary, so the type prefix is not needed
+const encodeBuffer = (data, supportsBinary) => {
+    return supportsBinary ? data : "b" + data.toString("base64")
+}

packages/websocket/src/engine.io-parser/index.ts

@@ -0,0 +1,42 @@
+import { encodePacket } from "./encodePacket"
+import { decodePacket } from "./decodePacket"
+
+const SEPARATOR = String.fromCharCode(30) // see https://en.wikipedia.org/wiki/Delimiter#ASCII_delimited_text
+
+const encodePayload = (packets, callback) => {
+    // some packets may be added to the array while encoding, so the initial length must be saved
+    const length = packets.length
+    const encodedPackets = new Array(length)
+    let count = 0
+
+    packets.forEach((packet, i) => {
+        // force base64 encoding for binary packets
+        encodePacket(packet, false, encodedPacket => {
+            encodedPackets[i] = encodedPacket
+            if (++count === length) {
+                callback(encodedPackets.join(SEPARATOR))
+            }
+        })
+    })
+}
+
+const decodePayload = (encodedPayload, binaryType) => {
+    const encodedPackets = encodedPayload.split(SEPARATOR)
+    const packets = []
+    for (let i = 0; i < encodedPackets.length; i++) {
+        const decodedPacket = decodePacket(encodedPackets[i], binaryType)
+        packets.push(decodedPacket)
+        if (decodedPacket.type === "error") {
+            break
+        }
+    }
+    return packets
+}
+
+export default {
+    protocol: 4,
+    encodePacket,
+    encodePayload,
+    decodePacket,
+    decodePayload
+}