feat(protocols): refactor protocol utilities into centralized protocols module

ts/protocols/websocket/utils.ts

@@ -0,0 +1,98 @@
+/**
+ * WebSocket Protocol Utilities
+ */
+
+import * as crypto from 'crypto';
+import { WEBSOCKET_MAGIC_STRING } from './constants.js';
+import type { RawData } from './types.js';
+
+/**
+ * Get the length of a WebSocket message regardless of its type
+ * (handles all possible WebSocket message data types)
+ */
+export function getMessageSize(data: RawData): number {
+  if (typeof data === 'string') {
+    // For string data, get the byte length
+    return Buffer.from(data, 'utf8').length;
+  } else if (data instanceof Buffer) {
+    // For Node.js Buffer
+    return data.length;
+  } else if (data instanceof ArrayBuffer) {
+    // For ArrayBuffer
+    return data.byteLength;
+  } else if (Array.isArray(data)) {
+    // For array of buffers, sum their lengths
+    return data.reduce((sum, chunk) => {
+      if (chunk instanceof Buffer) {
+        return sum + chunk.length;
+      } else if (chunk instanceof ArrayBuffer) {
+        return sum + chunk.byteLength;
+      }
+      return sum;
+    }, 0);
+  } else {
+    // For other types, try to determine the size or return 0
+    try {
+      return Buffer.from(data).length;
+    } catch (e) {
+      return 0;
+    }
+  }
+}
+
+/**
+ * Convert any raw WebSocket data to Buffer for consistent handling
+ */
+export function toBuffer(data: RawData): Buffer {
+  if (typeof data === 'string') {
+    return Buffer.from(data, 'utf8');
+  } else if (data instanceof Buffer) {
+    return data;
+  } else if (data instanceof ArrayBuffer) {
+    return Buffer.from(data);
+  } else if (Array.isArray(data)) {
+    // For array of buffers, concatenate them
+    return Buffer.concat(data.map(chunk => {
+      if (chunk instanceof Buffer) {
+        return chunk;
+      } else if (chunk instanceof ArrayBuffer) {
+        return Buffer.from(chunk);
+      }
+      return Buffer.from(chunk);
+    }));
+  } else {
+    // For other types, try to convert to Buffer or return empty Buffer
+    try {
+      return Buffer.from(data);
+    } catch (e) {
+      return Buffer.alloc(0);
+    }
+  }
+}
+
+/**
+ * Generate WebSocket accept key from client key
+ */
+export function generateAcceptKey(clientKey: string): string {
+  const hash = crypto.createHash('sha1');
+  hash.update(clientKey + WEBSOCKET_MAGIC_STRING);
+  return hash.digest('base64');
+}
+
+/**
+ * Validate WebSocket upgrade request
+ */
+export function isWebSocketUpgrade(headers: Record<string, string>): boolean {
+  const upgrade = headers['upgrade'];
+  const connection = headers['connection'];
+  
+  return upgrade?.toLowerCase() === 'websocket' && 
+         connection?.toLowerCase().includes('upgrade');
+}
+
+/**
+ * Generate random WebSocket key for client handshake
+ */
+export function generateWebSocketKey(): string {
+  return crypto.randomBytes(16).toString('base64');
+}