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

ts/protocols/http/parser.ts

@@ -0,0 +1,219 @@
+/**
+ * HTTP Protocol Parser
+ * Generic HTTP parsing utilities
+ */
+
+import { HTTP_METHODS, type THttpMethod, type THttpVersion } from './constants.js';
+import type { IHttpRequestLine, IHttpHeader } from './types.js';
+
+/**
+ * HTTP parser utilities
+ */
+export class HttpParser {
+  /**
+   * Check if string is a valid HTTP method
+   */
+  static isHttpMethod(str: string): str is THttpMethod {
+    return HTTP_METHODS.includes(str as THttpMethod);
+  }
+  
+  /**
+   * Parse HTTP request line
+   */
+  static parseRequestLine(line: string): IHttpRequestLine | null {
+    const parts = line.trim().split(' ');
+    
+    if (parts.length !== 3) {
+      return null;
+    }
+    
+    const [method, path, version] = parts;
+    
+    // Validate method
+    if (!this.isHttpMethod(method)) {
+      return null;
+    }
+    
+    // Validate version
+    if (!version.startsWith('HTTP/')) {
+      return null;
+    }
+    
+    return {
+      method: method as THttpMethod,
+      path,
+      version: version as THttpVersion
+    };
+  }
+  
+  /**
+   * Parse HTTP header line
+   */
+  static parseHeaderLine(line: string): IHttpHeader | null {
+    const colonIndex = line.indexOf(':');
+    
+    if (colonIndex === -1) {
+      return null;
+    }
+    
+    const name = line.slice(0, colonIndex).trim();
+    const value = line.slice(colonIndex + 1).trim();
+    
+    if (!name) {
+      return null;
+    }
+    
+    return { name, value };
+  }
+  
+  /**
+   * Parse HTTP headers from lines
+   */
+  static parseHeaders(lines: string[]): Record<string, string> {
+    const headers: Record<string, string> = {};
+    
+    for (const line of lines) {
+      const header = this.parseHeaderLine(line);
+      if (header) {
+        // Convert header names to lowercase for consistency
+        headers[header.name.toLowerCase()] = header.value;
+      }
+    }
+    
+    return headers;
+  }
+  
+  /**
+   * Extract domain from Host header value
+   */
+  static extractDomainFromHost(hostHeader: string): string {
+    // Remove port if present
+    const colonIndex = hostHeader.lastIndexOf(':');
+    if (colonIndex !== -1) {
+      // Check if it's not part of IPv6 address
+      const beforeColon = hostHeader.slice(0, colonIndex);
+      if (!beforeColon.includes(']')) {
+        return beforeColon;
+      }
+    }
+    return hostHeader;
+  }
+  
+  /**
+   * Validate domain name
+   */
+  static isValidDomain(domain: string): boolean {
+    // Basic domain validation
+    if (!domain || domain.length > 253) {
+      return false;
+    }
+    
+    // Check for valid characters and structure
+    const domainRegex = /^(?!-)[A-Za-z0-9-]{1,63}(?<!-)(\.[A-Za-z0-9-]{1,63})*$/;
+    return domainRegex.test(domain);
+  }
+  
+  /**
+   * Extract line from buffer
+   */
+  static extractLine(buffer: Buffer, offset: number = 0): { line: string; nextOffset: number } | null {
+    // Look for CRLF
+    const crlfIndex = buffer.indexOf('\r\n', offset);
+    if (crlfIndex === -1) {
+      // Look for just LF
+      const lfIndex = buffer.indexOf('\n', offset);
+      if (lfIndex === -1) {
+        return null;
+      }
+      
+      return {
+        line: buffer.slice(offset, lfIndex).toString('utf8'),
+        nextOffset: lfIndex + 1
+      };
+    }
+    
+    return {
+      line: buffer.slice(offset, crlfIndex).toString('utf8'),
+      nextOffset: crlfIndex + 2
+    };
+  }
+  
+  /**
+   * Check if buffer contains printable ASCII
+   */
+  static isPrintableAscii(buffer: Buffer, length?: number): boolean {
+    const checkLength = Math.min(length || buffer.length, buffer.length);
+    
+    for (let i = 0; i < checkLength; i++) {
+      const byte = buffer[i];
+      // Allow printable ASCII (32-126) plus tab (9), LF (10), and CR (13)
+      if (byte < 32 || byte > 126) {
+        if (byte !== 9 && byte !== 10 && byte !== 13) {
+          return false;
+        }
+      }
+    }
+    
+    return true;
+  }
+  
+  /**
+   * Quick check if buffer starts with HTTP method
+   */
+  static quickCheck(buffer: Buffer): boolean {
+    if (buffer.length < 3) {
+      return false;
+    }
+    
+    // Check common HTTP methods
+    const start = buffer.slice(0, 7).toString('ascii');
+    return start.startsWith('GET ') ||
+           start.startsWith('POST ') ||
+           start.startsWith('PUT ') ||
+           start.startsWith('DELETE ') ||
+           start.startsWith('HEAD ') ||
+           start.startsWith('OPTIONS') ||
+           start.startsWith('PATCH ') ||
+           start.startsWith('CONNECT') ||
+           start.startsWith('TRACE ');
+  }
+  
+  /**
+   * Parse query string
+   */
+  static parseQueryString(queryString: string): Record<string, string> {
+    const params: Record<string, string> = {};
+    
+    if (!queryString) {
+      return params;
+    }
+    
+    // Remove leading '?' if present
+    if (queryString.startsWith('?')) {
+      queryString = queryString.slice(1);
+    }
+    
+    const pairs = queryString.split('&');
+    for (const pair of pairs) {
+      const [key, value] = pair.split('=');
+      if (key) {
+        params[decodeURIComponent(key)] = value ? decodeURIComponent(value) : '';
+      }
+    }
+    
+    return params;
+  }
+  
+  /**
+   * Build query string from params
+   */
+  static buildQueryString(params: Record<string, string>): string {
+    const pairs: string[] = [];
+    
+    for (const [key, value] of Object.entries(params)) {
+      pairs.push(`${encodeURIComponent(key)}=${encodeURIComponent(value)}`);
+    }
+    
+    return pairs.length > 0 ? '?' + pairs.join('&') : '';
+  }
+}