qgenutils/lib/utilities/url/stripProtocol.js

A security-first Node.js utility library providing authentication, HTTP operations, URL processing, validation, datetime formatting, and template rendering. Designed as a lightweight alternative to heavy npm packages with comprehensive error handling and

/**
 * Strip Protocol and Trailing Slash from URL for Display
 * 
 * RATIONALE: User interfaces often need to display URLs without the protocol
 * prefix for cleaner presentation. This function removes http:// or https://
 * and normalizes trailing slashes for consistent display formatting.
 * 
 * IMPLEMENTATION STRATEGY:
 * - Use case-insensitive regex to match both HTTP and HTTPS
 * - Remove only protocol prefix, preserve the rest of the URL
 * - Handle trailing slash normalization for clean display
 * - Chain regex operations for predictable transformations
 * - Return original URL on any processing errors
 * 
 * COMMON USE CASES:
 * - URL display in configuration interfaces
 * - Shortened URL presentation in lists
 * - Clean domain names for user-facing displays
 * - Configuration file generation
 * 
 * TRANSFORMATION EXAMPLES:
 * - "https://example.com/" -> "example.com"
 * - "http://api.example.com/v1" -> "api.example.com/v1"
 * - "HTTPS://Example.COM/" -> "Example.COM"
 * 
 * SECURITY CONSIDERATIONS:
 * - Does not validate URL structure (use with validated URLs)
 * - Preserves original casing for display purposes
 * - Returns original input on processing errors
 * - No network requests or external validation
 * 
 * @param {string} url - URL to strip protocol from
 * @returns {string} URL without protocol prefix and normalized trailing slash
 * @throws Never throws - returns original URL on any error
 */

const { qerrors } = require('qerrors');
const logger = require('../../logger');
const isValidString = require('../../validation/isValidString');

function stripProtocol(url) {
  logger.debug(`stripProtocol is running with ${url}`);
  
  try {
    // Validate input
    if (!isValidString(url)) {
      logger.debug(`stripProtocol returning original input due to invalid type`);
      return url || ``;
    }

    // Chain replacements to remove protocol and trailing slash
    // Using case-insensitive regex pattern for consistency with other URL functions
    const processed = url
      .replace(/^https?:\/\//i, ``) // regex removes http:// or https:// prefix only
      .replace(/\/$/, ``);           // regex trims a single trailing slash
    
    logger.debug(`stripProtocol is returning ${processed}`);
    return processed;
  } catch (error) {
    // Handle unexpected errors in string processing
    qerrors(error, `stripProtocol`, { url });
    logger.error(`stripProtocol failed with error: ${error.message}`);
    return url; // fallback to input on failure
  }
}

module.exports = stripProtocol;