Path Joining API: The Complete Guide

Need to combine URL paths safely without worrying about double slashes or path traversal? This guide covers everything about path joining via API, including common pitfalls, security considerations, and implementation examples.

Why Use Path Joining?

Concatenating URL paths with simple string operations often leads to bugs. Consider joining "/api/v1/" and "/users" - naive concatenation gives "/api/v1//users" with a double slash.

A proper path joining function handles these edge cases automatically.

Common Issues

Double Slashes

When both segments have slashes at the join point: /path/ + /segment = /path//segment

Missing Slashes

When neither segment has a slash: path + segment = pathsegment

Path Traversal

Malicious input like "../../../etc/passwd" can escape intended directories.

Using the Path Joining API

TinyFn provides a safe endpoint for path joining:

POST https://api.tinyfn.io/v1/url/join-path
Headers: X-API-Key: your-api-key
Content-Type: application/json

{
  "base": "https://api.example.com/v1/",
  "segments": ["users", "123", "profile"]
}

{
  "result": "https://api.example.com/v1/users/123/profile",
  "path_only": "/v1/users/123/profile",
  "segments_joined": 3
}

Parameters

Code Examples

JavaScript / Node.js

const response = await fetch(
  'https://api.tinyfn.io/v1/url/join-path',
  {
    method: 'POST',
    headers: {
      'X-API-Key': 'your-api-key',
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({
      base: 'https://api.example.com/v1/',
      segments: ['users', '123', 'profile']
    })
  }
);
const { result } = await response.json();
console.log(result); // "https://api.example.com/v1/users/123/profile"

Python

import requests

response = requests.post(
    'https://api.tinyfn.io/v1/url/join-path',
    headers={'X-API-Key': 'your-api-key'},
    json={
        'base': 'https://api.example.com/v1/',
        'segments': ['users', '123', 'profile']
    }
)
result = response.json()['result']
print(result)  # "https://api.example.com/v1/users/123/profile"

cURL

curl -X POST "https://api.tinyfn.io/v1/url/join-path" \
  -H "X-API-Key: your-api-key" \
  -H "Content-Type: application/json" \
  -d '{"base": "https://api.example.com/v1/", "segments": ["users", "123"]}'

Common Use Cases

• API Client Libraries: Build endpoint URLs dynamically
• File Uploads: Construct storage paths from user input safely
• URL Generation: Create links with variable path components
• Configuration: Combine base URLs with configurable paths
• Routing: Build routes from path segments

Best Practices

1. Always sanitize: Keep sanitization enabled for user input
2. Validate segments: Ensure segments don't contain unexpected characters
3. Use arrays: Pass segments as array, not pre-concatenated strings
4. URL encode: Encode special characters in path segments