urljoin

Written as urljoin(argnum flags):options in a transform expression.

Minimum arguments	1
Maximum arguments	1
Default arguments	1
Argument modes	SINGLE_PRIMITIVE

Documentation

Join a base URL with a relative URL path component.

Features:

• Properly handles joining of URLs according to RFC 3986
• Resolves relative paths against the base URL
• Preserves query parameters and fragments when appropriate
• Automatically adds missing slashes between components

Behavior:

• If the relative URL is absolute (starts with scheme://), it will be returned as-is
• If the base URL ends with / and relative URL doesn’t start with /, they are joined directly
• If base URL doesn’t end with / and relative URL doesn’t start with /, a / is inserted
• Query parameters and fragments from the relative URL are preserved

Flags

Flag	Letter
noncaptive_input	I

Examples

Basic URL joining

Input args: ["users"]
Transforms: "urljoin:https://example.com/api"
Output: "https://example.com/users"

With trailing slash

Input args: ["users"]
Transforms: "urljoin:https://example.com/api/"
Output: "https://example.com/api/users"

Absolute relative URL

Input args: ["http://other.com/path"]
Transforms: "urljoin:https://example.com/api"
Output: "http://other.com/path"

With query parameters

Input args: ["users?id=123"]
Transforms: "urljoin:https://example.com/api/"
Output: "https://example.com/api/users?id=123"

Complex path joining

Input args: ["../v2/endpoint"]
Transforms: "urljoin:https://example.com/api/v1/"
Output: "https://example.com/api/v2/endpoint"