.. _library_url:

url

This library implements validation, parsing, generating, and normalization of URLs, which can be represented as atoms, character lists, or code lists. It currently supports the following URL schemes:

Web protocols:

• http
• https
• ws
• wss
• gopher File transfer and version control:
• ftp
• ftps
• sftp
• git File access:
• file Databases:
• jdbc
• mongodb
• mysql
• postgresql Email and news:
• mailto
• news
• nntp Media streaming:
• mms
• rtmp
• rtsp Shell access:
• ssh
• telnet Directory services:
• ldap
• ldaps Other protocols:
• tel
• urn The library predicates are defined in the url(_Representation_) parametric object where _Representation_ can be one of:
• atom - strings are represented as atoms
• chars - strings are represented as lists of characters
• codes - strings are represented as lists of character codes The parameter must be bound when sending messages to the object.

  The library also provides an utility predicate, file_path_components/2, for converting a file-system path into file URL components. This predicate also handles Windows drive-letter and UNC paths.

API documentation

Open the `../../apis/library_index.html#url <../../apis/library_index.html#url>`__ link in a web browser.

Loading

To load all entities in this library, load the loader.lgt file:

::

| ?- logtalk_load(url(loader)).

Testing

To test this library predicates, load the tester.lgt file:

::

| ?- logtalk_load(url(tester)).

Usage

The valid/1 and parse/2 predicates are intended for absolute URLs:

::

| ?- url(atom)::valid('https://example.com/path?x=1#frag'). true.

| ?- url(atom)::parse('https://example.com/path?x=1#frag', Components). Components = [scheme(https), authority('example.com'), path('/path'), query('x=1'), fragment(frag)].

For RFC 3986 relative references, use parse/3 or reference_kind/2:

::

| ?- url(atom)::parse('../users/42?verbose=true#details', Components, Kind). Components = [path('../users/42'), query('verbose=true'), fragment(details)], Kind = relative_path.

| ?- url(atom)::reference_kind('//example.com/v1', Kind). Kind = network_path.

The generate/2 and normalize/2 predicates work with both absolute URLs and relative references:

::

| ?- url(atom)::generate([authority('example.com'), path('/v1')], Reference). Reference = '//example.com/v1'.

| ?- url(atom)::normalize('../users/./42', NormalizedReference). NormalizedReference = '../users/42'.

The resolve/3 predicate resolves a reference against an absolute base URL, while relativize/3 computes a relative reference between compatible URLs:

::

| ?- url(atom)::resolve('http://example.com/a/b/c', '../d', Resolved). Resolved = 'http://example.com/a/d'.

| ?- url(atom)::relativize('http://example.com/a/b/c', 'http://example.com/v1', Relative). Relative = '../../v1'.

The file_path_components/2 predicate converts file-system paths into file URL components and supports both POSIX and Windows paths:

::

| ?- url(atom)::file_path_components('/home/user/document.txt', Components). Components = [authority(''), path('/home/user/document.txt')].

| ?- url(atom)::file_path_components('C:\\Temp\\app\\file.txt', Components). Components = [authority(''), path('/C:/Temp/app/file.txt')].