path_to_regexp

Pub Travis

Converts a path such as /user/:id into a regular expression.

Matching

pathToRegExp() converts a path specification into a regular expression that matches conforming paths.

final regExp = pathToRegExp('/user/:id');
regExp.hasMatch('/user/12'); // => true
regExp.hasMatch('/user/alice'); // => true

Custom Parameters

By default, parameters match anything until the next delimiter. This behavior can be customized by specifying a regular expression in parentheses following a parameter name.

final regExp = pathToRegExp(r'/user/:id(\d+)');
regExp.hasMatch('/user/12'); // => true
regExp.hasMatch('/user/alice'); // => false

Extracting Parameters

Parameters can be extracted from a path specification during conversion into a regular expression.

final parameters = <String>[];
final regExp = pathToRegExp('/user/:id', parameters: parameters);
parameters; // => ['id']

Extracting Arguments

extract() maps the parameters of a path specification to their corresponding arguments in a match.

final parameters = <String>[];
final regExp = pathToRegExp('/user/:id', parameters: parameters);
final match = regExp.matchAsPrefix('/user/12');
extract(parameters, match); // => {'id': '12'}

Generating

pathToFunction() converts a path specification into a function that generates matching paths.

final toPath = pathToFunction('/user/:id');
toPath({'id': '12'}); // => '/user/12'

Tokens

parse() converts a path specification into a list of tokens, which can be used to create a regular expression or path generating function.

final tokens = parse('/users/:id');
final regExp = tokensToRegExp(tokens);
final toPath = tokensToFunction(tokens);

Similar to pathToRegExp(), parameters can also be extracted during parsing.

final parameters = <String>[];
final tokens = parse('/users/:id', parameters: parameters);

If you intend to match and generate paths from the same path specification, parse() and the token-based functions should be preferred to their path-based counterparts. This is because the token-based functions can reuse the same tokens, whereas each path-based function must parse the path specification anew.

Options

Prefix Matching

By default, a regular expression created by pathToRegExp or tokensToRegExp matches the entire input. However, if the optional prefix argument is true, it may also match as a prefix until a delimiter.

final regExp = pathToRegExp('/user/:id', prefix: true);
regExp.hasMatch('/user/12/details'); // => true

Demo

Try the path_to_regexp_demo to experiment with this library.

Credit

This package is heavily inspired by its JavaScript namesake path-to-regexp.

Libraries

path_to_regexp