PathTemplate

Swift implementation of templated paths. Inspired by path-to-regexp and URITemplate.swift.

Installation

Swift Package Manager:

Append the following to your Package.swift dependencies: []

.package(url: "https://github.com/gjeck/PathTemplate.swift.git")

Cocoapods

Add the following to your Podfile

pod 'PathTemplate'

Basic Usage

A PathTemplate is useful for working on structured String data like URLs.

Expanding a path template

let template: PathTemplate = "/user/:id"
template.expand(["id": 123])
=> "/user/123"

Determine the parameters in a template

let template: PathTemplate = "https://api.github.com/repos/:owner/:repo/"
template.parameterNames
=> ["owner", "repo"]

Extract the parameters used in a given path

let template: PathTemplate = "/artist/:artistId/album/:albumId"
template.extract("/artist/123/album/456")
=> ["artistId": "123", "albumId": "456"]

Parameter Modifiers

Named parameters are defined by prefixing a colon to a segment of word characters [A-Za-z0-9_] like :user. Additional modifiers can be suffixed for different meaning:

1. ? the parameter is optional
2. * zero or more segments
3. + one or more segments

? Optional

let template: PathTemplate = "https://:hostname/:path?"
template.expand(["hostname": "github.com"])
=> "https://github.com"

template.expand(["hostname": "github.com", "path": "user"])
=> "https://github.com/user"

* Zero or More

let template: PathTemplate = "https://:hostname/:path*"
template.expand(["hostname": "github.com", "path": ["user", "gjeck"]])
=> "https://github.com/user/gjeck"

template.expand(["hostname": "github.com"])
=> "https://github.com"

+ One or More

let template: PathTemplate = "https://:hostname/:path+"
template.expand(["hostname": "github.com", "path": ["user", "gjeck"]])
=> "https://github.com/user/gjeck"

template.expand(["hostname": "github.com"])
=> nil

Regular Expression Parameters

Parameters can be provided a custom regular expression that overrides the default match. For example, you could enforce matching digits in a path.

let template: PathTemplate = "/image-:imageId(\d+).png"
template.expand(["imageId": 123])
=> "/image-123.png"

template.expand(["imageId": "abc"])
=> nil

Unnamed Parameters

It is possible to write an unnamed parameter that only consists of a matching group. It works the same as a named parameter, except it will be numerically indexed.

let template: PathTemplate = "/cool/(\d+)/(.*)"
template.parameterNames
=> ["0", "1"]

template.expand(["0": 123, "1": "wow"])
=> "/cool/123/wow"

Advanced Usage

Enforcing case sensitive matching

let template = PathTemplate("/User/:id", options: .init(isCaseSensitive: true))
template.extract("/user/123") // Note that "user" has a lowercase "u"
=> [] 

Accessing the underlying path regular expression

let template: PathTemplate = "/user/:id"
template.regex
=> <NSRegularExpression: 0x102745860> ^\/user\/([^\/]+?)(?:\/)?$