swift-web

A collection of frameworks for solving various problems in building a Swift web framework. Each framework focuses on a single problem, like HTML rendering, CSS preprocessing, routing, middleware, and more. They also do not depend on any other framework in the collection. You can choose which pieces you want and don't want, for example you can use Html without Css.

Stability

This library should be considered experimental. If you find its contents useful, please consider maintaining a fork.

Installation

import PackageDescription

let package = Package(
  dependencies: [
    .package(url: "https://github.com/pointfreeco/swift-web.git", .branch("master")),
  ]
)

Getting started

This library contains an extensive test suite and a set of playgrounds that can be explored. To get it running:

git clone https://github.com/pointfreeco/swift-web.git
cd swift-web
swift package generate-xcodeproj
xed .
Run tests: Command+U
Build: Command+B
Open a playground!

Included modules

Supporting modules

HttpPipelineHtmlSupport
HtmlCssSupport
CssReset

`Css`

An EDSL for a CSS preprocessor like Sass. A few simple value types and functions allow you to model most of CSS, and allow you express new things not possible in standard CSS.

import Css

let css = body % (
  padding(all: .rem(2))
    <> background(Color.hsl(60, 0.5, 0.8))
)

render(css: css)

body {
  padding-top    : 2rem;
  padding-right  : 2rem;
  padding-bottom : 2rem;
  padding-left   : 2rem;
  background     : #e6e6b3;
}

`HttpPipeline`

A few types and functions for modeling server middleware as a simple function that transforms a request to a response. It uses phantom types express the state transitions of when you are allowed to write the status, headers and response body.

import HttpPipeline

let middleware = writeStatus(.ok)
  >>> writeHeader(.contentType(.html))
  >>> closeHeaders
  >>> send(render(document).data(using: .utf8))
  >>> end

let request = URLRequest(url: URL(string: "/")!)
let conn = connection(from: request).map(const(Data?.none))

▿ Step
  ResponseEnded

▿ Request
  GET /

  (Data, 0 bytes)

▿ Response
  Status 200 OK
  Content-Type: text/html; charset=utf8

  <html><body><p>Hello world!</p><p>Goodbye!</p><a href="/">Home</a></body></html>

`ApplicativeRouter`

A router built on the principles of “applicatives” that unifies parsing requests and printing routes. It is robust, composable and type-safe. Its job is to take the incoming, unstructured URLRequest from the browser and turn it into a structured value so that your app can do what it needs to do to produce a response. Additionally, given a value, it can do the reverse in which it generates a request that can be used in a hyperlink. Most of the ideas for this library were taking from this paper.

import ApplicativeRouter

struct UserData: Decodable {
  let email: String
}

enum Route {
  case home
  case episodes
  case episode(String)
  case search(String?)
  case signup(UserData?)
}

let router = [
  // Matches: GET /
  Route.iso.home
    <¢> .get <% end,

  // Matches: GET /episode/:str
  Route.iso.episode
    <¢> get %> lit("episode") %> pathParam(.string) <% end,

  // Matches: GET /episodes
  Route.iso.episodes
    <¢> get %> lit("episodes") <% end,

  // Matches: GET /search?query=:optional_string
  Route.iso.search
    <¢> get %> lit("search") %> queryParam("query", opt(.string)) <% end,

  // Matches: POST /signup
  Route.iso.signup
    <¢> post %> jsonBody(Episode.self) <%> lit("signup") %> opt(.jsonBody)) <% end,
  ]
  .reduce(.empty, <|>)

// Match a route given a request
let request = URLRequest(url: URL(string: "https://www.pointfree.co/episode/001-hello-world")!)
let route = router.match(request: request)
// => Route.episode("001-hello-world")

// Generate a string from a route:
router.absoluteString(for: .episode("001-hello-world"))
// => /episode/001-hello-world

`HttpPipelineHtmlSupport`

Adds middleware for rendering an Html view:

import Foundation
import Html
import HttpPipeline
import HttpPipelineHtmlSupport

let view = View(p(["Hello world!"]))

let middleware = writeStatus(.ok)
  >>> respond(view)

let conn = connection(from: URLRequest(url: URL(string: "/")!))
middleware(conn).response.description

Status 200
Content-Type: text/html

<p>Hello world!</p>

`HtmlCssSupport`

Adds an element and attribute function to Html for render Css values into an internal stylesheet or inline styles. The element function style allows you to provide a Stylesheet value that will be rendered to an internal stylesheet:

import Css
import Html
import HtmlCssSupport

let css = body % background(red)
let document = html([head([style(css)])])
render(document)

<html>
  <head>
    <style>body{background:#ff0000}</style>
  </head>
</html>

The attribute function style allows you to render a stylesheet inline directly on an element:

import Css
import Html
import HtmlCssSupport

let anchorStyle = color(.red)
  <> textTransform(.capitalize)

let styledDocument = p([
  "Go back ",
  a([style(anchorStyle)], ["Home"])
  ])

print(render(styledDocument, config: pretty))

<p>
  Go back
  <a style="color:#ff0000;text-transform:capitalize">
    Home
  </a>
</p>

`CssReset`

Contains a single value reset of type Stylesheet that resets all of the defaults for a webpage. It can be combined with another stylesheet via reset <> otherStyles, or can be directly rendered to a stylesheet string via render(reset).

License

All modules are released under the MIT license. See LICENSE for details.