GitHub - pointfreeco/swift-web: ? A collection of Swift server-side frameworks f...

 4 years ago
source link: https://github.com/pointfreeco/swift-web
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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.


This library should be considered alpha, and not stable. Breaking changes will happen often.


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

Primary modules

Supporting modules


An embedded domain specific language (EDSL) in Swift for modeling HTML documents. A few simple value types and functions allow you to model most of HTML, and they compose easily.

import Html

let doc = document([
      p(["Hello world!"]),
      a([href("/")], ["Home"])

render(doc, config: pretty)
<!DOCTYPE html>
      Hello world!
    <a href="/">

The design of this library has been covered by the following articles:


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;


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

▿ 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>


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 /
    <¢> .get <% end,

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

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

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

  // Matches: POST /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


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: "/")!))
Status 200
Content-Type: text/html

<p>Hello world!</p>


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)])])

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


Contains functions for pretty printing an Html node (or nodes) using DoctorPretty, a wonderful little pretty printer library. The implementation of this library has been covered in this article.

The library not only takes care of adding newlines for tags so that the DOM structure is easy to read, but will also insert newlines when text goes past a column width, and even align smartly:

import HtmlPrettyPrint

let doc = document([
      comment("This is gonna be a long comment. Let's see what happens!"),
          [id("some-long-id"), Html.class("foo bar baz")],
          ["hello world"]),
        img(src: "cat.jpg", alt: "", [id("cat"), Html.class("cat")])

prettyPrint(node: doc, pageWidth: 40)
<!DOCTYPE html>
    <!-- This is gonna be a long
         comment. Let's see what
         happens! -->
      <div id="some-long-id"
           class="foo bar baz">
        hello world
      <img src="cat.jpg"


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).


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

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