HTML Parsing in Swift (iOS/macOS): SwiftSoup Library

HTML Parsing in Swift (iOS/macOS) with SwiftSoup

When developing applications for iOS and macOS, there is often a need to extract data from web pages. Unlike Python with its powerful libraries BeautifulSoup and Scrapy, the Swift world lacked a convenient tool for HTML parsing for a long time. The solution came with the SwiftSoup library — a pure Swift port of the popular Java library Jsoup. It provides a convenient API for working with HTML documents, navigating the DOM tree, searching for elements using CSS selectors, and extracting data.

What is SwiftSoup?

SwiftSoup is an open-source library that allows you to parse HTML, extract and modify data, and clean HTML from potentially dangerous elements. It works on all Apple platforms: iOS, macOS, tvOS, watchOS. Main features:

• Parsing HTML from a string, URL, or file
• Navigating the DOM tree using CSS selectors
• Extracting text, attributes, and HTML code of elements
• Modifying the document (adding, deleting, changing elements)
• Cleaning HTML from XSS attacks
• Support for all modern HTML standards

Installing SwiftSoup

The easiest way to install is via Swift Package Manager. Add the dependency to your Package.swift file:

// swift-tools-version:5.5import PackageDescription

let package = Package(    name: "MyProject",    dependencies: [        .package(url: "https://github.com/scinfu/SwiftSoup.git", from: "2.6.0")    ],    targets: [        .target(            name: "MyProject",            dependencies: ["SwiftSoup"])    ])

If you are using Xcode, open the menu File → Add Packages..., paste the repository URL, and click Add Package.

Basic HTML Parsing Example

Let's look at a simple example — extracting the page title:

import SwiftSoup

let html = "<html><head><title>PythonLib - tools for developers</title></head><body><p>Hello, world!</p></body></html>"

do {    let doc = try SwiftSoup.parse(html)    let title = try doc.title()    print("Title: \\(title)")        let bodyText = try doc.body()?.text()    print("Body text: \\(bodyText ?? "")")} catch Exception.Error(let type, let message) {    print("Error: \\(type) — \\(message)")} catch {    print("Unknown error")}

Console output:

Title: PythonLib - tools for developersBody text: Hello, world!

Searching for Elements with CSS Selectors

One of the strong points of SwiftSoup is its powerful selectors, familiar to web developers. You can use any CSS selectors:

let html = """<div class="articles">    <article id="post-1">        <h2 class="title">SwiftSoup tutorial</h2>        <p class="meta">Published: 2024-01-15</p>        <p>Article content...</p>    </article>    <article id="post-2">        <h2 class="title">HTML Parsing in Swift</h2>        <p class="meta">Published: 2024-02-20</p>        <p>More content...</p>    </article></div>"""

let doc = try SwiftSoup.parse(html)

// Search by classlet titles = try doc.select(".title")for title in titles {    print(try title.text())}

// Search by IDif let post = try doc.select("#post-1").first() {    let h2 = try post.select("h2").text()    let date = try post.select(".meta").text()    print("Article: \\(h2) — \\(date)")}

// Combined selectorlet articles = try doc.select("div.articles > article")