SwiftSoup is a Swift library for parsing and manipulating HTML and XML. It is inspired by the popular Java library, Jsoup. When it comes to handling parsing errors or malformed HTML, SwiftSoup, like Jsoup, is designed to be lenient and fault-tolerant. It uses a forgiving parsing algorithm that can handle many kinds of HTML found in the wild, even if it's not well-formed.
Here's how SwiftSoup manages parsing errors:
Tag Balancing: SwiftSoup automatically balances tags. If there are missing closing tags or tags are closed in the wrong order, SwiftSoup will try to make a logical structure by closing tags where it deems appropriate. This way, the resulting document tree makes sense and can be navigated and queried.
Tolerant Parsing: When encountering unrecognized or malformed tags, SwiftSoup will still try to parse them, integrating them into the document tree as best as it can. This is similar to how web browsers handle incorrect HTML.
Text Nodes: If SwiftSoup encounters something it can't parse as a tag, attribute, or recognizable HTML structure, it will usually create a text node for it. This ensures that the content is still accessible in some form, rather than being lost.
Error Tracking: SwiftSoup does not offer built-in error tracking functionality for parsing errors. Unlike XML parsers that throw exceptions or provide error handlers for malformed content, SwiftSoup aims to clean up the HTML and make it accessible without interrupting the parsing process.
Here's a simple example to show how SwiftSoup handles malformed HTML:
import SwiftSoup
let malformedHTML = "<html><head><title>Test</title><body><p>Paragraph without closing tag"
do {
let doc: Document = try SwiftSoup.parse(malformedHTML)
print(try doc.body()?.html() ?? "No body")
} catch Exception.Error(let type, let message) {
print(message)
} catch {
print("error")
}
In this example, we're parsing an HTML string where the <p> tag is not closed properly. SwiftSoup will handle this by implicitly closing the <p> tag when it encounters the end of the document. The resulting parsed HTML will have a logical structure, with the unclosed tag corrected.
Remember that while SwiftSoup can handle a wide range of malformed HTML, it's still possible to encounter HTML that can't be sensibly parsed into a valid document structure. In such cases, the resulting tree might not reflect the intended structure of the original HTML, but SwiftSoup will still do its best to create a navigable document.
