SwiftSoup is a pure Swift library for working with real-world HTML. It provides a very convenient API for extracting and manipulating data, using the best of DOM, CSS, and jquery-like methods. However, SwiftSoup itself does not provide direct functionality to validate HTML against a set of rules or a schema like W3C validation.
To validate HTML, you typically need a validator that checks the markup against HTML standards. The W3C provides an online service for validating HTML documents, but this is not built into SwiftSoup.
If you want to validate HTML within a Swift application, you would have to either:
- Send the HTML to an external service (like the W3C validator) via an HTTP request and then parse the response.
- Use a Swift library specifically designed for HTML validation if one exists.
- Implement your own basic validation rules depending on what you're trying to achieve.
Here's an example of how you might use SwiftSoup to clean up HTML to ensure it's well-formed, which is different from validation but can be a useful preprocessing step:
import SwiftSoup
func cleanHTML(input: String) -> String? {
do {
let doc: Document = try SwiftSoup.parse(input)
// You can use SwiftSoup to manipulate the HTML if needed
// For example, removing script tags:
try doc.select("script").remove()
// Output the cleaned HTML
return try doc.html()
} catch {
print("Error parsing HTML: \(error)")
return nil
}
}
if let cleanedHTML = cleanHTML(input: "<html><body><p>Invalid HTML without closing tags") {
print(cleanedHTML)
// This will print out cleaned HTML, which is now well-formed
}
Remember, while the above example can ensure that the HTML is well-formed, it does not validate the HTML for conformance to web standards.
For actual validation, you would need to either use an HTML validation service or integrate with an existing HTML validation library or API. Here's a conceptual example of how you might integrate with an external validation service:
import Foundation
func validateHTML(html: String, completion: @escaping (Bool, String?) -> Void) {
// URL to the W3C validator or any other HTML validation service
guard let validationURL = URL(string: "https://validator.w3.org/nu/?out=json") else { return }
var request = URLRequest(url: validationURL)
request.httpMethod = "POST"
request.httpBody = html.data(using: .utf8)
request.addValue("text/html; charset=utf-8", forHTTPHeaderField: "Content-Type")
let task = URLSession.shared.dataTask(with: request) { data, response, error in
guard let data = data, error == nil else {
completion(false, error?.localizedDescription)
return
}
// Parse the JSON response from the validator
// This is a simplified example, the actual implementation would depend on the validator's response format
do {
if let jsonResult = try JSONSerialization.jsonObject(with: data) as? [String: Any],
let messages = jsonResult["messages"] as? [[String: Any]] {
// Check if there are any errors in the messages
let errors = messages.filter { $0["type"] as? String == "error" }
completion(errors.isEmpty, errors.isEmpty ? nil : "HTML is not valid.")
}
} catch {
completion(false, "Failed to parse validation response.")
}
}
task.resume()
}
// Usage example
validateHTML(html: "<html><body><p>Some HTML to validate</p></body></html>") { isValid, errorMessage in
if isValid {
print("HTML is valid!")
} else {
if let errorMessage = errorMessage {
print(errorMessage)
}
}
}
Please note that this example is very basic and for demonstration purposes only. When using an external service, you should handle the request and response more robustly, including proper error handling and parsing based on the service's actual response format.
