How To Get HTML source from URL with Swift

Question

I need to look at the HTML of a page given by a certain URL. If I have this, what is the most efficient and synchronous way to get the HTML source for that URL using Swift? I haven't been able to find a concise way online that returns it into a variable as opposed to printing it in a completionHandler.

I need to manipulate the source outside of whatever call uses the URL. How is this done in Swift?

Answer 1

Disclaimer : Since this is getting quite a lot of views, I just want to remind everyone that this answer here is synchronous, and will block your app if you do it on the main thread. You should always do this asynchronously (in a background thread), but the question asked for a synchronous method, so it would be out of scope to explain how to do it here.

---

You should probably look at the method :

+ stringWithContentsOfURL:encoding:error (docs)

You would call it like this in Objective C :

NSString *myURLString = @"http://google.com";
NSURL *myURL = [NSURL URLWithString:myURLString];

NSError *error = nil;
NSString *myHTMLString = [NSString stringWithContentsOfURL:myURL encoding: NSUTF8StringEncoding error:&error];

if (error != nil)
{
    NSLog(@"Error : %@", error);
}
else
{
    NSLog(@"HTML : %@", myHTMLString);
}

So in Swift 3 and 4, the equivalent would be :

let myURLString = "https://google.com"
guard let myURL = URL(string: myURLString) else {
    print("Error: \(myURLString) doesn't seem to be a valid URL")
    return
}

do {
    let myHTMLString = try String(contentsOf: myURL, encoding: .ascii)
    print("HTML : \(myHTMLString)")
} catch let error {
    print("Error: \(error)")
}

You might want to adapt the encoding (see the constants) depending on which encoding your page's using.

---

Old answer, Swift 2.2 :

let myURLString = "http://google.com"
guard let myURL = NSURL(string: myURLString) else {
    print("Error: \(myURLString) doesn't seem to be a valid URL")
    return
}

do {
    let myHTMLString = try String(contentsOfURL: myURL)
    print("HTML : \(myHTMLString)")
} catch let error as NSError {
    print("Error: \(error)")
}

---

Old answer, Swift 1.2 :

let myURLString = "http://google.com"

if let myURL = NSURL(string: myURLString) {
    var error: NSError?
    let myHTMLString = NSString(contentsOfURL: myURL, encoding: NSUTF8StringEncoding, error: &error)

    if let error = error {
        println("Error : \(error)")
    } else {
        println("HTML : \(myHTMLString)")
    }
} else {
    println("Error: \(myURLString) doesn't seem to be a valid URL")
}