NSURL Response Status Meaning

Thanks and sorry for all the posts. I will try that code tonight. The project summary: I want to have the app go to Craigslist daily with given search parameter (Craigslist puts those parameters in the URL as shown below). Then if a result matches a search term I'm looking for, I want it to save that match and notify me. h ttps://detroit.craigslist.org/search/mcy?hasPic=1&search_distance=100&postal=48152&min_price=1000&max_price=4000&min_auto_year=1990&max_auto_year=2017&auto_title_status=1

Quinn,

Here's the new code with your format:

import UIKit
class ViewController: UIViewController, URLSessionDelegate {

    var session: URLSession!
    @IBAction func refreshData(_ sender: Any) {

        NSLog("start")
        if self.session == nil {
            let config = URLSessionConfiguration.default
            config.requestCachePolicy = .reloadIgnoringLocalCacheData
            self.session = URLSession(configuration: config, delegate: self, delegateQueue: .main)
        }
        let url = URL(string: "h t t p s : / / d e t r o i t . c r a i g s l i s t . o r g")!
        let req = URLRequest(url: url)
        self.session.dataTask(with: req) { (data, response, error) in
            if let error = error as NSError? {
                NSLog("transport error: %@ / %d", error.domain, error.code)
                return
            }
            NSLog("success")
            if let unwrappedData = data {
                let dataString = NSString(data: unwrappedData, encoding: String.Encoding.utf8.rawValue)
                print("Printing Response...")
                print(response)
                print("Printing Data...")
                print(dataString)

            }
     
            }.resume()


        func urlSession(_ session: URLSession, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
            NSLog("challenge %@", challenge.protectionSpace.authenticationMethod)
            completionHandler(.performDefaultHandling, nil)
        }

    }
    override func viewDidLoad() {
        super.viewDidLoad()
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }

}

And the output:

2017-08-14 20:46:06.925 Craigslist[1191:26211] start

2017-08-14 20:46:07.429 Craigslist[1191:26211] success

Printing Response...

Optional(<NSHTTPURLResponse: 0x61800003ff00> { URL: h ttps:/

"Strict-Transport-Security" = "max-age=86400";

} })

Printing Data...

Optional(

)

2017-08-14 20:46:07.429 Craigslist[1191:26211] success

So that’s work, right? Which means you should be able to remove your authentication challenge handler entirely, because it’s doing nothing other than logging.

Share and Enjoy
—
Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware

let myEmail = "eskimo" + "1" + "@apple.com"

Yes I'm getting the success, but as you can see by the output of (dataString) it's coming up blank despite there being stuff on the page. That's the issue I'm struggling with.

… as you can see by the output of (dataString) it's coming up blank despite there being stuff on the page. That's the issue I'm struggling with.

Ah, that’s a completely different kettle of fish. I’ll respond below (because this indentation is getting out of control)-:

Share and Enjoy
—
Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware

let myEmail = "eskimo" + "1" + "@apple.com"

… as you can see by the output of (dataString) it's coming up blank despite there being stuff on the page. That's the issue I'm struggling with.

With reference to the code you posted on 15 Aug, there’s a bunch of potential issues:

• First, you should be using Swift’s

  String

  here, not Foundation’s

  NSString

  . This isn’t the cause of your problem, but programming in Swift is easier if you stick with Swift’s standard data types.

• Next, you shouldn’t look at the data passed to your completion handler without first looking at the response’s status code. The fact that

  error

  is nil only tells you that

  URLSession

  was able to send the request to a server and get a response back. It doesn’t tell you that the request was successful on the server. You should always check the response status code (like the

  statusCode

  property) to verify that the response is valid.

• It’s also a good idea to check the response content type (via the

  mimeType

  property). In some cases (including captive networks and HTTP proxies) you can get a response that didn’t come from the origin server. In that case the body of the response may not be of the type you expect, and thus you should check for the type.

Putting all of the above together a typical completion handler should look like this:

let task = self.session.dataTask(with: request) { (data, response, error) in
    if let error = error {
        // … report transport error …
        return
    }
    let response = response as! HTTPURLResponse
    let data = data!
    guard response.statusCode == 200 else {
        // … report server error …
        return
    }
    guard response.mimeType == "text/plain" else {
        // … report server error …
        return
    }
    NSLog("%@", data as NSData)
}

Once you know the type of the data you can reasonably parse it. How you do that depends on the type itself. My guess is that you’re dealing with

text/html

Share and Enjoy
—
Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware

let myEmail = "eskimo" + "1" + "@apple.com"

Ok that makes sense. So I was there was a connection, but seeing a blank rather than any error because I wasn't checking the response. I get no output, but when I check, it's getting hung up in the guard response.statusCode == 200 block.

So what’s

statusCode

Share and Enjoy
—
Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware

let myEmail = "eskimo" + "1" + "@apple.com"

<NSHTTPURLResponse: 0x610000032800> { URL: https:/

"Strict-Transport-Security" = "max-age=86400";

} }

That’s a print out of the response object which, alas, does not show the status code. I’m looking for the

statusCode

Share and Enjoy
—
Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware

let myEmail = "eskimo" + "1" + "@apple.com"

I see where that line of code is (the 'return' part right?), however it's coming up blank for me. I put print statements in to verify it's going through that block of code, but the return part comes back blank.

guard response.statusCode == 200 else {
    print("Server Error")
    return
}

Output:

Server Error

If you want the code, you should ask to print it :

guard response.statusCode == 200 else {
    print("Server Error ", response.statusCode)
    return
}

I get this as the output:

Server Error 404

You know 404 : means the resource (typically the page) was not found on the server.

Check the url in your request ; try to access it manually in Safari to see if you get the same error.

No the URL (craigslist) works fine in my browser. I think there's something about the security of the site that it's running into problems with.

"Strict-Transport-Security" = "max-age=86400";