iOS: HTTP POST request times out when setting httpBody property

Question

The code below is based on this excellent SO answer for making POST requests on iOS. This code attempts to make a POST request to:

http://requestb.in/14090od1

The request works if there is no value for the httpBody property of the URLRequest object, or if the value is only the empty string.

However, once a non-empty value is assigned to httpBody, the request times out.

Anyone know why?

// Succeeds
let userOptions = ["url": "http://requestb.in/14090od1"]
userOptions["bodyString" : ""]
doPost(userOptions: userOptions)

// Fails
let userOptions = ["url": "http://requestb.in/14090od1"]
userOptions["bodyString" : "hi"]
doPost(userOptions: userOptions)


fileprivate func doPost(userOptions: [String:Any]) {
    // Get URL string
    let urlString = userOptions["url"] as? String ?? ""

    // If invalid URL, return early
    guard let url = URL(string: urlString) else {
        printError("Error in doPost: malformed URL")
        return
    }

    // If here, URL valid so execute request
    // Create request
    var request = URLRequest(url: url)

    // Add headers
    if let tHeaders = userOptions["headers"] as? [String:String] {
        for (key, value) in tHeaders {
            request.setValue(value, forHTTPHeaderField: key)
        }
    }

    // Add body data
    let bodyString = userOptions["bodyString"] as? String ?? ""
    request.httpBody = bodyString.data(using: .utf8)

    // Create data task
    let task = URLSession.shared.dataTask(with: request) { data, response, error in
        // If networking error, return early
        guard let data = data, let httpResponse = response as? HTTPURLResponse, error == nil else {
            printError("Error with network while executing POST request: \(error)")
            return
        }

        // Why, oh why, does it not reach here???
    }

    // Start data task
    print("Executing HTTP request: \(request)")
    task.resume()
}

Answer 1

If you want to do a POST request, not only do you want to set the httpBody, but you also want to set the httpMethod of the request to POST.

request.httpMethod = "POST"