Can't set headers on my WKWebView POST request

As the OP stated, I have also confirmed in Charles that the body is 0 bytes after webView.load(request).

There's a workaround for this WKWebView bug, we will initiate a POST request using URLSession convert the data returned by the server to String and instead of loading the url we will use loadHTMLString which will:

Set the webpage contents and base URL.

and the content is our converted string:

var request = URLRequest(url: URL(string: "http://www.yourWebsite")!)
request.httpMethod = "POST"
let params = "do=something&andAgain=something"
request.httpBody = params.data(using: .utf8)

let task = URLSession.shared.dataTask(with: request) { (data : Data?, response : URLResponse?, error : Error?) in
        if data != nil {
            if let returnString = String(data: data!, encoding: .utf8) {
                self.webView.loadHTMLString(returnString, baseURL: URL(string: "http://www.yourWebsite.com")!)
            }
        }
}
task.resume()

I had the same problem with WKWebView, that I decided to use instead of UIWebView to avoid the pickers crash in iOS 8. There are two ways that I can think of:

  1. Use NSURLConnection to make the request and then fill the WKWebView with it's response data. You can find an example here: https://stackoverflow.com/a/10077796/4116680 (You only need connection:didReceiveData: and connectionDidFinishLoading: from the delegate if you don't use a self signed SSL certificate)
  2. Use a JavaScript to make the POST request. Here is an example:

Create file eg. "POSTRequestJS.html":

<html>
    <head>
        <script>
            //POST request example:
            //post('URL', {key: 'value'});
            function post(path, params) {
                var method = "post";
                var form = document.createElement("form");
                form.setAttribute("method", method);
                form.setAttribute("action", path);

                for(var key in params) {
                    if(params.hasOwnProperty(key)) {
                        var hiddenField = document.createElement("input");
                        hiddenField.setAttribute("type", "hidden");
                        hiddenField.setAttribute("name", key);
                        hiddenField.setAttribute("value", params[key]);

                        form.appendChild(hiddenField);
                    }
                }

                document.body.appendChild(form);
                form.submit();
            }
        </script>
    </head>
    <body>
    </body>
</html>

And in your code after where you want to load your request:

NSString *path = [[NSBundle mainBundle] pathForResource:@"POSTRequestJS" ofType:@"html"];
NSString *html = [[NSString alloc] initWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];
WKWebView.navigationDelegate = self;
[WKWebView loadHTMLString:html baseURL:[[NSBundle mainBundle] bundleURL]];

Add method:

- (void)makePostRequest
{
    NSString *postData = [NSString stringWithFormat: @"email=%@&password=%@", email, password];
    NSString *urlString = @"http://materik.me/endpoint";
    NSString *jscript = [NSString stringWithFormat:@"post('%@', {%@});", urlString, postData];

    DLog(@"Javascript: %@", jscript);

    [WKWebView evaluateJavaScript:jscript completionHandler:nil];

    didMakePostRequest = YES;
}

And last add the WKNavigationDelegate:

- (void)webView:(WKWebView *)webView didFinishNavigation:(WKNavigation *)navigation
{
    if (!didMakePostRequest) {
        [self makePostRequest];
    }
}

This appears to be a bug.
https://bugs.webkit.org/show_bug.cgi?id=140188

Hopefully it will be addressed soon. In the meantime, reverting to UIWebView or implementing the workaround proposed by Spas Bilyarski in his answer seems to be the best options.

Tags:

Ios

Objective C

Nsurlrequest

Charles Proxy

Wkwebview

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