Adding custom http header field on all UIWebView requests

Question

I'm using the below code to set a custom HTTP header on requests sent from my UIWebView. The problem is that I'm seeing the page load for a second and then it goes to a white/blank screen. I've tested with different URLs but the behavior is the same. Any ideas?

func webView(webView: UIWebView, shouldStartLoadWithRequest request: NSURLRequest, navigationType: UIWebViewNavigationType) -> Bool {
        var headerIsPresent = false
        let headerFields = request.allHTTPHeaderFields
        for headerField in headerFields?.keys.array as [String] {
            if headerField == "X-Test-App" {
                headerIsPresent = true
            }
        }

        if headerIsPresent {
            return true
        } else {
            dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), {
                dispatch_async(dispatch_get_main_queue(), {
                let url = request.URL
                var newRequest: NSMutableURLRequest = request as NSMutableURLRequest

                // set new header
                newRequest.addValue("MyValue", forHTTPHeaderField: "X-Test-App")

                // reload the request
                self.webView.loadRequest(newRequest)
                })
            })
            return false
        }
    }

um, I haven't done much with swift, but that looks recursive...maybe put a debug break in there? — Mike M
– Mike M, Commented Jan 13, 2015 at 20:47
It is recursive, but shouldn't be an issue because they're checking for the presence of the header before adding it (and recursing) — David Berry
– David Berry, Commented Jan 13, 2015 at 20:51
I believe that shouldStartLoadWithRequest will only be invoked on page loads, not on resource loads, you might verify that that isn't the problem. — David Berry
– David Berry, Commented Jan 13, 2015 at 20:51
You can also replace all the code at the top with a single line using contains. var headerIsPresent = contains(request.allHTTPHeaderFields?.keys.array as [String], "X-Test-App") but that's unrelated to your problem. — David Berry
– David Berry, Commented Jan 13, 2015 at 20:57

codeman · Accepted Answer · 2015-01-14 15:17:12Z

7

Based on David's comments, I used the following solution:

func webView(webView: UIWebView, shouldStartLoadWithRequest request: NSURLRequest, navigationType: UIWebViewNavigationType) -> Bool {
        let headerFields = request.allHTTPHeaderFields
        var headerIsPresent = contains(request.allHTTPHeaderFields?.keys.array as [String], "X-Test-App")

        if headerIsPresent || navigationType == UIWebViewNavigationType.Other {
            return true
        } else {
            dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), {
                dispatch_async(dispatch_get_main_queue(), {
                    let url = request.URL
                    var newRequest: NSMutableURLRequest = request as NSMutableURLRequest
                    // set new header
                    newRequest.addValue("MyValue", forHTTPHeaderField: "X-Test-App")

                    // reload the request
                    self.webView.loadRequest(newRequest)
                })
            })
            return false
        }
    }

answered Jan 14, 2015 at 15:17

codeman

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4 Comments

kevindeleon Over a year ago

Just curious, as I am in the same position and would like to add custom headers to several webviews (but keep from having to put the same code in each view controller), where did you add this function? In a particular view controller, or did you override webView at a lower level somehow?

codeman Over a year ago

I put it in just a single view controller called WebViewController, which I re-used for several different screens within the app.

Lucas Over a year ago

may I ask why add navigationType == UIWebViewNavigationType.Other

Aji Saputra Raka Siwi Over a year ago

How about WKWebView?

phoenixbox · Accepted Answer · 2015-11-14 10:07:44Z

1

I think there is a syntactic error with the line var headerIsPresent... Might be due to updated String characters API in Swift?

I used map instead of array and then call contains() on the result.

let headerIsPresent = request.allHTTPHeaderFields?.keys.map({$0}).contains("YOUR_HEADER_NAME")

answered Nov 14, 2015 at 10:07

phoenixbox

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Comments

ytbryan · Accepted Answer · 2017-09-08 10:25:26Z

1

If you are looking for code in swift:

    _ = request.allHTTPHeaderFields
    let headerIsPresent = request.allHTTPHeaderFields?.keys.contains("doerlist")

    if headerIsPresent! || navigationType == UIWebViewNavigationType.other {
        return true
    } else {

        DispatchQueue.global(qos: .background).async {
            DispatchQueue.main.async {
                let newRequest: NSMutableURLRequest = request as! NSMutableURLRequest
                newRequest.addValue("doerlist-a61444ea-6fef-4366-a39e-e029e6d521ef", forHTTPHeaderField: "doerlist")
                self.webView.loadRequest(newRequest as URLRequest)
            }
        }

        return false
    }

answered Sep 8, 2017 at 10:25

ytbryan

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