UIWebView capturing the response headers

http-headers, ios, iphone, response, uiwebview

Solution

I love the objective-c runtime. Is there something that you want to do but don't have an API for it? DM;HR.

Alright, on a more serious note, here's the solution to this. It will capture every URL Response that initiated from `CFNetwork`, which is what UIWebView happens to use behind the scenes. It will also capture AJAX requests, image loads, and more.

Adding a filter to this should probably be as easy as doing a regex on the contents of the headers.

@implementation NSURLResponse(webViewHack)

static IMP originalImp;

static char *rot13decode(const char *input)
{
    static char output[100];

    char *result = output;

    // rot13 decode the string
    while (*input) {
        if (isalpha(*input))
        {
            int inputCase = isupper(*input) ? 'A' : 'a';

            *result = (((*input - inputCase) + 13) % 26) + inputCase;
        }
        else {
            *result = *input;
        }

        input++;
        result++;
    }

    *result = '\0';
    return output;
}

+(void) load {
    SEL oldSel = sel_getUid(rot13decode("_vavgJvguPSHEYErfcbafr:"));

    Method old = class_getInstanceMethod(self, oldSel);
    Method new = class_getInstanceMethod(self, @selector(__initWithCFURLResponse:));

    originalImp = method_getImplementation(old);
    method_exchangeImplementations(old, new);
}

-(id) __initWithCFURLResponse:(void *) cf {
    if ((self = originalImp(self, _cmd, cf))) {
        printf("-[%s %s]: %s", class_getName([self class]), sel_getName(_cmd), [[[self URL] description] UTF8String]);

        if ([self isKindOfClass:[NSHTTPURLResponse class]])
        {
            printf(" - %s", [[[(NSHTTPURLResponse *) self allHeaderFields] description] UTF8String]);
        }

        printf("\n");
    }

    return self;
}

@end

Problem

I searched/googled a lot but could not get the answer on how to capture HTTP response headers in `UIWebview`. Say I redirect to user to registration gateway(which is already active) in UIWebview on App Launch and when user finishes the registration, the app should be notified with the successful unique id assigned to the user on registration which is passed back in HTTP Response Headers. Is there any direct way to capture/print the HTTP Response headers using `UIWebview`?

Original source