Modify Request of webView shouldStartLoadWithRequest: - ios

Question

Currently I am developing an hybrid app which uses webView shouldStartLoadWithRequest: to provide a token for the login. My function works fine for every normal request I make (a click e.g.)
- (BOOL)webView:(UIWebView*)webView shouldStartLoadWithRequest:(NSURLRequest*)request
NSLog([NSString stringWithFormat:#"Loading View: %#",[[request URL] absoluteString]]);
if ([[[request URL] absoluteString] rangeOfString:BASE_URL].location != NSNotFound) {
NSString *token = [[NSUserDefaults standardUserDefaults] stringForKey:kDefaultsKeyLoginToken];
NSString *hash = [[NSUserDefaults standardUserDefaults] stringForKey:kDefaultsKeyLoginHash];
NSString *params = [NSString stringWithFormat:#"mobile=app&user_token=%#&user_hash=%#",token,hash];
if([[request URL] query] == nil) {
[self LoadUrl:[[request URL] absoluteString] withGetParams:params append:NO];
return NO;
}else{
if([[[request URL] absoluteString] rangeOfString:params].location == NSNotFound){
[self LoadUrl:[[request URL] absoluteString] withGetParams:params append:YES];
return NO;
}
}
}
-(void)LoadUrl:(NSString *)url withGetParams:(NSString *)params append:(BOOL)append{
NSString *PreUrl;
if(append == YES) PreUrl = [NSString stringWithFormat:#"%#&%#",url,params];
else PreUrl = [NSString stringWithFormat:#"%#?%#",url,params];
NSURL *nsurl = [NSURL URLWithString: PreUrl];
NSURLRequest *request = [NSURLRequest requestWithURL:nsurl];
[self.WebView loadRequest:request];
}
The Problem I have with this Code is that if I load an Image e.g. it will be detected as "to be hashed-appended" (which is correct, I want every request to have the Auth included) BUT the Image will get loaded in the Webview itself.
My first try (before I switched to this model) was to modify the request parsed. But every change got Ignored....
Has anyone an Idea how I could fix this problem? Is there a way to really modify requests? Or if not, can I at least determine the "target" of the request or forward it?
Thanks for any help

Answer 1

I found a Solution for my Problem. Sublcassing was the right approach but not UIWebView but a own NSURLProtocol.
So what I did:
Create an own Sublcass of NSURLProtocol
#interface MyURL : NSURLProtocol <NSURLConnectionDelegate>
Add some standard handling for HTTP-Connections
#interface MyURL () <NSURLConnectionDelegate>
#property (nonatomic, strong) NSURLConnection *connection;
#property (nonatomic, strong) NSMutableData *mutableData;
#property (nonatomic, strong) NSURLResponse *response;
#end
#implementation MyURL
+ (NSURLRequest *)canonicalRequestForRequest:(NSURLRequest *)request
{
return request;
}
- (void)stopLoading
{
[self.connection cancel];
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
[self.client URLProtocol:self didLoadData:data];
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
[self.client URLProtocol:self didFailWithError:error];
self.connection = nil;
}
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
[self.client URLProtocol:self didReceiveResponse:response cacheStoragePolicy:NSURLCacheStorageAllowed];
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
[self.client URLProtocolDidFinishLoading:self];
self.connection = nil;
}
#end
And now the interesting part - Modifying every request that goes to my server
So first: Check if this Request goes to my Server and determine if my protocol should take care of it
+ (BOOL)canInitWithRequest:(NSURLRequest *)request
{
NSString *token = [[NSUserDefaults standardUserDefaults] stringForKey:kDefaultsKeyLoginToken];
NSString *hash = [[NSUserDefaults standardUserDefaults] stringForKey:kDefaultsKeyLoginHash];
if([NSURLProtocol propertyForKey:#"TokenSet" inRequest:request]) return NO; // We already handled it
if((hash == nil) || (token == nil) ) return NO; // We are not logged in
NSString *params = [NSString stringWithFormat:#"mobile=app&user_token=%#&user_hash=%#",token,hash];
if (([[[request URL] absoluteString] rangeOfString:BASE_URL].location != NSNotFound) && ([[[request URL] absoluteString] rangeOfString:#"/assets/"].location == NSNotFound)){
if([[[request URL] absoluteString] rangeOfString:params].location == NSNotFound){
return YES; // URL does not contain the login token & we're not requesting an asset (js/img/etc.)
}
}
return NO;
}
So if + (BOOL)canInitWithRequest:(NSURLRequest *)request returned yes, I have to handle the request. I already know that it does not contain the login token & hash so I've got to determine if it has to be appended or not. To modify the request in general, I create a MutableCopy of our request, Modify it and set our URLConnection to the request.
- (void)startLoading
{
NSMutableURLRequest *newRequest = [self.request mutableCopy];
NSString *PreURL;
NSString *token = [[NSUserDefaults standardUserDefaults] stringForKey:kDefaultsKeyLoginToken];
NSString *hash = [[NSUserDefaults standardUserDefaults] stringForKey:kDefaultsKeyLoginHash];
NSString *params = [NSString stringWithFormat:#"mobile=app&user_token=%#&user_hash=%#",token,hash];
if([[newRequest URL] query] == nil) {
PreURL = [NSString stringWithFormat:#"%#?%#",[[newRequest URL] absoluteString],params];
}else{
if([[[newRequest URL] absoluteString] rangeOfString:params].location == NSNotFound){
PreURL = [NSString stringWithFormat:#"%#&%#",[[newRequest URL] absoluteString],params];
}
}
NSURL *nsurl = [NSURL URLWithString: PreURL];
[newRequest setURL:nsurl];
[NSURLProtocol setProperty:#"YES" forKey:#"TokenSet" inRequest:newRequest];
self.connection = [NSURLConnection connectionWithRequest:newRequest delegate:self];
}
And to finish it all, we register our URL-Protocol as Protocol in AppDelegate.
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
[NSURLProtocol registerClass:[MyURL class]];
}
With this Solution I first have the advantage of having my login token in ANY request ANY part of my App sends to my Server. No more worries about this. And I can do cool stuff, like saving resources after loading them the first time or even use Images from my App-Bundle in Webviews...
I hope this helps someone.