Caching web page in IOS using NSURLCache subclass

Question

I subclassed NSURLCache and overriden – cachedResponseForRequest: and – storeCachedResponse:forRequest: . I am storing all the files am getting in the application's documents directory.

Now, the problem is, the .html file when opened doesn't load all the resources (i.e, images,js and css). I didn't know wat the problem was, hence I did a "save page as" on the same web page and compared both the .html files (the one i saved from the browser and the one i cached.).

I found that in the html file saved from the browser, all the images and other files source paths have been replaced with the local paths..

<div><img src="./CNN.com International - Breaking, World, Business, Sports, Entertainment and Video News_files/footer_cnn_logo.png" width="23" height="11" alt="" border="0" class="cnn_ie6png">

But the html file that i cached, still has the url of the website..

<div><img src="http://i.cdn.turner.com/cnn/.e/img/3.0/global/footer/pngs/footer_cnn_logo.png" width="23" height="11" alt="" border="0" class="cnn_ie6png"/>

So how do I change it..?or what's the right way to save a web page along with all the resources..??

AM saving all the files am getting in storeCachedResponse:forRequest: method as it is. So do I have to do some modifications to this .html file before saving, so that it would refer all the resource path in the local folder properly ??

FYI, I do not want to use ASIWebPageRequest (Download and cache entire web page on ios)

//////////// Edit ////////////

So as Edwin Vermeer has answered, am able to get the right local file from my cache and return the response. but looks like, the UIWebView doesn't understand that data..! This is how am returning the response in cachedResponseForRequest: method

if (shouldFetchFromCache) {
            NSData* content = [NSData dataWithContentsOfFile:storagePath];

            NSDictionary *headers = @{@"Access-Control-Allow-Origin" : @"*", @"Access-Control-Allow-Headers" : @"Content-Type"};
            NSHTTPURLResponse *urlresponse = [[NSHTTPURLResponse alloc] initWithURL:request.URL statusCode:200 HTTPVersion:@"1.1" headerFields:headers];

            cachedresponse = [[NSCachedURLResponse alloc] initWithResponse:urlresponse data:content];
        }


return cachedresponse;!

This is how the web page loads on the webView..

Screenshot of the app

Is there some different way to return the response...? by the way, neither content or the response are nil.

an example of the request url is

Request : http://z.cdn.turner.com/cnn/tmpl_asset/static/intl_homepage/1021/js/intlhplib-min.js

and the file path where its stored is :

 file path: /Users/akshay/Library/Application Support/iPhone Simulator/5.1/Applications/86ED671C-AE45-449A-A2E1-D08281AB54CF/Documents/CVWebCache/cnn/tmpl_asset/static/intl_homepage/1021/js/intlhplib-min.js

score 0 · Accepted Answer · edited May 23 '13 at 12:09

0

If your custom NSUrlCache is still active, then the requests for the resources should go past it. You could there test for the URL and return the correct file from your documents folder.

You could then also open the original URL instead of the file from the documents folder. Again your NSUrlCache will return the file from your document folder.

You do not have to create a NSHTTPUrlResponse. A NSURLResponse is good enough.

 if (shouldFetchFromCache) {
            NSData* content = [NSData dataWithContentsOfFile:storagePath];

            NSURLResponse* response = [[NSURLResponse alloc] initWithURL:request.URL MIMEType:@"cache" expectedContentLength:[content length] textEncodingName:nil] ;

            cachedresponse = [[NSCachedURLResponse alloc] initWithResponse:response data:content];
        }
    }

    return cachedresponse;

edited May 23 '13 at 12:09

akshaynhegde

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answered May 23 '13 at 10:51

Edwin Vermeer

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you are right..! I just got that..:) I have all the files, and am also getting the right file path in the documents directory, and getting the NSData from the file too. but the webView is not interpreting the that data properly..! – akshaynhegde May 23 '13 at 11:03
1

Have a look at how I did that in https://github.com/evermeer/EVURLCache I have used that with a UIWebview. Also make sure you set the 'do not backup' attribute for the files that you save in the documents folder. Otherwise all webpages will also be backuped to iCloud. – Edwin Vermeer May 23 '13 at 11:07
i referred to the same and used almost most of its code..! I have edited my question.. can u please take a look at it..?? – akshaynhegde May 23 '13 at 11:13
1

You do not have to create a NSHTTPUrlResponse. A NSURLResponse is good enough. You could use something like: NSData* content = [NSData dataWithContentsOfFile:storagePath]; NSURLResponse* response = [[NSURLResponse alloc] initWithURL:request.URL MIMEType:@"cache" expectedContentLength:[content length] textEncodingName:nil] ; return [[NSCachedURLResponse alloc] initWithResponse:response data:content] ; – Edwin Vermeer May 23 '13 at 11:27
you are right..!! it worked now..Update the answer with that..!! i will accept it..:) Thanks..! – akshaynhegde May 23 '13 at 11:30

Caching web page in IOS using NSURLCache subclass

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