Ignore query params with SDWebImage

Question

I'm using SDWebImage to cache images in my app, however I recently ran into a problem where images that should be cached keep refreshing. Looking into it I found that the full image url from AWS is actually changing due to parameters tacked onto the end of the url. Every time I fetch the object that contains the image url, the image url returns with a dynamic "signature" and "expires" parameter (for security purposes). A different url so far as the image cache is concerned, but notice the same path to the image.

First fetch:

https://myapp.s3.amazonaws.com/path/image123.jpeg?AWSAccessKeyId=SOMEKEY&Signature=vrUFlMFEQ9fqQ%3D&Expires=1441702633

Fetch again 1 second later:

https://myapp.s3.amazonaws.com/path/image123.jpeg?AWSAccessKeyId=SOMEKEY&Signature=2mcMxUJLyJd7E%3D&Expires=1441703105

What's the best way to handle this situation? Sure would be awesome if SDWebImage had an option to ignore query params beyond the path to the file.

Washer

Answer 1

SDWebImage has a method that allows for using a custom key, which helps in this case as AWS changes the query every time it's called.

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary    *)launchOptions
{
    SDWebImageManager.sharedManager.cacheKeyFilter = ^(NSURL *url) {
        url = [[NSURL alloc] initWithScheme:url.scheme host:url.host path:url.path];
        return [url absoluteString];
    };

    // Your app init code...
    return YES;
}

For more reading: SDWebImage | Using the cache key filter

Hamburger

Answer 2

@John 's answer is very good, but I met sometimes crashed.

below is more stable version.

SDWebImageManager.sharedManager.cacheKeyFilter = ^(NSURL *url) {
    if( [[url absoluteString] isEqualToString:@""] ){
        return @"";
    }
    url = [[NSURL alloc] initWithScheme:url.scheme host:url.host path:url.path];
    return [url absoluteString];
};

This additional code checks if url is valid. [[NSURL alloc] initWithString:@""] or something like this makes crashes.

Weekday

Could you please explain your answer, even if it's going to explain similar stuff to the other answer it's useful for your answer to explain the code you've posted. – Unmuzzle

@Unmuzzle [[NSURL alloc] initWithString:@""] or something like that crashed @Hamburger 's code. – Weekday

Nice catch @SatoshiSuzuki. – Hamburger

Answer 3

The answer for Swift language:

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {

    ...............

    SDWebImageManager.sharedManager().cacheKeyFilter = { url in
        if url.absoluteString == "" {
            return ""
        }

        let newUrl = NSURL(scheme: url.scheme, host: url.host, path: url.path!)!
        return newUrl.absoluteString
    }

    return true
}

Cicala

Answer 4

[NSURL initWithScheme: host: path:] is deprecated in iOS10. should use NSURLComponents instead.

my updated solution:

SDWebImageManager.sharedManager.cacheKeyFilter = ^NSString *(NSURL *url) {
     if([[url absoluteString] isEqualToString:@""]){
        return @"";
    }
    NSURLComponents *urlComponents = [[NSURLComponents alloc] initWithURL:url resolvingAgainstBaseURL:NO];
    urlComponents.query = nil;
    return [[urlComponents URL] absoluteString];
};

Handsome

Answer 5

iOS 14 || Swift 5

SDWebImageManager.shared.cacheKeyFilter = SDWebImageCacheKeyFilter { url in
    var components = URLComponents(url: url, resolvingAgainstBaseURL: false)
    components?.query = nil

    print("SDWebImage Cache Key:", components?.url)

    return components?.url?.absoluteString ?? ""
}

So configure SDWebImageManager at launch & then whenever a url is supplied, it will be stripped of all it's query parameters to generate a common cache key identifier for SDWebImage cache logic to work properly again.

So something like:

https://bucket.s3.us-east-1.amazonaws.com/public/someAsset.ext?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=TILT&X-Amz-Date=20210602T113954Z&X-Amz-Expires=17999&X-Amz-SignedHeaders=host&X-Amz-Security-Token=TILT&X-Amz-Signature=TILT

will have the cache key:

https://bucket.s3.us-east-1.amazonaws.com/public/someAsset.ext

---

NOTE: Pay attention to the final url. If the url is dependent on its query parameters for a dynamic output then obviously you will need to modify the logic in SDWebImageCacheKeyFilter to fit your requirement.

Salsify

Succinct, well written, and complete with detailed description and caveats. If I could upvote you a thousand times I would. – Lefevre