I'm working on an Android application where I use Glide for image loading and caching. I need to retrieve the URLs associated with the cached images stored by Glide in order to perform further operations based on those URLs.
Here's what I've tried so far:
Attempted to directly extract URLs from Glide's cache keys, but found that the cache keys don't contain this information. Explored accessing the disk cache directory to iterate through cached image files, but encountered challenges in associating these files with their corresponding URLs. Given the above, I'm looking for guidance on how to effectively retrieve the URLs associated with the cached images stored by Glide. Is there a recommended approach or best practice for achieving this? Any insights or suggestions would be greatly appreciated.
please see this:
fun getAllCachedImages(context: Context) {
val glide = Glide.with(context)
val cacheDirectory = Glide.getPhotoCacheDir(context)
val cachedFiles = cacheDirectory?.listFiles()
if (cachedFiles != null) {
for (file in cachedFiles) {
val options: RequestOptions =
RequestOptions().diskCacheStrategy(DiskCacheStrategy.ALL)
val requestBuilder: RequestBuilder< Drawable> = glide.load(file).apply(options)
val cacheKey: Key = requestBuilder.signature
//it return EmptySignature
val cacheKey2 = Glide.with(context)
.load(Uri.fromFile(file))
.downloadOnly(com.bumptech.glide.request.target.Target.SIZE_ORIGINAL, com.bumptech.glide.request.target.Target.SIZE_ORIGINAL)
.get()
.toString()
//this return something like this:
// -> /data/user/0/MY_APP_PACKAGE_NAME/cache/image_manager_disk_cache/dac01c2968b075a386bcc7b8bcc4d0433e1225ae82264fb4cfc1740645e435b4.0
}
}
}
I'm using Glide version 4.12.0.
My goal is to associate each cached image with its original URL for further processing within my application.
In this Page, it mentioned that all cache keys contain File, Uri, and Url but I don't know how to retrieve
Any code examples or pointers to relevant documentation would be immensely helpful.
Retrieving the URLs associated with cached images in Glide for Android can be a bit challenging because Glide doesnt directly expose this information. However, with some workaround, you can achieve this by implementing a custom solution. One approach is to maintain a separate mapping between the cache keys and the corresponding URLs. Below is a suggested approach:
Use Custom Glide Module: You can create a custom Glide module to intercept image loading requests and store the mapping between URLs and cache keys.
Generate Cache Keys: When loading images with Glide, generate cache keys for each request. You can use a combination of the image URL and any specific transformations applied to it to create a unique cache key.
Store URL-Cache Key Mapping: Maintain a mapping (e.g., in a database or SharedPreferences) between the image URLs and the cache keys generated in step 2.
Retrieve URLs from Cache Keys: When you need to retrieve the URL associated with a cached image, you can use the cache key to look up the corresponding URL in your mapping.
Heres a basic implementation of how you can achieve this:
kotlin// Custom Glide module to intercept image loading requests
class CustomGlideModule : AppGlideModule() {
override fun registerComponents(context: Context, glide: Glide, registry: Registry) {
registry.append(InputStream::class.java, Bitmap::class.java, CustomImageLoader.Factory())
}
}
// Custom image loader to intercept loading requests
class CustomImageLoader(private val listener: ImageLoadedListener) : ModelLoader< Uri, InputStream> {
override fun handles(model: Uri): Boolean {
return model.scheme == "http" || model.scheme == "https"
}
override fun buildLoadData(model: Uri, width: Int, height: Int, options: Options): ModelLoader.LoadData< InputStream>? {
return ModelLoader.LoadData(
CustomImageFetcher(model.toString()),
CustomDataFetcher(model)
)
}
class Factory : ModelLoaderFactory< Uri, InputStream> {
override fun build(multiFactory: MultiModelLoaderFactory): ModelLoader< Uri, InputStream> {
return CustomImageLoader(ImageLoadedListenerImpl())
}
override fun teardown() {}
}
// Custom data fetcher to intercept image loading
inner class CustomDataFetcher(private val uri: Uri) : DataFetcher< InputStream> {
override fun loadData(priority: Priority, callback: DataFetcher.DataCallback< in InputStream>) {
// Implement loading logic here
val inputStream = /* Load image from cache or network */
callback.onDataReady(inputStream)
}
override fun cleanup() {}
override fun cancel() {}
override fun getDataClass(): Class< InputStream> {
return InputStream::class.java
}
override fun getDataSource(): DataSource {
return DataSource.REMOTE
}
}
// Custom image fetcher to handle loading requests
inner class CustomImageFetcher(private val url: String) : ModelLoader.LoadData< InputStream> {
override fun key(): String {
// Generate a unique cache key for this request (e.g., based on URL)
return url
}
override fun fetcher(): DataFetcher< InputStream> {
// Return the custom data fetcher
return CustomDataFetcher(Uri.parse(url))
}
}
// Listener interface to notify when an image is loaded
interface ImageLoadedListener {
fun onImageLoaded(url: String, cacheKey: String)
}
// Default implementation of ImageLoadedListener
private class ImageLoadedListenerImpl : ImageLoadedListener {
override fun onImageLoaded(url: String, cacheKey: String) {
// Handle image loaded event
// You can store the mapping between URL and cache key here
}
}
}
This is a simplified example, and youll need to adapt it to your specific requirements. The CustomImageLoader intercepts image loading requests and provides a custom data fetcher (CustomDataFetcher) for loading images. Inside the data fetcher, you can implement logic to load images from cache or network.
When an image is loaded, you can notify the listener (ImageLoadedListener) with the URL and cache key. You can then store this mapping in a database or SharedPreferences for later retrieval.
Remember to register your custom Glide module in your AndroidManifest.xml:
< meta-data
android:name="com.bumptech.glide.integration.okhttp3.OkHttpLibraryGlideModule"
android:value="GlideModule" />
< meta-data
android:name="your.package.name.CustomGlideModule"
android:value="GlideModule" />
This solution requires some additional setup and may have performance implications, so make sure to test and optimize as needed. Additionally, consider error handling and edge cases in your implementation.