Glide: downloadOnly and diskCacheStrategy/signature are not compatible

[TWiStErRob]

Glide Version/Integration library (if any): 3.5.2
Issue details/Repro steps:
I just wanted to _force the load of the url from the network every time_, but it's not possible because I get a compile error. The same is true for .signature().
I could understand diskCacheStrategy not being available since it's set to SOURCE in GenericTranscodeRequest.getDownloadOnlyRequest, but signature should work.

Glide load line:

Glide.with(this)
     .load("http://url")
     //.diskCacheStrategy(DiskCacheStrategy.NONE) // -> downloadOnly fails to compile
     .downloadOnly(200, 200)
     //.diskCacheStrategy(DiskCacheStrategy.NONE) // -> this line fails to compile
;

Compile error:

Cannot resolve method.

[Tolriq]

From what I read when doing my tests, downloadOnly() is to force the image to be downloaded into the cache.

So settings a strategy to none seems logically not compatible.

To get image from network into(width,height) is what the documentation says to use (and it works as I use it)

[TWiStErRob]

Yes, that's what I stated above, but signature should work, because whatever you download may change between your app's versions or any other outside trigger (date, etc).

[Tolriq]

Well signature works with into(x,y) and if you just want to force a dl each time DiskCacheStrategy.NONE works too.

I do not see what you want to achieve.

[TWiStErRob]

into(w,h) gives you a GlideDrawable while downloadOnly(w,h) gives you a File.

I just wanted to force load the URL every time (see itallic text above), for example if I had a changing image with an unchanging url, like an avatar with displayed reputation points or something.

[Tolriq]

There's a contradiction in your need, you want to put a file in the cache but do not use it.

Downloadonly give a file from the source cache so it can be reused after as a source cached image.

If the avatar is to be updated each time setting DiskCacheStrategy.NONE in the normal query will force a network download each time.

Why do you need a File ?

[TWiStErRob]

It's only a theoretical use case, but imagine this:
I get the File via downloadOnly() on application startup where the signature contains a today's date, because the server updates the reputation in an overnight job. If the user starts the app first time in the morning Glide'll request the image and store it in a file. Then I [optionally store that File reference somewhere global and] use it to for example put a stamp on user-generated content and/or display it. If the user starts the app later that day there's no download because signatures match. The next day a new image is loaded.

As I understand the whole point of downloadOnly is to support use cases like the above.

By the way I opened the bug when I tried to test an OkHttp loading bug without an ImageView, whereby I would have needed to skip the cache every time because I was debugging the networking part.

Hope this clears it up, feel free to close it as invalid if the use case above is highly unlikely.

[Tolriq]

I'm really not sure to still understand :)

Why not just use all normal glide usage with a signature Key like for example IntegerVersionSignature that will contain the current day.

This sounds way more logical and for me the way signature was added for.

[TWiStErRob]

The key here would be "put a stamp on user-generated content", you can't do that without downloading the stamp before attempting to have a transformation on an arbitrary image. It may be far stretching, I recognise that, but I was really puzzled when none of the above methods compiled.

[sjudd]

I think signature is legitimate use case for people who specifically want a File back. I'll think about this, it may need to wait until 4.0

[TWiStErRob]

Add .listener() to the list, that is .load().listener().downloadOnly() is not possible.

[duenytz]

You just need to cast .signature() to be DrawableTypeRequest which inherit from DrawableRequestBuilder, and has the downloadOnly() method, hopefuly it internally should work, I'm just about to test:

((DrawableTypeRequest<String>) Glide.with(context)
         .load(url)
         .signature(new StringSignature(signature)))
         .downloadOnly(Target.SIZE_ORIGINAL, Target.SIZE_ORIGINAL)

Sorry to be a bit late, lol...

[sjudd]

I believe this is now obsolete in v4.

[TWiStErRob]

Yes, v4 deprecated downloadOnly(...), we need to use

GlideApp
    .with(this)
    .downloadOnly() // this does the trick
    .load("http://url")
    //.signature/diskCacheStrategy works here
    .submit();