Add `exists` method to storage

[caseycrogers]

I would like to be able to check if a file exists in Supabase storage without having to download it: final bool fileExists = await supabase.storage.from('some-bucket-id').exists('/some/path');

[Vinzent03]

There is currently no api enpoint for this. See the documentation. For the time being, you can create your own postgres function, which queries the storage.objects table.

[dshukertjr]

@caseycrogers Thanks for the feedback!

As @Vinzent03 has said, there is currently no APIs for that, so I would recommend creating an issue on the Storage API repo.

[dshukertjr]

Come to think about it, what is the use case for this method? In what scenario would you not know if a file exists or not?

The way use storage is that after I upload a file, I either save the public URL or the path to the file in a database, and when I need to access the file, I would just access it via the saved URL or generate a URL from the saved path.

[Vinzent03]

You may have paths, where you don't have to save the path, because it's not random, but constructed from other parameter. For example, you may have a directory with profile images, where the file name is the uid of the user. You don't have to specifically save the filename, because you already know the uid.

[dshukertjr]

@Vinzent03 In that example, if they had saved the path on the database, they would save 1 extra http request, hence would be able to speed up whatever process that follows.

I fear that adding a exists method might steer the developers toward bad practices, where they would start making extra requests that can be mitigated, but what do you think?

[Vinzent03]

@dshukertjr I'm not sure if you fully understood my use case. Let's say profile images are stored in a predefined directory with the user's uid as the file's name. How do you know on the client whether you already uploaded an image or not? I think the only ways are providing an extra method in the client library, or the user uses a head request and checks for 404.

[dshukertjr]

@Vinzent03 I think I do understand the use case now. I was referring to a use case where you want to display other users' profile images, but I believe you are referring to a use case where you are displaying the logged in user's own profile image.

At least for now, there are some workarounds like doing a head request or to use a erorrBuilder on the profile image to show a fallback image in case there are no profile image set yet!

Let's keep this issue open to see if more users demand this feature!

[jherman]

Ran into this same exact use case today, so just want to give my +1 to this feature getting implemented.

While I do have a fallback image, I'd rather not show the request error in the console if it could be avoided.

EDIT:

Just wanted to include the database postgres function call I created for those stuck on this:

BEGIN RETURN
  (SELECT EXISTS
     (SELECT id
      FROM storage.objects
      WHERE bucket_id='avatars'
        AND OWNER=UID
        AND name=PATH
      LIMIT 1));

END;

And the call to it:

  const { data, error } = await supabase.rpc('storage_avatar_exists', {
    uid: '542eb4f2-c890-47d0-a32c-4ebba849a011',
    path: '542eb4f2-c890-47d0-a32c-4ebba849a011/avatar.png'
  });

[dshukertjr]

Transferring this issue to the storage-api repo to discuss its implementation on the backend.

[fenos]

We already have a backend method to check the existence of an object, simply using a HEAD request instead of a GET on a specific object will return empty content if the item exists else 404

We should probably update the client SDK to implement this method

[shriharip]

Running into this issue. User Avatars. Bucket is a public bucket, so I do not generate the url to save it to db.
I generate the url dynamically, baseStorageurl + sessionid + avatar.jpg

I want to check if the folder exists before i create the img source url like above.

[revulvgina]

We already have a backend method to check the existence of an object, simply using a HEAD request instead of a GET on a specific object will return empty content if the item exists else 404

We should probably update the client SDK to implement this method

tried now using HEAD on a deleted file, still 200. tried GET, got 400, with status 404 on json message

[softmarshmallow]

And why is this yet not available?

[phoenixbox]

Authed HEAD request for reference

const response = await fetch(`${process.env.SUPABASE_URL}/storage/v1/object/${bucket}/${path}`, {
  method: 'HEAD',
  headers: {
    authorization: session.access_token,
  },
});

[utkarsh1097]

This will be a useful method. It looks like Google Cloud Storage (and by extension, Firebase Storage?) has a similar method.

[Owez]

This is 100% needed, basic feature of storage that doesn't exist yet

[softmarshmallow]

Not a good way yo handle things, but for those who does not care about performance that much and looking for batch types of work, heres some extended utilities.

import type { SupabaseClient } from "@supabase/supabase-js";
import type { FileObject } from "@supabase/storage-js";

export namespace SupabaseStorageExtensions {
  type StorageClient = SupabaseClient["storage"];

  async function list(storage: StorageClient, bucket: string, path: string) {
    const { data, error } = await storage.from(bucket).list(path);

    if (error) {
      throw error;
    }

    return data;
  }

  export async function tree(
    storage: StorageClient,
    bucket: string,
    path = ""
  ) {
    let files: Record<string, FileObject> = {};
    let stack: string[] = [path];

    while (stack.length > 0) {
      const currentPath = stack.pop();
      const items = await list(storage, bucket, currentPath!);

      const promises = items.map(async (item) => {
        const itemPath = currentPath + "/" + item.name;
        const isfile = !!item.id;
        if (isfile) {
          files[itemPath] = item;
        } else {
          stack.push(itemPath);
        }
      });

      await Promise.all(promises);
    }

    return files;
  }

  export async function rmdir(
    storage: StorageClient,
    bucket: string,
    path: string
  ) {
    const files = await tree(storage, bucket, path);
    const paths = Object.keys(files);
    const { data, error } = await storage.from(bucket).remove(paths);

    if (error) {
      throw error;
    }

    return data;
  }

  export async function exists(
    storage: StorageClient,
    bucket: string,
    path: string
  ) {
    const { data, error } = await storage.from(bucket).list(path);

    if (error) {
      throw error;
    }

    return data.some((file) => file.name === path.split("/").pop());
  }
}

Alternatively, you can use createSignedUrl, it will return error when used on non-exist object.

[PaperPrototype]

@dshukertjr

I demand this feature 😛 I am intentionally avoiding saving a path_to_file and instead I have a uid for profiles, that I then construct whenever I need it.

getPublicUrl may only be constructing a URL and not actually querying, but maybe querying internal storage schema and store something like result.data.exists?

if (profiles) {
    for (let i = 0; i < profiles.length; i++) {
        const result = supabase.storage
            .from('profiles')
            .getPublicUrl(`/profiles/${profiles[i].id}/preview.png`, {
                transform: t200by200
            });

        // getPublicUrl may only be constructing a URL and not actually querying, 
        // but maybe query internal storage schema and store something like `result.data.exists`
        console.log(result.data.exists);
        if (result.data.exists) {
                 profiles[i]['image_url'] = result.data.publicUrl;
        }
    }

    profiles = data;
}

Although I can definitely see how this feature could be abused and result in way too many API calls just to check if they should put a URL for an image into a component. It's way cheaper to just leave an img_url even if it fails than query each image and check if it is available.

[06kellyjac]

Is this resolved by https://github.com/supabase/storage-js/pull/207 ?