How to get URL from Firebase Storage getDownloadUR

Question

I'm trying to get the "long term persistent download link" to files in our Firebase storage bucket. I've changed the permissions of this to

service firebase.storage {
  match /b/project-xxx.appspot.com/o {
    match /{allPaths=**} {
      allow read, write;
    }
  }
}

And my javacode looks like this:

private String niceLink (String date){
    String link;
    // Points to the root reference
    StorageReference storageRef = FirebaseStorage.getInstance().getReference();
    StorageReference dateRef = storageRef.child("/" + date+ ".csv");
    link = dateRef.getDownloadUrl().toString();
    return link;
}

When I run this I get the uri link that looks something like com.google.android.gms.tasks.zzh@xxx

Question 1. Can I from this get the download link similar to: https://firebasestorage.googleapis.com/v0/b/project-xxxx.appspot.com/o/20-5-2016.csv?alt=media&token=b5d45a7f-3ab7-4f9b-b661-3a2187adxxxx

When trying to get the link above I changed the last row before my return, like this:

private String niceLink (String date){
    String link;
    // Points to the root reference
    StorageReference storageRef = FirebaseStorage.getInstance().getReference();
    StorageReference dateRef = storageRef.child("/" + date+ ".csv");
    link = dateRef.getDownloadUrl().getResult().toString();
    return link;
}

But when doing this i get a 403 error, and the app crashing. The consol tells me this is bc user is not logged in /auth. "Please sign in before asking for token"

Question 2. How do I fix this?

Answer 1

When you call getDownloadUrl(), the call is asynchronous and you must subscribe on a success callback to obtain the results:

// Calls the server to securely obtain an unguessable download Url
private void getUrlAsync (String date){
    // Points to the root reference
    StorageReference storageRef = FirebaseStorage.getInstance().getReference();
    StorageReference dateRef = storageRef.child("/" + date+ ".csv");
    dateRef.getDownloadUrl().addOnSuccessListener(new OnSuccessListener<Uri>()
    {
        @Override
        public void onSuccess(Uri downloadUrl) 
        {                
           //do something with downloadurl
        } 
    });
}

This will return a public unguessable download url. If you just uploaded a file, this public url will be in the success callback of the upload (you do not need to call another async method after you've uploaded).

However, if all you want is a String representation of the reference, you can just call .toString()

// Returns a Uri of the form gs://bucket/path that can be used
// in future calls to getReferenceFromUrl to perform additional
// actions
private String niceRefLink (String date){
    // Points to the root reference
    StorageReference storageRef = FirebaseStorage.getInstance().getReference();
    StorageReference dateRef = storageRef.child("/" + date+ ".csv");
    return dateRef.toString();
}

Answer 2

//Firebase easy and Working uploads and downloads.

@Override

protected void onActivityResult(int requestCode, int resultCode, @Nullable final Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if(requestCode == RC_SIGN_IN){
        if(resultCode == RESULT_OK){
            Toast.makeText(this,"Signed in!", LENGTH_SHORT).show();
        } else if(resultCode == RESULT_CANCELED){
            Toast.makeText(this,"Signed in canceled!", LENGTH_SHORT).show();
            finish();
        }
    } else if(requestCode == RC_PHOTO_PICKER && resultCode == RESULT_OK){

        // HERE I CALLED THAT METHOD
        uploadPhotoInFirebase(data);

    }
}

private void uploadPhotoInFirebase(@Nullable Intent data) {
    Uri selectedImageUri = data.getData();

    // Get a reference to store file at chat_photos/<FILENAME>
    final StorageReference photoRef = mChatPhotoStorageReference
                    .child(selectedImageUri
                    .getLastPathSegment());

    // Upload file to Firebase Storage
    photoRef.putFile(selectedImageUri)
            .addOnSuccessListener(new OnSuccessListener<UploadTask.TaskSnapshot>() {
                @Override
                public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {

                    // Download file From Firebase Storage
                    photoRef.getDownloadUrl().addOnSuccessListener(new OnSuccessListener<Uri>() {
                        @Override
                        public void onSuccess(Uri downloadPhotoUrl) {
                            //Now play with downloadPhotoUrl
                            //Store data into Firebase Realtime Database
                            FriendlyMessage friendlyMessage = new FriendlyMessage
                                    (null, mUsername, downloadPhotoUrl.toString());
                            mDatabaseReference.push().setValue(friendlyMessage);
                        }
                    });
                }
            });
}

Answer 3

StorageReference mStorageRef = FirebaseStorage.getInstance().getReference();

final   StorageReference fileupload=mStorageRef.child("Photos").child(fileUri.getLastPathSegment());
UploadTask uploadTask = fileupload.putFile(fileUri);

Task<Uri> urlTask = uploadTask.continueWithTask(new Continuation<UploadTask.TaskSnapshot, Task<Uri>>() {
    @Override
    public Task<Uri> then(@NonNull Task<UploadTask.TaskSnapshot> task) throws Exception {
        if (!task.isSuccessful()) {
            throw task.getException();
        }
        return ref.getDownloadUrl();

    }
    }).addOnCompleteListener(new OnCompleteListener<Uri>() {
        @Override
        public void onComplete(@NonNull Task<Uri> task) {
            if (task.isSuccessful()) {
                Uri downloadUri = task.getResult();
                Picasso.get().load(downloadUri.toString()).into(image);

            } else {
                 // Handle failures
            }
       }
});