What is the difference between mediaLink and SignedUrl in firebase storage

Question

I have a firebase function to upload files to firebase storage, after upload I have to return the url (as Reset response) so that user can view the file

        const bucket = admin.storage().bucket();
        const [file, meta] = await bucket.upload(tempLocalFile, {
            destination: uploadPath,
            resumable: false,
            public: true,
        });

I have two options

1- const signedUrl = await file.getSignedUrl({ action: 'read', expires: '03-09-2491' });

2- meta.mediaLink

SignedUrl will be like https://storage.googleapis.com/web-scanner-dev.appspot.com/pwc%2Fwww.x.com%2F2019-11-17%2Fdesktop%2Fscreenshot-2019-11-17-1125.png?GoogleAccessId=firebase-gcloud%40scanner-dev.iam.gserviceaccount.com&Expires=16447035600&Signature=w49DJpGU9%2BnT7nlpCiJRgfAc98x4i2I%2FiP5UjQipZQGweXmTCl9n%2FnGWmPivkYHJNvkC7Ilgxfxc558%2F%2BuWWJ2pflsDY9HJ%2Bnm6TbwCrsmoVH56nuGZHJ7ggp9c3jSiGmQj3lOvxXfwMHXcWBtvcBaVj%2BH2H8uhxOtJoJOXj%2BOq3EC7XH8hamLY8dUbUkTRtaWPB9mlLUZ78soZ1mwI%2FY8DqLFwb75iob4zwwnDZe16yNnr4nApMDS7BYPxh4cAPSiokq30hPR8RUSNTn2GxpRom5ZiiI8dV4w%2BxYZ0DvdJxn%2FW83kqnjx6RSdZ%2B9S3P9yuND3qieAQ%3D%3D

and mediaLink will be like https://storage.googleapis.com/download/storage/v1/b/web-scanner-dev.appspot.com/o/pwc%2Fwww.x.com%2F2019-11-17%2Fdesktop%2Fscreenshot-2019-11-17-1125.png?generation=1574007908157173&alt=media

What is the pros and cons of each?

See https://stackoverflow.com/questions/42956250/get-download-url-from-file-uploaded-with-cloud-functions-for-firebase — Renaud Tarnec, Nov 17 '19 at 16:41

robsiemb · Accepted Answer · 2019-11-17T20:12:37.853

The mediaLink does not convey any access permissions on its own -- thus, the object itself will need to be publicly readable in order for end uers to make use of the link (or you will need to be authenticated as an account with read access to that bucket when you execute the link).

On the other hand, a URL returned by getSignedUrl will have a signature that allows access for as long as the URL hasn't expired. Thus, the link alone is sufficient (if temporary) permission to access the blob. Additionally, the URL that is generated maintains the permissions of the user who created it -- if that user loses access to the blob before the link would otherwise expire, the link will no longer function.

What is the difference between mediaLink and SignedUrl in firebase storage

1 Answers1