This sample demonstrates how to automatically generate thumbnails for each images that are uploaded to Firebase Storage.
See file functions/index.js for the thumbnail generation code.
The thumbnail generation is performed using ImageMagick which is installed by default on all Cloud Functions instances. This is a CLI so we execute the command from node using the child-process-promise package. The image is first downloaded locally from the Firebase Storage bucket to the tmp folder using the google-cloud SDK.
In order to generate a Signed URL, a Service Account Key is required. A Signed URL grants public read or write access to the URL for a specified limited time.
The dependencies are listed in functions/package.json.
The function triggers on upload of any file to your Firebase project's default Cloud Storage bucket.
To deploy and test the sample:
- Create a Firebase project on the Firebase Console and visit the Storage tab.
- Clone this repo:
git clone https://github.com/firebase/functions-samples. - Open this sample's directory:
cd functions-samples/generate-thumbnail - Setup your project by running
firebase use --addand select the project you had created. - Install dependencies in the functions directory:
cd functions; npm install; cd - - Go to the Firebase Console, select the gear image > project settings > Service Accounts and click Generate New Private Key to download a Service Account Key JSON document.
- Add the JSON service account credentials file to the Functions directory as functions/service-account-credentials.json.
- Deploy your project using
firebase deploy - Go to the Firebase Console Storage tab and upload an image. After a short time an thumbnail image with the same name but a
thumb_prefix will be created in the same folder (make sure you refresh the UI to see the new file). - Go to the Firebase Console Database tab and see that a child of
imageshas been created containing the Signed URLs for both images.