functions-samples/generate-thumbnail

Automatically Generate Thumbnails

This sample demonstrates how to automatically generate thumbnails for each images that are uploaded to Firebase Storage.

Functions Code

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.

The dependencies are listed in functions/package.json.

Trigger rules

The function triggers on upload of any file to your Firebase project's default Cloud Storage bucket.

Deploy and test

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 --add and select the project you had created.
• Install dependencies in the functions directory: cd functions; npm install; cd -
• 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).