Call Google Cloud Function from front-end application

Question

I am implementing a react-native application. Essentially, from this front-end application, I want to make an GET request to the Yelp Fusion API, which requires a Private API Key (which I have saved in my notes).

Considering a GET request with a private key should be executed from the server-side, and not the front-end react-native application, I wanted to implement this functionality through either Google Cloud Functions, or Firebase Functions.

Essentially, how do I trigger an event like this from a front-end Javascript client, and what do I need to set up on Firebase or Google Cloud Functions for this to work?

I was able to write a function in Firebase Functions, but I wasn't sure how to write a GET request to a URL external to the Google Cloud Platform. I also do not know how to trigger the request and receive data from the client side.

Answer 1

You can create a Cloud Function with a public HTTP trigger to accomplish this.

The samples on that page include HTTP based Cloud Functions.

Here's the doc on calling http triggers .

To deploy a Cloud Function with an public HTTP trigger:

gcloud functions deploy MYFUNCTION --runtime <your runtime> --trigger-http --allow-unauthenticated

This command allows anonymous access to call your functions, ordinarily you would need to be authenticated to do so.

Once you open a trigger to the inte.net though anybody can call it so keep that in mind with what data you accept and pass back. You may also want to set a budget on the project containing the function in case somebody were to calling it continuously racking up a bill for you.

Answer 2

Cloud Functions for Firebase are a thin wrapper around Google Cloud Functions, so any approach that you can use for GCF (such as the one Jake proposes in their answer ) also works on Firebase.

There are two ways to directly invoke a Cloud Function from within your application code with Firebase:

1. Create a HTTP endpoint and call that from your application code using something like fetch . This is described in the documentation on Call functions via HTTP requests
2. Implement a so-called Callable function in Firebase and then invoke that from your application code through the SDK. For more on this, see the documentation on Call functions from your app .

The second type essentially wraps the first type, but adds some features like named parameters, and it automatically passes the ID token and some other parameters.