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.
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 internet 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.
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:
fetch. This is described in the documentation on Call functions via HTTP requestsThe 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.