// The Cloud Functions for Firebase SDK to setup triggers and logging.const{onRequest}=require("firebase-functions/https");const{onValueCreated}=require("firebase-functions/database");const{logger}=require("firebase-functions");// The Firebase Admin SDK to access the Firebase Realtime Database.constadmin=require("firebase-admin");admin.initializeApp();
index.js

# The Cloud Functions for Firebase SDK to create Cloud Functions and set up triggers.fromfirebase_functionsimportdb_fn,https_fn# The Firebase Admin SDK to access the Firebase Realtime Database.fromfirebase_adminimportinitialize_app,dbapp=initialize_app()
main.py

// AllRealtime Database instances in default function region us-central1 at path "/user/{uid}"// There must be at least oneRealtime Database present in us-central1.constonWrittenFunctionDefault=onValueWritten("/user/{uid}",(event)=>{// …});// Instance named "my-app-db-2", at path "/user/{uid}".// The "my-app-db-2" instance must exist in this region.constOnWrittenFunctionInstance=onValueWritten({ref:"/user/{uid}",instance:"my-app-db-2"// This example assumes us-central1, but to set location:// region: "europe-west1"},(event)=>{// …});// Instance with "my-app-db-" prefix, at path "/user/{uid}", where uid ends with @gmail.com.// There must be at least oneRealtime Database with "my-app-db-*" prefix in this region.constonWrittenFunctionInstance=onValueWritten({ref:"/user/{uid=*@gmail.com}",instance:"my-app-db-*"// This example assumes us-central1, but to set location:// region: "europe-west1"},(event)=>{// …});

# All Realtime Database instances in default function region us-central1 at path "/user/{uid}"# There must be at least one Realtime Database present in us-central1.@db_fn.on_value_written(r"/user/{uid}")defonwrittenfunctiondefault(event:db_fn.Event[db_fn.Change]):# ...pass# Instance named "my-app-db-2", at path "/user/{uid}".# The "my-app-db-2" instance must exist in this region.@db_fn.on_value_written(reference=r"/user/{uid}",instance="my-app-db-2",# This example assumes us-central1, but to set location:# region="europe-west1",)defon_written_function_instance(event:db_fn.Event[db_fn.Change]):# ...pass# Instance with "my-app-db-" prefix, at path "/user/{uid}", where uid ends with @gmail.com.# There must be at least one Realtime Database with "my-app-db-*" prefix in this region.@db_fn.on_value_written(reference=r"/user/{uid=*@gmail.com}",instance="my-app-db-*",# This example assumes us-central1, but to set location:# region="europe-west1",)defon_written_function_instance(event:db_fn.Event[db_fn.Change]):# ...pass

// Listens for new messages added to /messages/:pushId/original and creates an// uppercase version of the message to /messages/:pushId/uppercase// for all databases in 'us-central1'exports.makeuppercase=onValueCreated("/messages/{pushId}/original",(event)=>{// Grab the current value of what was written to the Realtime Database.constoriginal=event.data.val();logger.log("Uppercasing",event.params.pushId,original);constuppercase=original.toUpperCase();// You must return a Promise when performing// asynchronous tasks inside a function, such as// writing to the Firebase Realtime Database.// Setting an "uppercase" sibling in the// Realtime Database returns a Promise.returnevent.data.ref.parent.child("uppercase").set(uppercase);},);
index.js

@db_fn.on_value_created(reference="/messages/{pushId}/original")defmakeuppercase(event:db_fn.Event[Any])->None:"""Listens for new messages added to /messages/{pushId}/original and    creates an uppercase version of the message to /messages/{pushId}/uppercase    """# Grab the value that was written to the Realtime Database.original=event.dataifnotisinstance(original,str):print(f"Not a string:{event.reference}")return# Use the Admin SDK to set an "uppercase" sibling.print(f"Uppercasing{event.params['pushId']}:{original}")upper=original.upper()parent=db.reference(event.reference).parentifparentisNone:print("Message can't be root node.")returnparent.child("uppercase").set(upper)
main.py

exportsmakeUppercase=onValueWritten("/messages/{pushId}/original",(event)=>{// Only edit data when it is first created.if(event.data.before.exists()){returnnull;}// Exit when the data is deleted.if(!event.data.after.exists()){returnnull;}// Grab the current value of what was written to the Realtime Database.constoriginal=event.data.after.val();console.log('Uppercasing',event.params.pushId,original);constuppercase=original.toUpperCase();// You must return a Promise when performing asynchronous tasks inside a Functions such as// writing to the Firebase Realtime Database.// Setting an "uppercase" sibling in the Realtime Database returns a Promise.returnevent.data.after.ref.parent.child('uppercase').set(uppercase);});

@db_fn.on_value_written(reference="/messages/{pushId}/original")defmakeuppercase2(event:db_fn.Event[db_fn.Change])->None:"""Listens for new messages added to /messages/{pushId}/original and    creates an uppercase version of the message to /messages/{pushId}/uppercase    """# Only edit data when it is first created.ifevent.data.beforeisnotNone:return# Exit when the data is deleted.ifevent.data.afterisNone:return# Grab the value that was written to the Realtime Database.original=event.data.afterifnothasattr(original,"upper"):print(f"Not a string:{event.reference}")return# Use the Admin SDK to set an "uppercase" sibling.print(f"Uppercasing{event.params['pushId']}:{original}")upper=original.upper()parent=db.reference(event.reference).parentifparentisNone:print("Message can't be root node.")returnparent.child("uppercase").set(upper)
main.py