Fixes an emulator issue where snapshot.ref could not point to multiple databases (#1339)

* yank first condition

* update changelog

* add emulator instance creation

* run prettier

Author: colerogers

CHANGELOG.md

@@ -0,0 +1 @@
+- Fixes an emulator issue where snapshot.ref could not point to multiple databases (#1339).

src/common/providers/database.ts

@@ -50,10 +50,7 @@ export class DataSnapshot implements database.DataSnapshot {
     instance?: string
   ) {
     const config = firebaseConfig();
-    if (app?.options?.databaseURL?.startsWith("http:")) {
-      // In this case we're dealing with an emulator
-      this.instance = app.options.databaseURL;
-    } else if (instance) {
+    if (instance) {
       // SDK always supplies instance, but user's unit tests may not
       this.instance = instance;
     } else if (app) {

src/v2/providers/database.ts

@@ -465,7 +465,7 @@ export function onChangedOperation<Ref extends string>(
   // wrap the handler
   const func = (raw: CloudEvent<unknown>) => {
     const event = raw as RawRTDBCloudEvent;
-    const instanceUrl = `https://${event.instance}.${event.firebasedatabasehost}`;
+    const instanceUrl = getInstance(event);
     const params = makeParams(event, pathPattern, instancePattern) as unknown as ParamsOf<Ref>;
     const databaseEvent = makeChangedDatabaseEvent(event, instanceUrl, params);
     return wrapTraceContext(handler)(databaseEvent);
@@ -492,7 +492,7 @@ export function onOperation<Ref extends string>(
   // wrap the handler
   const func = (raw: CloudEvent<unknown>) => {
     const event = raw as RawRTDBCloudEvent;
-    const instanceUrl = `https://${event.instance}.${event.firebasedatabasehost}`;
+    const instanceUrl = getInstance(event);
     const params = makeParams(event, pathPattern, instancePattern) as unknown as ParamsOf<Ref>;
     const data = eventType === deletedEventType ? event.data.data : event.data.delta;
     const databaseEvent = makeDatabaseEvent(event, data, instanceUrl, params);
@@ -505,3 +505,10 @@ export function onOperation<Ref extends string>(
 
   return func;
 }
+
+function getInstance(event: RawRTDBCloudEvent) {
+  const emuHost = process.env.FIREBASE_DATABASE_EMULATOR_HOST;
+  return emuHost
+    ? `http://${emuHost}/?ns=${event.instance}`
+    : `https://${event.instance}.${event.firebasedatabasehost}`;
+}