Auth: Add support for emulator

Author: fmasa

src/main/java/com/google/firebase/auth/FirebaseAuth.kt

@@ -43,6 +43,17 @@ import java.util.concurrent.TimeUnit
 
 val jsonParser = Json { ignoreUnknownKeys = true }
 
+class UrlFactory(
+    private val app: FirebaseApp,
+    private val emulatorUrl: String? = null,
+) {
+    fun buildUrl(uri: String): String {
+        val baseUrl = "${emulatorUrl ?: "https://"}www.googleapis.com/identitytoolkit"
+
+        return "$baseUrl/$uri?key=${app.options.apiKey}"
+    }
+}
+
 @Serializable
 class FirebaseUserImpl private constructor(
     @Transient
@@ -53,16 +64,19 @@ class FirebaseUserImpl private constructor(
     val refreshToken: String,
     val expiresIn: Int,
     val createdAt: Long,
+    @Transient
+    private val urlFactory: UrlFactory = UrlFactory(app),
 ) : FirebaseUser() {
 
-    constructor(app: FirebaseApp, data: JsonObject, isAnonymous: Boolean = data["isAnonymous"]?.jsonPrimitive?.booleanOrNull ?: false) : this(
+    constructor(app: FirebaseApp, data: JsonObject, isAnonymous: Boolean = data["isAnonymous"]?.jsonPrimitive?.booleanOrNull ?: false, urlFactory: UrlFactory = UrlFactory(app)) : this(
         app,
         isAnonymous,
         data["uid"]?.jsonPrimitive?.contentOrNull ?: data["user_id"]?.jsonPrimitive?.contentOrNull ?: data["localId"]?.jsonPrimitive?.contentOrNull ?: "",
         data["idToken"]?.jsonPrimitive?.contentOrNull ?: data.getValue("id_token").jsonPrimitive.content,
         data["refreshToken"]?.jsonPrimitive?.contentOrNull ?: data.getValue("refresh_token").jsonPrimitive.content,
         data["expiresIn"]?.jsonPrimitive?.intOrNull ?: data.getValue("expires_in").jsonPrimitive.int,
-        data["createdAt"]?.jsonPrimitive?.longOrNull ?: System.currentTimeMillis()
+        data["createdAt"]?.jsonPrimitive?.longOrNull ?: System.currentTimeMillis(),
+        urlFactory
     )
 
     val claims: Map<String, Any?> by lazy {
@@ -85,7 +99,7 @@ class FirebaseUserImpl private constructor(
         val source = TaskCompletionSource<Void>()
         val body = RequestBody.create(FirebaseAuth.getInstance(app).json, JsonObject(mapOf("idToken" to JsonPrimitive(idToken))).toString())
         val request = Request.Builder()
-            .url("https://www.googleapis.com/identitytoolkit/v3/relyingparty/deleteAccount?key=" + app.options.apiKey)
+            .url(urlFactory.buildUrl("v3/relyingparty/deleteAccount"))
             .post(body)
             .build()
         FirebaseAuth.getInstance(app).client.newCall(request).enqueue(object : Callback {
@@ -183,11 +197,13 @@ class FirebaseAuth constructor(val app: FirebaseApp) : InternalAuthProvider {
             }
         }
 
+    private var urlFactory = UrlFactory(app)
+
     fun signInAnonymously(): Task<AuthResult> {
         val source = TaskCompletionSource<AuthResult>()
         val body = RequestBody.create(json, JsonObject(mapOf("returnSecureToken" to JsonPrimitive(true))).toString())
         val request = Request.Builder()
-            .url("https://identitytoolkit.googleapis.com/v1/accounts:signUp?key=" + app.options.apiKey)
+            .url(urlFactory.buildUrl("v1/accounts:signUp"))
             .post(body)
             .build()
         client.newCall(request).enqueue(object : Callback {
@@ -222,7 +238,7 @@ class FirebaseAuth constructor(val app: FirebaseApp) : InternalAuthProvider {
             JsonObject(mapOf("token" to JsonPrimitive(customToken), "returnSecureToken" to JsonPrimitive(true))).toString()
         )
         val request = Request.Builder()
-            .url("https://www.googleapis.com/identitytoolkit/v3/relyingparty/verifyCustomToken?key=" + app.options.apiKey)
+            .url(urlFactory.buildUrl("v3/relyingparty/verifyCustomToken"))
             .post(body)
             .build()
         client.newCall(request).enqueue(object : Callback {
@@ -257,7 +273,7 @@ class FirebaseAuth constructor(val app: FirebaseApp) : InternalAuthProvider {
             JsonObject(mapOf("email" to JsonPrimitive(email), "password" to JsonPrimitive(password), "returnSecureToken" to JsonPrimitive(true))).toString()
         )
         val request = Request.Builder()
-            .url("https://www.googleapis.com/identitytoolkit/v3/relyingparty/verifyPassword?key=" + app.options.apiKey)
+            .url("v3/relyingparty/verifyPassword?key=" + app.options.apiKey)
             .post(body)
             .build()
         client.newCall(request).enqueue(object : Callback {
@@ -435,5 +451,8 @@ class FirebaseAuth constructor(val app: FirebaseApp) : InternalAuthProvider {
     fun signInWithEmailLink(email: String, link: String): Task<AuthResult> = TODO()
 
     fun setLanguageCode(value: String): Nothing = TODO()
-    fun useEmulator(host: String, port: Int): Unit = TODO()
+
+    fun useEmulator(host: String, port: Int) {
+        urlFactory = UrlFactory(app, "http://$host:$port/")
+    }
 }