[Google OAuth] Support custom Client IDs (bitfireAT/davx5#294)

* Support custom Client IDs

* Refactoring

---------

Co-authored-by: Ricki Hirner <hirner@bitfire.at>

app/src/main/java/at/bitfire/davdroid/network/GoogleOAuth.kt

@@ -4,11 +4,9 @@
 
 package at.bitfire.davdroid.network
 
-import android.content.Context
 import android.net.Uri
 import at.bitfire.davdroid.BuildConfig
 import net.openid.appauth.AuthorizationRequest
-import net.openid.appauth.AuthorizationService
 import net.openid.appauth.AuthorizationServiceConfiguration
 import net.openid.appauth.ResponseTypeValues
 
@@ -27,14 +25,12 @@ object GoogleOAuth {
         Uri.parse("https://oauth2.googleapis.com/token")
     )
 
-    fun authRequestBuilder() =
+    fun authRequestBuilder(clientId: String?) =
         AuthorizationRequest.Builder(
             serviceConfig,
-            CLIENT_ID,
+            clientId ?: CLIENT_ID,
             ResponseTypeValues.CODE,
             Uri.parse(BuildConfig.APPLICATION_ID + ":/oauth/redirect")
         )
 
-    fun createAuthService(context: Context) = AuthorizationService(context)
-
 }

app/src/main/java/at/bitfire/davdroid/network/HttpClient.kt

@@ -47,6 +47,7 @@ class HttpClient private constructor(
     @EntryPoint
     @InstallIn(SingletonComponent::class)
     interface HttpClientEntryPoint {
+        fun authorizationService(): AuthorizationService
         fun settingsManager(): SettingsManager
     }
 
@@ -176,7 +177,7 @@ class HttpClient private constructor(
                 certificateAlias = credentials.certificateAlias
 
             credentials.authState?.let { authState ->
-                val newAuthService = GoogleOAuth.createAuthService(context)
+                val newAuthService = EntryPointAccessors.fromApplication(context, HttpClientEntryPoint::class.java).authorizationService()
                 authService = newAuthService
                 BearerAuthInterceptor.fromAuthState(newAuthService, authState, authStateCallback)?.let { bearerAuthInterceptor ->
                     orig.addNetworkInterceptor(bearerAuthInterceptor)

app/src/main/java/at/bitfire/davdroid/network/OAuthModule.kt

@@ -0,0 +1,22 @@
+/*
+ * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
+ */
+
+package at.bitfire.davdroid.network
+
+import android.content.Context
+import dagger.Module
+import dagger.Provides
+import dagger.hilt.InstallIn
+import dagger.hilt.android.qualifiers.ApplicationContext
+import dagger.hilt.components.SingletonComponent
+import net.openid.appauth.AuthorizationService
+
+@Module
+@InstallIn(SingletonComponent::class)
+object OAuthModule {
+
+    @Provides
+    fun authorizationService(@ApplicationContext context: Context): AuthorizationService = AuthorizationService(context)
+
+}

app/src/main/java/at/bitfire/davdroid/ui/setup/GoogleLoginFragment.kt

@@ -13,7 +13,9 @@ import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
 import androidx.activity.result.contract.ActivityResultContract
+import androidx.compose.foundation.Image
 import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.wrapContentSize
@@ -26,11 +28,14 @@ import androidx.compose.material.Card
 import androidx.compose.material.MaterialTheme
 import androidx.compose.material.OutlinedTextField
 import androidx.compose.material.Text
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Warning
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.ComposeView
+import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.text.input.KeyboardType
 import androidx.compose.ui.tooling.preview.Preview
@@ -47,20 +52,30 @@ import at.bitfire.davdroid.log.Logger
 import at.bitfire.davdroid.network.GoogleOAuth
 import at.bitfire.davdroid.ui.UiUtils
 import com.google.accompanist.themeadapter.material.MdcTheme
+import dagger.hilt.android.AndroidEntryPoint
+import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.launch
 import net.openid.appauth.AuthState
 import net.openid.appauth.AuthorizationException
 import net.openid.appauth.AuthorizationRequest
 import net.openid.appauth.AuthorizationResponse
+import net.openid.appauth.AuthorizationService
 import net.openid.appauth.TokenResponse
+import org.apache.commons.lang3.StringUtils
 import java.net.URI
+import javax.inject.Inject
 
+@AndroidEntryPoint
 class GoogleLoginFragment: Fragment() {
 
     companion object {
+
+        val URI_TESTED_WITH_GOOGLE: Uri = Uri.parse("https://www.davx5.com/tested-with/google")
+
         fun googleBaseUri(googleAccount: String): URI =
             URI("https", "www.google.com", "/calendar/dav/$googleAccount/events/", null)
+
     }
 
     private val loginModel by activityViewModels<LoginModel>()
@@ -83,7 +98,15 @@ class GoogleLoginFragment: Fragment() {
     override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View {
         val v = ComposeView(requireActivity())
         v.setContent {
-            GoogleLogin()
+            GoogleLogin(onLogin = { account, clientId ->
+                loginModel.baseURI = googleBaseUri(account)
+
+                val authRequest = GoogleOAuth.authRequestBuilder(clientId)
+                    .setScopes(*GoogleOAuth.SCOPES)
+                    .setLoginHint(account)
+                    .build()
+                authRequestContract.launch(authRequest)
+            })
         }
 
         model.credentials.observe(viewLifecycleOwner) { credentials ->
@@ -100,77 +123,12 @@ class GoogleLoginFragment: Fragment() {
     }
 
 
-    @Composable
-    @Preview
-    fun GoogleLogin() {
-        MdcTheme {
-            Column(Modifier.padding(8.dp).verticalScroll(rememberScrollState())) {
-                Text(
-                    stringResource(R.string.login_type_google),
-                    style = MaterialTheme.typography.h5,
-                    modifier = Modifier.padding(vertical = 16.dp))
+    @HiltViewModel
+    class Model @Inject constructor(
+        application: Application,
+        val authService: AuthorizationService
+    ): AndroidViewModel(application) {
 
-                Card(Modifier.fillMaxWidth()) {
-                    Column(Modifier.padding(8.dp)) {
-                        Text(
-                            stringResource(R.string.login_google_guide),
-                            modifier = Modifier.padding(vertical = 8.dp))
-                        Button(
-                            onClick = {
-                                UiUtils.launchUri(requireActivity(), Uri.parse("https://www.davx5.com/tested-with/google"))
-                            },
-                            colors = ButtonDefaults.outlinedButtonColors(),
-                            modifier = Modifier.wrapContentSize()
-                        ) {
-                            Text(stringResource(R.string.intro_more_info))
-                        }
-                    }
-                }
-
-                val email = remember { mutableStateOf("") }
-                val emailError = remember { mutableStateOf<Boolean>(false) }
-                OutlinedTextField(
-                    email.value,
-                    singleLine = true,
-                    onValueChange = { account ->
-                        email.value = account
-                        loginModel.baseURI = googleBaseUri(account)
-                    },
-                    keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Email),
-                    label = { Text(stringResource(R.string.login_google_account)) },
-                    isError = emailError.value,
-                    placeholder = { Text("example@gmail.com") },
-                    modifier = Modifier.fillMaxWidth().padding(vertical = 16.dp)
-                )
-
-                Button({
-                    val valid = email.value.orEmpty().contains('@')
-                    emailError.value = !valid
-
-                    if (valid) {
-                        val authRequest = GoogleOAuth.authRequestBuilder()
-                            .setScopes(*GoogleOAuth.SCOPES)
-                            .setLoginHint(email.value)
-                            .build()
-                        authRequestContract.launch(authRequest)
-                    }
-                }, modifier = Modifier.wrapContentSize()) {
-                    Text(stringResource(R.string.login_login))
-                }
-
-                Text(
-                    stringResource(R.string.login_google_disclaimer, getString(R.string.app_name)),
-                    style = MaterialTheme.typography.body2,
-                    modifier = Modifier.padding(top = 24.dp))
-
-            }
-        }
-    }
-
-
-    class Model(application: Application): AndroidViewModel(application) {
-
-        val authService = GoogleOAuth.createAuthService(getApplication())
         val credentials = MutableLiveData<Credentials>()
 
         fun authenticate(resp: AuthorizationResponse) = viewModelScope.launch(Dispatchers.IO) {
@@ -194,4 +152,100 @@ class GoogleLoginFragment: Fragment() {
 
     }
 
+}
+
+
+@Composable
+fun GoogleLogin(
+    onLogin: (account: String, clientId: String?) -> Unit
+) {
+    val context = LocalContext.current
+    MdcTheme {
+        Column(
+            Modifier
+                .padding(8.dp)
+                .verticalScroll(rememberScrollState())) {
+            Text(
+                stringResource(R.string.login_type_google),
+                style = MaterialTheme.typography.h5,
+                modifier = Modifier.padding(vertical = 16.dp))
+
+            Card(Modifier.fillMaxWidth()) {
+                Column(Modifier.padding(8.dp)) {
+                    Row {
+                        Image(Icons.Default.Warning, contentDescription = "", modifier = Modifier.padding(top = 8.dp, end = 8.dp, bottom = 8.dp))
+                        Text(stringResource(R.string.login_google_see_tested_with))
+                    }
+                    Text(stringResource(R.string.login_google_unexpected_warnings), modifier = Modifier.padding(vertical = 8.dp))
+                    Button(
+                        onClick = {
+                            UiUtils.launchUri(context, GoogleLoginFragment.URI_TESTED_WITH_GOOGLE)
+                        },
+                        colors = ButtonDefaults.outlinedButtonColors(),
+                        modifier = Modifier.wrapContentSize()
+                    ) {
+                        Text(stringResource(R.string.intro_more_info))
+                    }
+                }
+            }
+
+            val email = remember { mutableStateOf("") }
+            val emailError = remember { mutableStateOf(false) }
+            OutlinedTextField(
+                email.value,
+                singleLine = true,
+                onValueChange = { email.value = it },
+                keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Email),
+                label = { Text(stringResource(R.string.login_google_account)) },
+                isError = emailError.value,
+                placeholder = { Text("example@gmail.com") },
+                modifier = Modifier
+                    .fillMaxWidth()
+                    .padding(top = 8.dp)
+            )
+
+            val userClientId = remember { mutableStateOf("") }
+            val userClientIdError = remember { mutableStateOf(false) }
+            OutlinedTextField(
+                userClientId.value,
+                singleLine = true,
+                onValueChange = { clientId ->
+                    userClientId.value = clientId
+                },
+                keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Text),
+                label = { Text(stringResource(R.string.login_google_client_id)) },
+                isError = userClientIdError.value,
+                placeholder = { Text("[...].apps.googleusercontent.com") },
+                modifier = Modifier
+                    .fillMaxWidth()
+                    .padding(top = 8.dp)
+            )
+
+            Button({
+                val validEmail = email.value.contains('@')
+                emailError.value = !validEmail
+
+                if (validEmail) {
+                    val clientId = StringUtils.trimToNull(userClientId.value.trim())
+                    onLogin(email.value, clientId)
+                }
+            }, modifier = Modifier
+                .padding(top = 8.dp)
+                .wrapContentSize()) {
+                Text(stringResource(R.string.login_login))
+            }
+
+            Text(
+                stringResource(R.string.login_google_disclaimer, stringResource(R.string.app_name)),
+                style = MaterialTheme.typography.body2,
+                modifier = Modifier.padding(top = 24.dp))
+
+        }
+    }
+}
+
+@Composable
+@Preview
+fun PreviewGoogleLogin() {
+    GoogleLogin(onLogin = { _, _ -> })
 }

app/src/main/res/values/strings.xml

@@ -293,8 +293,12 @@
     <string name="login_no_certificate_found">No certificate found</string>
     <string name="login_install_certificate">Install certificate</string>
     <string name="login_type_google">Google Contacts / Calendar</string>
-    <string name="login_google_guide">Please read our guide about the login to Google. There may be unexpected warnings which are explained there.</string>
+    <string name="login_google_see_tested_with">Please see our \"Tested with Google\" page for up-to-date information.</string>
+    <string name="login_google_unexpected_warnings">You may experience unexpected warnings and/or have to create your own client ID.</string>
     <string name="login_google_account">Google account</string>
+    <string name="login_google_client_id">Client ID (optional)</string>
+    <string name="login_google_client_id_description">You may use your own client ID, in case our does not work.</string>
+    <string name="login_google_client_id_description_link">Show me how!</string>
     <string name="login_google_disclaimer">%s is not affiliated to, nor has it been authorized, sponsored or otherwise approved by Google LLC.</string>
 
     <string name="login_configuration_detection">Configuration detection</string>