api [nfc]: Pull some common logic into an ApiConnection class

Author: gnprice

lib/api/core.dart

@@ -0,0 +1,36 @@
+import 'dart:convert';
+
+import 'package:http/http.dart' as http;
+
+abstract class Auth {
+  String get realmUrl;
+
+  String get email;
+
+  String get apiKey;
+}
+
+class ApiConnection {
+  ApiConnection({required this.auth});
+
+  final Auth auth;
+
+  Map<String, String> _headers() {
+    // TODO memoize
+    final authBytes = utf8.encode("${auth.email}:${auth.apiKey}");
+    return {
+      'Authorization': 'Basic ${base64.encode(authBytes)}',
+    };
+  }
+
+  Future<String> post(String route, Map<String, dynamic>? params) async {
+    final response = await http.post(
+        Uri.parse("${auth.realmUrl}/api/v1/$route"),
+        headers: _headers(),
+        body: params?.map((k, v) => MapEntry(k, jsonEncode(v))));
+    if (response.statusCode != 200) {
+      throw Exception("error on $route: status ${response.statusCode}");
+    }
+    return response.body;
+  }
+}

lib/api/route/register_queue.dart

@@ -1,36 +1,21 @@
 import 'dart:convert';
 
-import 'package:http/http.dart' as http;
-
-import '../../store.dart';
+import '../core.dart';
 import '../model/initial_snapshot.dart';
 
 /// https://zulip.com/api/register-queue
-Future<InitialSnapshot> registerQueue(Account account) async {
-  final response = await http.post(
-      Uri.parse("${account.realmUrl}/api/v1/register"),
-      headers: _headers(account),
-      body: {
-        'apply_markdown': 'true',
-        'slim_presence': 'true',
-        'client_capabilities': jsonEncode({
-          'notification_settings_null': true,
-          'bulk_message_deletion': true,
-          'user_avatar_url_field_optional': true,
-          'stream_typing_notifications': false, // TODO implement
-          'user_settings_object': true,
-        }),
-      });
-  if (response.statusCode != 200) {
-    throw Exception("registerQueue: status ${response.statusCode}");
-  }
-  final json = jsonDecode(response.body);
+Future<InitialSnapshot> registerQueue(ApiConnection connection) async {
+  final data = await connection.post('register', {
+    'apply_markdown': true,
+    'slim_presence': true,
+    'client_capabilities': {
+      'notification_settings_null': true,
+      'bulk_message_deletion': true,
+      'user_avatar_url_field_optional': true,
+      'stream_typing_notifications': false, // TODO implement
+      'user_settings_object': true,
+    },
+  });
+  final json = jsonDecode(data);
   return InitialSnapshot.fromJson(json);
 }
-
-Map<String, String> _headers(Account account) {
-  final authBytes = utf8.encode("${account.email}:${account.apiKey}");
-  return {
-    'Authorization': 'Basic ${base64.encode(authBytes)}',
-  };
-}

lib/store.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/foundation.dart';
 
+import 'api/core.dart';
 import 'api/model/initial_snapshot.dart';
 import 'api/route/register_queue.dart';
 import 'credential_fixture.dart' as credentials; // prototyping hack; not in Git
@@ -8,9 +9,10 @@ class PerAccountStore extends ChangeNotifier {
   // Load the user's data from storage.  (Once we have such a thing.)
   static Future<PerAccountStore> load() async {
     const account = _fixtureAccount;
+    final connection = ApiConnection(auth: account);
 
     final stopwatch = Stopwatch()..start();
-    final initialSnapshot = await registerQueue(account); // TODO retry
+    final initialSnapshot = await registerQueue(connection); // TODO retry
     final t = (stopwatch..stop()).elapsed;
     // TODO log the time better
     if (kDebugMode) print("initial fetch time: ${t.inMilliseconds}ms");
@@ -36,11 +38,14 @@ const Account _fixtureAccount = Account(
   apiKey: credentials.api_key,
 );
 
-class Account {
+class Account implements Auth {
   const Account(
       {required this.realmUrl, required this.email, required this.apiKey});
 
+  @override
   final String realmUrl;
+  @override
   final String email;
+  @override
   final String apiKey;
 }