core: Send hardcoded User-Agent header in requests

This is required for the server to automatically mark
sent messages as read. See `sent_by_human` in
`zulip/zerver/models.py`.

Fixes: #440

Author: sirpengi

lib/api/core.dart

@@ -80,6 +80,7 @@ class ApiConnection {
     assert(debugLog("${request.method} ${request.url}"));
 
     addAuth(request);
+    request.headers.addAll(userAgentHeader());
 
     final http.StreamedResponse response;
     try {
@@ -198,6 +199,13 @@ Map<String, String> authHeader({required String email, required String apiKey})
   };
 }
 
+// TODO(#453): Create real User-Agent string
+Map<String, String> userAgentHeader() {
+  return {
+    'User-Agent': 'ZulipMobile/?.?.? (Android 14)',
+  };
+}
+
 Map<String, String>? encodeParameters(Map<String, dynamic>? params) {
   return params?.map((k, v) =>
     MapEntry(k, v is RawParameter ? v.value : jsonEncode(v)));

test/api/core_test.dart

@@ -23,7 +23,10 @@ void main() {
         check(connection.lastRequest!).isA<http.Request>()
           ..method.equals('GET')
           ..url.asString.equals('${eg.realmUrl.origin}$expectedRelativeUrl')
-          ..headers.deepEquals(authHeader(email: eg.selfAccount.email, apiKey: eg.selfAccount.apiKey))
+          ..headers.deepEquals({
+            ...authHeader(email: eg.selfAccount.email, apiKey: eg.selfAccount.apiKey),
+            ...userAgentHeader(),
+          })
           ..body.equals('');
       });
     }
@@ -53,6 +56,7 @@ void main() {
           ..url.asString.equals('${eg.realmUrl.origin}/api/v1/example/route')
           ..headers.deepEquals({
             ...authHeader(email: eg.selfAccount.email, apiKey: eg.selfAccount.apiKey),
+            ...userAgentHeader(),
             if (expectContentType)
               'content-type': 'application/x-www-form-urlencoded; charset=utf-8',
           })
@@ -83,7 +87,10 @@ void main() {
         check(connection.lastRequest!).isA<http.MultipartRequest>()
           ..method.equals('POST')
           ..url.asString.equals('${eg.realmUrl.origin}/api/v1/example/route')
-          ..headers.deepEquals(authHeader(email: eg.selfAccount.email, apiKey: eg.selfAccount.apiKey))
+          ..headers.deepEquals({
+            ...authHeader(email: eg.selfAccount.email, apiKey: eg.selfAccount.apiKey),
+            ...userAgentHeader(),
+          })
           ..fields.deepEquals({})
           ..files.single.which(it()
             ..field.equals('file')
@@ -115,6 +122,7 @@ void main() {
           ..url.asString.equals('${eg.realmUrl.origin}/api/v1/example/route')
           ..headers.deepEquals({
             ...authHeader(email: eg.selfAccount.email, apiKey: eg.selfAccount.apiKey),
+            ...userAgentHeader(),
             if (expectContentType)
               'content-type': 'application/x-www-form-urlencoded; charset=utf-8',
           })