fix(client): wrap all subscription errors in QueryResults

zino-hofmann · Nov 9, 2020 · aae61ca · aae61ca
1 parent 7eb3f58
commit aae61ca
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Showing 2 changed files with 118 additions and 30 deletions.
diff --git a/packages/graphql/lib/src/core/query_manager.dart b/packages/graphql/lib/src/core/query_manager.dart
@@ -4,7 +4,7 @@ import 'package:meta/meta.dart';
 import 'package:collection/collection.dart';
 
 import 'package:gql_exec/gql_exec.dart';
-import 'package:gql_link/gql_link.dart' show Link;
+import 'package:gql_link/gql_link.dart' show Link, LinkException;
 
 import 'package:graphql/src/cache/cache.dart';
 import 'package:graphql/src/core/observable_query.dart';
@@ -75,39 +75,45 @@ class QueryManager {
       }
     }
 
-    yield* link.request(request).map((response) {
-      QueryResult queryResult;
-      bool rereadFromCache = false;
-      try {
-        queryResult = mapFetchResultToQueryResult(
-          response,
-          options,
-          source: QueryResultSource.network,
-        );
+    try {
+      yield* link.request(request).map((response) {
+        QueryResult queryResult;
+        bool rereadFromCache = false;
+        try {
+          queryResult = mapFetchResultToQueryResult(
+            response,
+            options,
+            source: QueryResultSource.network,
+          );
 
-        rereadFromCache = attemptCacheWriteFromResponse(
-          options.fetchPolicy,
-          request,
-          response,
-          queryResult,
-        );
-      } catch (failure) {
-        // we set the source to indicate where the source of failure
-        queryResult ??= QueryResult(source: QueryResultSource.network);
+          rereadFromCache = attemptCacheWriteFromResponse(
+            options.fetchPolicy,
+            request,
+            response,
+            queryResult,
+          );
+        } catch (failure) {
+          // we set the source to indicate where the source of failure
+          queryResult ??= QueryResult(source: QueryResultSource.network);
 
-        queryResult.exception = coalesceErrors(
-          exception: queryResult.exception,
-          linkException: translateFailure(failure),
-        );
-      }
+          queryResult.exception = coalesceErrors(
+            exception: queryResult.exception,
+            linkException: translateFailure(failure),
+          );
+        }
 
-      if (rereadFromCache) {
-        // normalize results if previously written
-        attempCacheRereadIntoResult(request, queryResult);
-      }
+        if (rereadFromCache) {
+          // normalize results if previously written
+          attempCacheRereadIntoResult(request, queryResult);
+        }
 
-      return queryResult;
-    });
+        return queryResult;
+      }).transform(StreamTransformer.fromHandlers(
+        handleError: (err, trace, sink) => sink.add(_wrapFailure(err)),
+      ));
+    } catch (ex) {
+      yield* Stream.fromIterable([_wrapFailure(ex)]);
+    }
   }
 
   Future<QueryResult> query(QueryOptions options) => fetchQuery('0', options);
@@ -476,3 +482,9 @@ class QueryManager {
     );
   }
 }
+
+QueryResult _wrapFailure(dynamic ex) => QueryResult(
+      // we set the source to indicate where the source of failure
+      source: QueryResultSource.network,
+      exception: coalesceErrors(linkException: translateFailure(ex)),
+    );
diff --git a/packages/graphql/test/graphql_client_test.dart b/packages/graphql/test/graphql_client_test.dart
@@ -435,6 +435,82 @@ void main() {
           ),
         );
       });
+
+      test('wraps stream exceptions', () async {
+        final ex = ServerException(
+          parsedResponse: null,
+          originalException: Error(),
+        );
+
+        when(
+          link.request(any),
+        ).thenAnswer(
+          (_) => Stream.error(ex),
+        );
+
+        final stream = client.subscribe(
+          SubscriptionOptions(
+            document: parseString(
+              r'''
+                subscription {
+                  item {
+                    id
+                    name
+                  }
+                }
+              ''',
+            ),
+          ),
+        );
+
+        expect(
+          stream,
+          emitsInOrder(
+            [
+              isA<QueryResult>().having(
+                (result) => result.exception.linkException,
+                'wrapped exception',
+                ex,
+              ),
+            ],
+          ),
+        );
+      });
+      test('wraps all exceptions from outside of stream', () async {
+        final err = Error();
+
+        when(
+          link.request(any),
+        ).thenThrow(err);
+
+        final stream = client.subscribe(
+          SubscriptionOptions(
+            document: parseString(
+              r'''
+                subscription {
+                  item {
+                    id
+                    name
+                  }
+                }
+              ''',
+            ),
+          ),
+        );
+
+        expect(
+          stream,
+          emitsInOrder(
+            [
+              isA<QueryResult>().having(
+                (result) => result.exception.linkException.originalException,
+                'wrapped exception',
+                err,
+              ),
+            ],
+          ),
+        );
+      });
     });
   });