Add support for global variables in GraphQL

angel_graphql/lib/src/graphql_http.dart

@@ -22,6 +22,11 @@ final Validator graphQlPostBody = new Validator({
 /// https://graphql.org/learn/serving-over-http/
 RequestHandler graphQLHttp(GraphQL graphQL) {
   return (req, res) async {
+    var globalVariables = <String, dynamic>{
+      '__requestctx': req,
+      '__responsectx': res,
+    };
+
     executeMap(Map map) async {
       var text = req.body['query'] as String;
       var operationName = req.body['operation_name'] as String;
@@ -37,6 +42,7 @@ RequestHandler graphQLHttp(GraphQL graphQL) {
           sourceUrl: 'input',
           operationName: operationName,
           variableValues: foldToStringDynamic(variables as Map),
+          globalVariables: globalVariables,
         ),
       };
     }
@@ -50,7 +56,11 @@ RequestHandler graphQLHttp(GraphQL graphQL) {
         if (req.headers.contentType?.mimeType == graphQlContentType.mimeType) {
           var text = utf8.decode(await req.lazyOriginalBuffer());
           return {
-            'data': await graphQL.parseAndExecute(text, sourceUrl: 'input')
+            'data': await graphQL.parseAndExecute(
+              text,
+              sourceUrl: 'input',
+              globalVariables: globalVariables,
+            ),
           };
         } else if (req.headers.contentType?.mimeType == 'application/json') {
           if (await validate(graphQlPostBody)(req, res)) {

example_star_wars/lib/src/models/human.dart

@@ -1,5 +1,6 @@
 import 'package:angel_model/angel_model.dart';
 import 'package:angel_serialize/angel_serialize.dart';
+import 'package:graphql_schema/graphql_schema.dart';
 
 import 'character.dart';
 import 'episode.dart';
@@ -7,6 +8,7 @@ import 'starship.dart';
 
 @serializable
 class Human extends Model implements Character {
+  @GraphQLDocumentation(description: "This human's name, of course.")
   String name;
   List<Character> friends;
   List<Episode> appearsIn;

graphql_schema/lib/src/object_type.dart

@@ -23,7 +23,8 @@ class GraphQLObjectType
   GraphQLObjectType(this.name, this.description, {this.isInterface: false});
 
   @override
-  GraphQLType<Map<String, dynamic>, Map<String, dynamic>> coerceToInputObject() {
+  GraphQLType<Map<String, dynamic>, Map<String, dynamic>>
+      coerceToInputObject() {
     return asInputObject('${name}Input', description: description);
   }
 
@@ -31,8 +32,9 @@ class GraphQLObjectType
   GraphQLInputObjectType asInputObject(String name, {String description}) {
     return new GraphQLInputObjectType(name,
         description: description ?? this.description,
-        inputFields:
+        inputFields: fields.map((f) => new GraphQLInputObjectField(
-            fields.map((f) => new GraphQLInputObjectField(f.name, f.type.coerceToInputObject())));
+            f.name, f.type.coerceToInputObject(),
+            description: f.description)));
   }
 
   void inheritFrom(GraphQLObjectType other) {
@@ -242,7 +244,8 @@ class GraphQLInputObjectType
   }
 
   @override
-  GraphQLType<Map<String, dynamic>, Map<String, dynamic>> coerceToInputObject() => this;
+  GraphQLType<Map<String, dynamic>, Map<String, dynamic>>
+      coerceToInputObject() => this;
 }
 
 class GraphQLInputObjectField<Value, Serialized> {

graphql_server/lib/graphql_server.dart

@@ -73,7 +73,8 @@ class GraphQL {
       {String operationName,
       sourceUrl,
       Map<String, dynamic> variableValues: const {},
-      initialValue}) {
+      initialValue,
+      Map<String, dynamic> globalVariables}) {
     var tokens = scan(text, sourceUrl: sourceUrl);
     var parser = new Parser(tokens);
     var document = parser.parseDocument();
@@ -86,26 +87,31 @@ class GraphQL {
           .toList());
     }
 
-    return executeRequest(_schema, document,
+    return executeRequest(
+      _schema,
+      document,
       operationName: operationName,
       initialValue: initialValue,
-        variableValues: variableValues);
+      variableValues: variableValues,
+      globalVariables: globalVariables,
+    );
   }
 
   Future<Map<String, dynamic>> executeRequest(
       GraphQLSchema schema, DocumentContext document,
       {String operationName,
       Map<String, dynamic> variableValues: const {},
-      initialValue}) async {
+      initialValue,
+      Map<String, dynamic> globalVariables}) async {
     var operation = getOperation(document, operationName);
     var coercedVariableValues =
         coerceVariableValues(schema, operation, variableValues ?? {});
     if (operation.isQuery)
-      return await executeQuery(
+      return await executeQuery(document, operation, schema,
-          document, operation, schema, coercedVariableValues, initialValue);
+          coercedVariableValues, initialValue, globalVariables);
     else {
-      return executeMutation(
+      return executeMutation(document, operation, schema, coercedVariableValues,
-          document, operation, schema, coercedVariableValues, initialValue);
+          initialValue, globalVariables);
     }
   }
 
@@ -175,11 +181,12 @@ class GraphQL {
       OperationDefinitionContext query,
       GraphQLSchema schema,
       Map<String, dynamic> variableValues,
-      initialValue) async {
+      initialValue,
+      Map<String, dynamic> globalVariables) async {
     var queryType = schema.queryType;
     var selectionSet = query.selectionSet;
-    return await executeSelectionSet(
+    return await executeSelectionSet(document, selectionSet, queryType,
-        document, selectionSet, queryType, initialValue, variableValues);
+        initialValue, variableValues, globalVariables);
   }
 
   Future<Map<String, dynamic>> executeMutation(
@@ -187,7 +194,8 @@ class GraphQL {
       OperationDefinitionContext mutation,
       GraphQLSchema schema,
       Map<String, dynamic> variableValues,
-      initialValue) async {
+      initialValue,
+      Map<String, dynamic> globalVariables) async {
     var mutationType = schema.mutationType;
 
     if (mutationType == null) {
@@ -196,8 +204,8 @@ class GraphQL {
     }
 
     var selectionSet = mutation.selectionSet;
-    return await executeSelectionSet(
+    return await executeSelectionSet(document, selectionSet, mutationType,
-        document, selectionSet, mutationType, initialValue, variableValues);
+        initialValue, variableValues, globalVariables);
   }
 
   Future<Map<String, dynamic>> executeSelectionSet(
@@ -205,7 +213,8 @@ class GraphQL {
       SelectionSetContext selectionSet,
       GraphQLObjectType objectType,
       objectValue,
-      Map<String, dynamic> variableValues) async {
+      Map<String, dynamic> variableValues,
+      Map<String, dynamic> globalVariables) async {
     var groupedFieldSet =
         collectFields(document, objectType, selectionSet, variableValues);
     var resultMap = <String, dynamic>{};
@@ -224,8 +233,16 @@ class GraphQL {
               .firstWhere((f) => f.name == fieldName, orElse: () => null)
               ?.type;
           if (fieldType == null) continue;
-          responseValue = await executeField(document, fieldName, objectType,
+          responseValue = await executeField(
-              objectValue, fields, fieldType, variableValues);
+              document,
+              fieldName,
+              objectType,
+              objectValue,
+              fields,
+              fieldType,
+              new Map<String, dynamic>.from(globalVariables)
+                ..addAll(variableValues),
+              globalVariables);
         }
 
         resultMap[responseKey] = responseValue;
@@ -242,14 +259,15 @@ class GraphQL {
       objectValue,
       List<SelectionContext> fields,
       GraphQLType fieldType,
-      Map<String, dynamic> variableValues) async {
+      Map<String, dynamic> variableValues,
+      Map<String, dynamic> globalVariables) async {
     var field = fields[0];
     var argumentValues =
         coerceArgumentValues(objectType, field, variableValues);
     var resolvedValue = await resolveFieldValue(
         objectType, objectValue, field.field.fieldName.name, argumentValues);
-    return completeValue(
+    return completeValue(document, fieldName, fieldType, fields, resolvedValue,
-        document, fieldName, fieldType, fields, resolvedValue, variableValues);
+        variableValues, globalVariables);
   }
 
   Map<String, dynamic> coerceArgumentValues(GraphQLObjectType objectType,
@@ -365,11 +383,12 @@ class GraphQL {
       GraphQLType fieldType,
       List<SelectionContext> fields,
       result,
-      Map<String, dynamic> variableValues) async {
+      Map<String, dynamic> variableValues,
+      Map<String, dynamic> globalVariables) async {
     if (fieldType is GraphQLNonNullableType) {
       var innerType = fieldType.ofType;
-      var completedResult = completeValue(
+      var completedResult = completeValue(document, fieldName, innerType,
-          document, fieldName, innerType, fields, result, variableValues);
+          fields, result, variableValues, globalVariables);
 
       if (completedResult == null) {
         throw new GraphQLException.fromMessage(
@@ -394,7 +413,7 @@ class GraphQL {
 
       for (var resultItem in (result as Iterable)) {
         out.add(await completeValue(document, '(item in "$fieldName")',
-            innerType, fields, resultItem, variableValues));
+            innerType, fields, resultItem, variableValues, globalVariables));
       }
 
       return out;
@@ -425,8 +444,8 @@ class GraphQL {
       }
 
       var subSelectionSet = mergeSelectionSets(fields);
-      return await executeSelectionSet(
+      return await executeSelectionSet(document, subSelectionSet, objectType,
-          document, subSelectionSet, objectType, result, variableValues);
+          result, variableValues, globalVariables);
     }
 
     throw new UnsupportedError('Unsupported type: $fieldType');