Bring operation middleware inline with other handler interfaces

99designs · Oct 30, 2019 · 4a69bcd · 4a69bcd
1 parent ab5665a
commit 4a69bcd
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Showing 4 changed files with 29 additions and 33 deletions.
diff --git a/graphql/context.go b/graphql/context.go
@@ -10,6 +10,7 @@ import (
 
 type Resolver func(ctx context.Context) (res interface{}, err error)
 type ResultMiddleware func(ctx context.Context, next ResultHandler) *Response
+type OperationMiddleware func(ctx context.Context, next OperationHandler, writer Writer)
 type FieldMiddleware func(ctx context.Context, next Resolver) (res interface{}, err error)
 type ComplexityLimitFunc func(ctx context.Context) int
 

diff --git a/graphql/handler.go b/graphql/handler.go
@@ -28,22 +28,17 @@ type (
 	}
 
 	// HandlerPlugin interface is entirely optional, see the list of possible hook points below
-	// Its important to understand the lifecycle of a graphql request and the terminology we use in gqlgen before working with these
-	// +---REQUEST POST /graphql------------------------------------------------+
-	// |                                                                        |
-	// | ++OPERATION query OpName { viewer { name } }+------------------------+ |
-	// | |                                                                    | |
-	// | | RESULT    { "data": { "viewer": { "name": "bob" } } }              | |
-	// | |                                                                    | |
-	// | ++OPERATION subscription OpName2 { chat { message } }+---------------+ |
-	// | |                                                                    | |
-	// | | RESULT    { "data": { "chat": { "message": "hello" } } }           | |
-	// | |                                                                    | |
-	// | | RESULT    { "data": { "chat": { "message": "byee" } } }            | |
-	// | |                                                                    | |
+	// Its important to understand the lifecycle of a graphql request and the terminology we use in gqlgen
+	// before working with these
+	//
+	// +--- REQUEST   POST /graphql --------------------------------------------+
+	// | +- OPERATION query OpName { viewer { name } } -----------------------+ |
+	// | |  RESULT    { "data": { "viewer": { "name": "bob" } } }             | |
+	// | +- OPERATION subscription OpName2 { chat { message } } --------------+ |
+	// | |  RESULT    { "data": { "chat": { "message": "hello" } } }          | |
+	// | |  RESULT    { "data": { "chat": { "message": "byee" } } }           | |
 	// | +--------------------------------------------------------------------+ |
 	// +------------------------------------------------------------------------+
-
 	HandlerPlugin interface{}
 
 	// RequestParameterMutator is called before creating a request context. allows manipulating the raw query
@@ -57,8 +52,10 @@ type (
 		MutateRequestContext(ctx context.Context, rc *RequestContext) *gqlerror.Error
 	}
 
+	// OperationInterceptor is called for each incoming query, for basic requests the writer will be invoked once,
+	// for subscriptions it will be invoked multiple times.
 	OperationInterceptor interface {
-		InterceptOperation(next OperationHandler) OperationHandler
+		InterceptOperation(ctx context.Context, next OperationHandler, writer Writer)
 	}
 
 	// ResultInterceptor is called around each graphql operation result. This can be called many times for a single

diff --git a/graphql/handler/executor.go b/graphql/handler/executor.go
@@ -11,7 +11,7 @@ import (
 )
 
 type executor struct {
-	operationHandler       graphql.OperationHandler
+	operationMiddleware    graphql.OperationHandler
 	resultHandler          graphql.ResultMiddleware
 	responseMiddleware     graphql.FieldMiddleware
 	es                     graphql.ExecutableSchema
@@ -25,7 +25,7 @@ func newExecutor(es graphql.ExecutableSchema, plugins []graphql.HandlerPlugin) e
 	e := executor{
 		es: es,
 	}
-	e.operationHandler = e.executableSchemaHandler
+	e.operationMiddleware = e.executableSchemaHandler
 	e.resultHandler = func(ctx context.Context, next graphql.ResultHandler) *graphql.Response {
 		return next(ctx)
 	}
@@ -37,8 +37,10 @@ func newExecutor(es graphql.ExecutableSchema, plugins []graphql.HandlerPlugin) e
 	for i := len(plugins) - 1; i >= 0; i-- {
 		p := plugins[i]
 		if p, ok := p.(graphql.OperationInterceptor); ok {
-			previous := e.operationHandler
-			e.operationHandler = p.InterceptOperation(previous)
+			previous := e.operationMiddleware
+			e.operationMiddleware = func(ctx context.Context, writer graphql.Writer) {
+				p.InterceptOperation(ctx, previous, writer)
+			}
 		}
 
 		if p, ok := p.(graphql.ResultInterceptor); ok {
@@ -75,7 +77,7 @@ func newExecutor(es graphql.ExecutableSchema, plugins []graphql.HandlerPlugin) e
 }
 
 func (e executor) DispatchRequest(ctx context.Context, writer graphql.Writer) {
-	e.operationHandler(ctx, writer)
+	e.operationMiddleware(ctx, writer)
 }
 
 func (e executor) CreateRequestContext(ctx context.Context, params *graphql.RawParams) (*graphql.RequestContext, gqlerror.List) {

diff --git a/graphql/handler/server_test.go b/graphql/handler/server_test.go
@@ -71,17 +71,13 @@ func TestServer(t *testing.T) {
 
 	t.Run("invokes operation middleware in order", func(t *testing.T) {
 		var calls []string
-		srv.Use(opFunc(func(next graphql.OperationHandler) graphql.OperationHandler {
-			return func(ctx context.Context, writer graphql.Writer) {
-				calls = append(calls, "first")
-				next(ctx, writer)
-			}
+		srv.Use(opFunc(func(ctx context.Context, next graphql.OperationHandler, writer graphql.Writer) {
+			calls = append(calls, "first")
+			next(ctx, writer)
 		}))
-		srv.Use(opFunc(func(next graphql.OperationHandler) graphql.OperationHandler {
-			return func(ctx context.Context, writer graphql.Writer) {
-				calls = append(calls, "second")
-				next(ctx, writer)
-			}
+		srv.Use(opFunc(func(ctx context.Context, next graphql.OperationHandler, writer graphql.Writer) {
+			calls = append(calls, "second")
+			next(ctx, writer)
 		}))
 
 		resp := get(srv, "/foo?query={a}")
@@ -108,10 +104,10 @@ func TestServer(t *testing.T) {
 	})
 }
 
-type opFunc func(next graphql.OperationHandler) graphql.OperationHandler
+type opFunc func(ctx context.Context, next graphql.OperationHandler, writer graphql.Writer)
 
-func (r opFunc) InterceptOperation(next graphql.OperationHandler) graphql.OperationHandler {
-	return r(next)
+func (r opFunc) InterceptOperation(ctx context.Context, next graphql.OperationHandler, writer graphql.Writer) {
+	r(ctx, next, writer)
 }
 
 type fieldFunc func(ctx context.Context, next graphql.Resolver) (res interface{}, err error)