Merge pull request #28 from rigglo/subscriptions

Subscriptions implementation

examples/custommarshaler/main.go

@@ -11,8 +11,8 @@ import (
 
 func main() {
 	h := handler.New(handler.Config{
-		Executor: gql.DefaultExecutor(Schema),
-		GraphiQL: true,
+		Executor:   gql.DefaultExecutor(Schema),
+		Playground: true,
 	})
 	http.Handle("/graphql", h)
 	if err := http.ListenAndServe(":9999", nil); err != nil {

examples/directives/main.go

@@ -11,8 +11,8 @@ import (
 
 func main() {
 	h := handler.New(handler.Config{
-		Executor: gql.DefaultExecutor(Schema),
-		GraphiQL: true,
+		Executor:   gql.DefaultExecutor(Schema),
+		Playground: true,
 	})
 	http.Handle("/graphql", h)
 	if err := http.ListenAndServe(":9999", nil); err != nil {

examples/extension/main.go

@@ -25,8 +25,8 @@ func main() {
 	})
 
 	h := handler.New(handler.Config{
-		Executor: exec,
-		GraphiQL: true,
+		Executor:   exec,
+		Playground: true,
 	})
 	http.Handle("/graphql", h)
 	if err := http.ListenAndServe(":9999", nil); err != nil {

examples/movies/main.go

@@ -11,8 +11,8 @@ import (
 
 func main() {
 	h := handler.New(handler.Config{
-		Executor: gql.DefaultExecutor(BlockBusters),
-		GraphiQL: true,
+		Executor:   gql.DefaultExecutor(BlockBusters),
+		Playground: true,
 	})
 	http.Handle("/graphql", h)
 	if err := http.ListenAndServe(":9999", nil); err != nil {

examples/pets/main.go

@@ -17,8 +17,8 @@ func init() {
 
 func main() {
 	h := handler.New(handler.Config{
-		Executor: gql.DefaultExecutor(PetStore),
-		GraphiQL: true,
+		Executor:   gql.DefaultExecutor(PetStore),
+		Playground: true,
 	})
 	http.Handle("/graphql", h)
 	if err := http.ListenAndServe(":9999", nil); err != nil {

examples/pizzeria/main.go

@@ -9,8 +9,8 @@ import (
 
 func main() {
 	http.Handle("/graphql", handler.New(handler.Config{
-		Executor: gql.DefaultExecutor(Schema),
-		GraphiQL: true,
+		Executor:   gql.DefaultExecutor(Schema),
+		Playground: true,
 	}))
 	if err := http.ListenAndServe(":9999", nil); err != nil {
 		panic(err)

execution.go

@@ -110,6 +110,45 @@ func (e *Executor) Execute(ctx context.Context, p Params) *Result {
 	return gqlctx.res
 }
 
+func (e *Executor) Subscribe(ctx context.Context, query string, operationName string, variables map[string]interface{}) (<-chan interface{}, error) {
+	if e.config.Schema.Subscription == nil {
+		return nil, errors.New("Schema does not provide subscriptions")
+	}
+	p := Params{
+		Query:         query,
+		OperationName: operationName,
+		Variables:     variables,
+	}
+
+	doc, err := parser.Parse([]byte(p.Query))
+	if err != nil {
+		return nil, err
+	}
+	types, directives, implementors := getTypes(e.config.Schema)
+
+	gqlctx := newContext(ctx, e.config.Schema, doc, &p, e.config.GoroutineLimit, e.config.EnableGoroutines)
+	gqlctx.types = types
+	gqlctx.directives = directives
+	gqlctx.implementors = implementors
+
+	validate(gqlctx)
+	if len(gqlctx.res.Errors) > 0 {
+		return nil, errors.New("validation error: invalid document")
+	}
+
+	getOperation(gqlctx)
+	if len(gqlctx.res.Errors) > 0 {
+		return nil, errors.New("invalid operation")
+	}
+
+	coerceVariableValues(gqlctx)
+	if len(gqlctx.res.Errors) > 0 {
+		return nil, errors.New("invalid variables")
+	}
+
+	return subscribe(gqlctx)
+}
+
 type Params struct {
 	Query         string                 `json:"query"`
 	Variables     map[string]interface{} `json:"variables"`
@@ -282,7 +321,7 @@ func resolveOperation(ctx *gqlCtx) {
 }
 
 func executeQuery(ctx *gqlCtx, op *ast.Operation) *Result {
-	rmap, hasNullErrs := executeSelectionSet(ctx, []interface{}{}, op.SelectionSet, ctx.schema.Query, nil)
+	rmap, hasNullErrs := executeSelectionSet(ctx, []interface{}{}, op.SelectionSet, ctx.schema.Query, ctx.schema.RootValue)
 	if hasNullErrs {
 		ctx.res.Data = nil
 	} else {
@@ -292,7 +331,7 @@ func executeQuery(ctx *gqlCtx, op *ast.Operation) *Result {
 }
 
 func executeMutation(ctx *gqlCtx, op *ast.Operation) *Result {
-	rmap, hasNullErrs := executeSelectionSet(ctx, []interface{}{}, op.SelectionSet, ctx.schema.Mutation, nil)
+	rmap, hasNullErrs := executeSelectionSet(ctx, []interface{}{}, op.SelectionSet, ctx.schema.Mutation, ctx.schema.RootValue)
 	if hasNullErrs {
 		ctx.res.Data = nil
 	} else {
@@ -301,6 +340,55 @@ func executeMutation(ctx *gqlCtx, op *ast.Operation) *Result {
 	return ctx.res
 }
 
+func subscribe(ctx *gqlCtx) (<-chan interface{}, error) {
+	gfields := collectFields(ctx, ctx.schema.Subscription, ctx.operation.SelectionSet, nil)
+
+	out := make(chan interface{})
+
+	// Since the subscription operations must have ONE selection ONLY
+	// it's not a problem to run the field.Subscribe function serially
+	for rkey, fs := range gfields {
+		fieldName := fs[0].Name
+		if !strings.HasPrefix(fieldName, "__") {
+			res, err := ctx.schema.Subscription.Fields[fieldName].Resolver(
+				&resolveContext{
+					ctx:    ctx.ctx, // this is the original context
+					gqlCtx: ctx,     // execution context
+					args:   coerceArgumentValues(ctx, []interface{}{rkey}, ctx.schema.Subscription, fs[0]),
+					parent: ctx.schema.RootValue, // root value
+					path:   []interface{}{rkey},
+				},
+			)
+			if err != nil {
+				return nil, err
+			}
+
+			if ch, ok := res.(chan interface{}); ok {
+				go func() {
+					for v := range ch {
+						res, hasErr := completeValue(ctx, nil, ctx.schema.Subscription.Fields[fieldName].Type, fs, v)
+						if hasErr {
+							out <- &Result{
+								Data:   nil,
+								Errors: ctx.res.Errors,
+							}
+							ctx.res.Errors = []*Error{}
+						}
+						out <- &Result{
+							Data: map[string]interface{}{
+								rkey: res,
+							},
+						}
+					}
+					close(out)
+				}()
+			}
+			return out, nil
+		}
+	}
+	return nil, errors.New("invalid subscription")
+}
+
 func executeSelectionSet(ctx *gqlCtx, path []interface{}, ss []ast.Selection, ot *Object, ov interface{}) (map[string]interface{}, bool) {
 	gfields := collectFields(ctx, ot, ss, nil)
 	resMap := map[string]interface{}{}
@@ -933,6 +1021,9 @@ func getTypes(s *Schema) (map[string]Type, map[string]Directive, map[string][]Ty
 	if s.Mutation != nil {
 		typeWalker(types, directives, implementors, s.Mutation)
 	}
+	if s.Subscription != nil {
+		typeWalker(types, directives, implementors, s.Subscription)
+	}
 	return types, directives, implementors
 }
 

introspection.go

@@ -11,7 +11,10 @@ func init() {
 			Type: NewList(NewNonNull(typeIntrospection)),
 			Resolver: func(ctx Context) (interface{}, error) {
 				if ctx.Parent().(Type).GetKind() == ObjectKind {
-					return ctx.Parent().(*Object).GetInterfaces(), nil
+					if ctx.Parent().(*Object).Implements == nil {
+						return []struct{}{}, nil
+					}
+					return ctx.Parent().(*Object).Implements, nil
 				}
 				return nil, nil
 			},

pkg/handler/handler.go

@@ -11,9 +11,9 @@ import (
 )
 
 type Config struct {
-	Executor *gql.Executor
-	GraphiQL bool
-	Pretty   bool
+	Executor   *gql.Executor
+	Playground bool
+	Pretty     bool
 }
 
 func New(c Config) http.Handler {
@@ -31,6 +31,11 @@ func (h *handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	switch r.Method {
 	case http.MethodGet:
 		{
+			if h.conf.Playground {
+				w.Header().Set("Content-Type", "text/html; charset=utf-8")
+				fmt.Fprint(w, playground)
+				return
+			}
 			params = &gql.Params{
 				Query:         html.UnescapeString(r.URL.Query().Get("query")),
 				Variables:     map[string]interface{}{}, // TODO: find a way of doing this..
@@ -44,11 +49,6 @@ func (h *handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 					return
 				}
 			}
-			if h.conf.GraphiQL {
-				w.Header().Set("Content-Type", "text/html; charset=utf-8")
-				fmt.Fprint(w, graphiql)
-				return
-			}
 		}
 	case http.MethodPost:
 		{

pkg/handler/playground.go

@@ -0,0 +1,64 @@
+package handler
+
+const playground = `
+<!DOCTYPE html>
+<html>
+
+<head>
+  <meta charset=utf-8/>
+  <meta name="viewport" content="user-scalable=no, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, minimal-ui">
+  <title>GraphQL Playground</title>
+  <link rel="stylesheet" href="//cdn.jsdelivr.net/npm/graphql-playground-react/build/static/css/index.css" />
+  <link rel="shortcut icon" href="//cdn.jsdelivr.net/npm/graphql-playground-react/build/favicon.png" />
+  <script src="//cdn.jsdelivr.net/npm/graphql-playground-react/build/static/js/middleware.js"></script>
+</head>
+
+<body>
+  <div id="root">
+    <style>
+      body {
+        background-color: rgb(23, 42, 58);
+        font-family: Open Sans, sans-serif;
+        height: 90vh;
+      }
+
+      #root {
+        height: 100%;
+        width: 100%;
+        display: flex;
+        align-items: center;
+        justify-content: center;
+      }
+
+      .loading {
+        font-size: 32px;
+        font-weight: 200;
+        color: rgba(255, 255, 255, .6);
+        margin-left: 20px;
+      }
+
+      img {
+        width: 78px;
+        height: 78px;
+      }
+
+      .title {
+        font-weight: 400;
+      }
+    </style>
+    <img src='//cdn.jsdelivr.net/npm/graphql-playground-react/build/logo.png' alt=''>
+    <div class="loading"> Loading
+      <span class="title">GraphQL Playground</span>
+    </div>
+  </div>
+  <script>window.addEventListener('load', function (event) {
+      var rootURL = window
+      GraphQLPlayground.init(document.getElementById('root'), {
+        // options as 'endpoint' belong here
+        endpoint: window.location.protocol + "//" + window.location.host + window.location.pathname,
+        subscriptionEndpoint: "ws://" + window.location.host + window.location.pathname
+      })
+    })</script>
+</body>
+
+</html>`

schema.go

@@ -18,6 +18,7 @@ type Schema struct {
 	Mutation     *Object
 	Subscription *Object
 	Directives   Directives
+	RootValue    interface{}
 }
 
 // TypeKind shows the kind of a Type