From d2b96f8d7aa2e13a1a85342acd20dc5eaae0a77b Mon Sep 17 00:00:00 2001
From: Dustin Oprea <myselfasunder@gmail.com>
Date: Mon, 29 Aug 2016 08:49:18 -0400
Subject: [PATCH 1/3] Added support for a context-generator.

---
 handler.go | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/handler.go b/handler.go
index 96483a8..8bf255f 100644
--- a/handler.go
+++ b/handler.go
@@ -21,8 +21,10 @@ const (
 type Handler struct {
 	Schema *graphql.Schema
 	
+	cg *ContextGenerator
 	pretty bool
 }
+
 type RequestOptions struct {
 	Query         string                 `json:"query" url:"query" schema:"query"`
 	Variables     map[string]interface{} `json:"variables" url:"variables" schema:"variables"`
@@ -143,6 +145,22 @@ func (h *Handler) ContextHandler(ctx context.Context, w http.ResponseWriter, r *
 	}
 }
 
+type ContextGenerator interface {
+	MakeContext(w http.ResponseWriter, r *http.Request) (context.Context, error)
+}
+
+func (h *Handler) SetContextGenerator(cg *ContextGenerator) {
+	h.cg = cg
+}
+
+func (h *Handler) GetContext(w http.ResponseWriter, r *http.Request) (ctx context.Context, err error) {
+	if h.cg != nil {
+		return h.cg.MakeContext(w, r)
+	} else {
+		return context.Background(), nil
+	}
+}
+
 // ServeHTTP provides an entrypoint into executing graphQL queries.
 func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	h.ContextHandler(context.Background(), w, r)

From 256f38f2f1d96f833c19799a9f81fa5e19ebb27c Mon Sep 17 00:00:00 2001
From: Dustin Oprea <myselfasunder@gmail.com>
Date: Mon, 29 Aug 2016 08:59:11 -0400
Subject: [PATCH 2/3] Can now equip handler with a context generator.

---
 handler.go | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/handler.go b/handler.go
index 8bf255f..d4003f1 100644
--- a/handler.go
+++ b/handler.go
@@ -21,7 +21,7 @@ const (
 type Handler struct {
 	Schema *graphql.Schema
 	
-	cg *ContextGenerator
+	rcg RequestContextGenerator
 	pretty bool
 }
 
@@ -145,17 +145,17 @@ func (h *Handler) ContextHandler(ctx context.Context, w http.ResponseWriter, r *
 	}
 }
 
-type ContextGenerator interface {
+type RequestContextGenerator interface {
 	MakeContext(w http.ResponseWriter, r *http.Request) (context.Context, error)
 }
 
-func (h *Handler) SetContextGenerator(cg *ContextGenerator) {
-	h.cg = cg
+func (h *Handler) SetRequestContextGenerator(rcg RequestContextGenerator) {
+	h.rcg = rcg
 }
 
 func (h *Handler) GetContext(w http.ResponseWriter, r *http.Request) (ctx context.Context, err error) {
-	if h.cg != nil {
-		return h.cg.MakeContext(w, r)
+	if h.rcg != nil {
+		return h.rcg.MakeContext(w, r)
 	} else {
 		return context.Background(), nil
 	}
@@ -163,7 +163,11 @@ func (h *Handler) GetContext(w http.ResponseWriter, r *http.Request) (ctx contex
 
 // ServeHTTP provides an entrypoint into executing graphQL queries.
 func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
-	h.ContextHandler(context.Background(), w, r)
+	if ctx, err := h.GetContext(w, r); err != nil {
+		panic(err)
+	} else {
+		h.ContextHandler(ctx, w, r)
+	}
 }
 
 type Config struct {

From b05c256270fb773dfd41f95d7f5f3ff675c9a7e2 Mon Sep 17 00:00:00 2001
From: Dustin Oprea <myselfasunder@gmail.com>
Date: Mon, 29 Aug 2016 09:04:05 -0400
Subject: [PATCH 3/3] Added RequestContextGenerator to documentation.

---
 README.md | 42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/README.md b/README.md
index 96cc881..d34ee08 100644
--- a/README.md
+++ b/README.md
@@ -32,6 +32,48 @@ func main() {
 }
 ```
 
+By default, `context.Background()` is used to generate contexts. If you need to provide an alternative method to support environments, like AppEngine, you can provide a RequestContextGenerator.
+
+```go
+package main
+
+import (
+  "net/http"
+
+  "golang.org/x/net/context"
+  "github.com/graphql-go/handler"
+  "google.golang.org/appengine"
+)
+
+type contextGenerator struct {
+
+}
+
+func (cg *contextGenerator) MakeContext(w http.ResponseWriter, r *http.Request) (context.Context, error) {
+    ctx := appengine.NewContext(r)
+
+    return ctx, nil
+}
+
+func main() {
+
+  // define GraphQL schema using relay library helpers
+  schema := graphql.NewSchema(...)
+  
+  h := handler.New(&handler.Config{
+    Schema: schema,
+    Pretty: true,
+  })
+
+  cg := &contextGenerator{}
+  h.SetRequestContextGenerator(cg)
+
+  // serve HTTP
+  http.Handle("/graphql", h)
+  http.ListenAndServe(":8080", nil)
+}
+```
+
 ### Details
 
 The handler will accept requests with