// Copyright 2015 Google Inc. All rights reserved.
// Use of this source code is governed by the Apache 2.0
// license that can be found in the LICENSE file.
// +build appengine
package internal
import (
"errors"
"fmt"
"net/http"
"time"
"appengine"
"appengine_internal"
basepb "appengine_internal/base"
"github.com/golang/protobuf/proto"
netcontext "golang.org/x/net/context"
)
var contextKey = "holds an appengine.Context"
// fromContext returns the App Engine context or nil if ctx is not
// derived from an App Engine context.
func fromContext(ctx netcontext.Context) appengine.Context {
c, _ := ctx.Value(&contextKey).(appengine.Context)
return c
}
// This is only for classic App Engine adapters.
func ClassicContextFromContext(ctx netcontext.Context) (appengine.Context, error) {
c := fromContext(ctx)
if c == nil {
return nil, errNotAppEngineContext
}
return c, nil
}
func withContext(parent netcontext.Context, c appengine.Context) netcontext.Context {
ctx := netcontext.WithValue(parent, &contextKey, c)
s := &basepb.StringProto{}
c.Call("__go__", "GetNamespace", &basepb.VoidProto{}, s, nil)
if ns := s.GetValue(); ns != "" {
ctx = NamespacedContext(ctx, ns)
}
return ctx
}
func IncomingHeaders(ctx netcontext.Context) http.Header {
if c := fromContext(ctx); c != nil {
if req, ok := c.Request().(*http.Request); ok {
return req.Header
}
}
return nil
}
func ReqContext(req *http.Request) netcontext.Context {
return WithContext(netcontext.Background(), req)
}
func WithContext(parent netcontext.Context, req *http.Request) netcontext.Context {
c := appengine.NewContext(req)
return withContext(parent, c)
}
type testingContext struct {
appengine.Context
req *http.Request
}
func (t *testingContext) FullyQualifiedAppID() string { return "dev~testcontext" }
func (t *testingContext) Call(service, method string, _, _ appengine_internal.ProtoMessage, _ *appengine_internal.CallOptions) error {
if service == "__go__" && method == "GetNamespace" {
return nil
}
return fmt.Errorf("testingContext: unsupported Call")
}
func (t *testingContext) Request() interface{} { return t.req }
func ContextForTesting(req *http.Request) netcontext.Context {
return withContext(netcontext.Background(), &testingContext{req: req})
}
func Call(ctx netcontext.Context, service, method string, in, out proto.Message) error {
if ns := NamespaceFromContext(ctx); ns != "" {
if fn, ok := NamespaceMods[service]; ok {
fn(in, ns)
}
}
if f, ctx, ok := callOverrideFromContext(ctx); ok {
return f(ctx, service, method, in, out)
}
// Handle already-done contexts quickly.
select {
case <-ctx.Done():
return ctx.Err()
default:
}
c := fromContext(ctx)
if c == nil {
// Give a good error message rather than a panic lower down.
return errNotAppEngineContext
}
// Apply transaction modifications if we're in a transaction.
if t := transactionFromContext(ctx); t != nil {
if t.finished {
return errors.New("transaction context has expired")
}
applyTransaction(in, &t.transaction)
}
var opts *appengine_internal.CallOptions
if d, ok := ctx.Deadline(); ok {
opts = &appengine_internal.CallOptions{
Timeout: d.Sub(time.Now()),
}
}
err := c.Call(service, method, in, out, opts)
switch v := err.(type) {
case *appengine_internal.APIError:
return &APIError{
Service: v.Service,
Detail: v.Detail,
Code: v.Code,
}
case *appengine_internal.CallError:
return &CallError{
Detail: v.Detail,
Code: v.Code,
Timeout: v.Timeout,
}
}
return err
}
func handleHTTP(w http.ResponseWriter, r *http.Request) {
panic("handleHTTP called; this should be impossible")
}
func logf(c appengine.Context, level int64, format string, args ...interface{}) {
var fn func(format string, args ...interface{})
switch level {
case 0:
fn = c.Debugf
case 1:
fn = c.Infof
case 2:
fn = c.Warningf
case 3:
fn = c.Errorf
case 4:
fn = c.Criticalf
default:
// This shouldn't happen.
fn = c.Criticalf
}
fn(format, args...)
}
