forked from GoogleCloudPlatform/appengine-goshorten
/
client.go
75 lines (68 loc) · 2.14 KB
/
client.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
//
// Copyright 2013 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
package goshorten
import (
"net/http"
"time"
"appengine"
"appengine/memcache"
"appengine/urlfetch"
)
// accessToken returns an access token for the given scope and caches it.
func accessToken(c appengine.Context, scope string) (string, error) {
if token, err := memcache.Get(c, "token"); err == nil {
return string(token.Value), nil
}
tok, expiry, err := appengine.AccessToken(c, scope)
if err != nil {
return "", err
}
// Ignore memcache errors and return the access token.
memcache.Set(c, &memcache.Item{
Key: "token",
Value: []byte(tok),
Expiration: expiry.Sub(time.Now()),
})
return tok, nil
}
// authorizedClient returns an *http.Client authorized for the given scope.
func authorizedClient(c appengine.Context, scope string) (*http.Client, error) {
tok, err := accessToken(c, scope)
if err != nil {
return nil, err
}
return &http.Client{
Transport: &authorizedTransport{
transport: &urlfetch.Transport{
Context: c,
Deadline: 0,
AllowInvalidServerCertificate: false,
},
token: tok,
},
}, nil
}
// authorizedTransport is an implementation of http.RoundTripper adding an access token to every request.
type authorizedTransport struct {
transport http.RoundTripper
token string
}
// RoundTrip issues an authorized HTTP request and returns its response.
func (t *authorizedTransport) RoundTrip(req *http.Request) (*http.Response, error) {
newReq := *req
newReq.Header.Set("Authorization", "OAuth "+t.token)
return t.transport.RoundTrip(&newReq)
}