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
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
|
package auth
////////////////////////////////////////////////////////////////////////////////
// Dependencies
////////////////////////////////////////////////////////////////////////////////
import (
"encoding/json"
"fmt"
"log"
"net/http"
"net/url"
"os"
"os/exec"
"utils"
)
////////////////////////////////////////////////////////////////////////////////
// Constants
////////////////////////////////////////////////////////////////////////////////
var (
BROWSER = os.Getenv("BROWSER")
REDIRECT_URI = "http://localhost:8080/authorization-code"
)
////////////////////////////////////////////////////////////////////////////////
// Types
////////////////////////////////////////////////////////////////////////////////
// This is the response returned from Monzo when we exchange our authorization
// code for an access token. While Monzo returns additional fields, I'm only
// interested in AccessToken and RefreshToken.
type accessTokenResponse struct {
AccessToken string `json:"access_token"`
RefreshToken string `json:"refresh_token"`
ExpiresIn int `json:"expires_in"`
}
type Tokens struct {
AccessToken string
RefreshToken string
ExpiresIn int
}
////////////////////////////////////////////////////////////////////////////////
// Functions
////////////////////////////////////////////////////////////////////////////////
// Returns the access token and refresh tokens for the Monzo API.
func GetTokensFromAuthCode(authCode string, clientID string, clientSecret string) *Tokens {
res, err := http.PostForm("https://api.monzo.com/oauth2/token", url.Values{
"grant_type": {"authorization_code"},
"client_id": {clientID},
"client_secret": {clientSecret},
"redirect_uri": {REDIRECT_URI},
"code": {authCode},
})
utils.FailOn(err)
defer res.Body.Close()
payload := &accessTokenResponse{}
json.NewDecoder(res.Body).Decode(payload)
return &Tokens{payload.AccessToken, payload.RefreshToken, payload.ExpiresIn}
}
// Open a web browser to allow the user to authorize this application. Return
// the authorization code sent from Monzo.
func GetAuthCode(clientID string) string {
// TODO(wpcarro): Consider generating a random string for the state when the
// application starts instead of hardcoding it here.
state := "xyz123"
url := fmt.Sprintf(
"https://auth.monzo.com/?client_id=%s&redirect_uri=%s&response_type=code&state=%s",
clientID, REDIRECT_URI, state)
exec.Command(BROWSER, url).Start()
authCode := make(chan string)
go func() {
log.Fatal(http.ListenAndServe(":8080",
http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
// 1. Get authorization code from Monzo.
if req.URL.Path == "/authorization-code" {
params := req.URL.Query()
reqState := params["state"][0]
code := params["code"][0]
if reqState != state {
log.Fatalf("Value for state returned by Monzo does not equal our state. %s != %s", reqState, state)
}
authCode <- code
fmt.Fprintf(w, "Authorized!")
} else {
log.Printf("Unhandled request: %v\n", *req)
}
})))
}()
result := <-authCode
return result
}
|
