Merge pull request #98 from jehiah/github_provider_98

Add Github Provider

README.md

@@ -101,6 +101,8 @@ Usage of google_auth_proxy:
   -version=false: print version string
 ```
 
+See below for provider specific options
+
 ### Environment variables
 
 The environment variables `GOOGLE_AUTH_PROXY_CLIENT_ID`, `GOOGLE_AUTH_PROXY_CLIENT_SECRET`, `GOOGLE_AUTH_PROXY_COOKIE_SECRET`, `GOOGLE_AUTH_PROXY_COOKIE_DOMAIN` and `GOOGLE_AUTH_PROXY_COOKIE_EXPIRE` can be used in place of the corresponding command-line arguments.
@@ -173,6 +175,10 @@ directive. Right now this includes:
 * `myusa` - The [MyUSA](https://alpha.my.usa.gov) authentication service
   ([GitHub](https://github.com/18F/myusa))
 * `linkedin` - The [LinkedIn](https://developer.linkedin.com/docs/signin-with-linkedin) Sign In service.
+* `github` - Via [Github][https://github.com/settings/developers] OAuth App. Also supports restricting via org and team.
+
+    -github-org="": restrict logins to members of this organisation
+    -github-team="": restrict logins to members of this team
 
 ## Adding a new Provider
 

api/api.go

@@ -10,8 +10,7 @@ import (
 )
 
 func Request(req *http.Request) (*simplejson.Json, error) {
-	httpclient := &http.Client{}
-	resp, err := httpclient.Do(req)
+	resp, err := http.DefaultClient.Do(req)
 	if err != nil {
 		return nil, err
 	}

main.go

@@ -17,6 +17,7 @@ import (
 )
 
 func main() {
+	log.SetFlags(log.Ldate | log.Ltime | log.Lshortfile)
 	flagSet := flag.NewFlagSet("google_auth_proxy", flag.ExitOnError)
 
 	googleAppsDomains := StringArray{}
@@ -35,6 +36,8 @@ func main() {
 	flagSet.Var(&skipAuthRegex, "skip-auth-regex", "bypass authentication for requests path's that match (may be given multiple times)")
 
 	flagSet.Var(&googleAppsDomains, "google-apps-domain", "authenticate against the given Google apps domain (may be given multiple times)")
+	flagSet.String("github-org", "", "restrict logins to members of this organisation")
+	flagSet.String("github-team", "", "restrict logins to members of this team")
 	flagSet.String("client-id", "", "the Google OAuth Client ID: ie: \"123456.apps.googleusercontent.com\"")
 	flagSet.String("client-secret", "", "the OAuth Client Secret")
 	flagSet.String("authenticated-emails-file", "", "authenticate against emails via file (one per line)")

oauthproxy.go

@@ -1,7 +1,6 @@
 package main
 
 import (
-	"bytes"
 	"crypto/aes"
 	"crypto/cipher"
 	"encoding/base64"
@@ -17,7 +16,6 @@ import (
 	"strings"
 	"time"
 
-	"github.com/bitly/google_auth_proxy/api"
 	"github.com/bitly/google_auth_proxy/providers"
 )
 
@@ -39,7 +37,6 @@ type OauthProxy struct {
 
 	redirectUrl         *url.URL // the url to receive requests at
 	provider            providers.Provider
-	oauthRedemptionUrl  *url.URL // endpoint to redeem the code
 	oauthLoginUrl       *url.URL // to redirect the user to
 	oauthValidateUrl    *url.URL // to validate the access token
 	oauthScope          string
@@ -143,21 +140,20 @@ func NewOauthProxy(opts *Options, validator func(string) bool) *OauthProxy {
 		CookieRefresh:  opts.CookieRefresh,
 		Validator:      validator,
 
-		clientID:           opts.ClientID,
-		clientSecret:       opts.ClientSecret,
-		oauthScope:         opts.provider.Data().Scope,
-		provider:           opts.provider,
-		oauthRedemptionUrl: opts.provider.Data().RedeemUrl,
-		oauthLoginUrl:      opts.provider.Data().LoginUrl,
-		oauthValidateUrl:   opts.provider.Data().ValidateUrl,
-		serveMux:           serveMux,
-		redirectUrl:        redirectUrl,
-		skipAuthRegex:      opts.SkipAuthRegex,
-		compiledRegex:      opts.CompiledRegex,
-		PassBasicAuth:      opts.PassBasicAuth,
-		PassAccessToken:    opts.PassAccessToken,
-		AesCipher:          aes_cipher,
-		templates:          loadTemplates(opts.CustomTemplatesDir),
+		clientID:         opts.ClientID,
+		clientSecret:     opts.ClientSecret,
+		oauthScope:       opts.provider.Data().Scope,
+		provider:         opts.provider,
+		oauthLoginUrl:    opts.provider.Data().LoginUrl,
+		oauthValidateUrl: opts.provider.Data().ValidateUrl,
+		serveMux:         serveMux,
+		redirectUrl:      redirectUrl,
+		skipAuthRegex:    opts.SkipAuthRegex,
+		compiledRegex:    opts.CompiledRegex,
+		PassBasicAuth:    opts.PassBasicAuth,
+		PassAccessToken:  opts.PassAccessToken,
+		AesCipher:        aes_cipher,
+		templates:        loadTemplates(opts.CustomTemplatesDir),
 	}
 }
 
@@ -200,29 +196,13 @@ func (p *OauthProxy) redeemCode(host, code string) (string, string, error) {
 	if code == "" {
 		return "", "", errors.New("missing code")
 	}
-	params := url.Values{}
-	params.Add("redirect_uri", p.GetRedirectUrl(host))
-	params.Add("client_id", p.clientID)
-	params.Add("client_secret", p.clientSecret)
-	params.Add("code", code)
-	params.Add("grant_type", "authorization_code")
-	req, err := http.NewRequest("POST", p.oauthRedemptionUrl.String(), bytes.NewBufferString(params.Encode()))
-	if err != nil {
-		log.Printf("failed building request %s", err.Error())
-		return "", "", err
-	}
-	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
-	json, err := api.Request(req)
-	if err != nil {
-		log.Printf("failed making request %s", err)
-		return "", "", err
-	}
-	access_token, err := json.Get("access_token").String()
+	redirectUri := p.GetRedirectUrl(host)
+	body, access_token, err := p.provider.Redeem(redirectUri, code)
 	if err != nil {
 		return "", "", err
 	}
 
-	email, err := p.provider.GetEmailAddress(json, access_token)
+	email, err := p.provider.GetEmailAddress(body, access_token)
 	if err != nil {
 		return "", "", err
 	}

oauthproxy_test.go

@@ -1,10 +1,10 @@
 package main
 
 import (
-	"github.com/bitly/go-simplejson"
 	"github.com/bitly/google_auth_proxy/providers"
 	"github.com/bmizerany/assert"
 	"io/ioutil"
+	"log"
 	"net"
 	"net/http"
 	"net/http/httptest"
@@ -15,6 +15,11 @@ import (
 	"time"
 )
 
+func init() {
+	log.SetFlags(log.Ldate | log.Ltime | log.Lshortfile)
+
+}
+
 func TestNewReverseProxy(t *testing.T) {
 	backend := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		w.WriteHeader(200)
@@ -89,8 +94,7 @@ type TestProvider struct {
 	ValidToken   bool
 }
 
-func (tp *TestProvider) GetEmailAddress(unused_auth_response *simplejson.Json,
-	unused_access_token string) (string, error) {
+func (tp *TestProvider) GetEmailAddress(body []byte, access_token string) (string, error) {
 	return tp.EmailAddress, nil
 }
 
@@ -113,16 +117,15 @@ func NewPassAccessTokenTest(opts PassAccessTokenTestOptions) *PassAccessTokenTes
 
 	t.provider_server = httptest.NewServer(
 		http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			log.Printf("%#v", r)
 			url := r.URL
 			payload := ""
 			switch url.Path {
 			case "/oauth/token":
 				payload = `{"access_token": "my_auth_token"}`
 			default:
-				token_header := r.Header["X-Forwarded-Access-Token"]
-				if len(token_header) != 0 {
-					payload = token_header[0]
-				} else {
+				payload = r.Header.Get("X-Forwarded-Access-Token")
+				if payload == "" {
 					payload = "No access token found."
 				}
 			}
@@ -189,8 +192,7 @@ func (pat_test *PassAccessTokenTest) getCallbackEndpoint() (http_code int,
 	return rw.Code, rw.HeaderMap["Set-Cookie"][0]
 }
 
-func (pat_test *PassAccessTokenTest) getRootEndpoint(
-	cookie string) (http_code int, access_token string) {
+func (pat_test *PassAccessTokenTest) getRootEndpoint(cookie string) (http_code int, access_token string) {
 	cookie_key := pat_test.proxy.CookieKey
 	var value string
 	key_prefix := cookie_key + "="

options.go

@@ -19,6 +19,8 @@ type Options struct {
 
 	AuthenticatedEmailsFile string   `flag:"authenticated-emails-file" cfg:"authenticated_emails_file"`
 	GoogleAppsDomains       []string `flag:"google-apps-domain" cfg:"google_apps_domains"`
+	GitHubOrg               string   `flag:"github-org" cfg:"github_org"`
+	GitHubTeam              string   `flag:"github-team" cfg:"github_team"`
 	HtpasswdFile            string   `flag:"htpasswd-file" cfg:"htpasswd_file"`
 	DisplayHtpasswdForm     bool     `flag:"display-htpasswd-form" cfg:"display_htpasswd_form"`
 	CustomTemplatesDir      string   `flag:"custom-templates-dir" cfg:"custom_templates_dir"`
@@ -153,11 +155,16 @@ func (o *Options) Validate() error {
 }
 
 func parseProviderInfo(o *Options, msgs []string) []string {
-	p := &providers.ProviderData{Scope: o.Scope}
+	p := &providers.ProviderData{Scope: o.Scope, ClientID: o.ClientID, ClientSecret: o.ClientSecret}
 	p.LoginUrl, msgs = parseUrl(o.LoginUrl, "login", msgs)
 	p.RedeemUrl, msgs = parseUrl(o.RedeemUrl, "redeem", msgs)
 	p.ProfileUrl, msgs = parseUrl(o.ProfileUrl, "profile", msgs)
 	p.ValidateUrl, msgs = parseUrl(o.ValidateUrl, "validate", msgs)
+
 	o.provider = providers.New(o.Provider, p)
+	switch p := o.provider.(type) {
+	case *providers.GitHubProvider:
+		p.SetOrgTeam(o.GitHubOrg, o.GitHubTeam)
+	}
 	return msgs
 }

providers/github.go

@@ -0,0 +1,136 @@
+package providers
+
+import (
+	"encoding/json"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+)
+
+type GitHubProvider struct {
+	*ProviderData
+	Org  string
+	Team string
+}
+
+func NewGitHubProvider(p *ProviderData) *GitHubProvider {
+	p.ProviderName = "GitHub"
+	if p.LoginUrl.String() == "" {
+		p.LoginUrl = &url.URL{
+			Scheme: "https",
+			Host:   "github.com",
+			Path:   "/login/oauth/authorize",
+		}
+	}
+	if p.RedeemUrl.String() == "" {
+		p.RedeemUrl = &url.URL{
+			Scheme: "https",
+			Host:   "github.com",
+			Path:   "/login/oauth/access_token",
+		}
+	}
+	if p.ValidateUrl.String() == "" {
+		p.ValidateUrl = &url.URL{
+			Scheme: "https",
+			Host:   "api.github.com",
+			Path:   "/user/emails",
+		}
+	}
+	if p.Scope == "" {
+		p.Scope = "user:email"
+	}
+	return &GitHubProvider{ProviderData: p}
+}
+func (p *GitHubProvider) SetOrgTeam(org, team string) {
+	p.Org = org
+	p.Team = team
+	if org != "" || team != "" {
+		p.Scope += " read:org"
+	}
+}
+
+func (p *GitHubProvider) hasOrgAndTeam(accessToken string) (bool, error) {
+
+	var teams []struct {
+		Name string `json:"name"`
+		Slug string `json:"slug"`
+		Org  struct {
+			Login string `json:"login"`
+		} `json:"organization"`
+	}
+
+	params := url.Values{
+		"access_token": {accessToken},
+	}
+
+	req, _ := http.NewRequest("GET", "https://api.github.com/user/teams?"+params.Encode(), nil)
+	req.Header.Set("Accept", "application/vnd.github.moondragon+json")
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return false, err
+	}
+
+	body, err := ioutil.ReadAll(resp.Body)
+	resp.Body.Close()
+	if err != nil {
+		return false, err
+	}
+
+	if err := json.Unmarshal(body, &teams); err != nil {
+		return false, err
+	}
+
+	for _, team := range teams {
+		if p.Org == team.Org.Login {
+			if p.Team == "" || p.Team == team.Slug {
+				return true, nil
+			}
+		}
+	}
+	return false, nil
+}
+
+func (p *GitHubProvider) GetEmailAddress(body []byte, access_token string) (string, error) {
+
+	var emails []struct {
+		Email   string `json:"email"`
+		Primary bool   `json:"primary"`
+	}
+
+	params := url.Values{
+		"access_token": {access_token},
+	}
+
+	// if we require an Org or Team, check that first
+	if p.Org != "" || p.Team != "" {
+		if ok, err := p.hasOrgAndTeam(access_token); err != nil || !ok {
+			return "", err
+		}
+	}
+
+	resp, err := http.DefaultClient.Get("https://api.github.com/user/emails?" + params.Encode())
+	if err != nil {
+		return "", err
+	}
+	body, err = ioutil.ReadAll(resp.Body)
+	resp.Body.Close()
+	if err != nil {
+		return "", err
+	}
+
+	if err := json.Unmarshal(body, &emails); err != nil {
+		return "", err
+	}
+
+	for _, email := range emails {
+		if email.Primary {
+			return email.Email, nil
+		}
+	}
+
+	return "", nil
+}
+
+func (p *GitHubProvider) ValidateToken(access_token string) bool {
+	return validateToken(p, access_token, nil)
+}

providers/google.go

@@ -2,10 +2,10 @@ package providers
 
 import (
 	"encoding/base64"
+	"encoding/json"
+	"errors"
 	"net/url"
 	"strings"
-
-	"github.com/bitly/go-simplejson"
 )
 
 type GoogleProvider struct {
@@ -35,28 +35,34 @@ func NewGoogleProvider(p *ProviderData) *GoogleProvider {
 	return &GoogleProvider{ProviderData: p}
 }
 
-func (s *GoogleProvider) GetEmailAddress(auth_response *simplejson.Json,
-	unused_access_token string) (string, error) {
-	idToken, err := auth_response.Get("id_token").String()
-	if err != nil {
+func (s *GoogleProvider) GetEmailAddress(body []byte, access_token string) (string, error) {
+	var response struct {
+		IdToken string `json:"id_token"`
+	}
+
+	if err := json.Unmarshal(body, &response); err != nil {
 		return "", err
 	}
+
 	// id_token is a base64 encode ID token payload
 	// https://developers.google.com/accounts/docs/OAuth2Login#obtainuserinfo
-	jwt := strings.Split(idToken, ".")
+	jwt := strings.Split(response.IdToken, ".")
 	b, err := jwtDecodeSegment(jwt[1])
 	if err != nil {
 		return "", err
 	}
-	data, err := simplejson.NewJson(b)
+
+	var email struct {
+		Email string `json:"email"`
+	}
+	err = json.Unmarshal(b, &email)
 	if err != nil {
 		return "", err
 	}
-	email, err := data.Get("email").String()
-	if err != nil {
-		return "", err
+	if email.Email == "" {
+		return "", errors.New("missing email")
 	}
-	return email, nil
+	return email.Email, nil
 }
 
 func jwtDecodeSegment(seg string) ([]byte, error) {

providers/google_test.go

@@ -2,7 +2,7 @@ package providers
 
 import (
 	"encoding/base64"
-	"github.com/bitly/go-simplejson"
+	"encoding/json"
 	"github.com/bmizerany/assert"
 	"net/url"
 	"testing"
@@ -68,39 +68,61 @@ func TestGoogleProviderOverrides(t *testing.T) {
 
 func TestGoogleProviderGetEmailAddress(t *testing.T) {
 	p := newGoogleProvider()
-	j := simplejson.New()
-	j.Set("id_token", "ignored prefix."+base64.URLEncoding.EncodeToString(
-		[]byte("{\"email\": \"michael.bland@gsa.gov\"}")))
-	email, err := p.GetEmailAddress(j, "ignored access_token")
+	body, err := json.Marshal(
+		struct {
+			IdToken string `json:"id_token"`
+		}{
+			IdToken: "ignored prefix." + base64.URLEncoding.EncodeToString([]byte(`{"email": "michael.bland@gsa.gov"}`)),
+		},
+	)
+	assert.Equal(t, nil, err)
+	email, err := p.GetEmailAddress(body, "ignored access_token")
 	assert.Equal(t, "michael.bland@gsa.gov", email)
 	assert.Equal(t, nil, err)
 }
 
 func TestGoogleProviderGetEmailAddressInvalidEncoding(t *testing.T) {
 	p := newGoogleProvider()
-	j := simplejson.New()
-	j.Set("id_token", "ignored prefix.{\"email\": \"michael.bland@gsa.gov\"}")
-	email, err := p.GetEmailAddress(j, "ignored access_token")
+	body, err := json.Marshal(
+		struct {
+			IdToken string `json:"id_token"`
+		}{
+			IdToken: "ignored prefix." + `{"email": "michael.bland@gsa.gov"}`,
+		},
+	)
+	assert.Equal(t, nil, err)
+	email, err := p.GetEmailAddress(body, "ignored access_token")
 	assert.Equal(t, "", email)
 	assert.NotEqual(t, nil, err)
 }
 
 func TestGoogleProviderGetEmailAddressInvalidJson(t *testing.T) {
 	p := newGoogleProvider()
-	j := simplejson.New()
-	j.Set("id_token", "ignored prefix."+base64.URLEncoding.EncodeToString(
-		[]byte("{email: michael.bland@gsa.gov}")))
-	email, err := p.GetEmailAddress(j, "ignored access_token")
+
+	body, err := json.Marshal(
+		struct {
+			IdToken string `json:"id_token"`
+		}{
+			IdToken: "ignored prefix." + base64.URLEncoding.EncodeToString([]byte(`{"email": michael.bland@gsa.gov}`)),
+		},
+	)
+	assert.Equal(t, nil, err)
+	email, err := p.GetEmailAddress(body, "ignored access_token")
 	assert.Equal(t, "", email)
 	assert.NotEqual(t, nil, err)
 }
 
 func TestGoogleProviderGetEmailAddressEmailMissing(t *testing.T) {
 	p := newGoogleProvider()
-	j := simplejson.New()
-	j.Set("id_token", "ignored prefix."+base64.URLEncoding.EncodeToString(
-		[]byte("{\"not_email\": \"missing!\"}")))
-	email, err := p.GetEmailAddress(j, "ignored access_token")
+	body, err := json.Marshal(
+		struct {
+			IdToken string `json:"id_token"`
+		}{
+			IdToken: "ignored prefix." + base64.URLEncoding.EncodeToString([]byte(`{"not_email": "missing"}`)),
+		},
+	)
+	assert.Equal(t, nil, err)
+	email, err := p.GetEmailAddress(body, "ignored access_token")
 	assert.Equal(t, "", email)
 	assert.NotEqual(t, nil, err)
 }

providers/internal_util_test.go

@@ -1,7 +1,6 @@
 package providers
 
 import (
-	"github.com/bitly/go-simplejson"
 	"github.com/bmizerany/assert"
 	"net/http"
 	"net/http/httptest"
@@ -13,9 +12,7 @@ type ValidateTokenTestProvider struct {
 	*ProviderData
 }
 
-func (tp *ValidateTokenTestProvider) GetEmailAddress(
-	unused_auth_response *simplejson.Json,
-	unused_access_token string) (string, error) {
+func (tp *ValidateTokenTestProvider) GetEmailAddress(body []byte, access_token string) (string, error) {
 	return "", nil
 }
 

providers/linkedin.go

@@ -8,7 +8,6 @@ import (
 	"net/http"
 	"net/url"
 
-	"github.com/bitly/go-simplejson"
 	"github.com/bitly/google_auth_proxy/api"
 )
 
@@ -50,8 +49,7 @@ func getLinkedInHeader(access_token string) http.Header {
 	return header
 }
 
-func (p *LinkedInProvider) GetEmailAddress(unused_auth_response *simplejson.Json,
-	access_token string) (string, error) {
+func (p *LinkedInProvider) GetEmailAddress(body []byte, access_token string) (string, error) {
 	if access_token == "" {
 		return "", errors.New("missing access token")
 	}

providers/linkedin_test.go

@@ -1,7 +1,6 @@
 package providers
 
 import (
-	"github.com/bitly/go-simplejson"
 	"github.com/bmizerany/assert"
 	"net/http"
 	"net/http/httptest"
@@ -97,9 +96,8 @@ func TestLinkedInProviderGetEmailAddress(t *testing.T) {
 
 	b_url, _ := url.Parse(b.URL)
 	p := testLinkedInProvider(b_url.Host)
-	unused_auth_response := simplejson.New()
 
-	email, err := p.GetEmailAddress(unused_auth_response,
+	email, err := p.GetEmailAddress([]byte{},
 		"imaginary_access_token")
 	assert.Equal(t, nil, err)
 	assert.Equal(t, "user@linkedin.com", email)
@@ -111,13 +109,11 @@ func TestLinkedInProviderGetEmailAddressFailedRequest(t *testing.T) {
 
 	b_url, _ := url.Parse(b.URL)
 	p := testLinkedInProvider(b_url.Host)
-	unused_auth_response := simplejson.New()
 
 	// We'll trigger a request failure by using an unexpected access
 	// token. Alternatively, we could allow the parsing of the payload as
 	// JSON to fail.
-	email, err := p.GetEmailAddress(unused_auth_response,
-		"unexpected_access_token")
+	email, err := p.GetEmailAddress([]byte{}, "unexpected_access_token")
 	assert.NotEqual(t, nil, err)
 	assert.Equal(t, "", email)
 }
@@ -128,10 +124,8 @@ func TestLinkedInProviderGetEmailAddressEmailNotPresentInPayload(t *testing.T) {
 
 	b_url, _ := url.Parse(b.URL)
 	p := testLinkedInProvider(b_url.Host)
-	unused_auth_response := simplejson.New()
 
-	email, err := p.GetEmailAddress(unused_auth_response,
-		"imaginary_access_token")
+	email, err := p.GetEmailAddress([]byte{}, "imaginary_access_token")
 	assert.NotEqual(t, nil, err)
 	assert.Equal(t, "", email)
 }

providers/myusa.go

@@ -5,7 +5,6 @@ import (
 	"net/http"
 	"net/url"
 
-	"github.com/bitly/go-simplejson"
 	"github.com/bitly/google_auth_proxy/api"
 )
 
@@ -43,8 +42,7 @@ func NewMyUsaProvider(p *ProviderData) *MyUsaProvider {
 	return &MyUsaProvider{ProviderData: p}
 }
 
-func (p *MyUsaProvider) GetEmailAddress(auth_response *simplejson.Json,
-	access_token string) (string, error) {
+func (p *MyUsaProvider) GetEmailAddress(body []byte, access_token string) (string, error) {
 	req, err := http.NewRequest("GET",
 		p.ProfileUrl.String()+"?access_token="+access_token, nil)
 	if err != nil {

providers/myusa_test.go

@@ -1,7 +1,6 @@
 package providers
 
 import (
-	"github.com/bitly/go-simplejson"
 	"github.com/bmizerany/assert"
 	"net/http"
 	"net/http/httptest"
@@ -102,10 +101,8 @@ func TestMyUsaProviderGetEmailAddress(t *testing.T) {
 
 	b_url, _ := url.Parse(b.URL)
 	p := testMyUsaProvider(b_url.Host)
-	unused_auth_response := simplejson.New()
 
-	email, err := p.GetEmailAddress(unused_auth_response,
-		"imaginary_access_token")
+	email, err := p.GetEmailAddress([]byte{}, "imaginary_access_token")
 	assert.Equal(t, nil, err)
 	assert.Equal(t, "michael.bland@gsa.gov", email)
 }
@@ -118,13 +115,11 @@ func TestMyUsaProviderGetEmailAddressFailedRequest(t *testing.T) {
 
 	b_url, _ := url.Parse(b.URL)
 	p := testMyUsaProvider(b_url.Host)
-	unused_auth_response := simplejson.New()
 
 	// We'll trigger a request failure by using an unexpected access
 	// token. Alternatively, we could allow the parsing of the payload as
 	// JSON to fail.
-	email, err := p.GetEmailAddress(unused_auth_response,
-		"unexpected_access_token")
+	email, err := p.GetEmailAddress([]byte{}, "unexpected_access_token")
 	assert.NotEqual(t, nil, err)
 	assert.Equal(t, "", email)
 }
@@ -135,10 +130,8 @@ func TestMyUsaProviderGetEmailAddressEmailNotPresentInPayload(t *testing.T) {
 
 	b_url, _ := url.Parse(b.URL)
 	p := testMyUsaProvider(b_url.Host)
-	unused_auth_response := simplejson.New()
 
-	email, err := p.GetEmailAddress(unused_auth_response,
-		"imaginary_access_token")
+	email, err := p.GetEmailAddress([]byte{}, "imaginary_access_token")
 	assert.NotEqual(t, nil, err)
 	assert.Equal(t, "", email)
 }

providers/provider_data.go

@@ -6,6 +6,8 @@ import (
 
 type ProviderData struct {
 	ProviderName string
+	ClientID     string
+	ClientSecret string
 	LoginUrl     *url.URL
 	RedeemUrl    *url.URL
 	ProfileUrl   *url.URL

providers/provider_default.go

@@ -0,0 +1,51 @@
+package providers
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+)
+
+func (p *ProviderData) Redeem(redirectUrl, code string) (body []byte, token string, err error) {
+	if code == "" {
+		err = errors.New("missing code")
+		return
+	}
+
+	params := url.Values{}
+	params.Add("redirect_uri", redirectUrl)
+	params.Add("client_id", p.ClientID)
+	params.Add("client_secret", p.ClientSecret)
+	params.Add("code", code)
+	params.Add("grant_type", "authorization_code")
+	req, err := http.NewRequest("POST", p.RedeemUrl.String(), bytes.NewBufferString(params.Encode()))
+	if err != nil {
+		return nil, "", err
+	}
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return nil, "", err
+	}
+	body, err = ioutil.ReadAll(resp.Body)
+	resp.Body.Close()
+	if err != nil {
+		return nil, "", err
+	}
+
+	// blindly try json and x-www-form-urlencoded
+	var jsonResponse struct {
+		AccessToken string `json:"access_token"`
+	}
+	err = json.Unmarshal(body, &jsonResponse)
+	if err == nil {
+		return body, jsonResponse.AccessToken, nil
+	}
+
+	v, err := url.ParseQuery(string(body))
+	return body, v.Get("access_token"), err
+}

providers/providers.go

@@ -1,13 +1,9 @@
 package providers
 
-import (
-	"github.com/bitly/go-simplejson"
-)
-
 type Provider interface {
 	Data() *ProviderData
-	GetEmailAddress(auth_response *simplejson.Json,
-		access_token string) (string, error)
+	GetEmailAddress(body []byte, access_token string) (string, error)
+	Redeem(string, string) ([]byte, string, error)
 	ValidateToken(access_token string) bool
 }
 
@@ -17,6 +13,8 @@ func New(provider string, p *ProviderData) Provider {
 		return NewMyUsaProvider(p)
 	case "linkedin":
 		return NewLinkedInProvider(p)
+	case "github":
+		return NewGitHubProvider(p)
 	default:
 		return NewGoogleProvider(p)
 	}