package auth
import (
"context"
"encoding/json"
"log"
"net/http"
"golang.org/x/oauth2"
)
func GitHub(authCallback AuthCallback, clientID, clientSecret, organisation string) (login, callback http.HandlerFunc) {
ctx := context.Background()
conf := &oauth2.Config{
ClientID: clientID,
ClientSecret: clientSecret,
Scopes: []string{"user", "read:org"},
Endpoint: oauth2.Endpoint{
AuthURL: "https://github.com/login/oauth/authorize",
TokenURL: "https://github.com/login/oauth/access_token",
},
}
login = func(w http.ResponseWriter, r *http.Request) {
url := conf.AuthCodeURL("state", oauth2.AccessTypeOnline)
http.Redirect(w, r, url, http.StatusFound)
}
callback = func(w http.ResponseWriter, r *http.Request) {
code := r.FormValue("code")
tok, err := conf.Exchange(ctx, code)
if err != nil {
log.Println(err)
return
}
client := conf.Client(ctx, tok)
user, err := getUser(client)
if err != nil {
log.Println(err)
return
}
inOrg, err := isInOrg(client, organisation)
if err != nil {
log.Println(err)
return
}
authCallback(w, r, inOrg, user)
}
return login, callback
}
func getUser(client *http.Client) (string, error) {
resp, err := client.Get("https://api.github.com/user")
if err != nil {
return "", err
}
defer resp.Body.Close()
var data struct {
Login string `json:"login"`
}
if err = json.NewDecoder(resp.Body).Decode(&data); err != nil {
return "", err
}
return data.Login, nil
}
func isInOrg(client *http.Client, expectedOrg string) (bool, error) {
resp, err := client.Get("https://api.github.com/user/orgs")
if err != nil {
return false, err
}
defer resp.Body.Close()
var data []struct {
Login string `json:"login"`
}
if err = json.NewDecoder(resp.Body).Decode(&data); err != nil {
return false, err
}
for _, org := range data {
if org.Login == expectedOrg {
return true, nil
}
}
return false, nil
}