Running the example:
base_url=https://gitlab.your-host client_secret=$client_secret client
_id=$client_id port=8081 go run main.go
2018/10/10 12:57:57 Using port: 8081
Now navigate to http://localhost:8081/start/ to begin the flow.
2018/10/10 12:57:58 URL: /oauth2/authorized?custom_param=1&code=xyz&state=state
2018/10/10 12:57:58 map[custom_param:[1] code:[xyz] state:[state]]
| package main | |
| import ( | |
| "fmt" | |
| "log" | |
| "net/http" | |
| "net/url" | |
| "os" | |
| "strconv" | |
| "time" | |
| ) | |
| func main() { | |
| router := http.NewServeMux() | |
| router.HandleFunc("/start/", MakeStartHandler()) | |
| router.HandleFunc("/oauth2/", MakeOAuth2Handler()) | |
| router.HandleFunc("/home/", MakeHomepageHandler()) | |
| timeout := time.Second * 10 | |
| port := 8080 | |
| if v, exists := os.LookupEnv("port"); exists { | |
| val, _ := strconv.Atoi(v) | |
| port = val | |
| } | |
| log.Printf("Using port: %d\n", port) | |
| s := &http.Server{ | |
| Addr: fmt.Sprintf(":%d", port), | |
| Handler: router, | |
| ReadTimeout: timeout, | |
| WriteTimeout: timeout, | |
| MaxHeaderBytes: 1 << 20, | |
| } | |
| log.Fatal(s.ListenAndServe()) | |
| } | |
| func MakeStartHandler() func(http.ResponseWriter, *http.Request) { | |
| // http://localhost:8081/start | |
| return func(w http.ResponseWriter, r *http.Request) { | |
| redirectRaw := "http://localhost:8081/oauth2/authorized" | |
| redirectURI, _ := url.Parse(redirectRaw) | |
| rQuery := redirectURI.Query() | |
| rQuery.Set("custom_param", "1") | |
| redirectURI.RawQuery = rQuery.Encode() | |
| redirect, _ := url.Parse(os.Getenv("base_url") + "/oauth/authorize") | |
| q := redirect.Query() | |
| q.Set("client_id", os.Getenv("client_id")) | |
| q.Set("response_type", "code") | |
| q.Set("state", "state") | |
| q.Set("redirect_uri", redirectURI.String()) | |
| redirect.RawQuery = q.Encode() | |
| w.Write([]byte(`<html><head></head>Redirecting.. <a href="redirect">to login</a>. <script>window.location.replace("` + redirect.String() + `");</script></html>`)) | |
| } | |
| } | |
| func MakeHomepageHandler() func(http.ResponseWriter, *http.Request) { | |
| return func(w http.ResponseWriter, r *http.Request) { | |
| w.Write([]byte("OK")) | |
| } | |
| } | |
| func MakeOAuth2Handler() func(http.ResponseWriter, *http.Request) { | |
| return func(w http.ResponseWriter, r *http.Request) { | |
| log.Printf("URL: %s", r.URL) | |
| if r.URL.Path != "/oauth2/authorized" { | |
| w.WriteHeader(http.StatusUnauthorized) | |
| w.Write([]byte("Unauthorized OAuth callback.")) | |
| return | |
| } | |
| if r.Body != nil { | |
| defer r.Body.Close() | |
| } | |
| log.Println(r.URL.Query()) | |
| w.Write([]byte(fmt.Sprintf("OK, got a code: %s", r.URL.Query().Get("code")))) | |
| } | |
| } |