feat: basic oidc client go

go/main.go

@@ -0,0 +1,88 @@
+package main
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/base64"
+	"log"
+	"os"
+
+	"github.com/coreos/go-oidc/v3/oidc"
+	"github.com/gin-contrib/sessions"
+	"github.com/gin-gonic/gin"
+	"golang.org/x/oauth2"
+)
+
+func createRandomString(n int) (string, error) {
+	s := make([]byte, n)
+	if _, err := rand.Read(s); err != nil {
+		return "", err
+	}
+	return base64.URLEncoding.EncodeToString(s), nil
+}
+
+var config oauth2.Config
+var userFunc func(userid string)
+
+func Configure(app_url string, scopes []string) {
+	provider, err := oidc.NewProvider(context.Background(), os.Getenv("OIDC_ISSUER"))
+	if err != nil {
+		log.Fatal("Provider resolution failed with error", err)
+	}
+	config = oauth2.Config{
+		ClientID:     os.Getenv("OIDC_CLIENT_ID"),
+		ClientSecret: os.Getenv("OIDC_CLIENT_SECRET"),
+		Endpoint:     provider.Endpoint(),
+		RedirectURL:  app_url + "/auth/v2/verify",
+		Scopes:       append([]string{"oidc"}, scopes[:]...),
+	}
+}
+
+func LoginHandler(c *gin.Context) {
+	state := rand.Text()
+	nonce := rand.Text()
+	codeVerifier := oauth2.GenerateVerifier()
+	session := sessions.Default(c)
+	session.Set("jhid_oauth_state", state)
+	session.Set("jhid_oauth_nonce", nonce)
+	session.Set("jhid_oauth_code_verifier", codeVerifier)
+	session.Save()
+	c.Redirect(301, config.AuthCodeURL(state, oidc.Nonce(nonce), oauth2.S256ChallengeOption(codeVerifier)))
+}
+
+func CallbackHandler(c *gin.Context) {
+	session := sessions.Default(c)
+	state := session.Get("jhid_oauth_state")
+	nonce := session.Get("jhid_oauth_nonce")
+	codeVerifier := session.Get("jhid_oauth_code_verifier").(string)
+
+	tok, err := config.Exchange(c, c.Query("code"), oauth2.VerifierOption(codeVerifier))
+	if err != nil {
+		log.Println("Token exchange failed with error", err)
+		c.AbortWithStatus(500)
+		return
+	}
+
+	idToken, ok := tok.Extra("id_token").(string)
+
+	session.Set("jhid_auth", true)
+	session.Save()
+}
+
+func EnsureLogin(redirectFail bool) func(c *gin.Context) {
+	return (func(c *gin.Context) {
+		session := sessions.Default(c)
+		if session.Get("jhid_auth") == true {
+			c.Next()
+		} else {
+			if redirectFail {
+				c.Redirect(307, "/auth/v2/login")
+				c.Abort()
+				return
+			} else {
+				c.AbortWithStatus(401)
+				return
+			}
+		}
+	})
+}