feat: add routes for app install tokens

api/routes.go

@@ -29,6 +29,7 @@ func SetupRoutes(params RouteParams) {
 	setupSettingsRoutes(params)
 	setupManifestsRoutes(params)
 	setupAppRoutes(params)
+	setupAppInstallRoutes(params)
 	setupWebhookRoutes(params)
 	setupRestRoutes(params)
 }

api/routes_app_installations.go

@@ -0,0 +1,119 @@
+package api
+
+import (
+	"crypto/x509"
+	"encoding/json"
+	"encoding/pem"
+	"git.lumeweb.com/LumeWeb/gitea-github-proxy/config"
+	"git.lumeweb.com/LumeWeb/gitea-github-proxy/db/model"
+	"github.com/golang-jwt/jwt"
+	"github.com/gorilla/mux"
+	"go.uber.org/zap"
+	"gorm.io/gorm"
+	"net/http"
+	"strconv"
+	"time"
+)
+
+type appInstallApi struct {
+	config *config.Config
+	logger *zap.Logger
+	db     *gorm.DB
+}
+
+func newAppInstallApi(cfg *config.Config, db *gorm.DB, logger *zap.Logger) *appInstallApi {
+	return &appInstallApi{config: cfg, logger: logger, db: db}
+}
+
+func (a *appInstallApi) handlerAppGetAccessToken(w http.ResponseWriter, r *http.Request) {
+
+	now := time.Now().Add(-30 * time.Second)
+	expirationTime := now.Add(10 * time.Minute)
+
+	appId := mux.Vars(r)["app_id"]
+	appIdInt, err := strconv.ParseInt(appId, 10, 64)
+
+	if err != nil {
+		http.Error(w, "Failed to parse app id", http.StatusBadRequest)
+		a.logger.Error("Failed to parse app id", zap.Error(err))
+		return
+	}
+
+	appRecord := &model.Apps{}
+	appRecord.ID = uint(appIdInt)
+
+	if err := a.db.First(appRecord).Error; err != nil {
+		http.Error(w, "Failed to find app", http.StatusNotFound)
+		a.logger.Error("Failed to find app", zap.Error(err))
+		return
+	}
+
+	block, _ := pem.Decode([]byte(appRecord.PrivateKey))
+	if block == nil {
+		http.Error(w, "Failed to parse PEM block containing the key", http.StatusInternalServerError)
+		a.logger.Error("Failed to parse PEM block containing the key")
+		return
+	}
+
+	privateKey, err := x509.ParsePKCS1PrivateKey(block.Bytes)
+	if err != nil {
+		http.Error(w, "Failed to parse DER encoded private key", http.StatusInternalServerError)
+		a.logger.Error("Failed to parse DER encoded private key", zap.Error(err))
+	}
+
+	claims := jwt.MapClaims{
+		"iss": appId,
+		"iat": now.Unix(),
+		"exp": expirationTime,
+	}
+
+	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
+
+	signedToken, err := token.SignedString(privateKey)
+	if err != nil {
+		http.Error(w, "Failed to sign token", http.StatusInternalServerError)
+		a.logger.Error("Failed to sign token", zap.Error(err))
+		return
+	}
+
+	out := struct {
+		Token     string    `json:"token"`
+		ExpiresAt time.Time `json:"expires_at"`
+	}{
+		Token:     signedToken,
+		ExpiresAt: expirationTime,
+	}
+
+	a.respond(w, http.StatusCreated, out)
+
+}
+
+func (r appInstallApi) respond(w http.ResponseWriter, status int, data interface{}) {
+	jsonData, err := json.Marshal(data)
+	if err != nil {
+		http.Error(w, "Failed to marshal response", http.StatusInternalServerError)
+		r.logger.Error("Failed to marshal response", zap.Error(err))
+		return
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	if data != nil {
+		_, _ = w.Write(jsonData)
+	}
+}
+
+func setupAppInstallRoutes(params RouteParams) {
+	logger := params.Logger
+	cfg := params.Config
+	db := params.Db
+	r := params.R
+
+	appInstallApi := newAppInstallApi(cfg, db, logger)
+
+	appRouter := r.PathPrefix("/app").Subrouter()
+	appRouter.Use(githubRestVerifyMiddleware(params.Db))
+	appRouter.Use(githubRestRequireAuthMiddleware(params.Config))
+
+	appRouter.HandleFunc("/installations/{installation_id}/access_tokens", appInstallApi.handlerAppGetAccessToken).Methods("POST").Name("app-install-get-access-token")
+}