GitHub Webhooks integration

controllers/routes.go

@@ -1,6 +1,7 @@
 package controllers
 
 import (
+	"github.com/Theodor-Springmann-Stiftung/lenz-web/config"
 	"github.com/Theodor-Springmann-Stiftung/lenz-web/helpers/middleware"
 	"github.com/Theodor-Springmann-Stiftung/lenz-web/server"
 	"github.com/Theodor-Springmann-Stiftung/lenz-web/views"
@@ -9,11 +10,21 @@ import (
 )
 
 const ASSETS_URL = "/assets"
+const WBHOOK_URL = "/webhook"
 
-func Register(server server.Server) {
+func Register(server server.Server, cfg config.Config) {
 	server.Server.Use(ASSETS_URL, compress.New(compress.Config{
 		Level: compress.LevelBestSpeed,
 	}))
 	server.Server.Use(ASSETS_URL, middleware.StaticHandler(&views.StaticFS))
 	server.Server.Get("/", GetIndex)
+
+	if cfg.WebHookSecret != "" {
+		whurl := WBHOOK_URL
+		if cfg.WebHookEndpoint != "" {
+			whurl = cfg.WebHookEndpoint
+		}
+		server.Server.Post(whurl, PostWebhook(cfg))
+	}
+
 }

controllers/webhook.go

@@ -0,0 +1,68 @@
+package controllers
+
+import (
+	"crypto/hmac"
+	"crypto/sha256"
+	"encoding/hex"
+	"path/filepath"
+	"strings"
+
+	"github.com/Theodor-Springmann-Stiftung/lenz-web/config"
+	gitprovider "github.com/Theodor-Springmann-Stiftung/lenz-web/git"
+	"github.com/Theodor-Springmann-Stiftung/lenz-web/xmlmodels"
+	"github.com/gofiber/fiber/v2"
+)
+
+const SIGNATURE_PREFIX = "sha256="
+
+func PostWebhook(cfg config.Config) fiber.Handler {
+	return func(c *fiber.Ctx) error {
+		body := c.Body()
+		if !verifySignature256([]byte(cfg.WebHookSecret), body, c.Get("X-Hub-Signature-256")) {
+			return c.SendStatus(fiber.StatusUnauthorized)
+		}
+
+		if c.Get("X-GitHub-Event") == "" {
+			return c.SendStatus(fiber.StatusBadRequest)
+		}
+
+		dir := filepath.Join(cfg.BaseDIR, cfg.GITPath)
+
+		commit, err := gitprovider.Pull(dir, cfg.GitURL, cfg.GitBranch)
+		if err != nil {
+			panic(err)
+			return c.SendStatus(fiber.StatusInternalServerError)
+		}
+
+		_, err = xmlmodels.Parse(dir, commit.Hash)
+		if err != nil {
+			panic(err)
+			return c.SendStatus(fiber.StatusInternalServerError)
+		}
+
+		return c.SendStatus(fiber.StatusOK)
+	}
+}
+
+func sign256(secret, body []byte) []byte {
+	computed := hmac.New(sha256.New, secret)
+	computed.Write(body)
+	return []byte(computed.Sum(nil))
+}
+
+func verifySignature256(secret, payload []byte, header string) bool {
+	if !strings.HasPrefix(header, SIGNATURE_PREFIX) {
+		return false
+	}
+
+	sig, err := hex.DecodeString(header[len(SIGNATURE_PREFIX):])
+	if err != nil {
+		return false
+	}
+
+	mac := hmac.New(sha256.New, secret)
+	mac.Write(payload)
+	expected := mac.Sum(nil)
+
+	return hmac.Equal(expected, sig)
+}