Added github webhooks to relaod on change

TODO: Reset cache on change

controllers/webhooks.go

@@ -0,0 +1,56 @@
+package controllers
+
+import (
+	"crypto/hmac"
+	"crypto/sha256"
+	"encoding/hex"
+	"strings"
+
+	"github.com/gofiber/fiber/v2"
+)
+
+const SIGNATURE_PREFIX = "sha256="
+
+func PostWebhook(secret string) (fiber.Handler, chan bool) {
+	devchan := make(chan bool)
+	return func(c *fiber.Ctx) error {
+		body := c.Body()
+		if !verifySignature256([]byte(secret), body, c.Get("X-Hub-Signature-256")) {
+			return c.SendStatus(fiber.StatusUnauthorized)
+		}
+
+		if c.Get("X-GitHub-Event") == "" {
+			return c.SendStatus(fiber.StatusBadRequest)
+		}
+
+		go func() {
+			devchan <- true
+		}()
+
+		c.SendStatus(fiber.StatusOK)
+		return nil
+	}, devchan
+}
+
+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)
+}