Fix webhook signature handling

app/main.py

@@ -7,7 +7,25 @@ import threading
 
 from fastapi import FastAPI, Header, HTTPException, Request
 
-WEBHOOK_SECRET = os.getenv("WEBHOOK_SECRET", "change-me-webhook-secret")
+
+def read_env_file_value(key: str, default: str = "") -> str:
+    try:
+        with open("/opt/appfactory/config/appfactory.env", "r", encoding="utf-8") as f:
+            for line in f:
+                line = line.strip()
+
+                if line.startswith(f"{key}="):
+                    return line.split("=", 1)[1].strip().strip('"')
+    except Exception:
+        pass
+
+    return default
+
+
+WEBHOOK_SECRET = os.getenv(
+    "WEBHOOK_SECRET",
+    read_env_file_value("WEBHOOK_SECRET", "change-me-webhook-secret")
+)
 
 APP_DEPLOY_SCRIPT = "/tools/deploy-app.sh"
 CORE_DEPLOY_SCRIPT = "/tools/deploy-core-service.sh"
@@ -17,6 +35,7 @@ CORE_SERVICES = {
     "appfactory-webhook",
 }
 
+
 app = FastAPI(title="AppFactory Webhook")
 
 
@@ -29,15 +48,13 @@ def verify_signature(body: bytes, signature: str | None):
     if not signature:
         raise HTTPException(status_code=401, detail="Missing signature")
 
-    valid_signatures = [
-        "sha256=" + hmac.new(
-            WEBHOOK_SECRET.encode("utf-8"),
-            body,
-            hashlib.sha256
-        ).hexdigest()
-    ]
+    expected = "sha256=" + hmac.new(
+        WEBHOOK_SECRET.encode("utf-8"),
+        body,
+        hashlib.sha256
+    ).hexdigest()
 
-    if not any(hmac.compare_digest(s, signature) for s in valid_signatures):
+    if not hmac.compare_digest(expected, signature):
         raise HTTPException(status_code=401, detail="Invalid signature")
 
 
@@ -69,9 +86,11 @@ async def gitea_webhook(
     x_gitea_signature: str | None = Header(default=None),
 ):
     body = await request.body()
+
     verify_signature(body, x_gitea_signature)
 
     payload = json.loads(body.decode("utf-8"))
+
     repo_name = payload.get("repository", {}).get("name")
 
     if not repo_name: