add: etag support

api/__init__.py

@@ -1,11 +1,10 @@
-#api/__init__.py
 import base64
 import os
 from functools import wraps
 
 from cryptography import x509
 from cryptography.hazmat.primitives import serialization
-from flask import jsonify, Blueprint, request
+from flask import jsonify, Blueprint, request, make_response
 from flask_limiter import Limiter
 from flask_limiter.util import get_remote_address
 from jwt import decode, ExpiredSignatureError, InvalidTokenError, get_unverified_header
@@ -14,6 +13,11 @@ import requests
 from threading import Lock
 
 import env_provider
+import hashlib
+import json
+
+
+
 
 _public_key_cache = {}
 _lock = Lock()
@@ -135,3 +139,24 @@ def register_blueprints(app):
                 app.register_blueprint(bp)
 
 
+
+def generate_etag(data):
+    serialized = json.dumps(data, sort_keys=True).encode('utf-8')
+    return hashlib.md5(serialized).hexdigest()
+
+def etag_response(f):
+    @wraps(f)
+    def decorator(*args, **kwargs):
+        response = f(*args, **kwargs)
+        if response[1] in (200, 201):
+            if isinstance(response[0], (dict, list)):
+                etag = generate_etag(response[0])
+                if_none_match = request.headers.get("if_none_match")
+                if if_none_match == etag:
+                    return jsonify({}), 200
+                resp = make_response(response[0], response[1])
+                resp.headers["ETag"] = etag
+                return resp
+        return response
+    return decorator
+