If-Modified-Since

main.py

@@ -4,7 +4,7 @@
 from seatable_thumbnail.thumbnail import Thumbnail
 from seatable_thumbnail.http_request import HTTPRequest
 from seatable_thumbnail.http_response import gen_error_response, \
-    gen_text_response, gen_thumbnail_response
+    gen_text_response, gen_thumbnail_response, gen_cache_response
 
 logger = logging.getLogger(__name__)
 
@@ -33,6 +33,13 @@ async def __call__(self, scope, receive, send):
 
 # ===== thumbnail =====
         elif 'thumbnail/' in request.url:
+            # cache
+            if request.headers.get('if-modified-since'):
+                response_start, response_body = gen_cache_response()
+                await send(response_start)
+                await send(response_body)
+                return
+
             # check
             try:
                 validator = ThumbnailValidator(request)

seatable_thumbnail/http_request.py

@@ -9,9 +9,22 @@ def __init__(self, **scope):
         self.parse()
 
     def parse(self):
+        self.parse_headers()
         self.parse_url()
         self.parse_query_dict()
 
+    def parse_headers(self):
+        raw_headers = self.headers
+        headers = {}
+        for item in raw_headers:
+            k = item[0].decode().lower()
+            v = item[1].decode()
+            if k in headers:
+                headers[k].append(v)
+            else:
+                headers[k] = [v]
+        self.headers = headers
+
     def parse_url(self):
         self.url = self.path[len(settings.URL_PREFIX):]
 

seatable_thumbnail/http_response.py

@@ -1,4 +1,5 @@
-from seatable_thumbnail.constants import TEXT_CONTENT_TYPE, THUMBNAIL_CONTENT_TYPE
+from seatable_thumbnail.constants import TEXT_CONTENT_TYPE, THUMBNAIL_CONTENT_TYPE, \
+    EMPTY_BYTES
 
 
 def gen_response_start(status, content_type):
@@ -32,11 +33,18 @@ def gen_text_response(text):
     return response_start, response_body
 
 
+def gen_cache_response():
+    response_start = gen_response_start(304, TEXT_CONTENT_TYPE)
+    response_body = gen_response_body(EMPTY_BYTES)
+
+    return response_start, response_body
+
+
 def gen_thumbnail_response(thumbnail, last_modified):
     response_start = gen_response_start(200, THUMBNAIL_CONTENT_TYPE)
     response_body = gen_response_body(thumbnail)
 
-    # Cache-Control
+    # cache
     if thumbnail:
         response_start['headers'].append([b'Cache-Control', b'public'])
         response_start['headers'].append([b'Cache-Control', b'max-age=86400'])