use proper library placeholders for response header

sharex_server.py

@@ -8,7 +8,7 @@ from collections import defaultdict
 
 from Cryptodome.Cipher import AES
 from Cryptodome.Util import Padding
-from aiohttp import web
+from aiohttp import web, hdrs
 
 
 class AttrDict(dict):
@@ -23,17 +23,17 @@ class AttrDict(dict):
     def __getattr__(self, item):
         return self.setdefault(item, AttrDict())
 
-
-def cast_to_ad(d):
-    if not isinstance(d, AttrDict):
-        d = AttrDict(d)
-    for k, v in dict(d.items()).items():
-        if " " in k:
-            del d[k]
-            d[k.replace(" ", "_")] = v
-        if isinstance(v, dict):
-            d[k] = cast_to_ad(v)
-    return d
+    @staticmethod
+    def from_dict_recur(d):
+        if not isinstance(d, AttrDict):
+            d = AttrDict(d)
+        for k, v in dict(d.items()).items():
+            if " " in k:
+                del d[k]
+                d[k.replace(" ", "_")] = v
+            if isinstance(v, dict):
+                d[k] = AttrDict.from_dict_recur(v)
+        return d
 
 
 def sizeof_fmt(num, suffix='B'):
@@ -47,7 +47,7 @@ def sizeof_fmt(num, suffix='B'):
 async def prepare(_, handler):
     async def prepare_handler(req):
         if 'acc' not in req.match_info:
-            return web.Response(text='internal server error', status=500)
+            return web.Response(text='bad request', status=400)
         return await handler(req, req.match_info["acc"], file_db[req.match_info["acc"]])
     return prepare_handler
 
@@ -126,8 +126,10 @@ async def handle_download(req, acc, acc_db):
     fhash = req.match_info.get('hash', '').split('.', 1)[0]
     if fhash not in acc_db:
         return web.Response(text='file not found', status=404)
+
     return web.FileResponse(f"{conf.data_path}/{acc}/{fhash}_{acc_db[fhash]}", headers={
-        'CONTENT-DISPOSITION': f'inline;filename="{acc_db[fhash]}"'
+        hdrs.CACHE_CONTROL: "no-cache",
+        hdrs.CONTENT_DISPOSITION: f'inline;filename="{acc_db[fhash]}"'
     })
 
 
@@ -138,8 +140,9 @@ def main():
         if not os.path.isdir(f'{conf.data_path}/{acc}'):
             continue
         for file in os.listdir(f"{conf.data_path}/{acc}"):
-            fhash, fname = file.split('_', 1)
-            file_db[acc][fhash] = fname
+            if "_" in file:
+                fhash, fname = file.split('_', 1)
+                file_db[acc][fhash] = fname
 
     app = web.Application(middlewares=[prepare])
     app.router.add_post(conf.prefix + '/post/{acc}', handle_upload)
@@ -154,7 +157,7 @@ if __name__ == '__main__':
     file_db = defaultdict(dict)
     confname = sys.argv[1] if sys.argv[1:] and os.path.isfile(sys.argv[1]) else 'config.yaml'
     with open(confname) as cf:
-        conf = cast_to_ad(yaml.load(cf))
+        conf = AttrDict.from_dict_recur(yaml.load(cf))
     if conf.url_hash_len > 31:
         raise ValueError('url_hash_len can\'t be bigger than 31')
     if not set(conf.max_filesize.replace(' ', ''))\