fix: downloadfile2url支持request=None + parse_request缓存BASEURL到env

- processorResource.parse_request: os.environ.setdefault('BASEURL', _preurl)
  首次HTTP请求后缓存base URL，后续无request场景也能构建完整URL
- filestorage.downloadfile2url: request=None时fallback到get_baseurl()
  与b64media2url保持一致，支持产品模块等非HTTP上下文调用

ahserver/filestorage.py

@@ -208,9 +208,14 @@ async def downloadfile2url(request, url, headers=None, params=None, data={}, met
 	fpath = await downloadfile(url, headers=headers, params=params, data=data, method=method)
 	fs = FileStorage()
 	webpath = fs.webpath(fpath)
-	env = request._run_ns
-	url = env.entire_url('/idfile?path=') + env.quote(webpath)
-	return url
+	if request:
+		env = request._run_ns
+		url = env.entire_url('/idfile?path=') + env.quote(webpath)
+		return url
+	baseurl = get_baseurl()
+	if baseurl:
+		return f'{baseurl}/idfile?path={quote(webpath)}'
+	return f'/idfile?path={quote(webpath)}'
 
 def get_baseurl():
 	baseurl = os.environ.get('BASEURL')

ahserver/processorResource.py

@@ -198,6 +198,7 @@ class ProcessorResource(StaticResource,Url2File):
 			portp = ''
 		self._preurl = f'{self._scheme}://{self._host}{portp}{self._prepath}'
 		request['base_url'] = self._preurl
+		os.environ.setdefault('BASEURL', self._preurl)
 		# print(f'{request.path=}, {self._preurl=}')