class_docstr: Implements the POST /upload_file endpoint.
class_docstr_tok: ["Implements","the","POST","\/upload_file","endpoint","."]
docstr: /OPTIONS handler for preflight CORS checks.
  
  When a browser is making a CORS request, it may sometimes first
  send an OPTIONS request, to check whether the server understands the
  CORS protocol. This is optional, and doesn't happen for every request
  or in every browser. If an OPTIONS request does get sent, and is not
  then handled by the server, the browser will fail the underlying
  request.
  
  The proper way to handle this is to send a 204 response ("no content")
  with the CORS headers attached. (These headers are automatically added
  to every outgoing response, including OPTIONS responses,
  via set_default_headers().)
  
  See https://developer.mozilla.org/en-US/docs/Glossary/Preflight_request
docstr_tok: ["\/OPTIONS","handler","for","preflight","CORS","checks",".","When","a","browser","is","making","a","CORS","request",",","it","may","sometimes","first","send","an","OPTIONS","request",",","to","check","whether","the","server","understands","the","CORS","protocol",".","This","is","optional",",","and","does","n't","happen","for","every","request","or","in","every","browser",".","If","an","OPTIONS","request","does","get","sent",",","and","is","not","then","handled","by","the","server",",","the","browser","will","fail","the","underlying","request",".","The","proper","way","to","handle","this","is","to","send","a","204","response","(","``","no","content","''",")","with","the","CORS","headers","attached",".","(","These","headers","are","automatically","added","to","every","outgoing","response",",","including","OPTIONS","responses",",","via","set_default_headers","(",")",".",")","See","https",":","\/\/developer.mozilla.org\/en-US\/docs\/Glossary\/Preflight_request"]
code: def options(self, **kwargs):
      """/OPTIONS handler for preflight CORS checks.
  
      When a browser is making a CORS request, it may sometimes first
      send an OPTIONS request, to check whether the server understands the
      CORS protocol. This is optional, and doesn't happen for every request
      or in every browser. If an OPTIONS request does get sent, and is not
      then handled by the server, the browser will fail the underlying
      request.
  
      The proper way to handle this is to send a 204 response ("no content")
      with the CORS headers attached. (These headers are automatically added
      to every outgoing response, including OPTIONS responses,
      via set_default_headers().)
  
      See https://developer.mozilla.org/en-US/docs/Glossary/Preflight_request
      """
      self.set_status(204)
      self.finish()
  
file_path: streamlit/lib/streamlit/web/server/upload_file_request_handler.py
imports: from typing import Any, Callable, Dict, List
  import tornado.httputil
  import tornado.web
  from streamlit import config
  from streamlit.logger import get_logger
  from streamlit.runtime.memory_uploaded_file_manager import MemoryUploadedFileManager
  from streamlit.runtime.uploaded_file_manager import UploadedFileManager, UploadedFileRec
  from streamlit.web.server import routes, server_util
label_desc: Use image node_id 3 for calling the UploadFileRequestHandler obj's underlying member method code with example usage: obj.options() without return types