Python tornado upload file function

Tornado is an open source version of web server software. Tornado has a clear difference from mainstream web server frameworks (including most Python frameworks): it is a non-blocking server and it is quite fast.

Thanks to its non-blocking method and the use of epoll, Tornado can handle thousands of connections per second, so Tornado is an ideal framework for real-time web services.

In the web development process, file upload is a frequently used function, such as uploading attachments, uploading photos, etc. Let's introduce the use of tornado to realize simple file upload function.

Normal upload

# coding: utf-8import tornado.ioloop
import tornado.web
import shutil
import os
import json
classFileUploadHandler(tornado.web.RequestHandler):
 def get(self):
 self.write('''
< html 
 < head <title Upload File</title </head 
 < body 
 < form action='file' enctype="multipart/form-data" method='post'<input type='file' name='file'/ <br/<input type='submit' value='submit'/</form 
 < /body 
< /html 
''')

 def post(self):
 ret ={'result':'OK'}
 upload_path = os.path.join(os.path.dirname(__file__),'files') #Temporary file path
 file_metas = self.request.files.get('file', None) #Extract the&#39;name'For&#39;file'File metadata

 if not file_metas:
  ret['result']='Invalid Args'return ret

 for meta in file_metas:
  filename = meta['filename']
  file_path = os.path.join(upload_path, filename)withopen(file_path,'wb')as up:
  up.write(meta['body'])
  # OR do other thing

 self.write(json.dumps(ret))

app = tornado.web.Application([(r'/file', FileUploadHandler),])if __name__ =='__main__':
 app.listen(8080)
 tornado.ioloop.IOLoop.instance().start()

Upload using ajax

With ajax upload, you need to modify the way the front-end sends requests. You can refer to the following methods:

< html 
 < head <title Upload File</title 
 < script type="text/javascript" src="/www/static/jquery.min.js"</script 
 < /head 
 < body 
 < form id='upload' action='upload' enctype="multipart/form-data" method='post'<input type='file' name='file'/ <br/<input type='button' id='submit' value='submit'/</form 
 < /body 
 < script 
 $('#submit').click(function(){var form =$('form')[0];var formData =newFormData(form);
  formData.append('image',$('input[type=file]')[0].files[0]);
  $.ajax({
  url:'/file/upload',
  data: formData,
  type:'POST',
  contentType:false,
  processData:false,
  success:function(data){var obj = jQuery.parseJSON(data);alert(obj.result);// TODO},
  error:function(data){var obj = jQuery.parseJSON(data);alert(data.result);}})});</script 
 < /html 

note

When tornado processes a file upload, it puts the entire file in memory.
If there is a need to upload large files, the file upload module of nginx (third-party module needs to be compiled) is generally used.

to sum up

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