Python Tornado 处理时只能打开一页 [英] Python tornado can only open one page when processing

问题描述

我有一个 python 代码，可以在单击按钮时将文件上传到另一台服务器.单击该按钮后，Web 服务器将开始将文件上传到另一台需要很长时间的服务器，在此期间浏览器正在加载，我无法打开我网站的其他页面.

I have a python code that upload files to another server when a button is click. After clicking the button, web server will start uploading file to another server that took a long process, during that time the the browser is loading, and I can't open another page of my website.

我尝试使用异步，但是异步示例都使用了我没有使用的 httpclient，然后我修改了如下代码

I try to use async, but async example all uses httpclient which I am not using, then I modify the code like below

上传本身是一个同步代码，我不想修改它，我想要的是一个包装器或一些可以让客户端打开另一个页面并且在处理时不锁定会话的东西.有这种方法吗?

The upload itself is a synchronous code, and I don't want to modify it, what I want is a wrapper or something that can allow the client to open another page and does not lock the session while processing. Is there such a way?

def Upload(self, filehost, uniqueno, username, password):
    Filename = self.GetFile(uniqueno)

    uploadfunc = None
    if (upload == "mega"):
        uploadfunc = MegaWrapper.Upload

    result = Thread(target=self.MyUpload, args=(uploadfunc, MyConfig.Folder + Filename, username, password))
    result.start()
    result.join(5 * 60)

    return self.UploadResult

def MyUpload(self, uploadfunc, filename, username, password):
    str = uploadfunc(filename, username, password)
    self.UploadResult = str
    return str

def post(self):
    filehost = self.get_argument("filehost")
    crc = self.get_argument("crc")
    username = self.get_argument("username")
    password = self.get_argument("password")

    fileList = dal.FileListByCRC(crc)
    messagetype = "error"
    mesasge = ""
    if (len(fileList) > 0):
        try:
            url = self.Upload(filehost, fileList[0].UniqueNo , username, password)
            message = url
            if (StringOps.StartWith(url, "http")):
                messagetype = "info"
                message = "Success Uploading : " + url
        except Exception, ex:
            messagetype = "error"
            message = "Fail Uploading : " + str(ex)    

    self.render("upload.html", title=MyConfig.DefaultSiteTitle + " - Administrative Page - Upload/Delete", messagetype=messagetype, message=message, crc=self.get_argument("crc"), filehost=self.get_argument("filehost"), username=self.get_argument("username"), password=self.get_argument("password"))

推荐答案

您基本上必须编写自己的处理程序，同时正确使用 IOLoop.查看tornado.ioloop.IOLoop.add_callback 和朋友们.话虽如此，这并不直观，我花了一些时间来弄清楚如何异步下载大型二进制数据，最后我得出结论，这可能不是提供大型二进制数据的最佳工具超过典型的传输窗口.

You basically have to write your own handler that also make use of the IOLoop correctly. Look into tornado.ioloop.IOLoop.add_callback and friends. That being said, this wasn't intuitive and took me some time to figure out how to do async downloading of large binary data, and at the end of it I concluded that this probably isn't the best tool for serving large binary data that exceed a typical transmission window.

当然，您可能想知道如何开始，这里有一些东西可以帮助您入门:

Of course, you probably want to know how to start, here is something to help you get started:

import time
import logging
from datetime import timedelta
from threading import Thread
from tornado.httpserver import HTTPServer
import tornado.ioloop
import tornado.web

logger = logging.getLogger(__name__)
logging.basicConfig(level=logging.INFO)


def blocking_task(callback, seconds=10):
    time.sleep(seconds)
    callback('slept for %d seconds' % seconds)


class CallbackRequestHandler(tornado.web.RequestHandler):
    wait = timedelta(seconds=1)

    @tornado.web.asynchronous
    def get(self):
        tornado.ioloop.IOLoop.current().add_callback(self.start_loop)

    def start_loop(self):
        self.task = Thread(target=blocking_task,
            kwargs={'callback': self.write})
        self.task.start()
        logger.info('starting %s', self.task)
        self.loop()

    def loop(self):
        if self.task.is_alive():
            logger.info('waiting on %s', self.task)
            tornado.ioloop.IOLoop.current().add_timeout(self.wait, self.loop)           
        else:
            logger.info('finished on %s', self.task)
            self.finish()


tornado_app = tornado.web.Application([
    (r"/", CallbackRequestHandler),
])

if __name__ == "__main__":
    http_server = HTTPServer(tornado_app)
    http_server.listen(9090)
    tornado.ioloop.IOLoop.instance().start()

一个示例，其中两个客户端在 http://localhost:9090 上戳这个实例.

An example run with two clients poking at this instance at http://localhost:9090.

$ python unblock.py
INFO:__main__:starting <Thread(Thread-1, started 139876219111168)>
INFO:__main__:waiting on <Thread(Thread-1, started 139876219111168)>
INFO:__main__:waiting on <Thread(Thread-1, started 139876219111168)>
INFO:__main__:starting <Thread(Thread-2, started 139876210718464)>
INFO:__main__:waiting on <Thread(Thread-2, started 139876210718464)>
INFO:__main__:waiting on <Thread(Thread-1, started 139876219111168)>
INFO:__main__:waiting on <Thread(Thread-2, started 139876210718464)>
INFO:__main__:waiting on <Thread(Thread-1, started 139876219111168)>
INFO:__main__:waiting on <Thread(Thread-2, started 139876210718464)>
INFO:__main__:waiting on <Thread(Thread-1, started 139876219111168)>
INFO:__main__:waiting on <Thread(Thread-2, started 139876210718464)>
INFO:__main__:waiting on <Thread(Thread-1, started 139876219111168)>
INFO:__main__:waiting on <Thread(Thread-2, started 139876210718464)>
INFO:__main__:waiting on <Thread(Thread-1, started 139876219111168)>
INFO:__main__:waiting on <Thread(Thread-2, started 139876210718464)>
INFO:__main__:waiting on <Thread(Thread-1, started 139876219111168)>
INFO:__main__:waiting on <Thread(Thread-2, started 139876210718464)>
INFO:__main__:waiting on <Thread(Thread-1, started 139876219111168)>
INFO:__main__:waiting on <Thread(Thread-2, started 139876210718464)>
INFO:__main__:waiting on <Thread(Thread-1, started 139876219111168)>
INFO:__main__:waiting on <Thread(Thread-2, started 139876210718464)>
INFO:__main__:finished on <Thread(Thread-1, stopped 139876219111168)>
INFO:tornado.access:200 GET / (::1) 10010.21ms
INFO:__main__:waiting on <Thread(Thread-2, started 139876210718464)>
INFO:__main__:finished on <Thread(Thread-2, stopped 139876210718464)>
INFO:tornado.access:200 GET / (::1) 10004.87ms

这可能不是最佳解决方案，因为我没有使用更新/更好的方法，例如 concurrent.futures 和 Tornado 提供的相关钩子，但希望这个示例代码能够指出你朝着正确的方向前进.

This is probably NOT the optimum solution as I don't make use of the newer/better methods such as concurrent.futures and the related hooks that Tornado provides, but hopefully this example code will point you towards the right direction.

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