How do I display real-time python script output on a website?

I have a Python script that outputs something every second or two, but takes a long while to finish completely. I 开发者_如何学编程want to set up a website such that someone can directly invoke the script, and the output is sent to the screen while the script is running.

I don't want the user to wait until the script finishes completely, because then all the output is displayed at once. I also tried that, and the connection always times out.

I don't know what this process is called, what terms I'm looking for, and what I need to use. CGI? Ajax? Need some serious guidance here, thanks!

If it matters, I plan to use Nginx as the webserver.

First of all - your script must output header:

Connection: Keep-Alive

Because browser must know that it will have to wait.

And your script must output data without buffering. And stackoverflow has already answered this question.

The solution is to flush the output buffer at select points in the script's execution - I've only ever done this in PHP via flush() but this looks like the Python equivalent:

cgiprint() also flushes the output buffer using sys.stdout.flush(). Most servers buffer the output of scripts until it's completed. For long running scripts, 8 buffering output may frustrate your user, who'll wonder what's happening. You can either regularly flush your buffer, or run Python in unbuffered mode. The command-line option to do this is -u, which you can specify as #!/usr/bin/python -u in your shebang line.

nginx doesn't support CGI, so you will need to use fastcgi or wsgi

Alternatively you could use something like webpy and proxy to it through nginx

From http://tools.cherrypy.org/wiki/Comet "Wikipedia describes Comet as, "a neologism to describe a web application model in which a long-held HTTP request allows a web server to push data to a browser, without the browser explicitly requesting it.". In other words, Comet is that asynchronous Javascript mojo you need to build really fancy AJAX applications.

The following code demonstrates how to write a Comet application using CherryPy and jQuery. It is a web interface into the console ping command. The ping command was chosen for this example because it will run indefinitely if given no arguments. Executing never-ending commands is usually a big no-no when it comes to web application programming but with CherryPy we can handle this quite easily:" SEE LINK

I am trying to do the exact same thing. So far I am using cherrypy because it is easy to integrate with my script.

As suggested by a few of the others you can use a keep alive connection and instead of "return" statements use yield statements and instead of "print" statements also use yield statements. This will basically show everything that happens in the python script onto the website page.

After extensive searching and testing I would advise nginx as a reverse proxy with gevent & bottle as the backend which allows for peace of mind as nginx will not serve up the python source file ever.