How can I schedule an email to be sent at some point in the future in django?

I want to schedule an email to be sent to a user upon a specific action. However, if the user takes 开发者_JS百科another action I want to cancel that email and have it not send.

How would I do that in django or python?

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Beanstalkd

If you can install beanstalkd and run python script from command line I would use that to schedule emails. With beanstalkc client you can easily accomplish this. On ubuntu you might first need to install:

• sudo apt-get install python-yaml python-setuptools

consumer.py:

import beanstalkc

def main():
    beanstalk = beanstalkc.Connection(host='localhost', port=11300)
    while True:
        job = beanstalk.reserve()
        print job.body
        job.delete()


if __name__ == '__main__':
    main()

Will print job 5 seconds after it get's inserted by producer.py. Offcourse this should be set longer to when you want to schedule your emails, but for demonstration purposes it will do. You don't want to wait half an hour to schedule message when testing ;).

producer.py:

import beanstalkc

def main():
    beanstalk = beanstalkc.Connection(host='localhost', port=11300)
    jid = beanstalk.put('foo', delay=5)

if __name__ == '__main__':
    main()

GAE Task Queue

You could also use Google App engine task queue to accomplish this. You can specify an eta for your Task. Google App engine has a generous free quota. In the task queue webhook make Asynchronous Requests to fetch URL on your server which does the sending of emails.

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I would set up a cron job which could handle everything you want to do...

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If you didn't have access to cron, you could easily do this:

1. Write a model that stores the email, the time to send, and a BooleanField indicating if the email has been sent.
2. Write a view which selects all emails that haven't been sent yet but should have by now, and sends them.
3. Use something like OpenACS Uptime, Pingdom or any other service capable of sending HTTP GET requests periodically to call that view, and trigger the email sending. (Both are free, the former should request once every 15 minutes, and the latter can be configured to request up to every minute, and will do so from several locations.)

Sure, it's inelegant, but it's a method that works on basically any web host. I used to do something like this when I was writing PHP apps to run on a host that killed all processes after something like 15 seconds.

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Are your using celery ? If true, see http://ask.github.com/celery/userguide/executing.html#eta-and-countdown

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You said that you want to do it through Python or Django, but it seems as though something else will need to be involved. Considering you are on a shared host, there is a chance installing other packages could also be a problem.

Another possible solution could be something like this:

Use a javascript framework which can setup timed events, start/cancel them etc. I have done timed events using a framework called ExtJS. Although ExtJS is rather large im sure other frameworks such as jQuery or even raw javascript you could do a similar thing.

Set up a task on a user action, that will execute in 5 minutes. The action could be an ajax call to a python script which sends the email... If a user does something where the task needs to be stopped, just cancel the event.

It kind of seems complicated and convoluted, but it really isn't. If this seems like a path you would like to try out, let me know and I'll edit with some code