How to download a file in Python (Jinja2) on-click Export button?

问题

I have a button export :

 <button class="aptButton" formaction="/export/" type="submit">export</button>

and I have this in the /export/

index.cgi

#! /apollo/sbin/envroot $ENVROOT/bin/python
# -*- coding: utf-8 -*-

    import cgitb
    cgitb.enable()

    import cgi

    def main():
        print "Content-Type: text/html"
        print
        form = cgi.FieldStorage()

        results = helpers.getResults()
        environment = helpers.get_environment()


        print environment.get_template('export.html').render(
                results = results)

    main()

and I have this in my export.html

<!doctype html>
{% for id in results %}
    {{ write_results_to_file(id) }}
{% endfor %}

I am trying to download the results to a tab separated file, so I thought of writing to a local file and then send(download) the file but I am not sure how to do the download part, I couldnt use flask or django which has some good libs.. is there any other lib which I can use to download the results to a tab delimited file on the users desktop?

export.py

def write_results_to_file(result):
    local_filename = "/home/testing.txt"
    # NOTE the stream=True parameter
    with open(local_filename, 'w') as f:
        f.write('\t'.join(result) + '\n')

回答1:

If you're using good old-fashioned CGI to produce a tab-separated file, all you need to do is print an appropriate header and then print the content on stdout, something like this:

def main():
    form = cgi.FieldStorage()
    results = helpers.getResults()

    print "Content-Type: text/plain"
    print "Content-Disposition: attachment; filename=testing.txt"
    print

    for result in results:
        print '\t'.join(result) + '\n'

main()

The essential parts are the 2 lines that print the header, followed by a blank line to separate from the content, followed by the plain text content.

If you want to make this happen on the click of an Export button, then you can, for example:

Make the Export button a link to another URL endpoint that will use the example script I put above
Or, use the same script, with a conditional statement on form parameters to decide to print the front page, or to print the content using the example script above

Let me know if you need further help.

来源：https://stackoverflow.com/questions/44959862/how-to-download-a-file-in-python-jinja2-on-click-export-button

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python

python-2.7

python-3.x

cgi

jinja2