Exporting a csv file with web.py

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This is how you export a csv file and get the browser to recognize that its a csv file and popups the download window with web.py. Lets say we have a database with a table called users and you want to create a csv file that contains all the users with their names and id’s here is how you do it.

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1class export:
2  def GET(self):
3    i = web.input()
4    users = web.select(’users’, vars=locals())
5    csv = []
6    csv.append(”id,name\n“)
7    for user in users:
8      row = []
9      row.append(user.id)
10      row.append(user.name)
11      csv.append(”,“.join(row))
12
13     web.header(’Content-Type’,’text/csv‘)
14     web.header(’Content-disposition’, ’attachment; filename=export.csv‘)
15     print "".join(csv)
16     return

I export the csv file in a GET method of a class called export which i map in the urls list to ‘/export’,‘export’

A quick breakdown, do a database query and iterate over the IterBetter object create a row and appending a comma seperated string to the csv list. Then at the end you send the appropirate HTTP headers , the first telling the type of the file and the second setting the filename and extension.