What does this Perl XML filter look like in Python?

curl -u $1:$2 --silent "https://mail.google.com/mail/feed/atom" | perl -ne 'print "\t" if /<name>/; print "$2\n" if /<(title|name)>(.*)<\/\1>/;'开发者_开发问答

I have this shell script which gets the Atom feed with command-line arguments for the username and password. I was wondering if this type of thing was possible in Python, and if so, how I would go about doing it. The atom feed is just regular XML.

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Python does not lend itself to compact one liners quite as well as Perl. This is primarily for three reasons:

1. With Perl, whitespace is insignificant in almost all cases. In Python, whitespace is very significant.
2. Perl has some helpful shortcuts for one liners, such as perl -ne or perl -pe that put an implicit loop around the line of code.
3. There is a large body a cargo-cult Perl one liners to do useful things.

That all said, this python is close to what you posted in Perl:

curl -u $1:$2 --silent "https://mail.google.com/mail/feed/atom" | python -c ' 
import sys
for s in sys.stdin:
    s=s.strip()
    if not s: print '\t',
    else: print s
' 

It is a little difficult to do better because, as stated in my comment, the Perl you posted is incomplete. You have:

perl -ne 'print "\t" if //; print "$2\n" if /(.*)/;'

Which is equivalent to:

LINE:
while (<>) {
  print "\t" if //;         # print a tab for a blank line
  print "$2\n" if /(.*)/;   # nonsensical. Print second group but only 
                            # a single match group defined...
}

Edit

While it is trivial to rewrite that Perl in Python, here is something a bit better:

#!/usr/bin/python
from xml.dom.minidom import parseString
import sys

def get_XML_doc_stdin(f):
    return xml.dom.minidom.parse(f)

def get_tagged_data2(tag, index=0):    
    xmlData = dom.getElementsByTagName(tag)[index].firstChild.data
    return xmlData

data=sys.stdin.read()
dom = parseString(data)

ele2=get_tagged_data2('title')
print ele2

count=int(get_tagged_data2('fullcount'))
print count,"New Messages:"

for i in range(0,count):
    nam=get_tagged_data2('name',i)
    email=get_tagged_data2('email',i)
    print "  {0}: {1} <{2}>".format(i+1,nam,email)

Now save that in a text file, run chmod +x on it, then:

curl -u $1:$2 --silent "https://mail.google.com/mail/feed/atom" | 
/path/pythonfile.py

It produces this:

Gmail - Inbox for xxxxxxx@gmail.com
2 New Messages:
  1: bob smith <bob@smith.com>
  2: Google Alerts <googlealerts-noreply@google.com>

edit 2 And if you don't like that, here is the Python 1 line filter:

curl -u $1:$2 --silent "https://mail.google.com/mail/feed/atom" |python -c ' 
import sys, re
for t,m in re.findall(r"<(title|name)>(.*)<\/\1>",sys.stdin.read()):
    print "\t",m
'

---

You may use an "URL opener" from the urllib2 standard Python module with a handler for authentication. For example:

#!/usr/bin/env python

import getpass
import sys
import urllib2

def main(program, username=None, password=None, url=None):

    # Get input if any argument is missing
    username = username or raw_input('Username: ')
    password = password or getpass.getpass('Password: ')
    url = url or 'https://mail.google.com/mail/feed/atom'

    # Create password manager
    password_mgr = urllib2.HTTPPasswordMgrWithDefaultRealm()
    password_mgr.add_password(None, url, username, password)

    # Create HTTP Authentication handler and URL opener
    authhandler = urllib2.HTTPBasicAuthHandler(password_mgr)
    opener = urllib2.build_opener(authhandler)

    # Fetch URL and print content
    response = opener.open(url)
    print response.read()

if __name__ == '__main__':
    main(*sys.argv)

If you'd like to extract information from the feed too, you should check how to parse Password-Protected Feeds with feedparser.