Extract a list of users from a text file

Question

fo=open("haproxyfile.txt","r")
users=[]
for lines in fo.readlines():
    if 'user' and 'password' in lines:
        items=lines.split() #converts to list"""
        users.append(items[1]) #append the second item that is the username"""

print users

The content of haproxyfile.txt is below

ssl-default-bind-ciphers EECDH+EDSA+ACM:CDH+aRSA+AEdfGCM:EECDH+ECDSA+SHA384:EEC+
ESA+SHA:EDH+aRSA+SHA384:EECDH+aRSA+SHA256:EDH:AES128-GCM-SHA256:AES128-SHA256:AES128-S
HA:EDH+SA:AES256-GCM-SHA384:AES-SHA256:AES256-SHA:!RC4:!aNULL:!eNULL:!LOW:!3D:!MD5:!EXP:
!PSK:!SRP:!DSS

        # Users
        userlist IntacctAdmins
          group admins users aasghar,achouchoulas,bwright,calla,gspiliotis,haris,pdam
          user aasghar password $1$CFdTKLSRSbQME/
          user achouchoulas password $1$uLy//uPCaVSNhfFG/
          user bwright password $1$q3Fk$kmqM.J531
          user calla password $1$f%g23a44$Bl.1fPj/
          user gspiliotis password $1$d/2OI.TQOiV1
          user haris password $1$mwQ$uG/1mUjE0
          user pdam password $1t24Z$K4FUH/

What I need to parse from the content

The line after having the words groups are the lines where my user names are located. They are the single words after user keyword.I have fetched it using the method above.Is there any better way to fetch it?

Answer 1

There are quite a few possible improvements.

You should open files with the with keyword, this way they get closed no matter what (you don't even close your file).

if 'user' and 'password' in lines: does not mean what you think it does. All non-empty strings are truthy in Python, so if "user" is always True. So you only really check that the line contains "password". Fortunately you don't have any lines containing "password", but not "users", so this bug has not yet become obvious.

The easiest fix for this would be using this:

if "user" in lines and "password" in lines:
    # Stuff

In summary, I would re-write your code like this:

with open("haproxyfile.txt") as f:
    users = [line.split()[1] for line in f 
             if line.strip().startswith("user") and "password" in line]

print users

Note that I omitted the "r" parameter to open, because read-only is the default mode. I also used str.startswith to check if it starts with a string. The strip is probably needed, to get rid of the whitespace at the beginning of your lines. If that is a copy&paste error as well, omit it.

I also wrote it as a list-comprehension and used the fact that you can directly iterate over a file.

Answer 2

It's not obvious what your code does or how it works. I have to figure out what the result of lines.split() looks like, and what items[1] represents — and all I have to go by, according to the code, is that the lines of interest contain the word 'password'.

I recommend doing it a completely different way, using regular expression matching, so that it is obvious what kind of text pattern you expect to extract. I would also write it using a list comprehension, so that the users list is defined declaratively, "all at once".

import re

with open('haproxyfile.txt') as f:
    users = [
        match.group(1) for match in (
            re.search(r'^\s*user\s+(\S+)\s+password', line) for line in f
        )
        if match
    ]

print users

Answer 3

Shouldn't passwords be coded? If passwords are not coded-could it put user privacy and/or administrator settings at risk?