Category: pro

Building an IRC (ro)bot

There are tons of (ro)bots out there for IRC (Internet Relay Chat). So how do you start and build one in Python, just for fun?

You will need a program that connects with an IRC server and acts like a traditional IRC client. IRC servers never ask for any type of complicated human verification such as solving captchas, which is why we can simply connect with a script. The script itself will use network sockets, a library that is often used to provide network interactions in many programming languages including Python and C/C++.

IRC and Python
To communicate with an IRC server, you need to use the IRC protocol. The IRC protocol has distinct messages such as PRIVMSG, USER, NICK and JOIN. If you are curious, you could read the entire protocol. But following this tutorial may be a lot simpler 😉 Authentication is achieved using only a few steps:

The IRC protocol is a layer on top of the IP protocol. To create a socket we use the command:

 irc = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

socket.AF_INET tells the library to use the network protocol IPv4. The second argument tells the library to use stream sockets, which are traditionally implemented on the TCP protocol. (IRC works over TCP/IP). We then must use the commands to authenticate with the server:

USER botname botname botname: phrase
NICK botname
JOIN #channel

Sometimes the IDENT command is neccesary too. Summing up, we get this class (save it as irc.py):

import socket
import sys
 
 
class IRC:
 
    irc = socket.socket()
  
    def __init__(self):  
        self.irc = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
 
    def send(self, chan, msg):
        self.irc.send("PRIVMSG " + chan + " " + msg + "n")
 
    def connect(self, server, channel, botnick):
        #defines the socket
        print "connecting to:"+server
        self.irc.connect((server, 6667))                                                         #connects to the server
        self.irc.send("USER " + botnick + " " + botnick +" " + botnick + " :This is a fun bot!n") #user authentication
        self.irc.send("NICK " + botnick + "n")               
        self.irc.send("JOIN " + channel + "n")        #join the chan
 
    def get_text(self):
        text=self.irc.recv(2040)  #receive the text
 
        if text.find('PING') != -1:                      
            self.irc.send('PONG ' + text.split() [1] + 'rn') 
 
        return text

Now that we have the network connectivity class, we can use it as an instance. We will keep our (ro)bot simple for explanatory purposes. The bot will reply “Hello!” if it gets the message “hello” in the channel it resides.

from irc import *
import os
import random
 
channel = "#testit"
server = "irc.freenode.net"
nickname = "reddity"
 
irc = IRC()
irc.connect(server, channel, nickname)
 
 
while 1:
    text = irc.get_text()
    print text
 
    if "PRIVMSG" in text and channel in text and "hello" in text:
        irc.send(channel, "Hello!")

Save it as bot.py and run with python bot.py. Connect with a traditional irc client (mirc,hexchat,irsii) to the the channel and observe the experiment has worked! You can now extend it with any cool features you can imagine.

Creating a gmail wordcloud

wordcloud python — word cloud based on gmail

We have created a python program that generates a wordcloud based on your gmail account. The output may look something like this depending on the contents of your emails.

First you will need a small script that interacts with the gmail service. We have created a small script that interact with gmail. It relies on gmaillib installed and you will need to set: allow “less-secure” applications to access gmail server: https://www.google.com/settings/security/lesssecureapps

Gmail example:

#!/usr/bin/env python
import gmaillib
from collections import Counter
 
 
def getMails(cnt,account, start,amount):
  emails = account.inbox(start, amount)
 
  for email in emails:
    cnt[email.sender_addr] += 1
 
amountOfMails = 100
cnt = Counter()
username = raw_input("Gmail account: ")
password = raw_input("Password: ")
 
account = gmaillib.account(username, password)
 
getMails(cnt,account,0,amountOfMails)
print cnt

If this script runs successfully you have almost all requirements installed. You will also need the library called wordcloud. We rebuild the system such that we get one long string containing the message bodies, which we feed as input to the wordcloud instance. The variable amount contains the number of mails to fetch. We have set it to 100 but you could set it to all messages using get_inbox_count() or you could simply fetch all emails of the last week.

Final program:

#!/usr/bin/env python
import gmaillib
from collections import Counter
from wordcloud import WordCloud
import matplotlib.pyplot as plt
 
amount = 100
cnt = Counter()
username = raw_input("Gmail account: ")
password = raw_input("Password: ")
 
account = gmaillib.account(username, password)
 
emails = account.inbox(0, amount)
 
data = ""
for email in emails:
  data = data + str(email.body)
 
wordcloud = WordCloud().generate(data)
plt.imshow(wordcloud)
plt.axis("off")
plt.show()

Requests: HTTP for Humans

If you want to request data from webservers, the traditional way to do that in Python is using the urllib library. While this library is effective, you could easily create more complexity than needed when building something. Is there another way?

Requests is an Apache2 Licensed HTTP library, written in Python. It’s powered by httplib and urllib3, but it does all the hard work for you.

To install type:

git clone https://github.com/kennethreitz/requests.git
cd requests
sudo python setup.py install

The Requests library is now installed. We will list some examples below:

Grabbing raw html using HTTP/HTTPS requests
We can now query a website as :

import requests
r = requests.get('http://pythonspot.com/')
print r.content

Save it and run with:

python website.py

It will output the raw HTML code.

Download binary image using Python

from PIL import Image
from StringIO import StringIO
import requests
 
r = requests.get('http://1.bp.blogspot.com/_r-MQun1PKUg/SlnHnaLcw6I/AAAAAAAAA_U$
i = Image.open(StringIO(r.content))
i.show()

An image retrieved using python

Website status code (is the website online?)

import requests
r = requests.get('http://pythonspot.com/')
print r.status_code

This returns 200 (OK). A list of status codes can be found here: https://en.wikipedia.org/wiki/List_of_HTTP_status_codes

Retrieve JSON from a webserver
You can easily grab a JSON object from a webserver.

import requests
 
import requests
r = requests.get('https://api.github.com/events')
print r.json()

HTTP Post requests using Python

from StringIO import StringIO
import requests
 
payload = {'key1': 'value1', 'key2': 'value2'}
r = requests.post("http://httpbin.org/post", data=payload)
print(r.text)

SSL verification, verify certificates using Python

from StringIO import StringIO
import requests
print requests.get('https://github.com', verify=True)

Extract data from the HTTP response header
With every request you send to a HTTP server, the server will send you some additional data. You can get extract data from an HTTP response using:

#!/usr/bin/env python
import requests
r = requests.get('http://pythonspot.com/')
print r.headers

This will return the data in JSON format. We can parse the data encoded in JSON format to a Python dict.

#!/usr/bin/env python
import requests
import json
r = requests.get('http://pythonspot.com/')
 
jsondata = str(r.headers).replace('\'','"')
headerObj = json.loads(jsondata)
print headerObj['server']
print headerObj['content-length']
print headerObj['content-encoding']
print headerObj['content-type']
print headerObj['date']
print headerObj['x-powered-by']

Extract data from HTML response
Once you get the data from a server, you can parse it using python string functions or use a library. BeautifulSoup is often used. An example code that gets the page title and links:

from bs4 import BeautifulSoup
import requests
 
# get html data
r = requests.get('http://stackoverflow.com/')
html_doc = r.content
 
# create a beautifulsoup object
soup = BeautifulSoup(html_doc)
 
# get title
print soup.title
 
# print all links
for link in soup.find_all('a'):
    print(link.get('href'))

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