A course on Udemy about Python GUI programming with Qt

http://www.reddit.com/r/Python/comments/14453f/hey_rpython_ive_started_teaching_a_course_on/

If you are lucky, you can put your hand on a free coupon :)

Official page at Udemy: http://www.udemy.com/python-gui-programming/.

submitting a link to reddit and adding a comment

Problem
You want to send a large number of links to reddit and you want to get it done with a script. How to send links and how to add comments to them?

Solution
First, install the reddit api:

sudo pip install reddit -U

Then you can use my RedBot to perform the task. It is part of my jabbapylib library.

#!/usr/bin/env python

"""
Simple API for:
* posting links to reddit
* commenting on a post

This requires that you have a reddit account. Put your username and
password in the following files:
* ~/reddit_username.txt
* ~/reddit_password.txt

To use RedBot, just make a subclass of it and give it a cool name:

class HyperBot(RedBot):
    def __init__(self):
        super(HyperBot, self).__init__()
        self.name = 'HyperBot'
        
Now you are ready to flood reddit :)

# from jabbapylib.reddit import red
"""

import reddit
from jabbapylib.filesystem import fs
from jabbapylib.platform import platform

USERNAME_TXT = '{home}/reddit_username.txt'.format(home=platform.get_home_dir())
PASSWORD_TXT = '{home}/reddit_password.txt'.format(home=platform.get_home_dir())
#
USERNAME = fs.read_first_line(USERNAME_TXT)
PASSWORD = fs.read_first_line(PASSWORD_TXT)


class RedBot(object):
    def __init__(self):
        self.name = 'RedBot'
        self.username = USERNAME
        self.password = PASSWORD
        #
        self.r = reddit.Reddit(user_agent=self.name)
        self.r.login(username=self.username, password=self.password)
        self.last_post = None   # Submission object
        self.permalink = None   # URL of the last post
        
    def submit_link(self, url, subreddit, title):
        """
        The return value (res) is a Submission object or None.
        URL of the newly created post: res.permalink
        """
        try:
            self.last_post = self.r.submit(subreddit, title, url=url)
            self.permalink = self.last_post.permalink
            print '# url to send: {url}'.format(url=url)
            print '# submitted to: {pl}'.format(pl=self.permalink)
            return self.last_post
        except:
            print >>sys.stderr, "Warning: couldn't submit {url}".format(url=url)
            return None
        
    def add_comment(self, comment):
        if self.last_post:
            self.last_post.add_comment(comment)
            print '# comment added'

#############################################################################

if __name__ == "__main__":
# here is how to use it:
#    url = '...'
#    subreddit = '...'
#    title = "..."
#    comment = '...'
#    r = RedBot()
#    r.submit_link(url, subreddit, title)
#    r.add_comment(comment)
    pass

You can find the current version here.

Thanks to Bryce Boe, the maintainer of the reddit api, who kindly answered my questions.

Links
Python Reddit API Wrapper’s documentation

Upload an image to imgur.com from Python

If you are familiar with reddit, you must have noticed that most images are hosted on imgur. I would like to upload several images from my computer and I want to collect their URLs on imgur. Let’s see how to do that.

Imgur has an API, this is what we’ll use. Anonymous upload is fine for my needs. For this you need to register and you get an API key. Under the examples there is a very simple Python code. When you execute it, pycurl prints the server’s XML response to the standard output. How to store that in a variable? From that XML we want to extract some data.

Here is an extended version of the uploader script:

#!/usr/bin/env python

import pycurl
import cStringIO
import untangle    # XML parser

def upload_from_computer(image):
    response = cStringIO.StringIO()   # XML response is stored here
    
    c = pycurl.Curl()
    
    values = [
              ("key", your_api_key),
              ("image", (c.FORM_FILE, image))]
    # OR:     ("image", "http://example.com/example.jpg")]
    # OR:     ("image", "YOUR_BASE64_ENCODED_IMAGE_DATA")]
    
    c.setopt(c.URL, "http://api.imgur.com/2/upload.xml")
    c.setopt(c.HTTPPOST, values)
    c.setopt(c.WRITEFUNCTION, response.write)   # put the server's output in here
    c.perform()
    c.close()
    
    return response.getvalue()

def process(xml):
    o = untangle.parse(xml)
    url = o.upload.links.original.cdata
    delete_page = o.upload.links.delete_page.cdata
    
    print 'url:        ', url
    print 'delete page:', delete_page

#############################################################################

if __name__ == "__main__":
    img = '/tmp/something.jpg'
    xml = upload_from_computer(img)
    process(xml)

The tip for storing the XML output in a variable is from here. Untangle is a lightweight XML parser; more info here.

Send a post to reddit from Python

Problem
How to send a post to reddit.com from a Python script? Motivation: when you send a post, you have to wait 8 minutes before you could send the next one. Imagine you have 10 posts to submit. It’d be nice to launch a script at night which would send everything till next morning.

Submit a post
Now I only show how to send one post. Batch processing is left as a future project.

The official Reddit API is here. There is a wrapper for it called reddit_api, which greatly simplifies its usage.

Install reddit_api:

sudo pip install reddit

Submit a post:

#!/usr/bin/env python

import reddit

subreddit = '...' # name of the subreddit where to send the post
url = '...'       # what you want to send
title = '...'     # title of your post

# change user_agent if you want:
r = reddit.Reddit(user_agent="my_cool_application")
# your username and password on reddit:
r.login(user="...", password="...")

# the output is a JSON text that contains the link to your post:
print r.submit(subreddit, url, title)

Submit a comment (update, 20111107)
Let’s see how to add a comment to a post. First, we need the URL of a post.

Example: http://www.reddit.com/r/thewalkingdead/comments/lkycy/that_look_on_the_kids_face/. Here, the last part of the URL is just garbage, the following URL is equivalent with it: http://www.reddit.com/r/thewalkingdead/comments/lkycy. The unique ID of the post is the last part: “lkycy”. Thus, this image can be accessed via this URL too: http://www.reddit.com/lkycy.

Now, let’s log in to reddit, fetch the post by its ID and add a comment.

def get_reddit_id(url):
    result = re.search('/comments/(.*?)/', url)
    return result.group(1)

def add_comment(r, reddit_url):
    reddit_id = get_reddit_id(reddit_url)
    post = r.get_submission_by_id(reddit_id)
    comment = "first"   # just to make reddit happy ;)
    post.add_comment(comment)
    print '# comment added:', comment

def main():
    r = reddit.Reddit(user_agent="my_cool_application")
    r.login(user="...", password="...")
    reddit_url = ...
    add_comment(r, reddit_url)

Python on reddit

I didn’t use reddit (wikipedia article) in the past but yesterday I visited its Python community and I found some really interesting links! So I think from now on I will check reddit regularly :)

Python-related communities on reddit:

• Python
• Python Educational (for beginners)

For a detailed list of subreddits, visit http://www.reddit.com/reddits/. Help, FAQ.

See this post for some notes about reddit.