py-url-shortener.py

# Imported Libraries
import random
import redis
import base64
import json


class UrlShortenerService(object):

    # local variables for Redis implementation
    redis_srv = None
    redis_shortened_url_key_fmt = 'shortened.url:%s'
    redis_global_urls_list = 'global:urls'
    redis_shortened_url_visitors_list_fmt = 'visitors:%s:url'
    redis_shortened_url_clicks_counter_fmt = 'clicks:%s:url'

    # our prefix base_url for our url shortener service
    base_url = 'http://rllytny.url/'

    def __init__(self):
        "Initializes self"
        self.redis_srv = redis.StrictRedis(host='localhost', port=6379, db=0)

    # Actionable methods
    def shorten_url(self, long_url):
        # jumbled them up
        url_str_arr = list(long_url)
        random.shuffle(url_str_arr)

        # get the last 10 items of the jumbled_url, assuming url is very longer than 20 chars
        if len(url_str_arr) > 20:
            shortened_url = url_str_arr[-10:]
        else:
            shortened_url = url_str_arr

        jumbled_url_suffix = ''.join(shortened_url)

        shortened_url = self.base_url + jumbled_url_suffix

        # encode shortened_url before saving
        encoded_url = encode_base64(shortened_url)

        shortened_url_key = url_string_formatter(
            self.redis_shortened_url_key_fmt, encoded_url)

        self.redis_srv.set(shortened_url_key, long_url)
        self.redis_srv.lpush(self.redis_global_urls_list, encoded_url)

        return shortened_url, encoded_url

    def expand_url(self, shortened_url):
        shortened_url_key = url_string_formatter(
            self.redis_shortened_url_key_fmt, shortened_url)
        return self.redis_srv.get(shortened_url_key)

    def visit(self, shortened_url=None, ip_address=None, agent=None, referrer=None):
        visitor_agent = {'ip_address': ip_address,
                         'agent': agent, 'referrer': referrer}

        url_visitors_list = url_string_formatter(
            self.redis_shortened_url_visitors_list_fmt, shortened_url)
        self.redis_srv.lpush(url_visitors_list, json.dumps(visitor_agent))

        url_clicks_counter = url_string_formatter(
            self.redis_shortened_url_clicks_counter_fmt, shortened_url)
        return self.redis_srv.incr(url_clicks_counter)

    # Retrieve counter properties from Redis
    def clicks(self, shortened_url=None):
        url_clicks_counter = url_string_formatter(
            self.redis_shortened_url_clicks_counter_fmt, shortened_url)
        return self.redis_srv.get(url_clicks_counter)

    def recent_visitors(self, shortened_url):
        visitor_agents = []

        url_visitors_list = url_string_formatter(
            self.redis_shortened_url_visitors_list_fmt, shortened_url)
        for visitor in self.redis_srv.lrange(url_visitors_list, 0, -1):
            visitor_agents.append(json.loads(visitor))
        return visitor_agents

    def short_urls(self):
        return self.redis_srv.lrange(self.redis_global_urls_list, 0, 100)

# End Class Methods

# Utility methods


def url_string_formatter(str_fmt, url):
    return str_fmt % url

#  Base64 Encoding and Decoding functions


def encode_base64(str_to_encode):
    bytes_to_encode = str_to_encode.encode("utf-8")
    result = base64.b64encode(bytes_to_encode)
    return result


def decode_base64(str_to_decode):
    result = base64.b64decode(str_to_decode)
    return result


def visitors_visiting(url_shortener_service):
    """
    Simulating web site traffic visits
    """

    print('Visitors visiting...')

    for i in range(0, 5):
        print('Visitor: %s' % i)
        for short_url in url_shortener_service.short_urls():
            decoded_url = decode_base64(short_url)
            print('... %s' % decoded_url)
            url_shortener_service.visit(decoded_url)

    print('Recent Visitors')

    for short_url in url_shortener_service.short_urls():
        expanded_url = url_shortener_service.expand_url(short_url)
        decoded_url = decode_base64(short_url)
        print('... %s' % decoded_url)
        visitor_agents = url_shortener_service.recent_visitors(decoded_url)
        print('Total recent vistors for {0} (ie {1}) are {2}'.format(
            decoded_url, expanded_url, len(visitor_agents)))

    return


def readInputFile(text_file, url_shortener_service):
    with open(text_file, 'r') as infile:
        for line in infile:
            # Ignore any comments in file
            if '#' not in line[0]:
                shortened_url, encoded_url = url_shortener_service.shorten_url(
                    line)
                expanded_url = url_shortener_service.expand_url(encoded_url)
                print("ShortenedURL: {0}; ExpandedURL: {1}".format(
                    shortened_url, expanded_url))

    return


def main():
    # inistantiate url_shorteer_service
    url_shortener_service = UrlShortenerService()

    # read text input file
    readInputFile('urls-to-read.txt', url_shortener_service)

    # Web visitor activity being tracking...
    visitors_visiting(url_shortener_service)


if __name__ == '__main__':
    main()