reddit_bot.py

#!/usr/bin/env python

"""
Reddit bot runner.
"""

import signal
import praw
import praw.models
from helpers import Interpreter, timeout_handler, TimeoutException, unescape
import config


# https://stackoverflow.com/questions/25027122/break-the-function-after-certain-time
# Change the behavior of SIGALRM
signal.signal(signal.SIGALRM, timeout_handler)

class BotRunner(object):
 """
 Class for the bot object, handles everything related to reddit and praw.
 """

 # pylint: disable=too-many-instance-attributes
 def __init__(self, bot, language):
 self.bot = bot
 self.interpreter = Interpreter(language)
 self.language = language["callsign"]
 self.callsign = config.BOT_USERNAME + " " + language["callsign"]
 self.new_comments = []
 self.outputs = []
 self.messages = []
 self.codes = []

 def get_new_comments(self):
 """
 Gets comment in which the bot is mentioned using the unread messages in the inbox
 """

 comments = []
 for comment in self.bot.inbox.unread():
 if self.callsign.lower() in comment.body.lower() and comment.author\
 not in config.BLOCKED_USERS and comment.subreddit in config.ALLOWED_SUBREDDITS:
 comments.append(comment)

 print("{}: Summon from: {}".format(self.language, comment.permalink()))

 self.new_comments = comments

 def get_code_from_comments(self):
 """
 Extracts codes to be run from the comments
 """

 codes = []
 for comment in self.new_comments:
 line_list = comment.body.split("\n")
 line_number = 0
 codes.append([])
 number_of_calls = min(config.MAX_CALLS_PER_POST, line_list.count(self.callsign))
 # get starting lines for code
 for _ in range(number_of_calls):
 code = ""
 line_number = line_list.index(self.callsign, line_number)
 for line in line_list[line_number+1:]:
 # if the comment block stops
 if line.startswith(" ") or line == "":
 code += "\n" + unescape(line[4:])
 line_number += 1
 else:
 codes[-1].append(code)
 break
 if len(codes[-1]) != number_of_calls:
 codes[-1].append(code)
 self.codes = codes

 def execute_codes(self):
 """
 Executes codes previously extracted and gets the output
 """

 for code in self.codes:
 self.outputs.append([])
 for sub_code in code:
 signal.alarm(config.MAX_TIME)
 try:
 self.interpreter.run(sub_code)
 self.outputs[-1].append(self.interpreter.output)
 except TimeoutException:
 self.outputs[-1].append(
 "You exceded the maximum time for interpreting your code.\n")
 # self.interpreter.clear_files()
 else:
 # reset alarm
 signal.alarm(0)

 def get_messages_from_outputs(self):
 """
 Formats messages to be replied
 """

 messages = []
 for output in self.outputs:
 messages.append("")
 for i, sub_output in enumerate(output):
 sub_output = " " + sub_output
 sub_output = sub_output.replace("\n", "\n ")
 if len(sub_output) > config.MAX_LENGTH_ALLOWED:
 sub_output = " " + sub_output[len(sub_output)-config.MAX_LENGTH_ALLOWED:]
 sub_output += "This message execeded the character limit"
 messages[-1] += config.OUTPUT_TEMPLATE.format(number=i+1, output=sub_output)
 messages[-1] += config.SIGNATURE

 self.messages = messages

 def reply(self):
 """
 Replies to every comment
 """
 for (comment, message) in zip(self.new_comments, self.messages):
 try:
 comment.reply(message)
 print("Replied.")
 comment.mark_read()
 except praw.exceptions.APIException as err:
 print(err)

 def clean_up(self):
 """
 Sets up for a new iteration of the main loop
 """

 self.new_comments = []
 self.outputs = []
 self.messages = []
 self.codes = []

 def run(self):
 """
 Does an iteration of the main loop, gets comments, executes code and replies
 """

 self.get_new_comments()
 self.get_code_from_comments()
 self.execute_codes()
 self.get_messages_from_outputs()


 if not config.TEST:
 self.reply()
 else:
 for message in self.messages:
 print(message)
 self.clean_up()

if __name__ == "__main__":
 print("Starting bot.")
 BOT = praw.Reddit('pythonBot')
 RUNNERS = []

 for LANGUAGE in config.LANGUAGES.values():
 RUNNERS.append(BotRunner(BOT, LANGUAGE))
 while True:
 try:
 for runner in RUNNERS:
 runner.run()
 except Exception as excep: # pylint: disable=W0703
 with open("log.txt", "a+") as f:
 print(str(excep))
 f.write(str(excep)+"\n")