Python: PMC Contest Info

######################################
# TODO:                              #
# - Add ordering by entry            #
######################################

import urllib.request
import sys
import time

user_agent = 'Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.0.7) Gecko/2009021910 Firefox/3.0.7'
headers = {'User-Agent':user_agent,}

base_url = "https://www.planetminecraft.com"
url = base_url + "/contests/?p="

#Defining defaults
default_max = 1
orders = ["type","date"]
default_order = "type"
default_output = "output.txt"

def error_handler(error):
    print (error)
    log = open("error_log.txt","w")
    log.write(str(error))
    log.close()

def get_page(url):
    request = urllib.request.Request(url,None,headers)
    response = urllib.request.urlopen(request)
    byte_page = response.readlines()
    page = [byte.decode("utf-8") for byte in byte_page]
    return page

def page_exists(url):
        page = get_page(url)
        for line in page:
            if ("Blast! No contests match your query." in line):
                return False
        return True

def get_entries(page):
    for line in page:
        if ("num_results" in line):
            search_start = line.find("stat") + 1
            entries_index_start = line.find("stat",search_start) + 7
            entries_index_end = line.find("pagination") - 23
            entries = line[entries_index_start:entries_index_end]
            return entries

def get_year(page):
    for line in page:
        if ("entry-preview" in line):
            line_number = page.index(line) + 1
            search_line = page[line_number]
            entries_index_end = search_line.find("title") - 2
            url = search_line[9:entries_index_end]
            entry_page = get_page(base_url + url)
            for entry_line in entry_page:
                if ("Posted on" in entry_line):
                    entry_index_start = entry_line.find(">") + 1
                    entry_index_end = entry_line.find("</")
                    date = entry_line[entry_index_start:entry_index_end]
                    year = date.split("/")[2]
                    return year

def get_type(page):
    for line in page:
        if ("sub_lrg sub_" in line):
            type_index_start = line.find("sub_lrg sub_") + 12
            type_index_end = line.find("style") - 3
            contest_type = line[type_index_start:type_index_end]
            return contest_type

def get_info(url,contest_dict):
    page = get_page(url)
    for line in page:
        if ("contest_info" in line):
            contest_info = line[34:-6]
            contest_info_split = contest_info.split(":",1)
            month = contest_info_split[0][:-1]
            contest_name_pre = contest_info_split[1][1:].replace("\"","").replace(":","").replace("-","").replace("  "," ")
            if ("#" in contest_name_pre):
                end_index = contest_name_pre.find("#")
                contest_name = contest_name_pre[:end_index].strip()
            else:
                contest_name = contest_name_pre
            line_number = page.index(line)
            url_line = page[line_number + 2]
            url_index_end = url_line.find("title") - 2
            contest_url = base_url + url_line[9:url_index_end] + "entries"
            contest_page = get_page(contest_url)
            entries = get_entries(contest_page)
            year = get_year(contest_page)
            contest_type = get_type(contest_page)
            if ((contest_type == "project") and ("Solo" in contest_name)):
                contest_type = "solo project"
            out = "%s %s - %s (%s entries)\n" % (month,year,contest_name,entries)
            if (order == "type"):
                if contest_type in contest_dict:
                    contest_dict[contest_type].append(out)
                else:
                    contest_dict[contest_type] = [out]
            if (order == "date"):
                if year in contest_dict:
                    contest_dict[year].append(out)
                else:
                    contest_dict[year] = [out]
    return contest_dict

#Setting default inputs
max_page = default_max
order = default_order
output_file = default_output

#Max pages input
max_page_input = input("Max pages (default=1): ")
if (max_page_input == ""):
    print ("Defaulting to \"1\"")
else:
    try:
        max_page = int(max_page_input)
    except ValueError:
        error_handler("Error: Page limit must be an integer.")
        sys.exit()
    check_url = url + str(max_page)
    if (page_exists(check_url) == False):
        error_handler("Error: Page limit is too high.")
        sys.exit()

#Ordering input
order_input = input("Ordering (\"type or date\"): ").lower()
if (order_input == ""):
    print ("Defaulting to \"type\"")
elif (order_input in orders):
    order = order_input
else:
    error_handler("Error: Invalid ordering. Defaulting to \"type\"")

#Output file name input
file_input = input("Output file name: ").lower()
if (file_input == ""):
    print ("Defaulting to \"output.txt\"")
else:
    file_split = file_input.split(".")
    if ((len(file_split) > 1) and (file_split[-1] == "txt")):
        output_file = file_input
    else:
        output_file = file_input + ".txt"

#Main
output = open(output_file,"w")
input_dict = {}
try:
    for page in range(1,max_page+1):
        output_dict = get_info(url + str(page),input_dict)
        input_dict = output_dict
        time.sleep(5)
    for order_key in output_dict:
        order = order_key.capitalize()
        output.write("%s contests:\n" % (order))
        for contest in output_dict[order_key]:
            output.write("    " + contest)
    output.close()
except Exception as e:
    error_handler(e)