在Discord Bot脚本中创建定时循环以重新加载网页（web刮板Bot）

Question

我目前正在设计一个discord机器人，它可以抓取一个不断更新与PBE服务器相关补丁的网页。我现在已经成功地让机器人通过了Heroku。我遇到的问题是，我想创建一个自动（定时循环）刷新，重新加载我请求的网站。目前，它只加载网站的一个实例，如果该网站发生更改/更新，我的任何内容都不会更新，因为我正在使用网站的“旧”请求

是否有一种方法可以将代码隐藏在函数中，以便创建一个定时循环，还是只需要围绕我的网站请求创建一个循环？那看起来怎么样？谢谢

from bs4 import BeautifulSoup
from urllib.request import urlopen
from discord.ext import commands
import discord

# what I want the commands to start with
bot = commands.Bot(command_prefix='!')

# instantiating discord client
token = "************************************"
client = discord.Client()

# begin the scraping of passed in web page
URL = "*********************************"
page = urlopen(URL)
soup = BeautifulSoup(page, 'html.parser')
pbe_titles = soup.find_all('h1', attrs={'class': 'news-title'})  # using soup to find all header tags with the news-title
                                                                 # class and storing them in pbe_titles
linksAndTitles = []
counter = 0

# finding tags that start with 'a' as in a href and appending those titles/links
for tag in pbe_titles:
    for anchor in tag.find_all('a'):
        linksAndTitles.append(tag.text.strip())
        linksAndTitles.append(anchor['href'])

# counts number of lines stored inside linksAndTitles list
for i in linksAndTitles:
    counter = counter + 1
print(counter)

# separates list by line so that it looks nice when printing
allPatches = '\n'.join(str(line) for line in linksAndTitles[:counter])
# stores the first two lines in list which is the current pbe patch title and link
currPatch = '\n'.join(str(line) for line in linksAndTitles[:2])


# command that allows user to type in exactly what patch they want to see information for based off date
@bot.command(name='patch')
async def pbe_patch(ctx, *, arg):
    if any(item.startswith(arg) for item in linksAndTitles):
        await ctx.send(arg + " exists!")
    else:
        await ctx.send('The date you entered: ' + '"' + arg + '"' + ' does not have a patch associated with it or that patch expired.')


# command that displays the current, most up to date, patch
@bot.command(name='current')
async def current_patch(ctx):
    response = currPatch
    await ctx.send(response)


bot.run(token)

我和你玩过

while True:

但是每当我在循环中嵌套任何东西时，我就不能在其他地方访问代码

Answer 1

discord有特殊的装饰程序tasks定期运行一些代码

from discord.ext import tasks

@tasks.loop(seconds=5.0)
async def scrape(): 
    # ... your scraping code ...


# ... your commands ...


scrape.start()
bot.run(token)

它将每隔5秒重复函数scrape

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文件：tasks

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在Linux上，我最终会使用标准服务cron定期运行一些脚本。此脚本可以刮取数据并保存在文件或数据库中，并且discord可以从此文件或数据库中读取。但是cron每1分钟检查一次任务，这样它就不能更频繁地运行任务

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编辑：

最小工作代码

我使用为刮式学习创建的页面http://books.toscrape.com

我改变了一些元素。当有bot时，不需要创建client，因为bot是一种特殊的client

我把title和link作为字典

            {
                'title': tag.text.strip(),
                'link': url + anchor['href'],
            }

因此，以后更容易创建像这样的文本

title: A Light in the ...
link: http://books.toscrape.com/catalogue/a-light-in-the-attic_1000/index.html

---

import os
import discord
from discord.ext import commands, tasks
from bs4 import BeautifulSoup
from urllib.request import urlopen

# default value at start (before `scrape` will assign new value)
# because some function may try to use these variables before `scrape` will create them
links_and_titles = []   # PEP8: `lower_case_namese`
counter = 0
items = []

bot = commands.Bot(command_prefix='!')

@tasks.loop(seconds=5)
async def scrape():
    global links_and_titles
    global counter
    global items

    url = "http://books.toscrape.com/"
    page = urlopen(url)
    soup = BeautifulSoup(page, 'html.parser')
    #pbe_titles = soup.find_all('h1', attrs={'class': 'news-title'})  
    pbe_titles = soup.find_all('h3')  

    # remove previous content
    links_and_titles = []

    for tag in pbe_titles:
        for anchor in tag.find_all('a'):
            links_and_titles.append({
                'title': tag.text.strip(),
                'link': url + anchor['href'],
            })

    counter = len(links_and_titles)
    print('counter:', counter)
    items = [f"title: {x['title']}\nlink: {x['link']}" for x in links_and_titles]

@bot.command(name='patch')
async def pbe_patch(ctx, *, arg=None):
    if arg is None:
        await ctx.send('Use: !patch date')
    elif any(item['title'].startswith(arg) for item in links_and_titles):        
        await ctx.send(arg + " exists!")
    else:
        await ctx.send(f'The date you entered: "{arg}" does not have a patch associated with it or that patch expired.')

@bot.command(name='current')
async def current_patch(ctx, *, number=1):
    if items:
        responses = items[:number]
        text = '\n  \n'.join(responses)
        await ctx.send(text)
    else:
        await ctx.send('no patches')

scrape.start()

token = os.getenv('DISCORD_TOKEN')
bot.run(token)

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PEP 8 Style Guide for Python Code