无法理解 flask url 使用表单输入的路由

Question

我一直在玩弄 Flask，并创建了一个简单的网络抓取应用程序，用于收集新闻文章，然后将它们放入 dataTables JQuery 插件中，以便在 HTML 中输出。当 ticker 被硬编码时，stockNews(ticker) 函数工作得很好。但是，我想更进一步，通过 html 表单检索 ticker 的用户输入。这是我遇到问题的地方，我尝试查找教程并阅读烧瓶文档，但似乎无法使应用程序按预期工作。

我想要达到的目标：

在页面加载时呈现 index.html
仅当用户通过 html 表单

stockNews(ticker)

路由到新页面 /<ticker> 作为新页面 URL

当前情况：

AttributeError: 'NoneType' object has no attribute 'find_all' 这是由我的函数运行ning 在用户以 html 表格输入股票代码之前引起的。

app.py

import pandas as pd
import datetime as dt
import time
import requests
from tabulate import tabulate
from bs4 import BeautifulSoup
from flask import Flask, render_template, request
import json

app = Flask(__name__)

@app.route('/', methods=['GET', 'POST'])
def index():
    # retreives user input
    ticker = request.form.get('ticker')
    return render_template('index.html', ticker=ticker)

@app.route('/<ticker>', methods=['GET', 'POST'])
index()
# scrapes stock news from finviz
def stockNews(ticker):
    url = 'https://finviz.com/quote.ashx?t=' + ticker
    html = requests.get(url, headers={'User-Agent': 'Mozilla/5.0'})
    soup = BeautifulSoup(html.text, 'lxml')
    
    # finds news table within finviz website
    match = soup.find('table', class_="fullview-news-outer")
    
    dates = []
    time = []
    # appends dates in html to list
    for d in match.find_all("td", width="130"):
        if len(d.text.split(' ')) == 2:
            dates.append(d.text.split(' ')[0])
            time.append(d.text.split(' ')[1])
        elif len(d.text.split(' ')) == 1:
            dates.append('None')
            time.append(d.text.split(' ')[0])  
    # uses an assignment expression to replace 'None' with previous element in list
    dates = [current:=d if d != 'None' else current for d in dates]
            
    articles = []
    # appends new title to titles list
    for t in match.find_all("a", class_="tab-link-news"):
        match.find(class_='tab-link-news')['class'] = "news-link"
        articles.append(str(t))
    
    df_news = pd.DataFrame(list(zip(dates, time, articles)), columns=['Date', 'Time', 'Article'])
    # formats Date column/datetime string in dataframe
    df_news['Date'] = pd.to_datetime(df_news['Date'], errors='ignore').dt.strftime('%Y-%m-%d')
    json_news = json.loads(df_news.to_json(orient='records'))
    
    return render_template('index.html', json_news=json_news)

index.html

{% extends 'base.html' %}

{% block title %} 
<title>Stock Info</title>
{% endblock %}

{% block body %}
<center>
    <form method="POST">
        <input name="ticker">
        <input type="submit">
    </form>
</center>

<div class="container">
        <h1 class="header">News</h1>
        <table class="table table-striped table-sm" id='news' style="width: 100%;">
            <thead style='position: relative; width: 100%;'>
                <tr>
                    <th>Date</th>
                    <th>Time</th>
                    <th>Article</th>
                </tr>
            </thead>
        </table>
</div>
<script>
    var news = {{ json_news | safe }};
    $(document).ready(function() {
        $('#news').DataTable( {
            "data": news,
            "scrollY": 600,
            "paging": false,
            "scrollCollapse": true,
            "order": [[ 0, "desc" ]],
            "columns": [
                { "data": "Date" },
                { "data": "Time" },
                { "data": "Article" },
            ]
        } )
    } );
    </script>
{% endblock %}

base.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <!-- CSS only -->
    <script src="https://code.jquery.com/jquery-3.5.1.js" integrity="sha256-QWo7LDvxbWT2tbbQ97B53yJnYU3WhH/C8ycbRAkjPDc=" crossorigin="anonymous"></script>
    <link href="https://stackpath.bootstrapcdn.com/bootswatch/4.5.0/slate/bootstrap.min.css" rel="stylesheet" integrity="sha384-idNH3UIOiZbCf8jxqu4iExnH34y5UovfW/Mg8T5WfNvoJolDvknoNqR69V2OexgF" crossorigin="anonymous">
    <link href="https://cdn.datatables.net/1.10.21/css/dataTables.bootstrap4.min.css" rel="stylesheet"/>
    <link href="{{ url_for('static', filename='css/main.css') }}" rel="stylesheet" type="text/css">    
    <link href="https://cdn.jsdelivr.net/npm/simplebar@latest/dist/simplebar.css" rel="stylesheet"/>
    <link href="https://cdn.datatables.net/1.10.21/js/dataTables.bootstrap4.min.js" rel="stylesheet" type="text/css">
    {% block title %} {% endblock %}
</head>
<body>
    {% block body %} {% endblock %}
    <!-- JS, Popper.js, and jQuery -->
    <script src="https://cdn.jsdelivr.net/npm/popper.js@1.16.0/dist/umd/popper.min.js" integrity="sha384-Q6E9RHvbIyZFJoft+2mJbHaEWldlvI9IOYy5n3zV9zzTtmI3UksdQRVvoxMfooAo" crossorigin="anonymous"></script>
    <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.5.0/js/bootstrap.min.js" integrity="sha384-OgVRvuATP1z7JjHLkuOU7Xw704+h835Lr+6QL9UvYjZE3Ipu6Tp75j7Bh/kR0JKI" crossorigin="anonymous"></script>
    <script type="text/javascript" charset="utf8" src="https://cdn.datatables.net/1.10.21/js/jquery.dataTables.js"></script>
</body>
</html>

Answer 1

属性错误

我认为你试图获得 td 的方式是问题所在，这样的事情可能更容易做到：

match = soup.findAll('table', {'class':'fullview-news-outer'})
rows = match.findAll('tr')
for row in rows:
    k = row.findAll('td') #This (k) is the td

路由选择

你遗漏了一件我认为可以解决你问题的主要事情。在定义路由时，它的方法如 POST 或 GET，您需要满足它们。

@app.route('/', methods=['GET', 'POST'])
def index():
    if request.method == "POST":
        ticker = request.form['ticker']
        #data processing or loading tables etc.
        return render_template('index.html', ticker=ticker)
    else:
        #Normal Page Load
        return render_template("index.html", ticker=None)

您可能还希望在您的 html 中使用 if statemen 允许 none 类型的自动收报机：

{% if ticker == None %} No news {% endif %}

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