我是Python和Flask的新手，我无法弄清楚为什么我没有这里可用的数据列表（ranked_list为空）。
如果我注释掉所有Flask部分并且只是调用getDataFromQuery来获取像普通脚本一样的数据，我可以看到数据并将其打印出来。谁能看到我做错了什么？数据是元组列表。 index.html页面位于代码下方，它位于templates文件夹中。我得到的只是一个带有标题行的空白表。
from flask import Flask
from flask import render_template
from flask import request
from queryProcessing_and_Ranking import *
app = Flask(__name__)
@app.route("/")
@app.route("/<query>")
def index():
query = request.args.get("query")
Processing = QueryProcessing()
ranked_list = Processing.getDataFromQuery( query )
return render_template( "index.html", ranked_list = ranked_list, user_input = query )
if __name__ == '__main__':
port = int( os.environ.get('PORT', 5000 ) )
app.run( host='0.0.0.0', port=port, debug=True)
<html>
<head>
<title>Product Vertical Search Engine</title>
<link rel="stylesheet" type="text/css" href="{{ url_for('static', filename='style.css') }}">
</head>
<body>
<form>
Product Search: <input type="text" name="query"> <input type="Submit" value="Search">
</form>
<h1>Ranked product listing for: {{user_input}}</h1>
<table border = "1">
<tr>
<th>Title</th><th>Price</th>
</tr>
{% for item in ranked_list %}
<tr>
<td>{{item[0]}}</td>
</tr>
{% endfor %}
</table>
</body>
</html>
鉴于你的路线设置query可能是None，因此你将None传递给你的.getDataFromQuery方法。
@app.route('/')
def index():
'''
Returns "None" if not found.
So when you open your browser to localhost:5000
this value is None
unless you visit localhost:5000/something
then query = "something"
'''
query = request.args.get('query')
Processing = QueryProcessing()
ranked_list = Processing.getDataFromQuery(query) # Value could be None
return render_template( "index.html", ranked_list = ranked_list, user_input = query )
您还应该删除捕获<query>的路由定义，因为它看起来像是在混淆path parameters和query string parameters的概念
编辑
这看起来像你要做的是搜索表单提交，所以我会做以下事情
@app.route('/')
def index():
user_input = None
ranked_list = None
if request.method == 'POST':
user_input = request.form['query']
Processing = QueryProcessing()
ranked_list = Processing.getDataFromQuery(user_input)
return render_template("index.html", ranked_list=ranked_list, user_input=user_input)
HTML文件
<html>
<head>
<title>Product Vertical Search Engine</title>
<link rel="stylesheet" type="text/css" href="{{ url_for('static', filename='style.css') }}">
</head>
<body>
<form>
Product Search: <input type="text" name="query"> <input type="Submit" value="Search">
</form>
{% if user_input %} <!-- See if you have searched yet -->
<h1>Ranked product listing for: {{user_input}}</h1>
<table border = "1">
<tr>
<th>Title</th><th>Price</th>
</tr>
{% for item in ranked_list %}
<tr>
<td>{{item[0]}}</td>
</tr>
{% endfor %}
</table>
{% else %} <!-- tell user to search for data or that there is no data -->
<h1>Search for data</h1>
{% endif %}
</body>
</html>
使用一些Jinja2逻辑明确声明没有任何东西可以获得更好的反馈