【发布时间】：2019-10-23 14:24:03
【问题描述】：
背景
我想做的是在一个用 Python Flask 和 SQLAlchemy 编写的 Web 应用程序上实现一个表单以插入具有特定数据类型（如 2019-10-23 22:38:18）的日期时间。
完整图像
id | name | city | datetime
----+--------+---------+---------
1 | Hans | London |2019-10-23 22:37:10
2 | John | NewYork |2019-10-23 22:38:18
数据库
List of relations
Schema | Name | Type | Owner
--------+-------+-------+-------
public | todos | table | username
问题
在添加日期时间列及其表单之前，我已检查是否已成功从表单中插入名称和城市列的数据。但是我在将日期时间从 GUI 表单插入数据库时遇到以下错误。
jinja2.exceptions.UndefinedError: 'form' is undefined
程序
app.py
>from flask import Flask, render_template, request, redirect, url_for, abort, jsonify
from flask_sqlalchemy import SQLAlchemy
import sys
import datetime
app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'postgres://username@localhost:5432/simplewr'
db = SQLAlchemy(app)
class Todo(db.Model):
__tablename__ = 'todos'
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String) # Jon
city = db.Column(db.String(120)) # New York
datetime = db.Column(db.DateTime()) # 2019-10-23 22:38:18
def __repr__(self):
return f'<Todo {self.id} {self.name} {self.city} {self.datetime}>'
db.create_all()
@app.route('/todos/create', methods=['POST'])
def create_todo():
error = False
body = {}
try:
name = request.form['name']
city = request.form['city']
datetime = request.form['datetime']
todo = Todo(name=name, city=city)
db.session.add(todo)
db.session.commit()
body['name'] = todo.name
body['city'] = todo.city
body['datetime'] = todo.datetime
except:
error = True
db.session.rollback()
print(sys.exc_info())
finally:
db.session.close()
if error:
abort (400)
else:
return jsonify(body)
# Filters
def format_datetime(value, format='medium'):
date = dateutil.parser.parse(value)
if format == 'full':
format="EEEE MMMM, d, y 'at' h:mma"
elif format == 'medium':
format="EE MM, dd, y h:mma"
return babel.dates.format_datetime(date, format)
app.jinja_env.filters['datetime'] = format_datetime
@app.route('/')
def index():
return render_template('index.html', data=Todo.query.all())
index.html
<html>
<head>
<title>Todo App</title>
<style>
.hidden{
display: none;
}
</style>
</head>
<body>
<form method="post" action="/todos/create">
<h4>name</h4>
<input type= "text" name="name" />
<h4>city</h4>
<input type= "text" name="city" />
<div>
<label for="datetime">Date Time</label>
{{ form.datetime(class_ = 'form-control', placeholder='YYYY-MM-DD HH:MM', autofocus = true) }}
</div>
<input type= "submit" value="Create" />
</form>
<div id= "error" class="hidden">Something went wrong!</div>
<ul>
{% for d in data %}
<li>{{d.name}}</li>
<li>{{d.city}}</li>
<li>{{d.datetime}}</li>
{% endfor %}
</ul>
<script>
const nameInput = document.getElementById('name');
const cityInput = document.getElementById('city');
const dtInput = document.getElementById('datetime');
document.getElementById('form').onsubmit = function(e) {
e.preventDefault();
const name = nameInput.value;
const city = cityInput.value;
const datetime = dtInput.value;
descInput.value = '';
fetch('/todos/create', {
method: 'POST',
body: JSON.stringify({
'name': name,
'city': city,
'datetime': datetime,
}),
headers: {
'Content-Type': 'application/json',
}
})
.then(response => response.json())
.then(jsonResponse => {
console.log('response', jsonResponse);
li = document.createElement('li');
li.innerText = name;
li.innerText = city;
li.innerText = datetime;
document.getElementById('todos').appendChild(li);
document.getElementById('error').className = 'hidden';
})
.catch(function() {
document.getElementById('error').className = '';
})
}
</script>
</body>
</html>
环境
Python 3.6.0
烧瓶 1.1.1
SQLAlchemy 1.3.10
PostgreSQL 11.5
【问题讨论】：
标签： python html datetime flask flask-sqlalchemy