Question

我需要用户输入才能保存到数据库，然后在应用上显示。如果用户的输入留空，我需要显示错误消息。

我在显示错误消息时遇到了麻烦。当用户输入为空白时，空白帖子将保存到数据库中，然后显示没有内容而不显示错误消息。

我正在使用Python，Jinja2，Flask，HTML

谢谢！

    if request.method == 'POST':

        blog_title = str(request.form['title'])
        blog_body = str(request.form['body'])

        title_error = ''
        body_error = ''

        if len(blog_title) == 0:
            title_error = 'Please give your blog a title'
            return title_error

        if len(blog_body) == 0:
            body_error = "Please give your blog some content"
            return body_error
        else:
            new_blog = Blog(blog_title, blog_body)
            db.session.add(new_blog)
            db.session.commit()

            blog_id = new_blog.id

            return redirect(url_for('blogs', id=blog_id))

    else:
        return render_template('/newpost_form.html')

Answer 1

我会考虑整合Flask-WTF。我只这样做烧瓶形式。提供了许多验证工具，使其易于使用

<强> forms.py

from flask_wtf import FlaskForm
from wtf.fields import StringField, TextAreaField, SubmitField
from wtf.validators import DataRequired

class NewBlogForm(FlaskForm):
    title = StringField('Title', validators=[DataRequired(message='one')])
    body = TextAreaField('Body', validators=[DataRequired(message='two')])
    submit = SubmitField('Save')

<强> routes.py

from forms import NewBlogForm

@app.route('/newpost', methods=['GET', 'POST'])
def new_post():
    form = NewBlogForm()
    if form.validate_on_submit():
        blog = Blog(form.title.data, form.body.data)
        db.session.add(blog)
        db.session.commit()  # should have try block to catch any errors
        return redirect(url_for('blogs', id=blog.id))
    return render_template('newposts_form.html', form=form)

<强> newposts_form.html

<form>
    <ul>
    {% for error in form.errors %}
        <li>{{ error }}</li>
    {% endfor %}
    </ul>
    {{ form.csrf_token }}
    {{ form.title.label }}{{ form.title }}
    {{ form.body.label }}{{ form.body }}
    {{ form.submit }}
</form>

如果您使用Flask-Bootstrap，则他们支持wtf forms并以非常干净的方式显示错误。

Answer 2

您正在重新定义变量的值，请执行以下操作：

if request.method == 'POST':

    blog_title = str(request.form['title'])
    blog_body = str(request.form['body'])

    if len(blog_title) == 0:
        return 'Please give your blog a title'
    elif len(blog_body) == 0:
        return "Please give your blog some content"
    else:
        new_blog = Blog(blog_title, blog_body)
        db.session.add(new_blog)
        db.session.commit()

        blog_id = new_blog.id

        return redirect(url_for('blogs', id=blog_id))

else:
    return render_template('/newpost_form.html')

为什么我的if语句不起作用？

2 个答案: