Python – How to create a link to another html page

flaskpython

I have a form on one page that I want to submit to another page. I can't figure out how to create the link to that second page.

Project layout:

Fileserver/
    config.py
    requirements.txt
    run.py
    setup.py
    app/
        __init__.py
        static/
            css/
            img/
            js/
        templates/
            formAction.html
            formSubmit.html
            index.html

__init__.py:

from flask import Flask

app = Flask(__name__)

@app.route('/')
def index():
    ip = request.remote_addr
    return render_template('index.html', user_ip=ip)

index.html:

<!DOCTYPE html>
<html lang="en">
<body>
    <ul>
        <li><a href="/formSubmit.html">Check Out This Form!</a>
    </ul>
</body>
</html>

I can see the page at localhost:5000/ without issue.

I have also tried:

<a href="{{ url_for('templates', 'formSubmit") }}"></a>

as well as:

<a href="{{ url_for('formSubmit') }}"></a>

What am I missing?

Best Answer

url_for generates urls to routes defined in your application. There are no (or should probably not be any) raw html files being served, especially out of the templates folder. Each template should be something rendered by Jinja. Each location you want to display or post a form to should be handled and generated by a route on your application.

In this case, you probably want to have one route to both render the form on GET and handle the form submit on POST.

__init__.py:

from flask import Flask, request, url_for, redirect, render_template

app = Flask(__name__)

@app.route('/')
def index():
    return render_template('index.html')

@app.route('/cool_form', methods=['GET', 'POST'])
def cool_form():
    if request.method == 'POST':
        # do stuff when the form is submitted

        # redirect to end the POST handling
        # the redirect can be to the same route or somewhere else
        return redirect(url_for('index'))

    # show the form, it wasn't submitted
    return render_template('cool_form.html')

templates/index.html:

<!doctype html>
<html>
<body>
    <p><a href="{{ url_for('cool_form') }}">Check out this cool form!</a></p>
</body>
</html>

templates/cool_form.html:

<!doctype html>
<html>
<body>
    <form method="post">
        <button type="submit">Do it!</button>
    </form>
</html>

I don't know what your forms and routes actually do, so this is just an example.

If you need to link static files, put them in the static folder, then use:

url_for('static', filename='a_picture.png')