How to pass a variable from HTML to the backend in Flask - flask

Question

There are so many td elements with a tag and I want to know that user clicked which element and I want to pass from HTML to the backend and process with the user's selection on the backend.
This is my HTML content:
<a href="/selected" ????><td>{{ options1 }}</td></a>
<td>{{ options2 }}</td>
<td>{{ options3 }}</td>
<td>{{ options4 }}</td>
<td>{{ options5 }}</td>
<td>{{ options6 }}</td>
When a user clicked one, I want to send it to the backend:
#app.route('/selected', methods=['GET', 'POST'])
def selected():
selected_option = request.args.get('????')
return render_template("selected.html", selected_option=selected_option)
How can I fill the question marks?

Answer 1

Having the separate variables for options1, options2, etc probably makes this a hassle for a few reasons:
You'll need to manually update the hard-coding of the template to add more options.
The URL part of each option, might be different from the link text.
You may wish to define your options in a dictionary:
sections = {'first-option': 'I am the first option',
'second-option': 'Click me for fun and profit',
'third-option': 'All flights have been cancelled',
}
Now on the page which generates your link bar, if you pass that across:
return render_template('some_page.html', SECTIONS=sections)
You can then do something like:
{% for key, value in SECTIONS.items() %}
{{value}}
{% endfor %}
This will automatically generate the correct URLs, which are compatible with the following view function:
#app.route('/selected/<section>')
def selected(section):
# Assuming the first URL:
print (section) # 'first-option'
print (sections[section]) # 'I am the first option'
return render_template("selected.html", selected_option=section)
You may also wish to have a look at this gist which takes the concept a bit further.
This also uses a context processor to insert that SECTIONS variable into all pages, rather than passing it to the individual render_template functions.