Receive and display HTML form data in Python

I received the HTML form data in Python and tried to display it.

HTML file description

First, write the code to submit the form in HTML.

`index.html`


<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
  </head>
  <body>
    <form method="POST" action="cgi-bin/index.py">
      <label>text:</label>
      <textarea name="text"></textarea>
      <button type="submit">Send</button>
    </form>
  </body>
</html>

--About method

The method has a GET method to get the data and a POST method to send the data. This time, we will send the data, so we will use the POST method.

--About ʻaction`

You can specify the URL to send the data with ʻaction. This time, send it to cgi-bin / index.py` that will appear later.

For more information on submitting form data, see the following articles. https://developer.mozilla.org/ja/docs/Learn/HTML/Forms/Sending_and_retrieving_form_data

Python file description

Next, write a CGI (Gateway Interface Standard) script that receives and displays data in Python. A CGI script is a script that is started by an HTTP server and processes data entered by the user in HTML or the like. For details, refer to the following article. https://docs.python.org/ja/3/library/cgi.html#module-cgi

`cgi-bin/index.py`


#!usr/bin/python
# -*- coding: utf-8 -*-

import cgi #Import CGI module
import cgitb
import sys

cgitb.enable() #Since it is used for debugging, it is not described in the production environment.

form = cgi.FieldStorage() #Get form data

print("Content-Type: text/html; charset=UTF-8") #Header for writing HTML
print("")

#If no form data has been entered
if "text" not in form:
    print("<h1>Error!</h1>")
    print("<br>")
    print("Enter the text!")
    print("<a href='/'><button type='submit'>Return</button></a>")
    sys.exit()

text = form.getvalue("text") #Get the value of the data

print(text)

Change the execution authority with the following command for later execution.

`Command`


$ chmod 755 cgi-bin/index.py

Run CGI server

(I referred to the following article. https://qiita.com/shuichi0712/items/5ddc5b4e30c2373b17fb ）

Next, run the CGI server. Write the script for that in cgiserver.py.

`cgiserver.py`


import http.server
http.server.test(HandlerClass=http.server.CGIHTTPRequestHandler)

After that, execute the following command to run the CGI server.

`Command`


$ python -m http.server --cgi

After that, if you search for http://0.0.0.0:8000 in the browser, the form will be displayed, and if you fill out and submit the form, the input contents will be displayed.