Sunday, March 20, 2016

POST data to CGI file using XMLHttpRequest causes BadHeader

Leave a Comment

When I try posting data to my CGI file, my CGI file says the actual post data is invalid. I am using HTML/JavaScript for the front end and Python for the backend.

Works:

<form name="login" action="/cgi-bin/register.py" method="POST"> Username:<input type="text" name="username"><br> Password:<input type="password" name="password"><br> Confirm password:<input type="password" name="confirmpassword"><br> </form> 

However, this causes the page to refresh. I am trying to avoid this and have text display within the same page(without reloading). Hence, I have chosen to use an XMLHTTPRequest to asynchronously process this event.

This is what I want to achieve:

<script> function validateLogin() { var username = document.getElementById("username").value; var password = document.getElementById("password").value;  if (username.length <= 0 || password.length <= 0)   {   document.alert("The username or password cannot be blank");   return;   }  var xmlhttp;      if (window.XMLHttpRequest) {// code for IE7+, Firefox, Chrome, Opera, Safari         xmlhttp=new XMLHttpRequest();   } else {// code for IE6, IE5         xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");   }  xmlhttp.onreadystatechange=function()     {         if (xmlhttp.readyState==4 && xmlhttp.status==200)         {             document.getElementById("resultText").innerHTML=xmlhttp.responseText;         }else if (xmlhttp.readyState==4) {             document.write(xmlhttp.status + xmlhttp.statusText);         } }  xmlhttp.open("POST","/cgi-bin/login.cgi",true); xmlhttp.setRequestHeader('Content-Type','application/x-www-form-urlencoded; charset=UTF-8') xmlhttp.send("username=" + username + "&password=" + password); } </script> 

CGI File:

#!/usr/bin/python  import cgi from dbmanager import openConnection from passlib.hash import sha256_crypt  s = "Content-type: text/html\n\n\n"  form = cgi.FieldStorage()  username = form["username"].value password = form["password"].value message = None 

I am getting an error in python stating Bad header=FieldStorage(None, None,

I don't get this error when I do it the first way, but the second way is giving me this error. I need it to work the second way.

2 Answers

Answers 1

For echo Server :

HTML :

<html>  <head>   <script> function validateLogin() { var username = document.getElementById("username").value; var password = document.getElementById("password").value;  if (username.length <= 0 || password.length <= 0)   {   document.alert("The username or password cannot be blank");   return;   }  var xmlhttp;      if (window.XMLHttpRequest) {// code for IE7+, Firefox, Chrome, Opera, Safari         xmlhttp=new XMLHttpRequest();   } else {// code for IE6, IE5         xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");   }  xmlhttp.onreadystatechange=function()     {         if (xmlhttp.readyState==4 && xmlhttp.status==200)         {             document.getElementById("resultText").innerHTML=xmlhttp.responseText;         }else if (xmlhttp.readyState==4) {             document.write(xmlhttp.status + xmlhttp.statusText);         } }  xmlhttp.open("POST","../post_test.py",true); xmlhttp.setRequestHeader('Content-Type','application/x-www-form-urlencoded; charset=UTF-8') xmlhttp.send("username=" + username + "&password=" + password); } </script>  </head>      <body>   <form name="login" > Username:<input type="text"  id="username"><br> Password:<input type="text"  id="password"><br> Confirm password:<input type="text"  id="repassword"><br>  </form> <button onclick="validateLogin()">Login</button> <span id="resultText"></span> </body> </html> 

CGI-SCRIPT:

#!/usr/bin/python2.7  import cgi   form = cgi.FieldStorage() print "Content-Type: text/html;charset=utf-8" print "Access-Control-Allow-Origin:*" print print form 

Replace input type password to text because got security bugs !

Yo got wrong answer on cgi script. Who know service is live ? So need some type, status, header, content..

Check post address : ..// mean currient_uri + new_path + target

On javascript: Call by ID but where ID parameter ?

Answers 2

JavaScript doesn't post the right values because of wrong HTML elements properties.

Try changing the name property of elements username and password into id property as requested by your JavaScript code.

The result will be something like this:

<form name="login" action="/cgi-bin/register.py" method="POST"> Username:<input type="text" id="username"><br> Password:<input type="password" id="password"><br> Confirm password:<input type="password" id="confirmpassword"><br> </form>

If You Enjoyed This, Take 5 Seconds To Share It

0 comments:

Post a Comment