hi...... filters in servlet

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Join Date: Dec 2006

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sach_ak47

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hi...... filters in servlet

Sep 4th, 2008

hi , actully i have read filters in servlet.
but i didnt understand , the actual working of filters ( in practicle environment).
i want to know that , when i am sending request to server and i am using filter before request went to server. so that process is happening on server side or client side ?

and i want to send password in encrypted format from html page to servlet how to do this ?
please if any one have any idea please response ( Atleast tell the process how to proceed).

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jwenting

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duckman

Re: hi...... filters in servlet

Sep 4th, 2008

Servlet filters always run on the server.
They can provide services that have to run before the web application processes the request, like authentication.
A filter can intercept the requests, look up credentials and permissions, and deny the request (with an error message) if the request is issued by someone who's not allowed to do so.

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jaka.ramdani jaka.ramdani is offline

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Re: hi...... filters in servlet

Sep 5th, 2008

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Originally Posted by sach_ak47

hi , actully i have read filters in servlet.
but i didnt understand , the actual working of filters ( in practicle environment).
i want to know that , when i am sending request to server and i am using filter before request went to server. so that process is happening on server side or client side ?

and i want to send password in encrypted format from html page to servlet how to do this ?
please if any one have any idea please response ( Atleast tell the process how to proceed).

filter always run in server env.

here's the way to send your encrypted password to server
1. add one hidden field in your login form i.e with name hashed_pass, and assume your password filed named pass
2. add onSubmit action in your form which will do these:

- hash your inputted plain password (try lo look some md5 hash javascript, there's a lot out of there)

- change you hashed_pass field value to hashed value of your inputted password

- set your password field to empty since you don't want plain value of your password is submitted

- submit the form

- authenticate using the hashed password

3. done

it may like these, except i don't provide the md5 javascript code, and assume the method to perform md5 hash is md5()

 Help with Code Tags 
 javascript Syntax (Toggle Plain Text) 
function hashOnSubmit(theForm) {
   var passwd_field = theForm.pass;
   var hashedpasswd_field = theForm.hashed_pass;
   var hashed = md5(passwd_field.value);
   hashedpasswd_field.value = hashed;
   passwd_field.value = "";
   theForm.submit();
}
function hashOnSubmit(theForm) {
   var passwd_field = theForm.pass;
   var hashedpasswd_field = theForm.hashed_pass;
   var hashed = md5(passwd_field.value);
   hashedpasswd_field.value = hashed;
   passwd_field.value = "";
   theForm.submit();
}

and in the html, form part:

 Help with Code Tags 
 html Syntax (Toggle Plain Text) 
<form name="login_form" action="bla_bla" method="post" onSubmit="hashOnSubmit(this);">
....//the fileds here
</form>
<form name="login_form" action="bla_bla" method="post" onSubmit="hashOnSubmit(this);">
....//the fileds here
</form>

hope will help.

regards,

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Lazy, Useless & Apathetic

Re: hi...... filters in servlet

Sep 7th, 2008

> here's the way to send your encrypted password to server [ snip ]

Which of course fails if Javascript is disabled on the clients' computer. And of course, using a Javascript equivalent of the hashing algorithm exposes your entire hashing logic. A better way would be to use a secure connection to send/receive critical user information like https.

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