NAME

HTML::EP::CGIEncryptForm - An EP interface to the CGI::EncryptForm module

SYNOPSIS

  <!--
    This is the first page. We receive some complex data
    here from an HTML form and want to pass it to nextpage.ep.
    Start with loading the package.
  -->
  <ep-package name="HTML::EP::CGIEncryptForm">

  <ep-perl>
    # Process some CGI input and store the results in the
    # hash ref $_->{'form'}, aka EP variable "form".
    ...
  </ep-perl>
  <form action=nextpage.ep method=post>
    <ep-cef-encrypt source=form dest=enc_form>
    <input type=hidden name=myform value="$@enc_form$">
    ...
  </form>


  <!--
    This is the second page. We want to get the data from
    the first page, in other words, restore the variable
    "form" and its contents. That's easy.
  -->
  <ep-package name="HTML::EP::CGIEncryptForm">
  <ep-cef-decrypt source="cgi->myform" dest=form>

DESCRIPTION

This package is rather similar to the HTML::EP::Session module. In fact, so similar, that they may be merged in the future. It was contributed by Peter Marelas <maral@phase-one.com.au>, the author of the CGI::Encryptform module.

The modules idea is as follows: Suggest you are building a wizard. In other words, an application gathering information on several HTML forms. As HTTP is a stateless protocol, the burden of moving the collected information from page to page is up to you. The HTML::EP::CGIEncryptForm module will greatly help you in this.

The idea is as follows: The collected information is stored in a single, structured variable, for example a hash ref. For example, you could have three pages for configuring an hosts network settings: The first page contains a form where the user enters IP address and network mask. The second page allows to add the DNS servers and the third page the routes. With HTML::EP::CGIEncryptForm, these pages could look like this (most details omitted):

  <!-- This is the first page  -->
  <!-- No EP here, just simple HTML -->
  <form action=page2.ep method=post>
    <table><tr><th>IP address</th>
               <td><input name="ipaddress" size=15></td></tr>
           <tr><th>Network mask</th>
               <td><input name="netmask" size=15></td></tr>
    </table>
  </form>


  <!-- This is the second page, page2.ep. We start with
       loading the package:
  -->
  <ep-package name="HTML::EP::CGIEncryptForm">
  <!-- Now, collect the information in $self->{settings}: -->
  <ep-perl>
    my $self = $_;
    my $cgi = $self->{cgi};
    $self->{settings}->{ipaddress} = $cgi->param('ipaddress');
    $self->{settings}->{netmask} = $cgi->param('netmask');
    ''
  </ep-perl>
  <!-- Encode the settings into a string: -->
  <ep-cef-encrypt source=settings dest=enc_settings
                  secret_key="Whatakey?">
  <!-- Finally, pass the settings variable to the next page
       by using a hidden field:
  -->
  <form action=page3.ep method=post>
    <table><tr><th>DNS Server 1:</th>
               <td><input name="dns1" size=15></td></tr>
           <tr><th>DNS Server 2:</th>
               <td><input name="dns2" size=15></td></tr>
    </table>
    <input type=hidden name=settings value="$@enc_settings$">
  </form>
  <p>So far, you have created the following settings:</p>
  <table>
    <tr><th>IP address:</th><td>$settings->ipaddress$</td></tr>
    <tr><th>Netmask:</th><td>$settings->netmask$</td></tr>
  </table>

  <!-- And, finally, this is page3.ep. We start with retrieving
       the collected data:
  -->
  <ep-package name="HTML::EP::CGIEncryptForm">
  <ep-cef-decrypt source="cgi->settings" dest="settings"
                  secret_key="Whatakey?">
  <!-- Add the DNS servers to the settings variable:  -->
  <ep-perl>
    my $self = $_;
    my $cgi = $self->{cgi};
    $self->{settings}->{dns1} = $cgi->param('dns1');
    $self->{settings}->{dns2} = $cgi->param('dns2');
    ''
  </ep-perl>
  <p>So far, you have created the following settings:</p>
  <table>
    <tr><th>IP address:</th><td>$settings->ipaddress$</td></tr>
    <tr><th>Netmask:</th><td>$settings->netmask$</td></tr>
    <tr><th>DNS Server 1:</th><td>$settings->dns1$</td></tr>
    <tr><th>DNS Server 2:</th><td>$settings->dns1$</td></tr>
  </table>

The main advantage of CGI::EncryptForm is that it is not only serializing data, but encrypting and decrypting as well.

METHOD INTERFACE

These are the methods offered by the HTML::EP::CGIEncryptForm class:

Encrypting a structured variable into a string

  <ep-cef-encrypt source="source_var" dest="dest_var"
                  secret_key="somekey" usecharset=1>

or, from within ep-perl:

  $self->_ep_cef_encrypt({'source' => 'source_var',
                          'dest' => 'dest_var',
                          'secret_key' => 'some_key',
                          'usecharset' => 1});

(Instance method) Takes the complex EP variable $source_var$ (aka $self->{'source_var'}) and encrypts it into a string. The secret_key attribute is used for encrypting the string. The optional attributes usecharset and charset are passed to the corresponding methods of CGI::EncryptForm.

If the dest attribute is present, the string is stored in the EP variable $dest_var$. If not, the output is returned and possibly inserted into the HTML stream.

Decrypting a structured variable from a string

  <ep-cef-decrypt source="source_var" dest="dest_var"
                  secret_key="somekey" usecharset=1>

or, from within ep-perl:

  $self->_ep_cef_decrypt({'source' => 'source_var',
                          'dest' => 'dest_var',
                          'secret_key' => 'some_key',
                          'usecharset' => 1});

(Instance method) Takes the EP variable $source_var$ (aka $self->{'source_var'}) and decrypts it into a complex Perl object. The secret_key attribute is used for decrypting the string. The optional attributes usecharset and charset are passed to the corresponding methods of CGI::EncryptForm.

If the dest attribute is present, the Perl object is stored in the EP variable $dest_var$. If not, the output is returned and possibly inserted into the HTML stream.

SEE ALSO

  L<CGI::EncryptForm>, L<HTML::EP>, L<HTML::EP::Session>