Provided by: libreverseproxy-formfiller-perl_0.5-1_all 
NAME
ReverseProxy::FormFiller - Let Apache fill and submit any html form in place of the user
VERSION
Version 0.5
SYNOPSIS
ReverseProxy::FormFiller makes an Apache server, positioned as a frontal server or as a
reverse-proxy, fill and submit html forms in place of users.
This is particularly intended for authentication forms, if you want users to be
authenticated with some account, but you don't want them to know and type any password.
But it also works with any html POST form.
ReverseProxy::FormFiller is based on Apache2 mod_perl filters. So, you have to enable
mod_perl.
Basic Example
Assume you want all users requesting some web app to be authenticated as "jdoe", but you
don't want to publish jdoe's password. If the app's authentication form is located at
http://auth.example.com/login.php and looks like
<form id="authForm" method="POST" action="/login/">
<div>login: <input type="text" name="login"></div>
<div>password: <input type="password" name="password"></div>
<div><input type="submit" value="Log in"></div>
</form>
create an Apache virtualhost called myauth.example.com, looking like :
<VirtualHost *>
ServerName myauth.example.com
PerlModule ReverseProxy::FormFiller
PerlSetVar FormFillerParamFile "/etc/apache2/FormFiller/example"
ProxyPass / http://auth.example.com/
ProxyPassReverse / http://auth.example.com/
<Location /login.php>
RequestHeader unset Accept-Encoding
Header unset Content-Length
PerlOutputFilterHandler ReverseProxy::FormFiller::output
</Location>
<Location /login/>
PerlInputFilterHandler ReverseProxy::FormFiller::input
</Location>
</VirtualHost>
and create a ReverseProxy::FormFiller config file at /etc/apache2/FormFiller/example,
looking like
form => '"#authForm"',
submit => "true",
publicFormData => {
login => '"jdoe"',
password => '"fake"',
},
secretFormData => {
password => '"secret"',
},
Quotes around strings are necessary for some parameters that are interpreted as perl
expressions. Look at ReverseProxy::FormFiller config parameters for more details.
Elaborate example
Assume you want some people to be authenticated as "user", and some other as "admin".
Besides, assume just submit form does not work, but it is necessary to click on the
button, since it will execute a javascript function.
Finally, assume jQuery is not loaded by the web page displaying the form.
/etc/apache2/FormFiller/example will look like
jQueryUrl => 'http://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js',
form => '"#authForm"',
submit => '"button[type=submit]"',
publicFormData => {
login => '$ENV{REMOTE_USER} =~ /(rtyler|msmith)/ ? "admin" : "user"',
password => '"fake"',
},
secretFormData => {
password => '$ENV{REMOTE_USER} =~ /(rtyler|msmith)/ ? "admin-secret" : "user-secret"',
},
Screwy example
Assume you have two authentication forms in the same page, one for the morning and another
one for the afternoon :
/etc/apache2/FormFiller/example will look like
form => '(localtime)[2] >= 12 ? "#morningForm" : "#afternoonForm"',
submit => "false",
publicFormData => {
login => '"jdoe"', # so, user believe he'll be authenticated as "jdoe"
password => '"fake"',
},
secretFormData => {
# but actually, he'll be authenticated as "admin" if he uses Firefox, as "user" else
login => '$ENV{HTTP_USER_AGENT} =~ /Firefox/ ? "admin" : "user"',
password => '$ENV{HTTP_USER_AGENT} =~ /Firefox/ ? "admin-secret" : "user-secret"',
},
Framework example
Some applications based on frameworks either use HTTP without HTML (e.g Flash), or they
send POST data out of any HTML form.
This module allows one to fill any HTML field from its jQuery selectors, thanks to the
publicFilledData parameter.
On the other hand, you can apply any substitution on POST datas, thanks to the postDataSub
parameter - but it may require some tuning to get the right substitution PCRE.
Here is an example from a real-life GWT application :
jQueryUrl => '//ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js',
form => '"body"',
submit => '"button.genericButton"',
publicFilledData => {
'input.gwt-TextBox' => '"jdoe"',
'input.gwt-PasswordTextBox' => '"fake"',
},
postDataSub => [
's/jdoe\|fake/jdoe\|secret/'
]
Details of Apache config
Load Module
This is done by
PerlModule ReverseProxy::FormFiller
This directive has to appear once in Apache config. It can be set in server config or in
a "<VirtualHost>" container.
Set config parameters
This is done by
PerlSetVar FormFillerParamFile "/etc/apache2/FormFiller/example"
This directive can be set in server config or in a any container directive (as a
"<VirtualHost>" container, a "<Location>" container or a "<Directory>" container). It is
applied only to requests matching the corresponding container directive.
This directive can be set several times, so a single server can manage several forms
(typically, on different virtualhosts, but you can also manage several forms in the same
virtualhost).
Filter response body
When Apache has received the response from the remote server (if Apache is used as a
reverse-proxy) or from the backend server (if used as a frontend), it rewrites html so as
to fill the form and possibly submitting it or clicking on a button.
Actually, this is done not by directly overwriting the form, but by including some
javascript filling and submitting the form.
This is done by the directive
PerlOutputFilterHandler ReverseProxy::FormFiller::output
Besides, ReverseProxy::FormFiller::output can not (or not yet) read zipped contents, so
HTTP request headers "Content-encoding" have to be removed. This is done by the directive
RequestHeader unset Accept-Encoding
And ReverseProxy::FormFiller::output can not (or not yet) set Content-Length response
header to the modified response body's length. So, remove Content-Length response header
to avoid some bugs:
Header unset Content-Length
For performances, it is better to handle only html pages containing the aimed form. So,
you should place these directives in a container directive matching the form URL (as a
"<Location>" directive), so as not to filter any html content.
Filter request body
When Apache receives a POST request from a client, it rewrites request POST body,
replacing empty or fake data with secret data. This is done by the directive
PerlInputFilterHandler ReverseProxy::FormFiller::input
For performances, it is better to handle only requests to the form "action" URL. So, you
should place this directive in a container directive matching this URL (as a "<Location>"
directive), so as not to filter any request.
ReverseProxy::FormFiller config parameters
Config file
ReverseProxy::FormFiller config file looks similar to a .ini file, but it is not. Actually
it is simply a hash content. So, don't forget commas ! In case of syntax error, you'll
have a message "<config file> content doesn't seem to be a valid perl hash" in Apache
error logs.
Parameters
Most of config parameters are interpreted as perl expressions, not just as strings. So,
they can rely on standard perl functions and request env vars (look at the examples
below). These parameters are:
• form
• submit
• publicFormData values
• publicFilledData values
• secretFormData values
• javascript
That's why these parameters, if they are set to strings, need quotes around. For example,
form => '#authForm', # bad !
form => '"#authForm"', # good !
Indeed, these parameters are evaled in a piece of code looking like
eval "\$x = $form";
Well, in some cases quotes are unnecessary, because Perl in laxist enough to work with
not-quoted strings:
$x = "foo"; # this is right syntax
$x = foo; # this is lazy syntax, but it works
$x = "39foo"; # this is right syntax
$x = 39foo; # this does not work, an error is thrown "Bareword found where operator expected"
jQueryUrl
URL to load jQuery, since ReverseProxy::FormFiller response filter relies on jQuery
(any version >= 1.0)
Optional: if empty or not defined, jQuery is supposed to be already loaded in the web
page
form
jQuery selector to the form to fill.
Optional: if empty or not defined, first form in web page will be filled. That is,
default value is "form:first"
Here are few examples :
form => '"form#authForm"',
form => '"form:last"',
form => '(localtime)[2] >= 12 ? "#morningForm" : "#afternoonForm"',
form => '$ENV{REMOTE_USER} =~ /(rtyler|msmith)/ ? "#adminForm" : "#userForm"',
submit
To enable form autosubmit, or to automatically click on a button.
It may be "true" (autosubmit enabled), "false" (autosubmit disabled), or a jQuery
selector to the button to click on (this is sometimes useful, when clicking runs a
javasript function).
Optional: if empty or not defined, autosubmit is disabled - that is, default value is
"false".
For example,
submit => 'true',
submit => '"button#login"',
publicFormData
Form fields to fill in html form : these data will be seen by user.
Additionnaly, these fields will be controled in POST request when the form will be
submitted, to prevent malicious users to change any value.
For example,
publicFormData => {
company => '"SnakeOilsInc"',
user => '$ENV{REMOTE_USER} =~ /(rtyler|msmith)/ ? "admin" : "user"',
password => '"hidden"'
},
Note that these data are filled through jQuery method '.val()', so it works only with
text inputs, password inputs, select tags and textarea, but not with checkboxes and
radio buttons. In order to select on radio buttons or check on checkboxes, look at the
javascript parameter.
publicFilledData
Input fields to fill, defined by jQuery selectors instead of their name attribute.
This is useful if an input field has no name attribute.
publicFilledData => {
'textarea.company' => '"SnakeOilsInc"',
'input#user' => '$ENV{REMOTE_USER} =~ /(rtyler|msmith)/ ? "user" : $ENV{REMOTE_USER} =~ /dwho/ ? "admin" : "nobody"',
'input[type=password]' => '"hidden"'
}
As same as publicFormData, these data will be seen by users, and it works only with
text inputs, password inputs, select tags and textarea.
Unlike to publicFormData, these fields are not controled in POST request against
malicious tampering of values.
Parameters publicFormData and publicFilledData can be used together.
secretFormData
Form fields to fill in request body, in addition or in overload to publicFormData. The
main difference with publicFormData is that these data will not be filled in the html
form, so users can't see them.
secretFormData => {
password => '$ENV{REMOTE_USER} =~ /(rtyler|msmith)/ ? "admin-secret" : "user-secret"',
},
postDataSub
Substitutions to apply to POST datas. Substitutions are defined with PCRE and may use
captures. They may rely on env vars, but not on perl functions.
Parameter postDataSub is an array ref and not a hash ref (unlike to publicFormData,
publicFilledData and secretFormData). Hence substitutions are applied in the order
they are defined.
Basic example:
postDataSub => [
's/foo/bar/gi',
]
If POST data are made of colon-separated values and you want to change 5th value into
"foo":
postDataSub => [
's/^((.+?:){4}).+?:/$1:foo:/' # if POST data are made of :-separated values and you want to change 5th value into "foo"
]
In order to rewrite POST data so as to force jdoe's password to "jdoe-secret" and
rtyler's to "rtyler-passwd", whereas these passwords are disclosed - assume POST data
is '[login]:[password]'
postDataSub => [
's/^.*$/$ENV{REMOTE_USER}:$ENV{REMOTE_USER}/',
's/jdoe:jdoe/jdoe:jdoe-secret/',
's/rtyler:rtyler/rtyler:rtyler-passwd/'
]
javascript
Arbitrary javascript code to run after fields are filled, but before posting the form.
If you call jQuery through its shortcut '$', you have to escape it. Use single quotes
and double quotes as in the example.
javascript => 'alert("Hello $ENV{REMOTE_USER}"); \$(input.mycheckbox).prop("checked", true)'
AUTHOR
FX Deltombe, "<fxdeltombe at gmail.com>"
BUGS
Please report any bugs or feature requests to "bug-reverseproxy-formfiller at
rt.cpan.org", or through the web interface at
<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=ReverseProxy-FormFiller>. I will be
notified, and then you'll automatically be notified of progress on your bug as I make
changes.
SUPPORT
You can find documentation for this module with the perldoc command.
perldoc ReverseProxy::FormFiller
You can also look for information at:
• RT: CPAN's request tracker
<http://rt.cpan.org/NoAuth/Bugs.html?Dist=ReverseProxy-FormFiller>
• AnnoCPAN: Annotated CPAN documentation
<http://annocpan.org/dist/ReverseProxy-FormFiller>
• CPAN Ratings
<http://cpanratings.perl.org/d/ReverseProxy-FormFiller>
• Search CPAN
<http://search.cpan.org/dist/ReverseProxy-FormFiller/>
ACKNOWLEDGEMENTS
LICENSE AND COPYRIGHT
Copyright 2013-2014 FX Deltombe.
This program is free software; you can redistribute it and/or modify it under the terms of
either: the GNU General Public License as published by the Free Software Foundation; or
the Artistic License.
See http://dev.perl.org/licenses/ for more information.