Variable name as a variable?

I need to store a variable name as a variable. Note quite a C-style
pointer, but a way to access one variable who's name is stored in
another variable.

As part of a spam-control measure, a certain public-facing form will
have dummy rotating text fields and a hidden field that will describe
which text field should be considered, like this:

input type="text" name="text_1"
input type="text" name="text_2"
input type="text" name="text_3"
input type="hidden" name="real_field" value="text_2"

As this will be a very general-purpose tool, a switch statement on the
hidden field's value would not be appropriate here. Naturally, the
situation will be much more complex and this is a non-obfuscated
generalization of the HTML side of things which should describe the
problem that I need to solve on the server side.

Thanks in advance for any ideas.

--
Dotan Cohen

http://what-is-what.com
http://gibberish.co.il

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Re: Variable name as a variable?

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On Mon, 2009-10-05 at 16:56 +0200, Dotan Cohen wrote:

> I need to store a variable name as a variable. Note quite a C-style
> pointer, but a way to access one variable who's name is stored in
> another variable.
>
> As part of a spam-control measure, a certain public-facing form will
> have dummy rotating text fields and a hidden field that will describe
> which text field should be considered, like this:
>
> input type="text" name="text_1"
> input type="text" name="text_2"
> input type="text" name="text_3"
> input type="hidden" name="real_field" value="text_2"
>
> As this will be a very general-purpose tool, a switch statement on the
> hidden field's value would not be appropriate here. Naturally, the
> situation will be much more complex and this is a non-obfuscated
> generalization of the HTML side of things which should describe the
> problem that I need to solve on the server side.
>
> Thanks in advance for any ideas.
>
> --
> Dotan Cohen
>
> http://what-is-what.com
> http://gibberish.co.il
>


What's wrong with this:

$user_value = $_REQUEST[$_REQUEST['real_field']];

Obviously this isn't production worthy code, you'd really need to put
the whole thing in a ternary if to check if the values actually exist,
but this would definitely solve your problem.

Thanks,
Ash
http://www.ashleysheridan.co.uk



--=-1cJ1fFo80WUXAjL9EoQr--

Re: Variable name as a variable?

----- Original Message ----
> From: Dotan Cohen
> To: php-general.
> Sent: Mon, October 5, 2009 7:56:48 AM
> Subject: [PHP] Variable name as a variable?
>
> I need to store a variable name as a variable. Note quite a C-style
> pointer, but a way to access one variable who's name is stored in
> another variable.
>
> As part of a spam-control measure, a certain public-facing form will
> have dummy rotating text fields and a hidden field that will describe
> which text field should be considered, like this:
>
> input type="text" name="text_1"
> input type="text" name="text_2"
> input type="text" name="text_3"
> input type="hidden" name="real_field" value="text_2"
>
> As this will be a very general-purpose tool, a switch statement on the
> hidden field's value would not be appropriate here. Naturally, the
> situation will be much more complex and this is a non-obfuscated
> generalization of the HTML side of things which should describe the
> problem that I need to solve on the server side.
>
> Thanks in advance for any ideas.
>
> --
> Dotan Cohen
>
> http://what-is-what.com
> http://gibberish.co.il
>
> --
> PHP General Mailing List (http://www.php.net/)
> To unsubscribe, visit: http://www.php.net/unsub.php

You mean something like this?

$var_name = "text_2";
echo $$var_name; // equivalent to echo $text_2;

Regards,
Tommy

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Re: Variable name as a variable?

On Mon, 5 Oct 2009 16:56:48 +0200
Dotan Cohen wrote:

> I need to store a variable name as a variable. Note quite a C-style
> pointer, but a way to access one variable who's name is stored in
> another variable.
>
> As part of a spam-control measure, a certain public-facing form will
> have dummy rotating text fields and a hidden field that will describe
> which text field should be considered, like this:
>
> input type="text" name="text_1"
> input type="text" name="text_2"
> input type="text" name="text_3"
> input type="hidden" name="real_field" value="text_2"
>
> As this will be a very general-purpose tool, a switch statement on the
> hidden field's value would not be appropriate here. Naturally, the
> situation will be much more complex and this is a non-obfuscated
> generalization of the HTML side of things which should describe the
> problem that I need to solve on the server side.
>
> Thanks in advance for any ideas.
>

Some reading on this if you're interested:

http://us2.php.net/manual/en/language.variables.variable.php

You can also access array properties using variables if you like:

$foo->some_prop = 'Hi there!';
$bar = 'some_prop';
echo $foo->$bar;


Regards,

Torben

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Re: Variable name as a variable?

Thanks, all! I will experiment with the three different solutions
presented and see what best fits this application. As to the security
aspect, yes, I am aware that this is a simplification and that the
values must be sanitized.

Have a great week.

--
Dotan Cohen

http://what-is-what.com
http://gibberish.co.il

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