POST (or GET) Associative Array to Script from Form

[Joseph_Sliker]

Hi;

Actually thought I understood this but I can't seem to make it happen this morning, and I can't seem to find a clear simple reference here.

Can I pass an associative array from a form (using either POST or GET) to a .php script all at once, in one simple step?

ie. Say I have the following variable/associative array

$graphtable = Array ( [TESTPHASE] => G085 [GRADE] => 3 [0_LE_1_A] => 0 [1_LE_1_A] => 7 [2_LE_1_A] => 28 [3_LE_1_A] => 22 [4_LE_1_A] => 7 [null_LE_1_A] => 0 [PROTOCOLS] => 64 )

And I pass it as a hidden variable in the following form:

<form method="POST" action="../jpgraph-1.19/src/SLFgraph2.php" target="_blank"><input type="submit" value="GRAPH" name="B1"><input type="hidden" name="graphdata" value=$graphtable></form>

When it arrives at the destination script via...

$graphdata = $_POST['graphdata'];

...and I do a

print_r ($graphdata);

All I get is the word "Array".

I'm almost certain I've done this before, but it does not seem to be working for me today.

Anything obviously wrong here?

Thanks.

[laserlight]

You need to quote your HTML attribute values.

[ahundiak]

And along with quoting you need to serialize the array.

<input
type="hidden"
name="graphdata"
value="<?php echo htlmspecialchars(serialize($graphdata)) ?>"
/>

And then unserialize when reading:
$graphdata = unserialize($_POST['graphdata']);

http://us3.php.net/manual/en/function.serialize.php

Serialize basically takes just about anything and turns it into a text string. Does not look pretty but it works well.

[Joseph_Sliker]

Thanks for the replies.

The instructions:

$graphdata2[$row]=(htmlspecialchars(serialize($graphdata2[$row])));

DOES appear to be doing something useful, because when I look at the page source, I now see strings like:

<input type="hidden" name="graphdata" value="a:63:{s:9:&quot;TESTPHASE&quot;;s:4:&quot;G085&quot;;s:5:&quot;GRADE&quot;;s:2:&quot;K5&quot;;s:7:&quot;0_K_1_A&quot;;s:1:&quot;0&quot;;s:7:&quot;1_K_1_A&quot;;s:2:&quot;12&quot;;s:7:&quot;2_K_1_A&quot;;s:2:&quot;12&quot;;s:7:&quot;3_K_1_A&quot;;s:2:&quot;16&quot;;s:7:&quot;4_K_1_A&quot;;s:1:&quot;4&quot;;s:10:&quot;null_K_1_A&quot;;s:1:&quot;0&quot;;s:7:&quot;PROTOCOLS&quot;;s:2:&quot;44&quot;;}">

BUT

On the following page, the instructions:

$ungather = $_POST['graphdata'];
$graphdata = (htmlspecialchars_decode(unserialize($ungather)));
PRINT_R ($graphdata);

still gets me nothing but a blank page.

[Joseph_Sliker]

I am not real familiar with the "htmlspecialchars" function, so I tried "urlencode()" and "urldecode()" and this seems to be working....

Form page:

$graphdata2[$row]=(urlencode(serialize($gather2[$row])));

Destination script:

$graphdata = (unserialize(urldecode($_POST['graphdata'])));
PRINT_R ($graphdata);

results in seeing:

Array ( [TESTPHASE] => G085 [GRADE] => K4 [0_K_1_A] => 0 [1_K_1_A] => 7 [2_K_1_A] => 1 [3_K_1_A] => 8 [4_K_1_A] => 2 [null_K_1_A] => 0 [PROTOCOLS] => 18 )

I think this may be close to resolved...lemme just see if I can get my pie charts to run properly off of this.

[ahundiak]

Using htmlspecialchars_decode() will will mess you up. Only need to worry about special chars on the way out. And of course make sure you only try pulling data from $_POST when the form is actually submitted.

Edited: Left out the part in bold.

[Joseph_Sliker]

I do not understand. How will urlencode/urldecode mess me up? I will try the htmlspecialchars function again tomorrow...but it simply did not appear to work after multiple tries today.

[laserlight]

hmm... sorry about that, I didnt notice that you were actually trying to pass an array rather than a multiword string starting with "Array".

You need to serialize your array, and then unserialize when it arrives at the destination.

As for htmlspecialchars() vs urlencode(), I think that since your data is in a form, you should use htmlspecialchars() on the serialized data. The web browser will decode for you, so there is no need to use htmlspecialchars_decode() or urldecode().

<?php
$graphtable = array(
	'TESTPHASE' => 'G085',
	'GRADE' => 3
	'0_LE_1_A' => 0
	'1_LE_1_A' => 7
	'2_LE_1_A' => 28
	'3_LE_1_A' => 22
	'4_LE_1_A' => 7
	'null_LE_1_A' => 0
	'PROTOCOLS => 64
	);
?>
<form method="POST" action="../jpgraph-1.19/src/SLFgraph2.php" target="_blank">
<input type="submit" value="GRAPH" name="B1">
<input type="hidden" name="graphdata" value="<?php
echo htmlspecialchars(serialize($graphtable));
?>">
</form>

Now, at SLFgraph2.php, you just need to unserialize($_POST['graphdata']).

[ahundiak]

Joseph Sliker wrote:

I do not understand. How will urlencode/urldecode mess me up? I will try the htmlspecialchars function again tomorrow...but it simply did not appear to work after multiple tries today.

Typo on my part. I left out the htmlspecialchars_decode word.

When passing anything intended to be in the html page itself you should always send it through htmlspecialchars(). urlencode is for url variables and has different rules.

However you do NOT need to take stuff being returned and run it through htmlspecialchars_decode. The browser basically takes care of that for you. And using htmlspecialchars_decode can have unexpected results.

http://us3.php.net/manual/en/function.htmlspecialchars.php
http://us3.php.net/manual/en/function.urlencode.php

And yes a serialized array does look funny but it's not intended to be looked at by people.

[Weedpacket]

Of course, if the submitted form is going back to the same server that sent it out (and the URL confirms this), then the whole serialize/html_special_chars/unserialize thing is unnecessary. Clearly, this information isn't intended for the - user or it would be in some format they can actually use - but for the server instead.

In which case, why not just store all this stuff in a session? As well as being simpler, it would be (a bit) faster and (quite a bit) safer.

[ahundiak]

Weedpacket wrote:

Of course, if the submitted form is going back to the same server that sent it out (and the URL confirms this), then the whole serialize/html_special_chars/unserialize thing is unnecessary. Clearly, this information isn't intended for the - user or it would be in some format they can actually use - but for the server instead.

In which case, why not just store all this stuff in a session? As well as being simpler, it would be (a bit) faster and (quite a bit) safer.

There are of course many times when you don't really want to use sessions. Maybe the user does not like cookies. Maybe you don't want to tie up server resources. Maybe you will post to a different server. Maybe a local javascript function might use the data though json would probably be better for that.

Just speculating.

[Weedpacket]

ahundiak wrote:

Maybe the user does not like cookies. Maybe you don't want to tie up server resources. Maybe you will post to a different server.

Taking these in turn:

1. Cookies aren't necessary for sessions to work

2. Tying up server bandwidth to transmit a few hundred bytes in and out is more expensive than tying up a few hundred bytes of disk space

3. I already observed this in my post.

[Joseph_Sliker]

Hi;

The following construction DOES seem to be packing up the array information correctly:

(note: this is taking place in a loop that ends up creating a table with form buttons that get graphs for the data reflected on each line)

//various loop stuff preceeds this...

$gather2[$row][$col_key]=$col_value;
} 

$graphdata2[$row]=(serialize($gather2[$row]));
echo "\t<input type=\"hidden\" name=\"graphdata\" value=\"".(htmlspecialchars($graphdata2[$row]))."\"></form></tr>\n"; 

anyway, trust me. It works out and when I look at the source code for the page the hidden value/variable array for the button on a particular row looks like this:

<input type="hidden" name="graphdata" value="a:73:{s:9:&quot;TESTPHASE&quot;;s:4:&quot;G085&quot;;s:5:&quot;GRADE&quot;;s:1:&quot;5&quot;;s:6:&quot;LE_1_A&quot;;s:6:&quot;LE_1_A&quot;;s:8:&quot;LE_1_A_0&quot;;s:1:&quot;0&quot;;s:8:&quot;LE_1_A_1&quot;;s:1:&quot;2&quot;;s:8:&quot;LE_1_A_2&quot;;s:2:&quot;11&quot;;s:8:&quot;LE_1_A_3&quot;;s:2:&quot;10&quot;;s:8:&quot;LE_1_A_4&quot;;s:1:&quot;9&quot;;s:11:&quot;LE_1_A_null&quot;;s:1:&quot;0&quot;;s:6:&quot;PROTOCOLS&quot;;s:2:&quot;32&quot;;}">

BUT on the destination page, the code:

$graphdata = unserialize($_POST['graphdata']);
PRINT_R ($graphdata);

...still gives me nothing but a blank page.

[ahundiak]

First off I assume you are using print_r and not PRINT_R? Can't remember if php function names are case sensitive or not.

Put
error_reporting(E_ALL);
At the top of your page just to catch any strange things that might be going on.

add a print_r($_POST); just to see what is getting posted.
and add echo "Hello"; just to be certain that the page is indeed getting kicked off.

And maybe even check the html source just to make sure that you do indeed have a form element and a submit element.

It really should come back ok. I've done this plenty of times.