Passing POST data from one web page to another with PHP

Question

Searching did not find a similar question, so: How can POST data used by PHP to generate one page be passed from that page to another PHP generated page? I have:

• A form on page 1 which sends data to a PHP script via POST.
• Page 2 is generated by that script and shows one or more graphs generated by an external program using the entries on page 1 and the back end database. This page also has another form with options to re-generate the graphs with new options (e.g. zoom in on or truncate the graph(s)).
• If requested, page 3 will be generated with the same PHP script using POST data glued together from pages 1 and 2. Except for the graphs, its basic appearance will be the same as page 2.
• Pages 4, 5, 6 ... should be generated in the same manner as page 3.

So, how can I put the POST data used to generate page 2 into the POST data for page 3?

EDIT: Due to organizational policy, cookies can't be used (so sessions are not feasible). GET is undesirable because we don't want the input to show in the URL.

Answer 1

I recall struggling with this issue long ago, wondering why I simply couldn't redirect with a modified POST header. The reason is a redirect is actually considered a GET.

Regardless, you need to store the post variables in hidden fields.

<input type="hidden" name="someValueFromPageOne" value="blah">

I would recommend prefixing all your field names from each form so that its easy to tell them apart during your consolidation phase at the end.

<input type="hidden" name="pageOne_firstName" value="Joe">
<input type="hidden" name="pageTwo_streetNumber" value="22">

Answer 2

Use GET.

In my opinion, POST requests should modify something (e.g. add records to a database). GET requests should retrieve something (e.g. results of a search query).

If you want to use POST anyway, look into PHP sessions.

Answer 3

Sessions are a pain, and if you needed them you'd already have implemented them.

As @Soviut said above, hidden input fields are probably the way to go for this.

Answer 4

If you decide to bite off the session route with the dbms option, I've had luck designing a state class to hold this stuff, and serializing an object using JSON to a single large field in the session record.

Answer 5

Wez Furlong recently wrote the php5 version on his blog (titled HTTP post from php, without cURL):

function do_post_request($url, $data, $optional_headers = null) { $params = array('http' => array( 'method' => 'post', 'content' => $data )); if ($optional_headers!== null) { $params['http']['header'] = $optional_headers; } $ctx = stream_context_create($params); $fp = @fopen($url, 'rb', false, $ctx); if (!$fp) { throw new Exception("Problem with $url, $php_errormsg"); } $response = @stream_get_contents($fp); if ($response === false) { throw new Exception("Problem reading data from $url, $php_errormsg"); } return $response; }

In the post he mentions that he always has to look up how to do this. Funny because he's one of the core developers!

Answer 6

John, any sample code? please send to [email protected] your email will be appreciated. thanks.