Question

I receive for example 26 results after a query using php. I want to paginate those results, showing 5 per-page.

The problem is that in order to send the query I have to do an http post using the information of a form I fill.

The first 5 results show, but then the next page will give me errors about some variables not being defined — the variables that came from the original request.

Here is the form code:

<form name="formulario" action="resultados.php" method="POST"> 
            <input name="titulo" type="text" id="cajatitulo" class="cuadrobusqueda" placeholder="T&iacute;tulo de la publicaci&oacute;n (Ej: La fotos&iacute;ntesis y sus procesos)"> 
            <input name="anio" type="text" id="cajaanio" class="cuadrobusqueda" placeholder="A&ntilde;o">
            <br><br>
            <input name="autor" type="text" id="cajaautor" class="cuadrobusqueda" placeholder="Apellido del autor (Ej: Rojas, J; Rojas; J)"> 
            <input name="issn" type="text" id="cajaissn" class="cuadrobusqueda" placeholder="ISSN">
            <br><br>
            <input type="radio" name="tipo_busqueda" value="1" checked>
            <span onmouseover="title='Busca todos los parámetros seleccionados en un artículo.'">B&Uacute;SQUEDA EXACTA</span>
            <input type="radio" name="tipo_busqueda" value="2"> 
            <span onmouseover="title='Busca cualquiera de los parámetros seleccionados en un artículo.'">B&Uacute;SQUEDA FLEXIBLE</span>            
            </br></br>
            <input type="submit" name="boton" id="botonenviar" value="Procesar">
</form>

That data is sent to the results.php, where the post is extracted and paginated with this code:

extract($_POST);

include("conectar.php");

$conexion= conectarse();

$consulta="";
$tipo="";

if($tipo_busqueda=="1")
    $tipo="AND";
else
    $tipo="OR";

if($titulo && $consulta == "" )
    $consulta=" web.titulo_paper_web LIKE '%$titulo%'";

$consulta = '
    SELECT 
        * 
    FROM 
        acw_papers_web web 
    WHERE 
        '.$consulta.'
    ORDER BY 
        web.probabilidad DESC';
$resultado= mysql_query($consulta, $conexion);

if (!isset($paginanum)) 
    $paginanum = 1; 
$mostrar_resultados = 5;            
$filas = mysql_num_rows($resultado);    
$ultima = ceil($filas/$mostrar_resultados);         
if ($paginanum < 1)
    $paginanum = 1; 
elseif ($paginanum > $ultima)
    $paginanum = $ultima;

$max = 'LIMIT '.(paginanum - 1) * $mostrar_resultados .',' .$mostrar_resultados; 
$consulta = $consulta . " $max";
$resultado= mysql_query($consulta, $conexion);

Below that code I generate the data that links me to the next page:

 if ($paginanum != 1) {
    echo "<a class='navegar' href='{$_SERVER['PHP_SELF']}?paginanum=1'> <b><<</b> Primera</a> ";
    echo " ";
    $anterior = $paginanum-1;
    echo " <a class='navegar' href='{$_SERVER['PHP_SELF']}?paginanum=$anterior'> <b><</b> Anterior</a> ";
} 
if ($paginanum != $ultima) {
    $siguiente = $paginanum+1;
    echo " <a class='navegar' href='{$_SERVER['PHP_SELF']}?paginanum=$siguiente'>Siguiente <b>></b> </a> ";
    echo " <span>  </span>";
    echo " <a class='navegar' href='{$_SERVER['PHP_SELF']}?paginanum=$ultima'>&Uacute;ltima <b>>></b> </a> ";
}
echo "</br>";

That code works, but subsequent pages do not work. I tried passing that data on the url:

&titulo=$titulo&issn=$issn&autor=$autor&anio=

but it did not work

Answer 1

Submit your form via get then create a querystring based on $_GET:

$querystring = "";
foreach ($_GET as $key => $val) {
    if ($key != 'paginanum') {
        $querystring .= ($querystring == "" ? "" : "&") . "$key=$val";
    }
}

Then append the querystring to your link URL.

It’s not very secure, but it works.

Update:

Sam Dufel just reminded me of PHP’s http_build_query() function, which is better:

$vals = $_GET;
unset($vals['paginanum']);
$querystring = http_build_query($vals);