El primer problema que nos surge al pasar a PHP es cómo enviar y recibir datos a través de un formulario web. Los datos enviados los podemos usar para ejecutar en el servidor nuestro script de Perl y generar resultados.
A continuación muestro el ejemplo de un formulario de búsqueda de secuencias DNA o Proteínas:
<?php
// Shows a search input data formulary
function showSearchForm(){
?>
<h3>Search form:</h3></br>
<form enctype="multipart/form-data" action="<?php print $_SERVER['PHP_SELF'] ?>" method="POST">
Search name: <input type="text" name="search_name" size="40" maxlength="127"></br></br>
Email: <input type="text" name="user_email" size="40" maxlength="127"></br></br>
Search input type:
<input type="radio" name="search_type" value="stamp"> DNA
<input type="radio" name="search_type" value="blastp"> Protein
</br></br>
Exclude query from results <input type="checkbox" name="search_exclude" value="yes"></br></br>
Limit number of results per query: <input type="text" name="search_limit" size="2" maxlength="2"></br></br>
Query data or file:</br></br>
<textarea name="query_data" rows="10" cols="67"></textarea>
</br></br>
<input type="file" name="query_file" size="20"></br></br>
Genomes:
<select name="specie" class="selectbutton">
<option value="human">Homo sapiens</option>
<option value="mouse">Mus musculus</option>
<option value="arabidopsis">Arabidopsis thaliana</option>
<option value="rice">Oryza sativa</option>
</select>
</br></br>
<input type="submit" name="search_submitted" value="Search">
</form>
<?php
}
?>
El siguiente paso consistirá en validar los datos introducidos para volver a mostrar el formulario si los datos fueran erróneos. Usaremos la variable especial $_SESSION para guardar los datos enviados con el formulario (almacenados en la variable $_POST). La variable $_SESSION nos permitirá acceder a su contenido si ejecutamos 'session_start()' al comienzo del código PHP. Antes de guardar los datos enviados, borraremos los contenidos anteriores de $_SESSION. Si en vez de enviar un archivo, hemos enviado datos en formato texto, guardaremos estos datos en un archivo temporal ($_SESSION['query_file']). Si faltan datos en algún campo del formulario, crearemos un mensaje de error en $_SESSION['errors'].
<?php
// Validates search form data
function validateSearchData(){
// Stores in $_SESSION variable all the post data and in $_SESSION['errors'] if some important data is missing
// Clear previous $_SESSION values
unset($_SESSION['errors']);
unset($_SESSION['search_name']);
unset($_SESSION['user_email']);
unset($_SESSION['search_type']);
unset($_SESSION['search_exclude']);
unset($_SESSION['search_limit']);
unset($_SESSION['specie']);
unset($_SESSION['output_dir']);
unset($_SESSION['query_file']);
unset($_SESSION['query_data']);
(!empty($_POST['search_name'])) ? $_SESSION['search_name'] = trim($_POST['search_name']) : $_SESSION['errors'][] = 'name for the search';
(!empty($_POST['user_email'])) ? $_SESSION['user_email'] = trim($_POST['user_email']) : $_SESSION['errors'][] = 'email';;
(!empty($_POST['search_type'])) ? $_SESSION['search_type'] = $_POST['search_type'] : $_SESSION['errors'][] = 'search input type';
if (!empty($_POST['search_exclude'])){
($_POST['search_exclude'] == 'yes') ? $_SESSION['search_exclude'] = 1 : $_SESSION['search_exclude'] = 0;
}
(!empty($_POST['search_limit'])) ? $_SESSION['search_limit'] = trim($_POST['search_limit']) : '';
(!empty($_POST['specie'])) ? $_SESSION['specie'] = $_POST['specie'] : '';
// Store the query data into a file inside the /tmp folder
if (!empty($_FILES['query_file']['name']) && !empty($_FILES['query_file']['tmp_name']) && $_FILES['query_file']['size']>0){
$_SESSION['query_file'] = $_FILES['query_file']['tmp_name'];
}elseif (!empty($_POST['query_data'])){
$_SESSION['query_data'] = $_POST['query_data'];
$_SESSION['query_file'] = '/tmp/'.$_SESSION['search_name'].".data";
$file_handle = fopen($_SESSION['query_file'], "w");
fwrite($file_handle, $_POST['query_data']);
fclose($file_handle);
} else{
$_SESSION['errors'][] = 'data or file to process';
}
if (isset($_SESSION['errors'])){
return;
}
}
?>
Finalmente, falta introducir las dos funciones anteriores en un archivo (por ejemplo 'index.php') para que sean leídas e interpretadas por el servidor web. Si los datos del formulario son válidos se ejecutará un pequeño código de Perl, si no se volverá a mostrar el formulario indicando los datos que faltan.
<?php
// Example file of a PHP search formulary with input data validation and script execution
session_start();
?>
<html>
<head>
<title>Search Form</title>
</head>
<body>
<?php
if(!isset($_POST['search_submitted'])){
?><h3>Search form:</h3><?php
showSearchForm();
} else {
validateSearchData();
if (!isset($_SESSION['errors'])){
executeScript();
} else {
?><h3>Search form:</h3><?php
print '<font color="red"><b>Please specify: '.join(', ',$_SESSION['errors']).'.</b></font></br></br>';
unset($_SESSION['errors']);
showSearchForm();
}
}
?>
</body>
</html>
<?php
// Shows an input data formulary filled with previous values
function showSearchForm(){
?>
<form enctype="multipart/form-data" action="<?php print $_SERVER['PHP_SELF'] ?>" method="POST">
Search name: <input type="text" name="search_name" size="40" maxlength="127" <?php ($_SESSION['search_name']) ? print 'value="'.$_SESSION['search_name'].'"' : '' ?> ></br></br>
Email: <input type="text" name="user_email" size="40" maxlength="127" <?php ($_SESSION['user_email']) ? print 'value="'.$_SESSION['user_email'].'"' : '' ?> ></br></br>
Search input type:
<input type="radio" name="search_type" value="stamp" <?php ($_SESSION['search_type'] == 'stamp') ? print 'checked' : '' ?>> DNA
<input type="radio" name="search_type" value="blastp" <?php ($_SESSION['search_type'] == 'blastp') ? print 'checked' : '' ?>> Protein
</br></br>
Exclude query from results <input type="checkbox" name="search_exclude" value="yes" <?php ($_SESSION['search_exclude'] == 'yes') ? print 'checked' : print 'checked' ?>></br></br>
Limit number of results per query: <input type="text" name="search_limit" size="2" maxlength="2" <?php ($_SESSION['search_limit']) ? print 'value="'.$_SESSION['search_limit'].'"' : print 'value="10"'; ?> ></br></br>
Query data or file:</br></br>
<textarea name="query_data" rows="10" cols="67"><?php ($_SESSION['query_data']) ? print $_SESSION['query_data'] : '' ?></textarea>
</br></br>
<input type="file" name="query_file" size="20"></br></br>
Genomes:
<select name="specie" class="selectbutton">
<option value="human" <?php (!isset($_SESSION['specie']) || $_SESSION['specie'] == 'human') ? print 'selected' : '' ?>>Homo sapiens</option>
<option value="mouse" <?php ($_SESSION['specie'] == 'mouse') ? print 'selected' : '' ?>>Mus musculus</option>
<option value="arabidopsis" <?php ($_SESSION['specie'] == 'arabidopsis') ? print 'selected' : '' ?>>Arabidopsis thaliana</option>
<option value="rice" <?php ($_SESSION['specie'] == 'rice') ? print 'selected' : '' ?>>Oryza sativa</option>
</select>
</br></br>
<input type="submit" name="search_submitted" value="Search">
</form>
<?php
}
// Validates search form data
function validateSearchData(){
// Stores in $_SESSION variable all the post data and in $_SESSION['errors'] if some important data is missing
// Clear previous $_SESSION values
unset($_SESSION['errors']);
unset($_SESSION['search_name']);
unset($_SESSION['user_email']);
unset($_SESSION['search_type']);
unset($_SESSION['search_exclude']);
unset($_SESSION['search_limit']);
unset($_SESSION['specie']);
unset($_SESSION['output_dir']);
unset($_SESSION['query_file']);
unset($_SESSION['query_data']);
(!empty($_POST['search_name'])) ? $_SESSION['search_name'] = trim($_POST['search_name']) : $_SESSION['errors'][] = 'name for the search';
(!empty($_POST['user_email'])) ? $_SESSION['user_email'] = trim($_POST['user_email']) : $_SESSION['errors'][] = 'email';;
(!empty($_POST['search_type'])) ? $_SESSION['search_type'] = $_POST['search_type'] : $_SESSION['errors'][] = 'search input type';
if (!empty($_POST['search_exclude'])){
($_POST['search_exclude'] == 'yes') ? $_SESSION['search_exclude'] = 1 : $_SESSION['search_exclude'] = 0;
}
(!empty($_POST['search_limit'])) ? $_SESSION['search_limit'] = trim($_POST['search_limit']) : '';
(!empty($_POST['specie'])) ? $_SESSION['specie'] = $_POST['specie'] : '';
// Store the query data into a file inside the /tmp folder
if (!empty($_FILES['query_file']['name']) && !empty($_FILES['query_file']['tmp_name']) && $_FILES['query_file']['size']>0){
$_SESSION['query_file'] = $_FILES['query_file']['tmp_name'];
}elseif (!empty($_POST['query_data'])){
$_SESSION['query_data'] = $_POST['query_data'];
$_SESSION['query_file'] = '/tmp/'.$_SESSION['search_name'].".data";
$file_handle = fopen($_SESSION['query_file'], "w");
fwrite($file_handle, $_POST['query_data']);
fclose($file_handle);
} else{
$_SESSION['errors'][] = 'data or file to process';
}
if (isset($_SESSION['errors'])){
return;
}
}
// Executes a Perl script and prints the output
function executeScript(){
$output = `perl -e 'print "Hello world\n"'`;
print '<pre>'.$output.'</pre>';
}
?>
