问：如何校验和提交表单？
答：Drupal允许定义默认的表单校验处理函数和提交处理函数。
function practice_demo_form($form, &$form_state) {
... ...
return $form;
}
function practice_demo_form_validate($form, &$form_state) {
if (...) {
form_set_error(...);
}
}
function practice_demo_form_submit($form, &$form_state) {
... ...
}
这些函数在drupal_prepare_form()中查找：
function drupal_prepare_form($form_id, &$form, &$form_state) {
...
if (!isset($form[‘#validate‘])) {
// Ensure that modules can rely on #validate being set.
$form[‘#validate‘] = array();
// Check for a handler specific to $form_id.
// 默认的表单校验函数以_validate结尾
if (function_exists($form_id . ‘_validate‘)) {
$form[‘#validate‘][] = $form_id . ‘_validate‘;
}
// Otherwise check whether this is a shared form and whether there is a
// handler for the shared $form_id.
elseif (isset($form_state[‘build_info‘][‘base_form_id‘]) && function_exists($form_state[‘build_info‘][‘base_form_id‘] . ‘_validate‘)) {
$form[‘#validate‘][] = $form_state[‘build_info‘][‘base_form_id‘] . ‘_validate‘;
}
}
if (!isset($form[‘#submit‘])) {
// Ensure that modules can rely on #submit being set.
$form[‘#submit‘] = array();
// Check for a handler specific to $form_id.
// 默认的表单提交函数以_submit结尾
if (function_exists($form_id . ‘_submit‘)) {
$form[‘#submit‘][] = $form_id . ‘_submit‘;
}
// Otherwise check whether this is a shared form and whether there is a
// handler for the shared $form_id.
elseif (isset($form_state[‘build_info‘][‘base_form_id‘]) && function_exists($form_state[‘build_info‘][‘base_form_id‘] . ‘_submit‘)) {
$form[‘#submit‘][] = $form_state[‘build_info‘][‘base_form_id‘] . ‘_submit‘;
}
}
...
}
问：$form_state[‘build_info‘][‘args‘]是什么用途？
答：$form_state[‘build_info‘][‘args‘]是page
arguments中除第一个参数外其它所有的参数，第一个参数是表单标识$form_id。
function practice_menu() {
$items[‘practice/demo‘] = array(
‘title‘ => ‘Demo‘,
‘page callback‘ => ‘drupal_get_form‘,
// 第一个参数是表单标识practice_demo_from
// 第二个参数是ultramen，第三个参数是25
‘page_arguments‘ => array(‘practice_demo_from‘, ‘ultramen‘, 25),
‘access callback‘ => TRUE,
);
return $items;
}
function practice_demo_form($form, &$form_state, $name, $age) {
... ...
}
function drupal_get_form($form_id) {
$form_state = array();
$args = func_get_args();
// Remove $form_id from the arguments.
array_shift($args);
$form_state[‘build_info‘][‘args‘] = $args;
return drupal_build_form($form_id, $form_state);
}
问：form_build_id是什么？
答：Drupal为每个表单定义一个唯一的form
build id，是一组随机字符串。form build id在客服端浏览器以hidden
field的方式呈现，表单提交时回传给Drupal。
function drupal_prepare_form($form_id, &$form, &$form_state) {
...
// Generate a new #build_id for this form, if none has been set already. The
// form_build_id is used as key to cache a particular build of the form. For
// multi-step forms, this allows the user to go back to an earlier build, make
// changes, and re-submit.
// @see drupal_build_form()
// @see drupal_rebuild_form()
// Drupal为每个表单定义一个唯一的form_build_id
if (!isset($form[‘#build_id‘])) {
$form[‘#build_id‘] = ‘form-‘ . drupal_random_key();
}
// form_buikd_id会在浏览器表单中以hidden的形式出现
$form[‘form_build_id‘] = array(
‘#type‘ => ‘hidden‘,
‘#value‘ => $form[‘#build_id‘],
‘#id‘ => $form[‘#build_id‘],
‘#name‘ => ‘form_build_id‘,
// Form processing and validation requires this value, so ensure the
// submitted form value appears literally, regardless of custom #tree
// and #parents being set elsewhere.
‘#parents‘ => array(‘form_build_id‘),
);
// 同form_build_id
if (isset($form_id)) {
$form[‘form_id‘] = array(
‘#type‘ => ‘hidden‘,
‘#value‘ => $form_id,
‘#id‘ => drupal_html_id("edit-$form_id"),
// Form processing and validation requires this value, so ensure the
// submitted form value appears literally, regardless of custom #tree
// and #parents being set elsewhere.
‘#parents‘ => array(‘form_id‘),
);
}
if (!isset($form[‘#id‘])) {
$form[‘#id‘] = drupal_html_id($form_id);
}
...
}
form
build id用来做什么？Drupal用它来标识缓存的表单数据。
function drupal_build_form($form_id, &$form_state) {
...
// If the incoming input contains a form_build_id, we‘ll check the cache for a
// copy of the form in question. If it‘s there, we don‘t have to rebuild the
// form to proceed. In addition, if there is stored form_state data from a
// previous step, we‘ll retrieve it so it can be passed on to the form
// processing code.
// 用$form_state[‘input‘][‘form_id‘]标识表单，例如practice_demo_form
// 用$form_state[‘input‘][‘form_build_id‘]标识缓存
$check_cache = isset($form_state[‘input‘][‘form_id‘]) && $form_state[‘input‘][‘form_id‘] == $form_id && !empty($form_state[‘input‘][‘form_build_id‘]);
if ($check_cache) {
$form = form_get_cache($form_state[‘input‘][‘form_build_id‘], $form_state);
}
...
}
function drupal_process_form($form_id, &$form, &$form_state) {
...
// After processing the form, the form builder or a #process callback may
// have set $form_state[‘cache‘] to indicate that the form and form state
// shall be cached. But the form may only be cached if the ‘no_cache‘ property
// is not set to TRUE. Only cache $form as it was prior to form_builder(),
// because form_builder() must run for each request to accommodate new user
// input. Rebuilt forms are not cached here, because drupal_rebuild_form()
// already takes care of that.
// 用$form_state[‘cache‘]和$form_state[‘no_cache‘]标识是否允许表单缓存
if (!$form_state[‘rebuild‘] && $form_state[‘cache‘] && empty($form_state[‘no_cache‘])) {
form_set_cache($form[‘#build_id‘], $unprocessed_form, $form_state);
}
...
}
问：form token是什么？
答：Drupal为每个表单定义一个form
token，与当前session会话关联在一起。form token的存在是为了避免处理长时间未提交的表单。
function drupal_prepare_form($form_id, &$form, &$form_state) {
...
// Add a token, based on either #token or form_id, to any form displayed to
// authenticated users. This ensures that any submitted form was actually
// requested previously by the user and protects against cross site request
// forgeries.
// This does not apply to programmatically submitted forms. Furthermore, since
// tokens are session-bound and forms displayed to anonymous users are very
// likely cached, we cannot assign a token for them.
// During installation, there is no $user yet.
if (!empty($user->uid) && !$form_state[‘programmed‘]) {
// Form constructors may explicitly set #token to FALSE when cross site
// request forgery is irrelevant to the form, such as search forms.
if (isset($form[‘#token‘]) && $form[‘#token‘] === FALSE) {
unset($form[‘#token‘]);
}
// Otherwise, generate a public token based on the form id.
else {
$form[‘#token‘] = $form_id;
// 将form token发送到客户端
$form[‘form_token‘] = array(
‘#id‘ => drupal_html_id(‘edit-‘ . $form_id . ‘-form-token‘),
‘#type‘ => ‘token‘,
‘#default_value‘ => drupal_get_token($form[‘#token‘]),
// Form processing and validation requires this value, so ensure the
// submitted form value appears literally, regardless of custom #tree
// and #parents being set elsewhere.
‘#parents‘ => array(‘form_token‘),
);
}
}
...
}
function drupal_validate_form($form_id, &$form, &$form_state) {
...
// If the session token was set by drupal_prepare_form(), ensure that it
// matches the current user‘s session.
// $form[‘#token‘]是表单标识，例如practice_demo_form
if (isset($form[‘#token‘])) {
if (!drupal_valid_token($form_state[‘values‘][‘form_token‘], $form[‘#token‘])) {
$path = current_path();
$query = drupal_get_query_parameters();
$url = url($path, array(‘query‘ => $query));
// Setting this error will cause the form to fail validation.
form_set_error(‘form_token‘, t(‘The form has become outdated. Copy any unsaved work in the form below and then <a href="@link">reload this page</a>.‘, array(‘@link‘ => $url)));
// Stop here and don‘t run any further validation handlers, because they
// could invoke non-safe operations which opens the door for CSRF
// vulnerabilities.
$validated_forms[$form_id] = TRUE;
return;
}
}
...
}
问：$form_state[‘input‘]是怎么来的？
答：$form_state[‘input‘]来自与$_GET或者$_POST，取决于$form_state[‘method‘]。
function drupal_build_form($form_id, &$form_state) {
...
if (!isset($form_state[‘input‘])) {
$form_state[‘input‘] = $form_state[‘method‘] == ‘get‘ ? $_GET : $_POST;
}
...
}
问：$form_state[‘values‘]是怎么来的？
答：$form_state[‘values‘]是$form_state[‘input‘]经过过滤处理后的结果。$form_state[‘input‘]是原始数据，$form_state[‘values‘]是过滤后的数据。
问：$form_state[‘rebuild‘]是用来做什么的？
答：不清楚。
问：$form_state[‘redirect‘]是用来做什么的？
答：redirect用在表单提交成功后，表示需要重定向的新地址。等同于调用drupal_goto()。
function practice_demo_form_submit($form, &$form_state) {
$form_state[‘redirect‘] = ‘admin/people/expiration‘;
// 等同 drupal_goto(‘admin/people/expiration‘);
}
function drupal_redirect_form($form_state) {
// Skip redirection for form submissions invoked via drupal_form_submit().
if (!empty($form_state[‘programmed‘])) {
return;
}
// Skip redirection if rebuild is activated.
if (!empty($form_state[‘rebuild‘])) {
return;
}
// Skip redirection if it was explicitly disallowed.
if (!empty($form_state[‘no_redirect‘])) {
return;
}
// Only invoke drupal_goto() if redirect value was not set to FALSE.
if (!isset($form_state[‘redirect‘]) || $form_state[‘redirect‘] !== FALSE) {
if (isset($form_state[‘redirect‘])) {
if (is_array($form_state[‘redirect‘])) {
call_user_func_array(‘drupal_goto‘, $form_state[‘redirect‘]);
}
else {
// This function can be called from the installer, which guarantees
// that $redirect will always be a string, so catch that case here
// and use the appropriate redirect function.
$function = drupal_installation_attempted() ? ‘install_goto‘ : ‘drupal_goto‘;
$function($form_state[‘redirect‘]);
}
}
drupal_goto(current_path(), array(‘query‘ => drupal_get_query_parameters()));
}
}
问：$form_state[‘submitted‘]是用来做什么的？
答：不清楚。
问：$form_state[‘executed‘]是用来做什么的？
答：不清楚。
问：$form_state[‘programmed‘]是用来做什么的？
答：不清楚。
问：$form_state[‘groups‘]是用来做什么的？
答：不清楚。
问：$form_state[‘buttons‘]是用来做什么的？
答：buttons是表单中所有的按钮。什么样的元素是按钮？在hook_element_info()中用button_type标识。
// If the form was submitted by the browser rather than via Ajax, then it
// can only have been triggered by a button, and we need to determine which
// button within the constraints of how browsers provide this information.
if (isset($element[‘#button_type‘])) {
// All buttons in the form need to be tracked for
// form_state_values_clean() and for the form_builder() code that handles
// a form submission containing no button information in $_POST.
$form_state[‘buttons‘][] = $element;
if (_form_button_was_clicked($element, $form_state)) {
$form_state[‘triggering_element‘] = $element;
}
}function system_element_info() {
$types[‘submit‘] = array(
‘#input‘ => TRUE,
‘#name‘ => ‘op‘,
‘#button_type‘ => ‘submit‘,
‘#executes_submit_callback‘ => TRUE,
‘#limit_validation_errors‘ => FALSE,
‘#process‘ => array(‘ajax_process_form‘),
‘#theme_wrappers‘ => array(‘button‘),
);
$types[‘button‘] = array(
‘#input‘ => TRUE,
‘#name‘ => ‘op‘,
‘#button_type‘ => ‘submit‘,
‘#executes_submit_callback‘ => FALSE,
‘#limit_validation_errors‘ => FALSE,
‘#process‘ => array(‘ajax_process_form‘),
‘#theme_wrappers‘ => array(‘button‘),
);
}
问：$form_state[‘triggering_element‘]是用来做什么的？
答：triggering_element用来标识是哪个元素触发的表单提交事件。通常是按钮。
问：可不可以为某个表单定制主题？
答：可以的。Drupal默认用表单标识作为该表单的主题。
function drupal_prepare_form($form_id, &$form, &$form_state) {
...
// If no #theme has been set, automatically apply theme suggestions.
// theme_form() itself is in #theme_wrappers and not #theme. Therefore, the
// #theme function only has to care for rendering the inner form elements,
// not the form itself.
if (!isset($form[‘#theme‘])) {
$form[‘#theme‘] = array($form_id); // 表单默认主题
if (isset($form_state[‘build_info‘][‘base_form_id‘])) {
$form[‘#theme‘][] = $form_state[‘build_info‘][‘base_form_id‘];
}
}
...
}
问：可不可以用alter钩子修改表单？
答：可以的。Drupal构造表单时，允许为表单定义通用和专用两种alter钩子。
function drupal_prepare_form($form_id, &$form, &$form_state) {
...
// Invoke hook_form_alter(), hook_form_BASE_FORM_ID_alter(), and
// hook_form_FORM_ID_alter() implementations.
$hooks = array(‘form‘); // 表单通用钩子
if (isset($form_state[‘build_info‘][‘base_form_id‘])) {
$hooks[] = ‘form_‘ . $form_state[‘build_info‘][‘base_form_id‘];
}
$hooks[] = ‘form_‘ . $form_id; // 表单专用钩子
drupal_alter($hooks, $form, $form_state, $form_id);
...
}
Drupal Form问题汇总