how to save meta box value? - wordpress

Question

I've created a meta box. The code is:
// Create your custom meta box
add_action( 'add_meta_boxes', 'hotel_amenities' );
// Add a custom meta box to a post
function hotel_amenities( $post ) {
add_meta_box(
'Meta Box Amenities', // ID, should be a string
'Amenities', // Meta Box Title
'amenities_content', // Your call back function, this is where your form field will go
'post', // The post type you want this to show up on, can be post, page, or custom post type
'normal', // The placement of your meta box, can be normal or side
'high' // The priority in which this will be displayed
);
}
// Content for the custom meta box
function amenities_content( $post ) {
echo '<label>Bed room</label>';
echo '<input type="text" name="amenity_bed_room" value="" />';
}
// Save your meta box content
add_action( 'save_post', 'save_amenities' );
// save newsletter content
function save_amenities(){
global $post;
// Get our form field
if( $_POST ) :
$amenities_meta = esc_attr( $_POST['amenity_bed_room'] );
// Update post meta
update_post_meta($post->ID, '_amenities_custom_meta', $amenities_meta);
endif;
}
It shows a meta box on admin post page with a text field. but it gets blank if I save or update the post after I put some thing on the text field.
Seems function save_amenities() is not working. What I am doing wrong in this code?
Also for getting that value I use the function below. Is that correct?
//get amenities meta box values
function get_amenities_meta_box() {
global $post;
$meta_values = get_post_meta($post->ID, '_amenities_custom_meta', true);
}

Answer 1

There are a few things going wrong there. The final value that you want to see will be displayed by the value attribute in the amenities_content function. Right now it is just displaying an empty string (""). Try putting any value in that attribute and you should see it show up in the meta box (value="this is a test").
The save_amenities function should take $post_id as a parameter. You'll need that to update the post meta-data and give a real value for the amenities_content function to echo back to the admin screen.
The amenities_content function should really have a nonce field that should then be verified by the save_amenities function. And user input should be sanitized before it is saved (I'm doing it both when I save it and when I display it. I'm not sure if that's necessary.)
try this out for the amenities_content function:
function amenities_content( $post ) {
// This is the value that was saved in the save_amenities function
$bed_room = get_post_meta( $post->ID, '_amenity_bed_room', true );
wp_nonce_field( 'save_amenity', 'amenity_nonce' );
echo '<label>Bed room</label>';
echo '<input type="text" name="amenity_bed_room"
value="' . sanitize_text_field( $bed_room ) . '" />';
}
and this for the save_amenities function:
function save_amenities( $post_id ) {
// Check if nonce is set
if ( ! isset( $_POST['amenity_nonce'] ) ) {
return $post_id;
}
if ( ! wp_verify_nonce( $_POST['amenity_nonce'], 'save_amenity' ) ) {
return $post_id;
}
// Check that the logged in user has permission to edit this post
if ( ! current_user_can( 'edit_post' ) ) {
return $post_id;
}
$bed_room = sanitize_text_field( $_POST['amenity_bed_room'] );
update_post_meta( $post_id, '_amenity_bed_room', $bed_room );
}