Resolve the debugs

Question

I enable the debugs, and i have these that describe below. In the wp-config.php write :

define('WP_DEBUG', true);
define('WP_DEBUG', false);

1)

Notice: Undefined index: type in C:\xampp\htdocs\mywebsite\wp-content\plugins\oqey-gallery\gallcore.php on line 252

on line 252 :

//media_upload_header();
    if($_GET['type'] == "oqeygallery"){ include ("insert_in_post.php"); }

2) Notice: add_custom_background is deprecated since version 3.4! Use add_theme_support( 'custom-background', $args ) instead. in C:\xampp\htdocs\mywebsite\wp-includes\functions.php on line 2638

3) Notice: attribute_escape is deprecated since version 2.8! Use esc_attr() instead. in C:\xampp\htdocs\mywebsite\wp-includes\functions.php on line 2638

4)Notice: Trying to get property of non-object in C:\xampp\htdocs\mywebsite\wp-content\themes\mywebsite\includes\for_articles\get_excerpt.php on line 12

function get_excerpt()
    {
        $excerpt = get_the_content();
        $excerpt = preg_replace(" (\[.*?\])",'',$excerpt);
        $excerpt = strip_shortcodes($excerpt);
        $excerpt = strip_tags($excerpt);
        $excerpt = substr($excerpt, 0, 440);
        $excerpt = substr($excerpt, 0, strripos($excerpt, " "));
        $excerpt = trim(preg_replace( '/\s+/', ' ', $excerpt));
        $excerpt = $excerpt.'<a class="read-more" <a href="'. get_permalink($post->ID) . '">Read more &raquo;&raquo;</a>';
        return $excerpt;
    }
?>

Edit:

Notice: attribute_escape is deprecated since version 2.8! Use esc_attr() instead. in /home/www/server/mywebsite/www/wp-includes/functions.php on line 2638

function _deprecated_function( $function, $version, $replacement = null ) {

    do_action( 'deprecated_function_run', $function, $replacement, $version );

    // Allow plugin to filter the output error trigger
    if ( WP_DEBUG && apply_filters( 'deprecated_function_trigger_error', true ) ) {
            if ( ! is_null($replacement) )
**2638**                trigger_error( sprintf( __('%1$s is <strong>deprecated</strong> since version %2$s! Use %3$s instead.'), $function, $version, $replacement ) );
            else
                trigger_error( sprintf( __('%1$s is <strong>deprecated</strong> since version %2$s with no alternative available.'), $function, $version ) );

        }
    }

Update : Only when activate the plugin oQey Gallery, display some errors like:

Notice: Undefined index: type in C:\xampp\htdocs\website\wp-content\plugins\oqey-gallery\gallcore.php on line 252
Notice: Undefined index: page in C:\xampp\htdocs\website\wp-content\plugins\oqey-gallery\oqeygallery.php on line 346
Notice: has_cap was called with an argument that is deprecated since version 2.0! Usage of user levels by plugins and themes is deprecated. Use roles and capabilities instead. in C:\xampp\htdocs\website\wp-includes\functions.php on line 2723

Answer 1

Number 1 is not wordPress, but PHP. $_GET['type'] is undefined. Use an isset( $_GET['type'] ) conditional.

Number 2 the error message tells you exactly what to do. Instead of calling:

add_custom_background();

...call:

add_theme_support( 'custom-background' );

Number 3 the error message tells you exactly what to do. Instead of calling:

attribute_escape();

...call:

esc_attr();

Number 4 is telling you that you're trying to get the property of an object that isn't set. In this yes, that object is $post, which needs to be globalized before you use it. Instead of this:

$excerpt = $excerpt.'<a class="read-more" <a href="'. get_permalink($post->ID) . '">Read more &raquo;&raquo;</a>';

...do this:

global $post;
$excerpt = $excerpt.'<a class="read-more" <a href="'. get_permalink($post->ID) . '">Read more &raquo;&raquo;</a>';