这个replace_uploaded_image() 功能非常好！我知道这是可行的，因为当我登录到WP Admin并上传一个图像时，它完全按照它应该做的做。此外，如果我删除该功能并上传图像，则原始上传的图像就在那里。（正是您所期望的。）

我试图查看函数中变量的内容。我很困惑为什么它似乎能执行所有的代码except 这个write_log() 零件。

custom\\u gallery功能正常，我在那里没有问题。我只是为了说明使用write_log() 在该功能内工作正常。

这个only 时间write_log() 从内部调用时不起作用replace_uploaded_image().

你知道为什么会这样吗？

<?php

/**
 * Replace default gallery HTML with my own.
 */
function custom_gallery ( $output, $attr ) {
    // Do some stuff
    // A bunch of code that works good.
    write_log ( \'test\' );  // Writing string from here works.
    write_log( $object );  // writing array or object from here works.

    return $output;
}
add_filter( \'post_gallery\', \'custom_gallery\', 10, 2 );

/**
 * Delete the original uploaded image and use the large format in its place.
 */
function replace_uploaded_image ( $image_data ) {
    write_log ( \'test\' );  // Nothing appears in error_log
    write_log ( $image_data );  // Nothing appears in error_log

    // if there is no large image : return
    if ( !isset ( $image_data[\'sizes\'][\'large\'] ) ) return $image_data;

    // paths to the uploaded image and the large image
    $upload_dir = wp_upload_dir();
    $uploaded_image_location = $upload_dir[\'basedir\'] . \'/\' . $image_data[\'file\'];
    $current_subdir = substr( $image_data[\'file\'], 0, strrpos($image_data[\'file\'], \'/\' ) );
    $large_image_location = $upload_dir[\'basedir\'] . \'/\' . $current_subdir . \'/\' . $image_data[\'sizes\'][\'large\'][\'file\'];

    // delete the uploaded image
    unlink( $uploaded_image_location );

    // rename the large image
    rename( $large_image_location, $uploaded_image_location );

    // update image metadata and return them
    $image_data[\'width\'] = $image_data[\'sizes\'][\'large\'][\'width\'];
    $image_data[\'height\'] = $image_data[\'sizes\'][\'large\'][\'height\'];
    unset( $image_data[\'sizes\'][\'large\'] );

    write_log ( \'test\' );  // Nothing appears in error_log
    write_log ( $image_data );  // Nothing appears in error_log

    return $image_data;
}
add_filter( \'wp_generate_attachment_metadata\', \'replace_uploaded_image\' );

// for debugging. write to error log.
if ( !function_exists( \'write_log\' ) ) {
    function write_log ( $log ) {
        if ( true === WP_DEBUG ) {
            error_log( \'******************************\' );
            if ( is_array( $log ) || is_object( $log ) ) {
                error_log( print_r( $log, true ) );
            } else {
                error_log( $log );
            }
        }
    }
}

?>