WP Editor.md是本人很喜欢的一个编辑器插件。他可以实现在Wordpress上编写Markdown，也支持粘贴图片自动上传到服务器。但是博主感觉他有个功能不是很完善，就是粘贴图片自动上传的时候他虽然可以把图片上传到服务器，但是并不会上传到媒体库。这样的话上传的图片在媒体库就找不到，时间久了那些没用的图片就会占据服务器很大空间，难以清理。
于是我自己试着完善了一下，给他增加了上传到媒体库的功能。

WP Editor.md 10.1.1版本有一个大更新，所以在10.1.1之后的版本和之前的版本修改方法并不一样，因此在这里分开来写。

对于10.1.1以后的版本

修改了很多地方，具体改了哪不记得了，因此直接把整个代码拷过来了。
将WP Editor.md插件的src/App/ImagePaste.php文件内容改为以下即可：

<?php
/**
 * 图片上传接口
 */

namespace EditormdApp;

use EditormdUtils\Config;

/**
 * json数据结构：
 * - url    : 返回的图片地址，如果存在error可以为空
 * 
 * - error  : 返回的错误信息，可能值如下：
 *  1. file_extension_error: 文件扩展名错误，无论图片本身是什么格式，传递上来都应为image/png，致命错误，不返回图片地址
 *  2. file_too_large: 文件过大，常见于第三方图床，不返回图片地址
 *  3. file_repeated: 文件重复，常见于第三方图床，返回正确的图片地址
 *  4. unknown_error: 未知错误，详见detail
 * 
 * - detail : 其他信息，可能为以下几种格式：
 *  1. 在第三方图床请求正常的情况下，返回第三方图床返回的raw数据
 *  2. 在出现未知错误时，返回错误内容
 */
class ImagePaste {
    /*
     * WordPress预置常量
     */
    private $uploadUrl;
    private $uploadDir;
    private $tempDir;

    /*
     * 与图片相关的变量
     */
    private $extension;         // 保存的文件扩展名，一般为png
    private $name;              // 文件名，是所传递base64的md5值
    private $content;           // 文件二进制数据
    private $type;
    /*
     * 返回的数据
     */
    private $result;

    public function __construct() {
        add_action("wp_ajax_imagepaste_action", array($this, "editormd_imagepaste_action_callback"));
    }

    // 入口方法，根据配置进行下一步路由
    public function editormd_imagepaste_action_callback() {
        // 1. 采集用户上传的数据信息
        try {
            $this->result = array("error" => "");
            $this->uploadUrl = wp_upload_dir()["url"];
            $this->uploadDir = wp_upload_dir()["path"];
            $this->tempDir   = get_temp_dir();

            list($data, $image) = explode(";", $_REQUEST["dataurl"]);
            list($field, $type) = explode(":", $data);
            list($encoding, $this->content) = explode(",", $image);
            $this->type = $type;
            if ($type == "image/png") {
                $this->extension = "png";
            } else {
                $this->editormd_return_json("", "file_extension_error");
            }
            $this->name = "wp_editor_md_" . md5($_REQUEST["dataurl"]);
        } catch (Exception $e) {
            $this->editormd_return_json("", "unknown_error", "Exception occurred when parsing requests:" . $e->getMessage());
        }


        // 2. 选择上传目的地
        try {
            switch(Config::get_option("imagepaste_sm", "editor_basics")) {
                case "on":
                    $this->editormd_imagepaste_smms();
                    break;
                default:
                    $this->editormd_imagepaste_save();
                    break;
            }
            if($this->result["error"])
                die();
            //修改开始
            $attachment = array(
                'guid'           => $this->result["url"],
                'post_mime_type' => $this->type,
                'post_title'     => $this->name,
                'post_content'   => '',
                'post_status'    => 'inherit'
            );//文件属性
            // 插入附件信息
            $post_id = explode("&",explode("post=",wp_get_referer())[1])[0];//从request请求头refer中获取post_id
            $attach_id = wp_insert_attachment( $attachment, $this->result["url"],$post_id );
            // Make sure that this file is included, as wp_generate_attachment_metadata() depends on it.
            require_once( ABSPATH . 'wp-admin/includes/image.php' );

            // Generate the metadata for the attachment, and update the database record.
            $attach_data = wp_generate_attachment_metadata( $attach_id, $this->result["url"] );
            wp_update_attachment_metadata( $attach_id, $attach_data );
            //修改结束
            die();
        } catch (Exception $e) {
            $this->editormd_return_json("", "unknown_error", "Exception occurred when uploading:" . $e->getMessage());
        }

    }

    // 存储图片到本地
    private function editormd_imagepaste_save() {
        // 保存后进行转换
        $file    = $this->uploadDir . "/" . $this->name . "." . $this->extension;
        file_put_contents($file, base64_decode($this->content));
        $this->editormd_png2jpg($file);

        $this->extension = "jpg";
        $this->type = "image/jpeg";
        $fileUrl = $this->uploadUrl . "/" . $this->name . "." . $this->extension;

        $this->editormd_return_json($fileUrl);
    }

    // 上传图片到sm.ms
    private function editormd_imagepaste_smms() {       
        // 保存到临时目录
        $tempFile = $this->editormd_save_to_temp_dir();

        list($result, $reqCode) = $this->editormd_curl_post_file(
            "https://sm.ms/api/v2/upload", 
            array(
                "smfile" => new \CURLFile(realpath($tempFile)),
                "format" => "json"
            ), 
            array("Content-type: multipart/form-data")
        );

        switch($reqCode) {
            case 200:
                $data = json_decode($result, true);
                // 对图片重复的情况进行特殊处理
                if ($data["code"] == "image_repeated") {
                    $imageUrl = $data["images"];
                } else {
                    $imageUrl = $data["data"]["url"];
                }
                $this->editormd_return_json($imageUrl, "", $result);
                break;
            case 413:
                $this->editormd_return_json("", "file_too_large", "");
                break;
            default:
                $this->editormd_return_json("", "unknown_error", $reqCode . $result);
                break;
        }
    }

    // 以JSON形式返回结果
    private function editormd_return_json($url, $error="", $detail="") {
        // 格式化detail数据类型为字符串
        if (is_array($detail)) {
            $detail = json_encode($detail);
        }

        $this->result = [
            "url"       =>  $url,
            "error"     =>  $error,
            "detail"    =>  $detail
        ];
        echo json_encode($this->result, JSON_UNESCAPED_UNICODE);

    }

    // 将当前读取的数据保存到临时目录
    private function editormd_save_to_temp_dir() {
        $tempFile = $this->tempDir . $this->name . "." . $this->extension;
        file_put_contents($tempFile, base64_decode($this->content));
        $tempFile = $this->editormd_png2jpg($tempFile);

        return $tempFile;
    }

    // 将Base64生成的PNG保存为JPG以减小体积，加快上传和访问的速度
    private function editormd_png2jpg($filePath, $deleteOldFile=true) {
        $quality = 50;
        $newFilename = str_replace(".png", ".jpg", $filePath);

        $image = imagecreatefrompng($filePath);
        $bg = imagecreatetruecolor(imagesx($image), imagesy($image));

        imagefill($bg, 0, 0, imagecolorallocate($bg, 255, 255, 255));
        imagealphablending($bg, TRUE);
        imagecopy($bg, $image, 0, 0, 0, 0, imagesx($image), imagesy($image));
        imagedestroy($image);

        imagejpeg($bg, $newFilename, $quality);
        imagedestroy($bg);

        if ($deleteOldFile) {
            unlink($filePath);
        }

        return $newFilename;
    }

    // 使用curl发送post请求，可用于多种图床
    private function editormd_curl_post_file($url, $postField, $header) {
        $user_agent = "Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.1750.146 Safari/537.36";

        $ch      = curl_init();
        curl_setopt($ch, CURLOPT_URL,            $url);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);
        curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0); 
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt($ch, CURLOPT_POST,           1);
        curl_setopt($ch, CURLOPT_POSTFIELDS,     $postField);
        curl_setopt($ch, CURLOPT_USERAGENT,      $user_agent);
        curl_setopt($ch, CURLOPT_HTTPHEADER,     $header); 

        $result  = curl_exec($ch);

        $reqCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);

        return array($result, $reqCode);
    }
}

对于10.1.1之前的版本

找到WP Editor.md插件的src/App/ImagePaste.php文件。
找到这里，在第40行左右：

if ( defined( 'W3TC' ) ) {
    $result['w3tc'] = 1;
    ob_start();
    $result['log']    = $this->log;
    $result['output'] = ob_get_clean();
} else {
    $result['w3tc'] = 0;
}

在其下面添加：

//修改开始
$attachment = array(
    'guid'           => $fileUrl,
    'post_mime_type' => $type,
    'post_title'     => $name,
    'post_content'   => '',
    'post_status'    => 'inherit'
);//文件属性
// 插入附件信息

$post_id = explode("&",explode("post=",wp_get_referer())[1])[0];//从request请求头refer中获取post_id
$attach_id = wp_insert_attachment( $attachment, $file,$post_id );
// Make sure that this file is included, as wp_generate_attachment_metadata() depends on it.
require_once( ABSPATH . 'wp-admin/includes/image.php' );

// Generate the metadata for the attachment, and update the database record.
$attach_data = wp_generate_attachment_metadata( $attach_id, $file );
wp_update_attachment_metadata( $attach_id, $attach_data );
//修改结束

保存。再去试一下，粘贴图片在媒体库是不是就可以看到图片啦！