我在你的评论中注意到。。。

返回上载的图像ID，以便用于更新ACF字段

这里有两个函数可以帮助您解决。。。

• gf_handle_attachments() 将gform提交图像文件转换为wordpress媒体附件。正在返回媒体（附件）id。
• gf_upload_to_media_acf() 处理gform提交的图像或多个图像，并使用媒体附件更新定义的acf（图像、文件或库）字段

文件类型jpeg, jpg, png, 和gif 仅在我测试过的情况下才适用。文件类型pdf 不喜欢添加到acfimage 和gallery 字段。这个pdf 仍会添加，但WordPress会添加not 创建任何预览。

$filename 参数不仅仅是文件名，它是通过https 或http. 基本上gform提交的协议。

以下是gf_handle_attachments() 处理转换单个$filename 进入wordpress媒体附件。返回附件id。

// save image to media library and then save the image to acf field
function gf_handle_attachments($filename, $parent_post_id) {

    // check the type of file
    // we\'ll use this as the \'post_mime_type\'
    $file_type = wp_check_filetype( basename( $filename ), null );

    // get the path to the upload directory
    $wp_upload_dir = wp_upload_dir();

    // prepare an array of attachment post data
    $attachment = [
        \'guid\'           => $wp_upload_dir[\'url\'] . \'/\' . basename( $filename ),
        \'post_mime_type\' => $file_type[\'type\'],
        \'post_title\'     => preg_replace( \'/\\.[^.]+$/\', \'\', basename( $filename ) ),
        \'post_content\'   => \'\',
        \'post_status\'    => \'inherit\'
    ];

    // insert the attachment
    $attach_id = wp_insert_attachment($attachment, $filename, $parent_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,$filename);
    wp_update_attachment_metadata($attach_id, $attach_data);

    // delete file from gf uploads
    //unlink($filename);

    // return attachment id
    return $attach_id;

}

这是gf_upload_to_media_acf() 接受提交的gfrom文件上载或gfrom多文件上载条目的函数$value 并将它们添加到定义的acf（图像、文件或库）$field 已定义为$post_id.

// upload gf uploads media to post acf field
function gf_upload_to_media_acf($value, $post_id, $field) {

    // if entry value begins with json brackets (gfrom multi-file upload entry)
    if(substr($value,0,2) === \'["\') {

        // decode gfrom entry value into array
        $filenames = json_decode(stripslashes($value));

        // lets begin multiple attachment array
        $attach_ids = [];

        // for each filenames as filename
        foreach ($filenames as $filename) {

            // handle each filename to wordpress media attachment linked to post
            $attach_ids[] = gf_handle_attachments($filename, $post_id);

        }

        // update acf (gallery) field with the attachment ids
        update_field($field, $attach_ids, $post_id);

    // else if single gform image upload entry
    } else {

        // handle single media attachment and return attachment id
        $attach_id = gf_handle_attachments($value, $post_id);

        // update acf (image, file or gallery) field for post with the attachment id
        update_field($field, $attach_id, $post_id);

    }

}

以下是使用gform_confirmation 创建新帖子并使用update_entry_data_fields() 函数传递条目数据，然后处理指定的条目字段（文件上载）。。。

// filter to fire when gfrom id 1 hits confirmation
add_filter(\'gform_confirmation_1\', \'form_confirmation\', 10, 4 );

// form confirmation function for above gform filter
function form_confirmation($confirmation, $form, $entry, $ajax) {

    // new post settings array
    $post = [
        \'post_type\'     => \'post\',
        \'post_status\'   => \'pending\'
    ];

    // create new post for our submission using post array settings and return the newly created post id to result variable
    $result = wp_insert_post($post);

    // if result post id and is not a wp_error then...
    if($result && !is_wp_error($result)) {

        // get the created result post id
        $post_id = $result;

        // create our post title
        $title = \'Post #\' . $post_id;

        // new submission array to use to update the created post
        $submission = [
            \'ID\'            => $post_id,
            \'post_title\'    => $title,
            \'post_name\'     => sanitize_title($title)
        ];

        // update the created submission post with new submission array data
        wp_update_post($submission);

        // update this post acf fields with entry data
        update_entry_data_fields($post_id, $entry);

        // return submission post id if you wana 
        return $post_id;

    }

    // return false
    return false;

}

此update_entry_data_fields() 函数是我们使用的地方gf_upload_to_media_acf() 用于gform提交文件上载条目数据的函数。。。

// update acf fields or anything else for defined post id using gform submission entry array data
function update_entry_data_fields($post_id, $entry) {

    // if form submission entry is array
    if(is_array($entry)) {

        // for each entry item
        foreach ($entry as $key => $value) {

            // if entry key is our gform file upload or multi-file upload entry field
            if($key === \'1.8\') {

                // if we have a entry value
                if($value) {

                    // image, file or gallery acf field name
                    $acf_field = \'acf_field_name\';

                    // handle the media attachment(s) creation and add attachment(s) to acf (image, file, or gallery) field via acf_field_name
                    gf_upload_to_media_acf($value, $post_id, $acf_field);

                }

            }

        }

    }

}