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File Upload

The file upload field displays an inline upload area that you can drag and drop or select files to upload. It doesn't open the Media Library popup for selecting existing files. You can upload new files only.



Besides the common settings, this field has the following specific settings, the keys are for use with code:

Max number of filesmax_file_uploadsMax number of uploaded files. Optional.
Force deleteforce_deleteWhether or not delete the files from Media Library when deleting them from post meta. true or false (default). Optional. Note: it might affect other posts if you use the same file for multiple posts.
MIME typesmime_typeMIME type of files which we want to show in the Media Library. Note: this is a filter for items in the media popup, it doesn't restrict file types when uploading.
Show statusmax_statusDisplay how many files uploaded/remaining. Applied only when "Max number of files" is defined. true (default) or false. Optional.
Max file sizemax_file_sizeMaximum file size that the user can upload, in bytes. Optionally supports b, kb, mb, gb, tb suffixes. e.g. "10mb" or "1gb".

This is a sample field settings array when creating this field with code:

'id' => 'file',
'name' => 'File upload',
'type' => 'file_upload',
'force_delete' => false,
'max_file_uploads' => 2,
'mime_type' => 'application,audio,video',
'max_status' => false,


This field saves multiple attachment IDs in the database. Each value (attachment ID) is stored in a single row in the database with the same meta key (similar to what add_post_meta does with the last parameter false).

Template usage

Displaying uploaded files with links:

<?php $files = rwmb_meta( 'my_field_id' ); ?>
<h3>Uploaded files</h3>
<?php foreach ( $files as $file ) : ?>
<li><a href="<?= $file['url']; ?>"><?= $file['name']; ?></a></li>
<?php endforeach ?>

or simpler:

<h3>Uploaded files</h3>
<?php rwmb_the_value( 'my_field_id' ) ?>

rwmb_the_value() outputs files in an unordered list, while rwmb_meta() returns an array of files, each file has the following information:

'ID' => 123,
'name' => 'intro.txt',
'path' => '/var/www/wp-content/uploads/intro.txt',
'url' => '',
'title' => 'Introduction',

Displaying only one file:

<?php $files = rwmb_meta( 'my_field_id', ['limit' => 1] ) ?>
<?php $file = reset( $files ) ?>
<a class="button" href="<?= $file['url'] ?>">Download file</a>


This field has some filters to change the texts displayed on the screen..

rwmb_media_add_string+ Add MediaAdd new file string
rwmb_media_single_files_stringfileSingular "file" string
rwmb_media_multiple_files_stringfilesPlural "files" string
rwmb_media_remove_stringRemoveFile remove string
rwmb_media_edit_stringEditFile edit string
rwmb_media_view_stringViewFile view string
rwmb_media_select_stringSelect FilesSelect files string
rwmb_media_or_stringorThe string "or" in "Drop files here to upload or Select Files"
rwmb_media_upload_instructions_stringDrop files here to uploadThe upload instruction string

The code below changes the "+ Add Media" string:

add_filter( 'rwmb_media_add_string', function () {
return '+ New File';
} )

Binding events

You can bind various events during uploading via the data-uploader of the input like this:

jQuery( function( $ ){
setTimeout( function() {
const myUploader = $( 'input.rwmb-file_upload.rwmb-media' ).data( 'uploader' );

myUploader.uploader.bind( 'FileUploaded', function( up, file, res ) {
console.log( 'File Uploaded' );
} );
}, 1000 );
} );

You need to use setTimeout to make sure your code runs after the uploader is initialized.

Here is the list of events of the uploader. You can see more details about them in the official documentation of plupload, the library WordPress and Meta Box use for uploading files.

InitFires when the current uploader has been initialized.
PostInitFires after the init event in case you need to perform actions there.
RefreshFires when the silverlight/flash or other shim needs to move.
BrowseFires when browse_button is clicked and browse dialog shows.
BeforeUploadFires just before a file is uploaded. Can be used to cancel the upload for the specified file by returning false from the handler.
UploadFileFires when a file is to be uploaded by the runtime.
UploadProgressFires while a file is being uploaded. Use this event to update the current file upload progress.
BeforeChunkUploadFires just before a chunk is uploaded. This event enables you to override settings on the uploader instance before the chunk is uploaded.
ChunkUploadedFires when a file chunk is uploaded.
FileUploadedFires when a file is successfully uploaded.
UploadCompleteFires when all files in a queue are uploaded.
ErrorFires when an error occurs.
DestroyFires when destroy method is called.