DropzoneJS & WordPress REST API with Custom Endpoint

readme.txt

About:
The plugin provides drag’n’drop file uploads and uses the wp rest api to upload the file. 
This version adds a custom endpoint, has code for handling the upload and uploads the file to uploads/yyyy/mm without 
adding the file to the media library.

Installation:

Save dropzonejs-wp-rest-api-custom-endpoint.php in wp-content/plugins/dropzonejs-wp-rest-api-custom-endpoint/
Save dropzonejs-wp-rest-api-custom-endpoint.js in wp-content/plugins/dropzonejs-wp-rest-api-custom-endpoint/js/

Use:
After activating the plugin, add the [dropzonerest] shortcode to a post

Credits:
http://www.dropzonejs.com/
https://github.com/WP-API/WP-API, I learned a lot reading the wp-api source

Copyright:
The plugin is copyright Per Soderlind - per@soderlind.no

License: GPL, please feel free to modify the plugin as long as you make it GPL

dropzonejs-wp-rest-api-custom-endpoint.js

// dropzoneWordpressRestApiForm is the configuration for the element that has an id attribute
// with the value dropzone-wordpress-rest-api-form (or dropzoneWordpressRestApiForm)
Dropzone.options.dropzoneWordpressRestApiForm = {
	//acceptedFiles: "image/*", // all image mime types
	acceptedFiles: ".jpg", // only .jpg files
	maxFiles: 1,
	uploadMultiple: false,
	maxFilesize: 5, // 5 MB
	init: function() {
		console.group('dropzonejs-wp-rest-api:');
		var myDropzone = this; // closure
		myDropzone.on("sending", function(file, xhr, data) {
			console.log("file: %O", file);

			//add nonce, from: http://v2.wp-api.org/guide/authentication/
			xhr.setRequestHeader('X-WP-Nonce', WP_API_Settings.nonce);
		});
		// myDropzone.on("processing", function(file) {
		//   this.options.url = WP_API_Settings.root + 'wp/v2/media/';
		// });
		myDropzone.on("error", function(file, error, xhr) {
			console.error("ERROR: %o", error);
			console.groupEnd();
		});
		myDropzone.on("success", function(file, response) {
			console.log("success: %o", response);
			// etc
		});
	}
};

dropzonejs-wp-rest-api-custom-endpoint.php

<?php
/*
Plugin Name: DropzoneJS & WordPress REST API with Custom Endpoint
Version: 0.0.1
Description: Demos how to upload files using DropzoneJS and the  WordPress REST API (wp-api v2)
Author: Per Soderlind
Author URI: https://soderlind.no
Plugin URI: https://gist.github.com/soderlind/
License: GPL
 */


define( 'DROPZONEJS_WP_REST_API_PLUGIN_URL',   plugin_dir_url( __FILE__ ) );
define( 'DROPZONEJS_WP_REST_API_PLUGIN_VERSION', '0.0.1' );
define( 'DROPZONEJS_WP_REST_API_NAMESPACE', 'dropzonejs/v' . DROPZONEJS_WP_REST_API_PLUGIN_VERSION );
define( 'DROPZONEJS_WP_REST_API_BASE', 'upload' );


add_action( 'plugins_loaded', 'dropzonejs_wp_rest_api_init' );

function dropzonejs_wp_rest_api_init() {
	add_action( 'wp_enqueue_scripts', 'dropzonejs_wp_rest_api_enqueue_scripts' );
	add_shortcode( 'dropzonerest', 'dropzonejs_wp_rest_api_shortcode' );
}

function dropzonejs_wp_rest_api_enqueue_scripts() {

	wp_enqueue_script(
		'dropzonejs',
		'https://cdnjs.cloudflare.com/ajax/libs/dropzone/4.2.0/min/dropzone.min.js',
		array(),
		DROPZONEJS_WP_REST_API_PLUGIN_VERSION
	);

	// Load custom dropzone javascript
	wp_enqueue_script(
		'dropzone-wp-rest',
		DROPZONEJS_WP_REST_API_PLUGIN_URL . '/js/dropzonejs-wp-rest-api-custom-endpoint.js',
		array( 'wp-api', 'dropzonejs' ),
		DROPZONEJS_WP_REST_API_PLUGIN_VERSION
	);

	wp_enqueue_style(
		'dropzonecss',
		'https://cdnjs.cloudflare.com/ajax/libs/dropzone/4.2.0/min/dropzone.min.css',
		array(),
		DROPZONEJS_WP_REST_API_PLUGIN_VERSION
	);

	// from: http://v2.wp-api.org/guide/authentication/
	wp_enqueue_script( 'wp-api' );
	wp_localize_script(
		'wp-api',
		'WP_API_Settings',
		array(
			'root'        => esc_url_raw( rest_url() ),
			'nonce'       => wp_create_nonce( 'wp_rest' ),
			'title'       => 'Media Title',
			'description' => 'Media Description',
			'alt_text'    => 'Media Alt Text',
			'caption'     => 'Media Caption'
		)
	);
}


// Add Shortcode
function dropzonejs_wp_rest_api_shortcode( $atts ) {

	//user can ?
	if ( ! is_user_logged_in() || !current_user_can( 'upload_files' ) ) {
		return;
	}

	$url   = rest_url() . DROPZONEJS_WP_REST_API_NAMESPACE . '/' . DROPZONEJS_WP_REST_API_BASE;
	return <<<ENDFORM
<div id="dropzone-wordpress-rest-api"><form action="$url" class="dropzone needsclick dz-clickable" id="dropzone-wordpress-rest-api-form">
	<div class="dz-message needsclick">
		Drop files here or click to upload.<br>
		<span class="note needsclick">(Files are uploaded to uploads/yyyy/mm)</span>
  	</div>
	<input type='hidden' name='action' value='submit_dropzonejs'>
</form></div>
ENDFORM;

}


/**
 * register custom endpoint, see http://v2.wp-api.org/extending/adding/
 */
add_action( 'rest_api_init', function () {
		register_rest_route( DROPZONEJS_WP_REST_API_NAMESPACE, '/' . DROPZONEJS_WP_REST_API_BASE , array(
				'methods' => 'POST',
				'callback' => 'dropzonejs_upload',
				'permission_callback' => function () {
					return current_user_can( 'upload_files' );
				}
			) );
	} );


/**
 * dropzonejs_upload hadles the upload, code from https://github.com/WP-API/WP-API/blob/47491996f08a3f51883dbae6f6fd0c94ade90c9f/lib/endpoints/class-wp-rest-attachments-controller.php#L56
 *
 * @param WP_REST_Request $request The request object has the  multipart file parameters and the given header from the request.
 * @return WP_HTTP_Response   The response has the name, file type and url of the uploaded file
 */
function dropzonejs_upload( WP_REST_Request $request ) {
	// Get the file via $_FILES (raw data ignored)
	$files   = $request->get_file_params();
	$headers = $request->get_headers();
	$file = dropzonejs_upload_file( $files, $headers );

	if ( is_wp_error( $file ) ) {
		return $file;
	}

	// Wrap the data in a response object
	$data = array();
	$data['name'] = basename( $file['file'] );
	$data['url']  = $file['url'];
	$data['type'] = $file['type'];
	$response     = rest_ensure_response( $data );
	$response->set_status( 201 );
	return $response;
}

/**
 * dropzonejs_upload_file does the actual upload, it's a strip down version of https://github.com/WP-API/WP-API/blob/47491996f08a3f51883dbae6f6fd0c94ade90c9f/lib/endpoints/class-wp-rest-attachments-controller.php#L451
 *
 * @param array   $files   Data from $_FILES
 * @param array   $headers HTTP headers from the request
 * @return array|WP_Error Data from {@see wp_handle_upload()}
 */
function dropzonejs_upload_file( $files, $headers ) {
	if ( empty( $files ) ) {
		return new WP_Error( 'rest_upload_no_data', __( 'No data supplied' ), array( 'status' => 400 ) );
	}
	// Verify hash, if given
	if ( ! empty( $headers['content_md5'] ) ) {
		$content_md5 = array_shift( $headers['content_md5'] );
		$expected    = trim( $content_md5 );
		$actual      = md5_file( $files['file']['tmp_name'] );
		if ( $expected !== $actual ) {
			return new WP_Error( 'rest_upload_hash_mismatch', __( 'Content hash did not match expected' ), array( 'status' => 412 ) );
		}
	}
	// Pass off to WP to handle the actual upload
	$overrides = array(
		'test_form'   => false,
	);
	// Bypasses is_uploaded_file() when running unit tests
	if ( defined( 'DIR_TESTDATA' ) && DIR_TESTDATA ) {
		$overrides['action'] = 'wp_handle_mock_upload';
	}
	/** Include admin functions to get access to wp_handle_upload() */
	require_once ABSPATH . 'wp-admin/includes/admin.php';
	$file = wp_handle_upload( $files['file'], $overrides );
	if ( isset( $file['error'] ) ) {
		return new WP_Error( 'rest_upload_unknown_error', $file['error'], array( 'status' => 500 ) );
	}
	return $file;
}