WPGraphQL search by field with regular expressions support

README.md

WPGraphQL search by field with regular expressions support

Adds a where field to WPGraphQL content nodes (post, page and custom post types) to search by field using regexp or like. Supported fields are name, title, author, excerpt, status and mime_type.

Usage

0. Install WPGraphQL
1. Download or copy the wpgraphql-search-field.php file
2. Place it under wp-content/mu-plugins
3. Done

wpgraphql-search-field.php

<?php
/**
 * Plugin Name:     WPGraphQL Search by Field
 * Plugin URI:      https://gist.github.com/lightningspirit/45b63ab7baa5bf076f2f2be5da400431
 * Author:          Move Your Digital, Inc.
 * Author URI:      https://moveyourdigital.com
 * Version:         0.1.0
 *
 * @package         WPGraphQL_Search_By_Field
 */

/*
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

use WPGraphQL\Registry\TypeRegistry;

/**
 *
 */
add_action('graphql_register_types', function (TypeRegistry $registry) {
  register_graphql_enum_type('SearchFieldFieldsEnum', [
    'description' => __('Search field available fields', 'wp-graphql'),
    'values' => [
      'NAME' => [
        'value' => 'name',
      ],
      'TITLE' => [
        'value' => 'title',
      ],
      'AUTHOR' => [
        'value' => 'author',
      ],
      'EXCERPT' => [
        'value' => 'excerpt',
      ],
      'STATUS' => [
        'value' => 'status',
      ],
      'MIME_TYPE' => [
        'value' => 'mime_type',
      ],
    ]
  ]);

  register_graphql_enum_type('SearchFieldOperatorEnum', [
    'description' => __('Search field available operators', 'wp-graphql'),
    'values' => [
      'LIKE' => [
        'value' => 'like',
      ],
      'REGEXP' => [
        'description' => __('Only available for MySQL 5.6+', 'wp-graphql'),
        'value' => 'regexp',
      ],
    ]
  ]);

  register_graphql_input_type('SearchFieldInput', [
    'description' => __('Search field input options', 'wp-graphql'),
    'fields' => [
      'field' => [
        'description' => __('The field to search in', 'wp-graphql'),
        'type' => [
          'non_null' => 'SearchFieldFieldsEnum',
        ]
      ],
      'operator' => [
        'description' => __('The search operator', 'wp-graphql'),
        'type' => 'SearchFieldOperatorEnum'
      ],
      'search' => [
        'description' => __('The search term', 'wp-graphql'),
        'type' => 'String',
      ]
    ]
  ]);

  $args = [
    'searchField' => [
      'description' => __('Filter by search of one field', 'wp-graphql'),
      'type' => 'SearchFieldInput',
    ],
  ];

  register_graphql_fields(
    "RootQueryToContentNodeConnectionWhereArgs",
    $args
  );

  foreach (\WPGraphQL::get_allowed_post_types() as $post_type) {
    $post_type = get_post_type_object($post_type);
    $type = ucfirst($post_type->graphql_single_name);

    register_graphql_fields(
      "RootQueryTo${type}ConnectionWhereArgs",
      $args
    );
  }
});

/**
 *
 */
add_filter('graphql_post_object_connection_query_args', function (
  $query_args, $_, $args
) {

  $isset_search_field = isset($args['where']['searchField']);

  if ($isset_search_field) {
    $query_args['search_field'] = $args['where']['searchField'];
  }

  return $query_args;
}, 10, 3);

/**
 * Since core query cannot search in one field,
 * we need to hack the posts_where filter and
 * generate our own SQL
 */
add_filter('posts_where', function ($where, $query) {
  global $wpdb;

  $search_field = $query->get('search_field');

  if ($search_field) {
    $field = esc_sql($search_field['field']);
    $search = esc_sql($search_field['search']);

    switch ($search_field['operator']) {
      case 'regexp':
        $operator = 'REGEXP';
        break;

      case 'like':
      default:
        $operator = 'LIKE';
        if (empty($search)) {
          $search = '%';
        }
    }

    $where .= " AND $wpdb->posts.post_$field $operator '$search'";
  }

  return $where;
}, 10, 2);