WordPress Plugin Front End Posting

front-end-posting.php

<?php
/*
Plugin Name: Front End Posting
Description: Create posts from the front end
Author: David Perálvarez
Version: 1.0
Author URI: https://silicodevalley.com
*/

// Front end submission form
function scv_submission_form(){
  if( !is_user_logged_in() ) return '<p>' . __( 'Para publicar un post, debes estar logueado.', 'scv' ) . '</p>';

  if( !is_page()) return '<p>' . __( 'Este shortcode sólo funciona dentro de páginas.', 'scv' ) . '</p>';

  ob_start();
  ?>
  <style>
  #scv-submission-form input,
  #scv-submission-form textarea{
    margin-bottom: 20px;
  }
  .scv-alert{
    padding: 10px;
    border: 1px solid black;
  }
  .scv-alert.error{
    border-color: #f44250;
  }
  .scv-alert.success{
    border-color: #09ef71;
  }
  </style>

  <?php do_action( 'scv_alerts' ); ?>
  <form id="scv-submission-form" action="" method="post">

    <label for="post-title"><?php _e( 'Título del post', 'scv' ); ?></label>
    <input name="post-title" id="post-title" type="text">

    <label for="post-content"><?php _e( 'Contenido del post', 'scv' ); ?></label>
    <textarea name="post-content" id="post-content" rows="4" cols="50"></textarea>

    <?php wp_nonce_field( 'post_nonce_action', 'post_nonce_field' ); ?>

    <input type="submit" value="<?php _e( 'Enviar para revisión', 'scv' ); ?>">

  </form><!-- #scv-submission-form -->
  <?php
  $output = ob_get_contents();
  ob_end_clean();
  return $output;
}

// Create the shortcode
add_shortcode( 'submission_form', 'scv_submission_form');

// Create the post
function scv_add_pending_post(){
  // Validate that the contents of the form came from the location on the current site and not somewhere else
  if( isset( $_POST['post_nonce_field'] )
      && wp_verify_nonce( $_POST['post_nonce_field'], 'post_nonce_action')){

      global $current_user;
      $userId = $current_user->ID;

      // Validate & escape the form fields
      $postTitle = $_POST['post-title'];
      $postContent = $_POST['post-content'];

      if( empty($postTitle) || empty($postContent) ){
        // Show error
        add_action( 'scv_alerts', 'scv_form_error' );
      }else{
        $postId = wp_insert_post( array(
          'post_content' => $postContent,
          'post_title' => $postTitle,
          'post_status' => 'pending',
          'post_author' => $userId,
          'post_type' => 'post'
        ) );
        // Show success
        add_action( 'scv_alerts', 'scv_form_success' );
      }
  }
}
add_action( 'init', 'scv_add_pending_post');

// Form error alert
function scv_form_error(){
  echo '<p class="scv-alert error">' . __( 'Completa todos los campos del formulario', 'scv' ) . '</p>';
}

// Form success alert
function scv_form_success(){
  echo '<p class="scv-alert success">' . __( 'Se ha publicado correctamente', 'scv' ) . '</p>';
}