wp_insert_post() post_author and return post_id are not working

Question

This is my first time creating a plugin for WordPress and I'm trying to create a plugin for Front-end form for logged in users. So far, the front-end form shows up on a page with a shortcode [write-here] and I check data goes into DB but there are couple things not working properly.

1. post_author does not get any value (According to this codex, it sets current user as default but no value goes into DB)

2. No return $post_id. I can't get the post ID return value after submitting the form.

3. Redirect is not working (This is probably becuase of wp_insert_post not working properly. Seems like nothing works after wp_insert_post)

Here is the code I have so far.

defined( 'ABSPATH' ) or die( 'No script kiddies please!' );
// Define plug-in path
define('WH_PATH', plugins_url() . '/write-here');
// Load css & js files
function my_enqueued_assets() {
    wp_enqueue_style( 'write-here', WH_PATH . '/css/write-here.css' );
    wp_enqueue_script( 'write-here', WH_PATH . '/js/write-here.js', array( 'jquery' ), '1.0', true );
}
add_action( 'wp_enqueue_scripts', 'my_enqueued_assets' );
/*
**  Add front end from in a Shortcode
    https://codex.wordpress.org/Function_Reference/add_shortcode
*/
function form_write_here(){
    $postdate = date('Y-m-d H:i:s');

    // Show only to logged in users
    if ( is_user_logged_in() ) {
?>
    <div class="write-here">
        <form id="new_post" name="new_post" method="post" action="">
            <label for="title">Title</label>
            <input type="text" id="title" name="title" />

            <label for="content">Content</label>
            <textarea id="content" name="content" rows="6"></textarea>

            <label for="cat">Category</label>
            <?php wp_dropdown_categories( 'show_option_none=Category&taxonomy=category&hide_empty=0' ); ?>

            <label for="post_tags">Tags</label>
            <input type="text" id="post_tags" name="post_tags" />

            <label for="date">Date</label>
            <input type="text" value="<?php echo $postdate; ?>" id="date" name="date" />

            <input type="submit" value="Publish" id="submit" name="submit" />
            <input type="hidden" name="action" value="write_here_new_post" />
            <?php wp_nonce_field( 'new-post' ); ?>
        </form>
    </div>
<?php
    }else{
        echo 'Please Sign in to continue...';
    }
}
add_shortcode('write-here', 'form_write_here');
/*
**  Process data from front end form
    http://codex.wordpress.org/Function_Reference/wp_insert_post
*/
if( 'POST' == $_SERVER['REQUEST_METHOD'] && !empty( $_POST['action'] ) &&  $_POST['action'] == "write_here_new_post") {
    // Do some minor form validation to make sure there is content
    if ($_POST['title']) {
        $title =  wp_strip_all_tags($_POST['title']);
    } else {
        echo 'Please enter a title';
    }
    if ($_POST['content']) {
        $content = $_POST['content'];
    } else {
        echo 'Please enter the content';
    }
    if ($_POST['date']) {
        $postdate = $_POST['date'];
    } else {
        $postdate = date('Y-m-d H:i:s');
    }
    $tags = $_POST['post_tags'];
    $cat  = $_POST['cat'];
    // Add the content of the form to $post as an array
    $new_post = array(
        'post_title'    => $title,
        'post_content'  => $content,
        'post_category' => array($cat),   // Default empty.
        'tags_input'    => array($tags),    // Default empty.
        'post_status'   => 'publish',       // Choose: publish, preview, future, draft, etc. Default 'draft'.
        'post_date'     => $postdate,      // The time post was made.
        'post_date_gmt' => $postdate       // The time post was made, in GMT.
    );
    //save the new post and return its ID
    $post_id = wp_insert_post($new_post, $wp_error ); // this not working
    // redirect after submition
    wp_redirect( site_url()."?post=".$post_id);
    exit();
}

Feel free to make comments for any suggestions as well. Thank you!

Answer 1

Updating answer for people who might have same issue as me.

I wrapped up front end form and the code to execute the date from the form into functions and it started to work.

I also added additional functions for loading CSS/JS files only on the page where plugin is being used. Along with error message function.

Here is the new code

defined( 'ABSPATH' ) or die( 'No script kiddies please!' );

// Define plug-in path
define('WH_PATH', plugins_url() . '/write-here');


/*
** Register CSS & JS assets for plug in
------------------------------------------------------------------
*/
// register our form css
function write_here_register_assets() {
    wp_register_style('write-here', WH_PATH . '/css/write-here.css');
    wp_register_script( 'write-here', WH_PATH . '/js/write-here.js', array( 'jquery' ), '1.0', true );
}
add_action('init', 'write_here_register_assets');

// load our form css
function write_here_print_assets() {
    global $write_here_load_assets;

    if ( !$write_here_load_assets )
        return;

    wp_print_styles('write-here');
    wp_print_scripts('write-here');
}
add_action('wp_footer', 'write_here_print_assets');


/*
**  Add a shortcode for front end form
    https://codex.wordpress.org/Function_Reference/add_shortcode
*/
function form_write_here(){
    // Load CSS & JS files
    global $write_here_load_assets;
    $write_here_load_assets = true;

    // Show only to logged in users
    if ( is_user_logged_in() ) {
        $output = write_here_form();
        return $output;
    }else{
        echo 'Please Sign in to continue...';
    }
}
add_shortcode('write-here', 'form_write_here');


/*
**  Front end From
    ------------------------------------------------------------------
*/
function write_here_form(){
    ob_start();
    $postdate = date('Y-m-d H:i:s');
?>
<div class="write-here">
    <?php write_here_show_error_messages(); ?>
    <form id="new_post" name="new_post" method="post" action="">
        <label for="title">Title</label>
        <input type="text" id="title" name="title" />

        <label for="content">Content</label>
        <textarea id="content" name="content" rows="6"></textarea>

        <label for="cat">Category</label>
        <?php wp_dropdown_categories( 'show_option_none=Category&taxonomy=category&hide_empty=0' ); ?>

        <label for="post_tags">Tags</label>
        <input type="text" id="post_tags" name="post_tags" />

        <label for="date">Date</label>
        <input type="text" value="<?php echo $postdate; ?>" id="date" name="date" />

        <input type="submit" value="Publish" id="submit" name="submit" />
        <input type="hidden" name="action" value="write_here_new_post" />
        <?php wp_nonce_field( 'new-post' ); ?>
    </form>
</div>
<?php  
    return ob_get_clean();
}


/*
**  Process data from front end form
    http://codex.wordpress.org/Function_Reference/wp_insert_post
*/
function write_here_add_new_post() {
    if( 'POST' == $_SERVER['REQUEST_METHOD'] && !empty( $_POST['action'] ) &&  $_POST['action'] == "write_here_new_post") {

        $title =  wp_strip_all_tags($_POST['title']);
        $content = $_POST['content'];
        $postdate = $_POST['date'];
        $tags = $_POST['post_tags'];
        $cat  = $_POST['cat'];

        // Do some minor form validation to make sure there is content
        if ($title == '') {
            write_here_errors()->add('title_not_vaild', __('Title not valid'));
        }
        if ($content == '') {
            write_here_errors()->add('content_not_vaild', __('Content not valid'));
            return false;
        }
        if (!$postdate) {
            $postdate = date('Y-m-d H:i:s');
        }

        // Add the content of the form to $post as an array
        $new_post = array(
            'post_title'    => $title,
            'post_content'  => $content,
            'post_category' => array($cat),   // Default empty.
            'tags_input'    => array($tags),    // Default empty.
            'post_status'   => 'publish',       // Choose: publish, preview, future, draft, etc. Default 'draft'.
            'post_date'     => $postdate,      // The time post was made.
            'post_date_gmt' => $postdate       // The time post was made, in GMT.
        );

        $errors = write_here_errors()->get_error_messages();

        // only create post if there are no errors
        if(empty($errors)) {
            //save the new post and return its ID
            $post_id = wp_insert_post($new_post);

            if($post_id) {
                // This will redirect you to the newly created post (Using GUID)
                $post = get_post($post_id);
                wp_redirect($post->guid);
                exit();
            }
        }
    }
}
add_action('init', 'write_here_add_new_post');

// used for tracking error messages
function write_here_errors(){
    static $wp_error; // Will hold global variable safely
    return isset($wp_error) ? $wp_error : ($wp_error = new WP_Error(null, null, null));
}

// displays error messages from form submissions
function write_here_show_error_messages() {
    if($codes = write_here_errors()->get_error_codes()) {
        echo '<div class="form-error">';
        // Loop error codes and display errors
        foreach($codes as $code){
            $message = write_here_errors()->get_error_message($code);
            echo '<span class="error"><strong>' . __('Error') . '</strong>: ' . $message . '</span><br/>';
        }
        echo '</div>';
    }   
}

Please feel free to make comments for any suggestions.