How to filter posts by author on edit.php

Question

Let's suppose the user visits the page of

http://mywpsite/wp-admin/edit.php?author=john-doe

Let's suppose there is an author with the name of 'John Doe' and the given author has three posts. Yet, when I visit the page, I see an empty grid, as if there were no posts created by this author.

I would like to search for posts created by the given user. Based on my research, I can see that people are claiming that something like this should work:

function posts_for_current_author($query) {

    if($query->is_admin) {

        global $user_ID;
        $query->set('author',  $user_ID);
    }
    return $query;
}
add_filter('pre_get_posts', 'posts_for_current_author');

Source .

However, here the author's ID is expected as input, yet, I do not know how to get the author's id by the slug of 'john-doe' .

How can I get the ID of the author by slug and search for posts based on that ID?

EDIT:

This is one failed try, based on NATH's comment:

function wpshock_search_filter( $query ) {
    if ((is_admin()) && (isset($_GET["author"])) && (preg_match('/[^a-zA-Z_0-9]/i', $_GET["author"]))) {
        $query->set("author_name", $_GET["author"]);
    }
    return $query;
}
add_filter('pre_get_posts','wpshock_search_filter');

The query still returns no elements. I have var_dump ed $query and seen that $query->query["author"] has the textual problem, which is a potential problem. Also, $query->tax_query contains data related to author. I am sorry if this question is worthy of down-votes, I thought others might be confused by Wordpress's database handling as well and thus this question might be useful. Maybe I was wrong.

Answer 1

This should work for you :

get_user_by('slug','john-doe');

EDIT : From this you can get author object and you can carry forward with your code.

Link

Answer 2

WordPress provides an author_name query variable to you. You can use the following by default:

http://mywpsite/wp-admin/edit.php?author_name=john-doe

Read more about public query variables in the Codex .

Answer 3

I'm wotking on wp front-end and reach similar feauture you are requested

The code you provide are woking current on wp-admin page but any one uses that code prevent his own SuperAdmin account form reviewing other editors posts .
just add !is_super_admin() to your first contition like this :-

if($query->is_admin && !is_super_admin() )

BTW the author's ID are already provided with global $user_ID; and when you add this $query->set('author',$user_ID); the main query will filter posts result accurding to author ID , see WP_Query();

Answer 4

See this-

https://wordpress.stackexchange.com/questions/89990/how-we-can-get-the-author-id-by-its-name

And, a better way to get posts by an author would be-

get_posts('author'=>AUTHOR_ID);