Login redirect to previous page

You can filter the login_redirect function like so, adapt according to your needs.

add_filter('login_redirect', 'redirect_previous_page', 10, 1);

function redirect_previous_page( $redirect_to ){
    global $user;

    $request = $_SERVER["HTTP_REFERER"];

    if ( in_array( $user->roles[0], array( 'administrator') ) ) {

        return admin_url();

    } elseif ( in_array( $user->roles[0], array( 'subscriber') ) ) {

        return $request;
    } 

    return $redirect_to;
}

Update 1:

Code (above) has been modified above and tested – it works.

Update 2: (by Tanya)

Chatted with @userabuser and came up with this answer that works.

// Redirect to previous page 
remove_all_filters('login_redirect', 99);
add_filter('bbp_user_login_redirect_to', 'function_name');

Important note:

It turns out that Tanya was using the bbPress forum plugin, therefore despite the original snippet which uses,

add_filter('login_redirect', 'function_name'); //the standard WordPress API filter

which is correct and does work under “normal” WordPress conditions, was, in this case being overwritten in priority by the bbPress filter,

add_filter('bbp_user_login_redirect_to', 'function_name'); //the bbPress API filter

Now since the documentation on the bbPress.org website which details these actions and hooks is poorly organized and somewhat incomplete (far as I can tell), I suggest that (anyone) seeking further information about what hooks where and what filters what, should take a look at this resource here which provides a detailed list of hooks and filters.

Notes: (miscellaneous)

Change 'subscriber' to match the role you are using for that type of user. It can also accept multiple roles since its in the form of an array.

in_array( $user->roles[0], array( 'subscriber', 'role2, role3', 'etc')