any good way to redirect to original url from a custom login form ?

[adrianmak]

This is my original question asking for access control for a template

https://processwire.com/talk/topic/8847-redirect-to-a-url-in-the-access-tab-of-a-template/

Eventually, as of Soma suggestion, I implemented access control and redirection in template itself.

The problem is after a sucessful login, the $session ->redirect method only destinate to one assigned url (in my case it is the homepage).

Reading the api doc, the session redirect provide just a simple url redirection. NO MORE functionality provided.

Then I append a GET variable on redirect url

a page template  required a specific user role privilege

<?php

if (!$user->isLoggedin()) {
    /* get current page id for page redirection after a successful login */
    $pageId = $page->id;
    $session->redirect(($pages->get("template=login")->url . "?redirect=" . $pageId));   
} 

/* required user with role registered to view this template */
if ($user->hasRole("registered")) {
    $page->title;
    $page->body;
} else {
    $page->body = "Your account do not have enough access privileges to view this page.";
}
include('./main.php');

login form template

<?php
$pageID = $_GET["redirect"];

    $lang = ($user->language->name == 'default') ? '' : $user->language->name . '/';
    if ($user->isLoggedin()) {
        $session->redirect($config->urls->root . $lang);
    }

    if ($input->post->user && $input->post->pass) {
        $username = $sanitizer->username($input->post->user);
        $password = $input->post->pass;
        $pageID = $input->post->redirect;
        $redirectPage = $pages->get($pageID)->url;

        try {
            if ($session->login($username, $password)) {
                if ($redirectPage) 
                    $session->redirect($redirectPage);

                $session->redirect($config->urls->root . $lang);
            } else {
                $error = "Wrong username or password. Login failed.";
            }
        } catch (Exception $e) {
            $error = $e->getMessage();
        }        
    }

$form_title = __("Sign In");
$form_user = __("User");
$form_pass = __("Password");
$form_submit_btn = __("Sign in");
$form_error =  __("Login failed");


$page->title = "User Login";
$page->body .= "
<div class='container'>
    <div class='col-md-12'>
        <div class='login-box'>
        <div class='panel panel-default'>
            <div class='panel-heading'>
                <h3 class='panel-title'><span class='lock-icon'></span><strong>$form_title</strong></h3>
            </div>
            <div class='panel-body'>
                <form role='form' action='./' method='post'>
                    <div class='message-error'>$error</div>
                    <input type='hidden' name='redirect' value=$pageID />
                    <div class='form-group'>
                        <label for='user'>$form_user</label>
                        <input type='text' name='user' id='user' class='form-control' placeholder=$form_user />
                    </div>
                    <div class='form-group'>
                        <label for='pass'>$form_pass</label>
                        <input type='password' name='pass' id='pass' class='form-control' placeholder=$form_pass />
                    </div>
                    <button type='submit' class='btn btn-sm btn-primary'>$form_submit_btn</button>
                </form>
            </div>
        </div>
        </div>
    </div>
</div>
";

include('./main.php');
?>

Retrieve the original url from the GET variable and  store in a form hidden field.

When  a successful login, checking this variable, if null , redirect to homepage or otherwise to that url

is it secure to implement in this way ?

[ESRCH]

Your method seems secure enough. You are after all not sending a 404, so your user already knows that the url that they originally requested exists.

Another method is to use the session to store the redirect url. So in the restricted page you would do:

if (!$user->isLoggedin()) {
    // Store requested url in the session, then redirect
    $session->set('redirect', $page->url);
    $session->redirect($pages->get('template=login')->url);
}

and on the login page you could have

// Edit: This code is not correct as-is, please note Soma's post below including the try-catch block around the login code!

<?php

    if ($user->isLoggedin()) {
        $session->redirect($pages->get('/')->url);
    }

    if ($input->post->user && $input->post->pass) {
        $username = $sanitizer->username($input->post->user);
        $password = $input->post->pass;

        if ($session->login($username, $password)) {
            if ($redirectUrl = $session->get('redirect')){
                $session->remove('redirect');
                $session->redirect($redirectUrl);
            } else {
                $session->redirect($pages->get('/')->url);
            }
        } else {
            $error = "Wrong username or password. Login failed.";
        }
    }

[pjg]

For a very elegant solution you could change the behaviour of the access control via hooking into the execute function of the ProcessPageView module. You'd either have to modify the behaviour of the checkAccess function (which isn't hookable, but you can define a replacement in your hook) to change the way the redirect url option on the existing templates behaves, or you could add an additional method by hooking into the ProcessTemplates module as well.

I've got an example on one of my boxes, but can't access the files from here - will try and remember tonight.

The usual disclaimer about relying on hooks as a way of changing core behaviour potentially causing issues in future releases applies.

EDIT: The solution becomes elegant when utilising ESRCH's approach in the hook, in addition to modifying the login behaviour accordingly to handle the stored (or not) redirect session variable.

[Soma]

@ESRCH

That login code will throw error if you login 3 times with wrong credentials... I already tried to put a note in those various (dozens already and lost track of) threads that use this "exact" frontend login code, which works but has one flaw. Problem is that once the login throttle kicks in you're left with a exception error. It's not obvious and I think posting that code in the forum over and over just creates problems in the long run for everyone copy paste such code. Funny thing is that the code originally is from Ryan himself.

Either Ryan should change the behaviour of the throttle code or you need to use this code instead with a try catch to catch the login throttle error:

if ($user->isLoggedin()) {
    $session->redirect($pages->get('/')->url);
}

if ($input->post->user && $input->post->pass) {
    $username = $sanitizer->username($input->post->user);
    $password = $input->post->pass;
    
    try{
        $u = $session->login($username, $password);
        if ($u) {
            if ($redirectUrl = $session->get('redirect')){
                $session->remove('redirect');
                $session->redirect($redirectUrl);
            } else {
                $session->redirect($pages->get('/')->url);
            }
        } else {
            $error = "Wrong username or password. Login failed.";
        }
    } catch(Exception $e){
       $error = $e->getMessage();
    
    }
}

[ESRCH]

@Soma

Thanks for the correction, I wasn't aware of this (and I incorrectly changed adrianmak's code). I made an edit in my post so that others might look at your comment.

[adrianmak]

Using session method suggested by ESRCH is much nicer than mine

[alan]

Sorry for perhaps not understanding the above Soma (and others) post, but does anyone know if there is, ideally, a best practice way to have SessionLoginThrottle setup so it redirects to somewhere where a friendly error may be displayed, like the Maintenance Mode module can?

Context: I have a site on PW dev 2.6.17 and when it hit a session throttle problem (me logged in on one computer logging in or out too quickly on a 2nd I think at almost the same time (I wasn't trying to break it—honest)) the result was the generic empty white "Website has encountered an error it has been logged" type message.