Laravel Error Message : TokenMismatchExeption

This is an article which written for discussing on facing an error generated in the process of developing a web-based application using Laravel framework as its base framework. It happens in the time of using Form class. Having already defined the following snippet code :

<form id="general_form" class="form-horizontal">
</form>

Inside the file located in resources/views which is a blade view template file, it is actually generated the following error as presented in the image below :

An error is shown as defined above which is the same with the titled of this article written, ‘TokenMismatchException’.

Defining form tag in a blade view file template located in resources/views inside the root folder of a web-based application project using Laravel framework definitely generate the above error.

The error is presented whenever a specific URL accessed after defined in the route file located normally in routes/web.php in a Laravel framework version 5.3. And in a file named routes.php located in app/Http for Laravel framework before version 5.3.

To resolve the error above, it needs the following snippet code so that the page can be displayed property as follows :

<input type="hidden" name="_token" value="{{ csrf_token() }}">

The above snippet code must be inserted in the form tag declaration. So, the full declaration is shown as follows :

<form id="general_form" class="form-horizontal">
<input type="hidden" name="_token" value="{{ csrf_token() }}">
</form>

It is a mechanism used to define token which is going to be sent each type a form is being submitted. This token has a specific function to protect HTML form in a web-based application using Laravel framework from CSRF (Cross Site Request Forgery). So, the token is managed by Laravel framework to generate automatically CSRF “token” for each active user session managed by the application. This token is used for verifying that the one actually making the requests to the application can be verified.

But defining form tags normally using the normal HTML form tag needs to be accompanied with defining the hidden variable named ‘csrf_token’. On the other hand, if the definition of form is using the following definition :

{{Form::open(array('url'=>'test/store'))}}
{{Form::close}}

There is no need to define a hidden field named ‘csrf_token’. It is because the definition itself is automatically generated and defined along with with above snippet code definition.