What's wrong with laravel's new addition and the inability to edit it?

Recently, when developing a project using the Laravel framework, I discovered a problem: the newly added data cannot be edited. After further troubleshooting and analysis, I found the problem and solved it. Let me share some solution ideas below.

First of all, we need to clarify a concept - HTTP request method. HTTP request method refers to the method used by the client when requesting resources from the server, including GET, POST, PUT, DELETE, etc. Among them, the GET method is used to obtain resources, the POST method is used to create resources, the PUT method is used to update resources, and the DELETE method is used to delete resources.

In Laravel, when using form submission, the default request method is POST, for example:

<form action="/user" method="POST">
    <input type="text" name="name">
    <button type="submit">提交</button>
</form>

Then, we use the store method in the controller to handle this request ：

public function store(Request $request)
{
    $user = new User;
    $user->name = $request->input('name');
    $user->save();
    return redirect('/user');
}

In the above code, we create a new User object, assign the name field submitted by the form to the name attribute of the User object, and then save the data and redirect to /user page.

However, the above code sometimes has a problem: the newly added data cannot be edited. When we access the edit page, we will find that there is no originally created data information in the page. Why is this? We can first look at the code of the edit page:

<form action="/user/{{ $user->id }}" method="POST">
    {{ method_field('PUT') }}
    <input type="text" name="name" value="{{ $user->name }}">
    <button type="submit">提交</button>
</form>

In this code, we use the method_field method to specify the request method as PUT, because in the HTTP protocol, updating resources requires PUT method. However, in the Laravel framework, the default POST request cannot recognize the PUT request. Therefore, when accessing the edit page, Laravel will process it according to the default POST request instead of the PUT request we expect.

There are two ideas to solve this problem: one is to use the PUT request method to create data; the other is to use the _method parameter to specify the request method when using the POST method to create data.

The first solution is a simpler method, but it requires more code changes. We need to use the PUT request method in the form:

<form action="/user/{{ $user->id }}" method="POST">
    {{ method_field('PUT') }}
    <input type="hidden" name="_token" value="{{ csrf_token() }}">
    <input type="text" name="name" value="{{ $user->name }}">
    <button type="submit">提交</button>
</form>

Then, handle the PUT request in the controller:

public function update(Request $request, $id)
{
    $user = User::findOrFail($id);
    $user->name = $request->input('name');
    $user->save();
    return redirect('/user');
}

Using this method, we need to specify the PUT method in the form, and A _token parameter needs to be passed to prevent CSRF attacks, which will increase a lot of code workload.

The second solution is much simpler. We need to use the POST method in the form, but add the _method parameter when submitting to specify the request method as PUT:

<form action="/user/{{ $user->id }}" method="POST">
    <input type="hidden" name="_method" value="PUT">
    <input type="hidden" name="_token" value="{{ csrf_token() }}">
    <input type="text" name="name" value="{{ $user->name }}">
    <button type="submit">提交</button>
</form>

Then, when processing the POST request in the controller, use method Method to identify PUT requests:

public function update(Request $request, $id)
{
    $user = User::findOrFail($id);
    $user->name = $request->input('name');
    $user->save();
    return redirect('/user');
}

Using this method, we only need to add a _method parameter to the form, which is more readable and requires less code work.

In the process of developing Laravel projects, it is inevitable to encounter problems. Solving problems requires our patience and care, as well as an in-depth understanding and mastery of the framework and technology. I hope this article can provide some reference and help to readers.

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