getting_started_with_laravel

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getting_started_with_laravel [03.12.2020 15:29] – Pascal Sutergetting_started_with_laravel [04.12.2020 11:44] (current) – [Basics] Pascal Suter
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 **processing delete requests** are like posts, but we can't set the form method to ''DELETE'' so we need to use a blade function ''@method('DELETE')'' just after the form tag.  **processing delete requests** are like posts, but we can't set the form method to ''DELETE'' so we need to use a blade function ''@method('DELETE')'' just after the form tag. 
  
 +**sessions and flashing data** in laravel we can either store data into our session, like in normal php.. we can do this either via the ''session()'' helper which will save new key=>value pairs when it is passed an array as argument like ''session(['newkey',$someVar])'' for example. to get ''$someVar'' back we would use the helper like ''$someVar=session('newkey')''. alternatively, we can use an instance of the ''Request'' class and the ''put()'' and ''get()'' functions for the ''session'' property like so: ''$request->session()->put('tmpfiles',$tmpfiles);'' and vice versa ''$tmpfiles = $request->session()->get('tmpfiles',[]);'' notice a nice feature of the ''get()'' method: we can pass a default value as a second argument which will be returned in case the session variable is not set. that's pretty helpful. Session variables are also available in blades by using the ''session()'' helper like above. <br>
 +a specialty in laravel is, that we can **flash** data to a session. flashing means, that the data will only remain in the session for the next request. after that it will either be unset or we need to **reflash** to keep the flashed variables. to flash a variable to a session, we do the same as above with the ''get()'' function but now use a ''flash()'' method, that's it. 
 ===== Relations ===== ===== Relations =====
 relations are defined in the Model by adding a new public function to it.  relations are defined in the Model by adding a new public function to it. 
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   * foreign keys in should be named in the singular, lowercase and underscored form of the target table plus ''_id'' appended to it. so for example ''notebook_part_id'' if the target table is ''notebook_parts'' or ''pizza_id'' if the target table is ''pizzas''    * foreign keys in should be named in the singular, lowercase and underscored form of the target table plus ''_id'' appended to it. so for example ''notebook_part_id'' if the target table is ''notebook_parts'' or ''pizza_id'' if the target table is ''pizzas'' 
  
 +
 +===== Form validation =====
 +Laravel provides a nice Method for validating forms. Typically the validator is added in the Controller ''store()'' method. here is an example: 
 +<code php>
 +    public function store(Request $request){
 +        $validData = $request->validate([
 +            'name' => ['required', 'string', 'max:255'],
 +            'email' => ['required', 'string', 'email', 'max:255', 'unique:users'],
 +            'password' => ['required', 'string', 'min:8', 'confirmed'],
 +        ]);
 +        // anything from here on will only be executed if the above validation was successful
 +     }
 +</code>
 +there are many [[https://laravel.com/docs/8.x/validation#available-validation-rules|validation rules]] available already in Laravel and custom rules can be added if needed. 
 +
 +also note, that the ''$validData'' variable now contains an array with the validated data in a format that is compatible with the ''create'' methods for the laravel models. So if you set up your model's ''$fillable'' property correctly and your form field names correspond to your database field names, you can pass this array straight to the ''create()'' method of your model and create a new database entry like that!
 +
 +now here are a few cool things about the validator: 
 +  * if it finds an invalid field, it will stop right there and laravel will show you the form page again without any further routes needed. 
 +  * in addition to bringing the user back to the form, laravel will provide an ''$error'' variable which can be used in the balde 
 +  * even better, there is a ''@error(fieldname)'' blade syntax which will do whatever follows after it if the specified field is invalid
 +  * you also get a ''old(fieldname)'' function which you can use to populate your input fields with the original inputs, so the user won't have to enter eveything again.. see the eample below. 
 +here's an example part of a (bootstrap based) blade with a form that will show some info if the validation fails: 
 +
 +<code html>
 +    @if ($errors->any())
 +      <div class="alert alert-danger col-12" role="alert">
 +        You did not fill in all the form fields correctly, please correct or complete the Information given below
 +      </div>
 +    @endif
 +  <form action="{{ route('address.create') }}" method="POST">
 +    @csrf
 +    <div class="row pt-4">
 +      <div class="form-group col-12">
 +        <label for="inputName">Name</label>
 +        <input type="text" class="form-control @error('name') is-invalid @enderror" id="inputName" name="name" value="{{ old('name') }}">
 +        <div class="invalid-feedback">Please enter your name here</div>
 +      </div>
 +      .... 
 +</code>
  
 ===== Tricks ===== ===== Tricks =====
 +==== dump / dump and die ====
 +this has to be the first tip :) .. there is a helper function called ''dd()'' which stands for ''dump and die''. it dumps a variable and then stops further execution of the script. this is of course extremely helpful when learning stuff and trying out things. 
 +
 +you may not always want to stop the execution, so another helper called ''dump()'' comes in handy here. it produces the same output but contines the execution of your script 
 +
 +to use those helpers in a blade, there are special blade syntax helpers available which make it even easier: 
 +<code>@dump($__data)</code>
 +for example dumps all defined variables. there is also a ''@dd()'' helper available. 
 +
 +note that using <code>{{ dump($__data) }}</code> won't work. there is a detailed explanation why [[https://stackoverflow.com/questions/48731507/laravel-dump-unexpected-output|on stackexchange]]
 ==== Create Model + Controller + Migration all in one step ==== ==== Create Model + Controller + Migration all in one step ====
   artisan make:model Pizza -mc   artisan make:model Pizza -mc
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 @extends('layouts.mylaout', [ 'title' => "Details for ".$section->name, 'image' => 'section_details.jpg' ]) @extends('layouts.mylaout', [ 'title' => "Details for ".$section->name, 'image' => 'section_details.jpg' ])
 </code> </code>
-and in the layout you would then simply use ''{{ $title }}'' to echo the title you passed along. +and in the layout you would then simply use <code>{{ $title }}</code> to echo the title you passed along. 
  
 === 2.) create a mini-section === === 2.) create a mini-section ===
  • getting_started_with_laravel.1607005754.txt.gz
  • Last modified: 03.12.2020 15:29
  • by Pascal Suter