PHP check input type for validation

Question

I'm wondering if there is a way to check what type of input was used for $_POST information. I want to then use that type for validation. For instance, if an input type="text" then I would want to be able to create certain validations for that type of input.

So this is my code to generate the form:

$fields = array(
    array(
        'label' => 'Name:',
        'id' => $meta.'_nhm_lead_name',
        'class' => 'field-name input', // optional
        'wrapper_class' => 'four columns', // optional
        'type' => 'text',
        'required' => true,
    ),
)

and this is how I generate the html:

    public function make_fields(){
    foreach($this->fields as $field => $value){
        switch ($value['type']) {
            case 'text':
                $inputs .= '<li class="field '.$value['wrapper_class'].'">';
                $inputs .= '<input type="text" name="'.$value['id'].'" class="'.$value['class'].'" />';
                $inputs .= '<span class="error-message"></span>';
                $inputs .= '</li>';
            break;
         }
     } 
     }

No. The client side is waaay to easy to manipulate. I would never use it... — qwertynl
– qwertynl, Commented Dec 9, 2013 at 21:53
No, but you already know it since you wrote it, so you can write the server-side validation — Francisco Presencia
– Francisco Presencia, Commented Dec 9, 2013 at 21:53
you should validate according to the intended input certain text inputs may need extra constrains than others — Andreas
– Andreas, Commented Dec 9, 2013 at 21:54

Francisco Presencia · Accepted Answer · 2013-12-09 22:04:54Z

1

When receiving the data from $_POST only the values are passed. However, you can use an structure like this:

$Fields = array( 
  array('type' => 'text',   'name' => 'name'),
  array('type' => 'text',   'name' => 'password'),
  array('type' => 'number', 'name' => 'age'));

Then generate the html form from that. So then, you can use that same variable to generate the validation. However, this is normally too much work for few forms (engine to generate form inputs from an array), and it's preferred to make it 'hardcoded' unless you are using already a framework with this functionality.

To give you an idea, the form would be like:

<form method = "POST" action = "/post.php">
  <?php foreach ($Fields as $Input) {
    switch($Input['type']) {
      case "text": 
        echo "<input type = 'text' name = '" . $Input['name'] . "'>";
        break;
      case "number":
        echo "<input type = 'number' name = '" . $Input['name'] . "'>";
        break;
      }
    }
   ?>
 </form>

And then in post.php:

foreach ($Fields as $Input) {
  $Name = $Input['name'];
  if (array_key_exists($Name, $_POST) &&
      // You need to define this:
      checktype($_POST[$Name], $Input['type'])) {
    $Posted = $_POST[$Name];
    }
  }

edited Dec 9, 2013 at 22:04

answered Dec 9, 2013 at 21:58

Francisco Presencia

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9 Comments

Carlos Rios Over a year ago

Thats exactly what I'm doing. Here is an example of the array I use to generate the html: $fields = array( array( 'label' => 'Name:', 'id' => $meta.'_nhm_lead_name', 'class' => 'field-name input', // optional 'wrapper_class' => 'four columns', // optional 'type' => 'text', 'required' => true, ),

Carlos Rios Over a year ago

Sorry I'm not sure why it isn't displaying as code, but thats the general idea of what I'm using

Francisco Presencia Over a year ago

There's no enter in the comments nor 'proper code', you can do only one-lines. I'll try to decypher it (; However you might want to put that in your OP so others know what you've done so far.

Francisco Presencia Over a year ago

Then what's the problem? Why are you asking your original question if you already have this?

Carlos Rios Over a year ago

Will do. It'll be the first thing I put out there and it is going to be open source. Without giving too much away, I'm trying to create a WP post, and add metadata to the post at the same time. All this will be done by users in the frontend.

|

Schleis · Accepted Answer · 2013-12-09 21:56:13Z

0

You would want to do that based on the name of the key in the $_POST array. A user can submit data without using any type (Javascript for example) making what you are asking to do impractical. They would be sending data that had no type.

Data being posted to your page can come from anywhere.

For re-usability, create a data object for the submission of your form that contains the validations for each of the inputs or write a validation function. Keep that on the server so that a malicious user isn't able to manipulate the data and change how you validate what is being submitted.

answered Dec 9, 2013 at 21:56

Schleis

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Comments

Sablefoste · Accepted Answer · 2013-12-10 14:06:28Z

0

You could write a jQuery script that checks the prop of the input, and then adds it to the $_POST. Something like:

HTML:

<form method="POST" action = "here.php" id="myform">
   <input type="text" value="hello" id= "input1" />
</form>

jQuery:

var input1type="&input1type=" + $('#input1').prop('type');
$.post('here.php', $('#myform').serialize()+input1type );

This would be best used if you can't affect the originating HTML.

Please note, that this is dangerous, and you can't trust the data from the www, but it might work in a secured (such as intranet) system.

edited Dec 10, 2013 at 14:06

answered Dec 9, 2013 at 22:29

Sablefoste

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