javascript switch statement/case expression

Question 1

RGdent’s Question:

I am using a switch statement to search for undefined values to manually change it. but I am having trouble using boolean expressions as I would when using an if statement.

Like: if statemant

if(Item1 == undefined)
{
  item1 ="No";
}
else if (Item2 == undefined)
{
  item2 = "No";
}

etc..

I tried this with the switch statement:

 switch (array) {
 case (item1 == undefined):
 item1 = "No";
 console.log('item1 result', item1 );
 break;
 case item2 == undefined:
 item2 = "No";
 console.log('item2 result', item2 );
 break;
 default:

 }

It does not run through the switch statement, except for when I remove == undefined and only use item1. then it works?

Answer

Starx

The switch cannot evaluate values of the array like that and that is why it does not run through the switch statement. You need to define which value of that array you want to switch.

Inside case statement you also cannot use expression, you have to use a value there as well.

So, if you are dead set on using switch for what you are trying to accomplish, you can do something like this:

item1 = array[1];
switch(item1) {
    case "undefined":
        // so on
    break;
}

But, based on your example you are probably trying to check if the values are set or not, for that if statements are still the best choice rather than switch.

$arr = []; // Your array
if(typeof $arr[0] == "undefined") {
    $arr[0] = "No";
}

Question 2

H0mebrewer’s Question:

h0mebrewer

I’m writing my first MVC application in PHP. I don’t want to use any framework.

Now I’m searching for a good solution or best practise to display elements for users in views, only if they are allowed to interact with the function that a specific element calls.

The app loads a template file in the view.
Within the template file I show the data from the model, which is passed from the controller to the view.

From controller

public function showUserList() {
    $userList = $this->model->getUserList();
    $this->view->loadTemplate($userList, 'user_list.php');
}

From view:

class user_view  {
    public function loadTemplate($data, $file, $buffer= false){
        if($buffer === true){
            ob_start();
            include dirname(__FILE__).'/templates/'.$file;
            $c = ob_get_contents();
            ob_end_clean();
            return $c;
        }else{
            include dirname(__FILE__).'/templates/'.$file;
        }
    }
}

Template:

<table class="table" id="data-table">
    <thead>
        <tr>
        <th>Name</th>
        <th>Username</th>
        <th>E-Mail</th>
        <th>Group</th>
        <th>Action</th>
        </tr>
    </thead>
    <tbody>
    <?php
       if(is_array($data)){

          foreach($data as $key => $value){
          ?>
            <tr>
                <td><?php echo $data['name'].' '.$data['surname']; ?></td>
                    <td><?php echo $data['abbr']; ?></td>
                    <td><?php echo $data['email']; ?></td>
                    <td><?php echo $data['gr_name']; ?></td>
                    <td>

                    <div data-access="," onclick="$user_controller.showUserChangeView('<?php echo $data['id']; ?>')" class="btn btn-primary">edit</div>
                    <div data-access="checkAccess" onclick="$user_controller.deleteUser('<?php echo $data['id']; ?>')" class="btn btn-danger">delete</div>

                    </td>
                </tr>

          <?php
          }

       }
    ?>
    </tbody>
</table>
</div>

I want to display buttons or menuitmes only, if a user is permitted to call the function of the button or the menuitem.

My first approach ist to create a template file with all elements which could be displayed. Elements which should not be accessible for all users get an data attribute.

The view loads the template, a DOM parser pareses the file, checks if the user is permitted to call that function with a data attribute.
If the user is not permitted to call that function, the element will be removed.
This is not yet implemented because I’m not sure if this is that a good solution or how I can do it even better?

Answer

Starx

My suggestion is to implement either ACL (Access Control List) or RBAC (Role Based Access Control) depending on what you find useful. I prefer RBAC so I will give a minimalistic example of one.

Create a list of all possible actions a user can make and define roles which might have acess to them.

// List of permissions (the actual term to define resources in RBAC) for the users
$actions = array(
    'view' => array(ROLE_USER, ROLE_OWNER, ROLE_MANAGER, ROLE_ADMIN),
    'edit' => array(ROLE_OWNER, ROLE_ADMIN),
    'delete' => array(ROLE_OWNER, ROLE_ADMIN),
    'change_pass' => array(ROLE_OWNER, ROLE_MANAGER, ROLE_ADMIN)
)

Now when you display the button for these actions, you can check if current user has any of the role which allows him to access the actions. If answer to that is “yes” then show them otherwise don’t show them at all.

$currentUserRole = '..'; //Retrieve however you want
foreach($actions as $allowed_roles) {
    if(in_array($currentUserRole, $allowed_roels)) {
        echo "<div ...>"; // Basically show the action
    }
    // If not carry on to next action with out showing
}

^{(Note: Not showing only might not be enough for it be secured, so we must also the check then when executing the action as well)}

Update: You would the put the above code in the following part:

<table class="table" id="data-table">
    <thead>
        <tr>
        <th>Name</th>
        <th>Username</th>
        <th>E-Mail</th>
        <th>Group</th>
        <th>Action</th>
        </tr>
    </thead>
    <tbody>
    <?php
       if(is_array($data)){

          foreach($data as $key => $value){
          ?>
            <tr>
                <td><?php echo $data['name'].' '.$data['surname']; ?></td>
                    <td><?php echo $data['abbr']; ?></td>
                    <td><?php echo $data['email']; ?></td>
                    <td><?php echo $data['gr_name']; ?></td>
                    <td>
                        $currentUserRole = '..'; //Retrieve however you want
                        foreach($actions as $allowed_roles) {
                            if(in_array($currentUserRole, $allowed_roels)) {
                               echo "<div ...>"; // Basically show the action
                            }
                            // If not carry on to next action with out showing
                        }
                    </td>
                </tr>

          <?php
          }

       }
    ?>
    </tbody>
</table>
</div>

Question 3

Agus Maloco’s Question:

Agus Maloco

I tried to create a table this way:

create table attendance (
      userId char(10) primary key not null, 
      name varchar(35) not null, 
      date_attendance date not null, 
      start_time timestamp 'HH24:MI:SS', 
      finish_time timestamp 'HH24:MI:SS'
);

Am I right about creating the time fields this way or there is some better option?

Answer

Starx

Timestamp will hold both date and time. There is data type time as well, which might be better suited for your use case.

CREATE TABLE attendance (
      userId char(10) primary key not null, 
      name varchar(35) not null, 
      date_attendance date not null, 
      start_time time,
      finish_time time
);

Month: April 2016

javascript switch statement/case expression

RGdent’s Question:

MVC Design – views with content for a usergroup

H0mebrewer’s Question:

How to create time attribute in SQL?

Agus Maloco’s Question:

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