CODEWITHSUNDEEP
phpoop
Jim
Jim

Reputation: 1315

How to call a function correctly in PHP OOP

I am attempting to learn better OOP in PHP and I have been trying to resolve this for a number of hours now and need some assistance. I am using php 5.4 so I believe I can use late static binding.
I have a class called DatabaseObject (database_object.php) which has a function called create that looks like:

    public function create() { 
      echo "in Create() ";
      global $database; echo "<br> table: ".static::$table_name;
      $attributes = $this->sanitized_attributes(); 
      $sql = "INSERT INTO " .static::$table_name." (";
      $sql .= join(", ", array_keys($attributes));
      $sql .= ") VALUES ('";
      $sql .= join("', '", array_values($attributes));
      $sql .= "')"; echo $sql; 
      if($database->query($sql)) {
        $this->id = $database->insert_id();
        return TRUE;
      } else {
        return FALSE;
      }
    }

I am calling this from my Cart class (in a file called cart_id.php)that extends DatabaseObject in a function called add_to_cart() which looks like:

    public function add_to_cart($cart_id,$isbn) { 
      global $database;
      $isbn = $database->escape_value($isbn);
      $amazon = Amazon::get_info($isbn);
      //get cart id if there is not one
      if (empty($cart_id)) {echo " getting cart_id";
        $cart_id = static::get_new_cart_id();
      }
      if(!empty($amazon['payPrice']) && !empty($isbn)) {
        echo "<br> getting ready to save info";
        $cart = new Cart();
        $cart->price = $amazon['payPrice'];
        $cart->qty = $amazon['qty'];
        $cart->cart_id =$cart_id;
        $cart->isbn = $isbn;
        if(isset($cart->cart_id)) { 
          echo " Saving...maybe";
          static::create();
        }
      }

      return $amazon;
    }

The static:create(); is calling the function, but when it gets to

$attributes = $this->sanitized_attributes();

it is not calling the sanitized_attributes function which is in my DatabaseObject class

    protected function sanitized_attributes() {
      echo "<br>in Sanatized... ";
      global $database;
      $clean_attributes = array();
      //Sanitize values before submitting
      foreach($this->attributes() as $key=>$value) {
        $clean_attributes[$key] = $database->escape_value($value);
      }
      return $clean_attributes;
    }

Attributes is

    protected function attributes() {
      //return get_object_vars($this);
      $attributes = array();
      foreach (static::$db_fields as $field) {
        if(property_exists($this, $field)) {
          $attributes[$field] = $this->$field;
        }
       }
       return $attributes;
     }

I get the echo "in create()" as well as the echo "table ".static:table_name, which does show the correct table to save to. I do not get the echo $sql, nor am I getting the "In Sanitized". If I take out the static:create() line, it continues on without a problem and shows me the information in my return $amazon statement. My question is, how am I supposed to correctly call the create function from my add_to_cart() function? If you are going to down vote my question, could you please explain why so I do not duplicate the same error again? Thanks!

Upvotes: 0

Views: 157

Answers (1)

Marc
Marc

Reputation: 514

Since you are calling create statically you have to call any other methods of the same class statically as you are not working with an "instance" of the class but a static version of it.

I do not know the structure of the rest of your code but you can either change static::create() to $this->create() and the static calls inside create to calling $this or change the $this->sanitized_attributes() to static::sanitized_attributes().

Also on another note you should refrain from using global variables. Since you going OOP you should practice proper dependency injection and pass those global variables into your classes instead of using global $blah

Upvotes: 2

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