验证时类构造函数错误

Question

I am developing a file uploaded class, and trying to perform few validation before other codes, but its returning all vars instead of false, check following code....

class FileUploader
{

   private $filePath;

   function __construct($file_path) {

      if(file_exists($file_path)) {

           $this->filePath = $file_path;

      }

     else return false;

   }

}

When I am using this class like following....

$file_path = getcwd().'\img.pn'; //invalid path

$file_uploader = new FileUploader($file_path);

if($file_uploader) {
    //process
}
else {
    echo 'Invalid File Path!';
}

But it doesn't echo Invalid File Path as expected, when i tried var_dump, it returned following output...

  object(FileUploader)[1]
  private 'filePath' => null

Please help to fix this. thanks.

Answer 1

You might consider using an exception in the constructor as constructors should no return anything. (Have a look at this question).
Otherwise you may create a function to check the file_path :

class FileUploader
{

   private $filePath;

   function __construct($file_path) {
      $this->filePath = $file_path;
   }



   function isValidFilePath() {
      return file_exists($this->file_path);
   }

}

and then :

$file_path = getcwd().'\img.pn'; //invalid path

$file_uploader = new FileUploader($file_path);

if($file_uploader->isValidFilePath()) {
    //process
}
else {
    echo 'Invalid File Path!';
}