Home arrow PHP arrow Page 3 - Developing a Modular Class For a PHP File Uploader

Completing the definition of the FileUploader class - PHP

If you’re a PHP programmer who needs to learn the basic concepts surrounding the implementation of file uploads via the HTTP protocol, then look no further, because you’ve come to the right place. Welcome to the final installment of the series “Building file uploaders with PHP 5.” In a step-by-step process, this series teaches you how to build several PHP-driven file uploading applications by using not only a procedural approach, but the object-oriented paradigm as well.

TABLE OF CONTENTS:
  1. Developing a Modular Class For a PHP File Uploader
  2. Handling file uploads using the object-oriented paradigm
  3. Completing the definition of the FileUploader class
  4. Testing the FileUploader class
By: Alejandro Gervasio
Rating: starstarstarstarstar / 3
April 16, 2008

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As you saw in the previous section, the only method of the pertinent “FileUploader” class that remains undefined is the one called “upload().” However, as its name suggests, the method should encapsulate all the logic required to upload a selected file to its final location in the web server, as well as check if this process has been performed successfully.

Therefore, taking into account all of the tasks that must be accomplished by the  “upload()” class method, below I listed its complete definition, which looks like this:


public function upload(){

if(move_uploaded_file($this->tmp_name,$this->uploadFile)){

return true;

}

// throw exception according to error number

switch($this->error){

case 1:

throw new Exception('Target file exceeds maximum allowed size.');

break;

case 2:

throw new Exception('Target file exceeds the MAX_FILE_SIZE value specified on the upload form.');

break;

case 3:

throw new Exception('Target file was not uploaded completely.');

break;

case 4:

throw new Exception('No target file was uploaded.');

break;

case 6:

throw new Exception('Missing a temporary folder.');

break;

case 7:

throw new Exception('Failed to write target file to disk.');

break;

case 8:

throw new Exception('File upload stopped by extension.');

break;

}

}


In this case, if you had the chance to read the preceding article of this series, you'll find the implementation of the above “upload()” class method quite simple to grasp, since it looks very similar to the “uploadFile()” procedural function defined in that tutorial. In either case, the prior method uses the “move_uploaded_file()” PHP built-in function to transfer the target file to its final location in the web server, assuming that the file upload has been completed successfully.

On the other hand, if this process fails for whatever reason, an exception will be triggered, indicating the cause of this error. Quite easy to grasp, right?

Having explained how the previous “upload()” method does its business, I'm now going to list the complete signature of the “FileUploader” class, only this time including the method in question. Here’s how this class now looks:


class FileUploader{

private $uploadFile;

private $name;

private $tmp_name;

private $type;

private $size;

private $error;

private $allowedTypes=array
('image/jpeg','image/gif','image/png','text/plain','application/ms-word');

public function __construct($uploadDir='C:uploaded_files'){

if(!is_dir($uploadDir)){

throw new Exception('Invalid upload directory.');

}

if(!count($_FILES)){

throw new Exception('Invalid number of file upload parameters.');

}

foreach($_FILES['userfile'] as $key=>$value){

$this->{$key}=$value;

}

if(!in_array($this->type,$this->allowedTypes)){

throw new Exception('Invalid MIME type of target file.');

}

$this->uploadFile=$uploadDir.basename($this->name);

}

// upload target file to specified location

public function upload(){

if(move_uploaded_file($this->tmp_name,$this->uploadFile)){

return true;

}

// throw exception according to error number

switch($this->error){

case 1:

throw new Exception('Target file exceeds maximum allowed size.');

break;

case 2:

throw new Exception('Target file exceeds the MAX_FILE_SIZE value specified on the upload form.');

break;

case 3:

throw new Exception('Target file was not uploaded completely.');

break;

case 4:

throw new Exception('No target file was uploaded.');

break;

case 6:

throw new Exception('Missing a temporary folder.');

break;

case 7:

throw new Exception('Failed to write target file to disk.');

break;

case 8:

throw new Exception('File upload stopped by extension.');

break;

}

}

}


At this moment, you’ll have to agree with me that the above “FileUploader” class is much more useful, while maintaining a high level of modularity. Of course, there’s the possibility that you may want to add some additional logic to some of its existing methods, or even define new ones, but this will depend exclusively on your personal requirements.

With the previous “FileUploader” class defined completely, it’s time to see how it can be used in the context of a hands-on example. Thus, in the last section of this tutorial, I’ll be setting up this example for you, completing this series on handling file uploads with PHP 5.

Click on the link below and keep reading. We’re almost done!



 
 
>>> More PHP Articles          >>> More By Alejandro Gervasio
 

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