Archive | GNU/Linux

SplFileObject Class

In this post, we will use the SplFileObject class which is a part of Standard PHP Library.

For our demonstration, I will create a class to process large files using PHP.

The class will take the file name as input to the constructor:

class BigFile
{
protected $file;
public function __construct($filename, $mode = "r")
{
if (!file_exists($filename)) {
throw new Exception("File not found");
}
$this->file = new SplFileObject($filename, $mode);
}
}

Now we will define a method for iterating through the file, this method will use fgets() function to read one line at a time.

You can create another method that uses fread() function.

Read Text Files

The fgets() is suitable for parsing text files that include line feeds while fread() is suitable for parsing binary files.

protected function iterateText()
{
$count = 0;
while (!$this->file->eof()) {
yield $this->file->fgets();
$count++;
}
return $count;
}

This function will be used to iterate through lines of text files.

Read Binary Files

Another function which will be used for parsing binary files:

protected function iterateBinary($bytes)
{
$count = 0;
while (!$this->file->eof()) {
yield $this->file->fread($bytes);
$count++;
}
}

Read in One Direction

Now we will define a method that will take the iteration type and return NoRewindIterator instance.

We use the NoRewindIterator to enforce reading in one direction.

public function iterate($type = "Text", $bytes = NULL)
{
if ($type == "Text") {
return new NoRewindIterator($this->iterateText());
} else {
return new NoRewindIterator($this->iterateBinary($bytes));
}
}

Now the entire class will look like this:

class BigFile
{
protected $file;
public function __construct($filename, $mode = "r")
{
if (!file_exists($filename)) {
throw new Exception("File not found");
}
$this->file = new SplFileObject($filename, $mode);
}
protected function iterateText()
{
$count = 0;
while (!$this->file->eof()) {
yield $this->file->fgets();
$count++;
}
return $count;
}
protected function iterateBinary($bytes){
$count = 0;
while (!$this->file->eof()) {
yield $this->file->fread($bytes);
$count++;
}
}
public function iterate($type = "Text", $bytes = NULL)
{
if ($type == "Text") {
return new NoRewindIterator($this->iterateText());
} else {
return new NoRewindIterator($this->iterateBinary($bytes));
}
}
}

Parse large Files

Let’s test our class:

$largefile = new BigFile("file.csv");
$iterator = $largefile->iterate("Text"); // Text or Binary based on your file type
foreach ($iterator as $line) {
echo $line;
}

This class should read any large file without limitations Great!!

You can use this class in your Laravel projects by autoloading your class and add it to composer.json file.

Now you can parse and process large files using PHP easily.

Keep coming back.

Thank you.