FileReader

FileReader

The FileReader class provides a memory-efficient, line-by-line file reader powered by PHP generators. It supports concatenating multiple files into a single sequential stream.

Methods

| Method | Return | Description |

| --- | --- | --- |

| __construct(string $filePath) | — | Open the first file for reading |

| append(string $filePath) | FileReader | Append another file to the read queue |

| prepend(string $filePath) | FileReader | Prepend another file before the current queue |

| fetch() | ?string | Return the next line, or null when exhausted |

Basic Usage

use Razy\FileReader;



$reader = new FileReader('/path/to/data.txt');



// Read line by line

while (($line = $reader->fetch()) !== null) {

    echo $line . "\n";

}

Multi-File Concatenation

Chain multiple files together — they are read sequentially as a single stream:

$reader = new FileReader('/logs/app-2026-01.log');

$reader->append('/logs/app-2026-02.log')

       ->append('/logs/app-2026-03.log');



// Reads all three files in order

while (($line = $reader->fetch()) !== null) {

    // Process each line from all files

}

Prepending Files

$reader = new FileReader('/data/main.csv');



// Add a header file before the main data

$reader->prepend('/data/header.csv');



// Reads header.csv first, then main.csv

while (($line = $reader->fetch()) !== null) {

    $fields = str_getcsv($line);

    // Process CSV row

}

Example: Reading CSV Files

use Razy\FileReader;



$reader = new FileReader('/data/users.csv');

$headers = null;

$users   = [];



while (($line = $reader->fetch()) !== null) {

    $row = str_getcsv($line);

    if ($headers === null) {

        $headers = $row;

        continue;

    }

    $users[] = array_combine($headers, $row);

}

Example: Processing Large Log Files

use Razy\FileReader;



$reader = new FileReader('/var/log/app/error.log');

$errors = [];



while (($line = $reader->fetch()) !== null) {

    if (str_contains($line, '[ERROR]')) {

        $errors[] = $line;

    }

}



echo 'Found ' . count($errors) . ' errors';

Example: Merging Multiple Data Files

use Razy\FileReader;



// Merge daily report files into a single stream

$reader = new FileReader('/reports/day1.csv');

$reader->append('/reports/day2.csv')

       ->append('/reports/day3.csv');



$totalRows = 0;

while ($reader->fetch() !== null) {

    $totalRows++;

}



echo "Processed $totalRows lines across 3 files";

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