PHP Stream

Key Stream Functions

fopen($filename, $mode);

fread($stream, $length);

fwrite($stream, $data);

fclose($stream);

🔹 Reading Files with Streams

Open and read file content using stream functions. Streams provide fine-grained control over how you read data, allowing you to process large files efficiently.

<?php
// Open file for reading
$file = fopen('example.txt', 'r');

if ($file) {
    // Read entire file
    $content = fread($file, filesize('example.txt'));
    echo "File content: " . $content;
    
    // Close the stream
    fclose($file);
} else {
    echo "Unable to open file";
}

// Alternative: Read line by line
$file = fopen('example.txt', 'r');
while (($line = fgets($file)) !== false) {
    echo $line . "<br>";
}
fclose($file);
?>

🔹 Writing to Files

Create or modify files using stream write operations. Different modes control whether you append, overwrite, or create new files when writing data.

<?php
// Open file for writing (creates if doesn't exist)
$file = fopen('output.txt', 'w');

if ($file) {
    $text = "Hello, World!\n";
    $text .= "This is a new line.";
    
    fwrite($file, $text);
    fclose($file);
    
    echo "File written successfully";
} else {
    echo "Unable to open file for writing";
}

// Append to existing file
$file = fopen('output.txt', 'a');
fwrite($file, "\nAppended text");
fclose($file);
?>

🔹 Stream Context Options

Configure stream behavior using context options. This allows you to set HTTP headers, timeouts, and other parameters when working with remote resources.

<?php
// Create stream context with options
$options = array(
    'http' => array(
        'method' => 'GET',
        'header' => 'User-Agent: PHP Script\r\n',
        'timeout' => 10
    )
);

$context = stream_context_create($options);

// Use context when opening stream
$url = 'https://api.example.com/data';
$response = file_get_contents($url, false, $context);

if ($response !== false) {
    echo "Data fetched successfully";
} else {
    echo "Failed to fetch data";
}
?>

🔹 Stream Filters

Apply filters to transform data as it passes through a stream. Filters can compress, encrypt, or convert data on-the-fly without loading everything into memory.

<?php
// Open file stream
$file = fopen('data.txt', 'r');

// Apply uppercase filter
stream_filter_append($file, 'string.toupper');

// Read filtered content
$content = fread($file, 1024);
echo "Filtered content: " . $content;

fclose($file);

// Example with compression filter
$compressed = fopen('compressed.gz', 'w');
stream_filter_append($compressed, 'zlib.deflate');
fwrite($compressed, "This text will be compressed");
fclose($compressed);

echo "<br>File compressed successfully";
?>

🔹 Stream Wrappers

Access different types of resources using stream wrappers. PHP supports file://, http://, ftp://, and other protocols through a unified stream interface.

<?php
// File wrapper (default)
$local = fopen('file://path/to/file.txt', 'r');

// HTTP wrapper
$web = fopen('http://example.com/data.txt', 'r');
if ($web) {
    $content = fread($web, 1024);
    echo "Web content: " . substr($content, 0, 50) . "...";
    fclose($web);
}

// PHP input stream (for POST data)
$input = file_get_contents('php://input');
echo "<br>Received input: " . $input;

// Memory stream
$memory = fopen('php://memory', 'r+');
fwrite($memory, 'Temporary data');
rewind($memory);
echo "<br>Memory: " . fread($memory, 1024);
fclose($memory);
?>

🔹 Checking Stream Status

Monitor stream state and position using status functions. These help you determine if you've reached the end of a file or check the current read/write position.

<?php
$file = fopen('example.txt', 'r');

// Check if end of file
if (feof($file)) {
    echo "End of file reached<br>";
} else {
    echo "More data available<br>";
}

// Get current position
$position = ftell($file);
echo "Current position: " . $position . "<br>";

// Move to position 10
fseek($file, 10);
echo "New position: " . ftell($file) . "<br>";

// Rewind to beginning
rewind($file);
echo "After rewind: " . ftell($file);

fclose($file);
?>

🔹 Stream Metadata

Retrieve information about streams and files. Metadata includes file size, modification time, permissions, and other properties useful for file management.

<?php
$file = fopen('example.txt', 'r');

// Get stream metadata
$meta = stream_get_meta_data($file);

echo "Stream type: " . $meta['stream_type'] . "<br>";
echo "Mode: " . $meta['mode'] . "<br>";
echo "Seekable: " . ($meta['seekable'] ? 'Yes' : 'No') . "<br>";

fclose($file);

// Get file stats
$stats = stat('example.txt');
echo "File size: " . $stats['size'] . " bytes<br>";
echo "Last modified: " . date('Y-m-d H:i:s', $stats['mtime']);
?>