使用PHP在.lst播放列表文件每n行后插入广告URL的需求

Here's a PHP solution that does exactly what you need—inserting your 10 ads in order every 5 lines of your playlist, and cycling through the ads once you hit file10.mp3:

<?php
// Define your input and output file paths (adjust these to match your setup)
$inputFile = 'playlist.lst';
$outputFile = 'playlist_with_ads.lst';

// Read the input playlist file into an array of lines
// FILE_IGNORE_NEW_LINES removes trailing newlines; FILE_SKIP_EMPTY_LINES skips blank lines
$playlistLines = file($inputFile, FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);

// Handle cases where the file can't be read or is empty
if (!$playlistLines) {
    die("Error: Could not read the input file, or the file is empty.");
}

$outputLines = [];
$contentLineCounter = 0;
$totalAds = 10; // Total number of ad files we have
$currentAdIndex = 0; // Starts at 0 to map to file1.mp3

foreach ($playlistLines as $line) {
    // Add the original audio URL to our output
    $outputLines[] = $line;
    $contentLineCounter++;

    // Check if we've reached 5 content lines (time to insert an ad)
    if ($contentLineCounter % 5 === 0) {
        // Generate the ad URL using the current index (add 1 since ads start at file1.mp3)
        $adUrl = "file" . ($currentAdIndex + 1) . ".mp3";
        $outputLines[] = $adUrl;

        // Update the ad index, cycling back to 0 after file10.mp3
        $currentAdIndex = ($currentAdIndex + 1) % $totalAds;
    }
}

// Write the modified playlist to the output file
if (file_put_contents($outputFile, implode(PHP_EOL, $outputLines))) {
    echo "Success! Your playlist with ads has been saved to {$outputFile}";
} else {
    die("Error: Could not write to the output file. Check file permissions.");
}
?>

How this works: #

1. File Reading: The file() function reads your .lst file into an array, skipping empty lines and removing trailing newlines for clean processing.
2. Counter Logic: We track how many content lines we've added with $contentLineCounter. Every time this hits a multiple of 5, we insert an ad.
3. Ad Cycling: The $currentAdIndex variable keeps track of which ad to insert next. Using modulo % $totalAds ensures we loop back to file1.mp3 after file10.mp3.
4. Output Writing: We join the modified lines with proper line breaks (PHP_EOL) and write them to a new file to avoid overwriting your original playlist.

Notes: #

• Permissions: Make sure your PHP script has read access to the input file and write access to the directory where you're saving the output file.
• Empty Lines: If you want to include empty lines in your playlist and count them towards the 5-line limit, remove the FILE_SKIP_EMPTY_LINES flag from the file() call.
• Running the Script: You can run this via the command line (php playlist_ad_inserter.php) or through a web server (though command line is more straightforward for file processing tasks).

内容的提问来源于stack exchange，提问作者Vikalp