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10 個超實用 PHP 代碼片段：反垃圾、隨機色、下載、排名、強制下載、Gravatar、RSS、時間差、裁圖、站點監控

編輯：PHP 相關知識

10 個超實用 PHP 代碼片段：反垃圾、隨機色、下載、排名、強制下載、Gravatar、RSS、時間差、裁圖、站點監控

PHP 雖常被調侃，但以「Quick and Dirty」之姿佔據全球 Web 開發首位。善用前輩沉澱的代碼片段，能大幅提升開發效率。以下 10 片段覆蓋高頻實戰場景，建議收藏至個人知識庫。

1. 黑名單關鍵字過濾（反垃圾評論/內容）

function is_spam($text, $file, $split = ':', $regex = false){
    $handle = fopen($file, 'rb');
    $contents = fread($handle, filesize($file));
    fclose($handle);
    $lines = explode("\n", $contents);
    $arr = array();
    foreach($lines as $line){
        list($word, $count) = explode($split, $line);
        if($regex) $arr[$word] = $count;
        else $arr[preg_quote($word)] = $count;
    }
    preg_match_all("~".implode('|', array_keys($arr))."~", $text, $matches);
    $temp = array();
    foreach($matches[0] as $match){
        if(!isset($temp[$match])) $temp[$match] = 0;
        $temp[$match]++;
        if($temp[$match] >= $arr[$word]) return true;
    }
    return false;
}

// 關鍵字檔 spam.txt 格式：關鍵字:閾值
// ab:3
// dog:3
// cat:2
// monkey:2

2. 隨機十六進位顏色生成器

function randomColor() {
    $str = '#';
    for($i = 0; $i < 6; $i++) {
        $randNum = rand(0, 15);
        if($randNum >= 10) $randNum = chr(ord('A') + $randNum - 10);
        $str .= $randNum;
    }
    return $str;
}
$color = randomColor(); // 例：#3F7A2B

3. cURL 下載遠端檔案（支援大檔、斷點、重定向）

set_time_limit(0);
$url = 'https://example.com/video.flv';
$pi = pathinfo($url);
$ext = $pi['extension']; $name = $pi['filename'];

$ch = curl_init();
curl_setopt_array($ch, array(
    CURLOPT_URL => $url,
    CURLOPT_HEADER => false,
    CURLOPT_BINARYTRANSFER => true,
    CURLOPT_AUTOREFERER => true,
    CURLOPT_FOLLOWLOCATION => true,
    CURLOPT_RETURNTRANSFER => true
));
$opt = curl_exec($ch);
curl_close($ch);

$saveFile = $name.'.'.$ext;
if(preg_match("/[^0-9a-z._-]/i", $saveFile)) $saveFile = md5(microtime(true)).'.'.$ext;
$handle = fopen($saveFile, 'wb');
fwrite($handle, $opt);
fclose($handle);

4. Alexa / Google PageRank 查詢

function page_rank($page, $type = 'alexa'){
    switch($type){
        case 'alexa':
            $url = 'https://alexa.com/siteinfo/';
            $handle = fopen($url.$page, 'r');
            break;
        case 'google':
            $url = 'https://google.com/search?client=navclient-auto&ch=6-1484155081&features=Rank&q=info:';
            $handle = fopen($url.'https://'.$page, 'r');
            break;
    }
    $content = stream_get_contents($handle);
    fclose($handle);
    $content = preg_replace("~(\n|\t|\s+)~", '', $content);
    // 解析邏輯略...
    return $rank;
}

5. 強制下載（防止瀏覽器直接開啟）

$filename = $_GET['file'];
$query = sprintf("SELECT * FROM files WHERE id = '%s'", mysql_real_escape_string($filename));
$sql = mysql_query($query);
if(mysql_num_rows($sql) > 0){
    $row = mysql_fetch_array($sql);
    header("Pragma: public");
    header("Expires: 0");
    header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
    header("Content-Type: application/force-download");
    header("Content-Type: application/octet-stream");
    header("Content-Type: application/download");
    header("Content-Disposition: attachment; filename=".basename($row['FileName']).";");
    header("Content-Transfer-Encoding: binary");
    header("Content-Length: ".filesize($row['FileName']));
    @readfile($row['FileName']);
    exit(0);
}else{
    header("Location: /");
    exit;
}

6. 根據 Email 顯示 Gravatar 頭像

$gravatar_link = 'https://www.gravatar.com/avatar/' . md5($comment_author_email) . '?s=32';
echo '<img src="' . $gravatar_link . '" />';

7. cURL 獲取 FeedBurner RSS 訂閱數

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, 'https://feedburner.google.com/api/awareness/1.0/GetFeedData?id=xxx');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 2);
$content = curl_exec($ch);
$subscribers = get_match('/circulation="(.*)"/isU', $content);
curl_close($ch);

8. 人性化時間差顯示（X 秒/分/小時/天/週/月/年前）

function ago($time){
    $periods = array("second", "minute", "hour", "day", "week", "month", "year", "decade");
    $lengths = array("60","60","24","7","4.35","12","10");
    $now = time();
    $difference = $now - $time;
    $tense = "ago";
    for($j = 0; $difference >= $lengths[$j] && $j < count($lengths)-1; $j++) {
        $difference /= $lengths[$j];
    }
    $difference = round($difference);
    if($difference != 1) $periods[$j] .= "s";
    return "$difference $periods[$j] ago";
}

9. GD 圖片裁剪（指定區域複製到新畫布）

$filename = "test.jpg";
list($w, $h, $type, $attr) = getimagesize($filename);
$src_im = imagecreatefromjpeg($filename);
$src_x = 0; $src_y = 0; $src_w = 100; $src_h = 100;
$dst_x = 0; $dst_y = 0;
$dst_im = imagecreatetruecolor($src_w, $src_h);
$white = imagecolorallocate($dst_im, 255, 255, 255);
imagefill($dst_im, 0, 0, $white);
imagecopy($dst_im, $src_im, $dst_x, $dst_y, $src_x, $src_y, $src_w, $src_h);
header("Content-type: image/png");
imagepng($dst_im);
imagedestroy($dst_im);

10. 站點存活監控（cURL 檢測 HTTP 狀態碼）

function Visit($url){
    $agent = "Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)";
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_USERAGENT, $agent);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_TIMEOUT, 5);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
    curl_setopt($ch, CURLOPT_SSLVERSION, 3);
    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, FALSE);
    $page = curl_exec($ch);
    $httpcode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
    curl_close($ch);
    return ($httpcode >= 200 && $httpcode < 300);
}
if (Visit("https://www.google.com")) echo "Website OK"; else echo "Website DOWN";