PHP 系列 (一)

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浮点数计算不准确|保留两位小数不四舍五入

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// 结果 float(0.099999999999998) 
var_dump(19.45 - 19.35);

// 设置所有bc数学函数的小数点保留位数
bcscale(2);
var_dump(bcsub(19.45, 19.35));

// 保留两位小数,不四舍五入
var_dump(bcsub(1.339, 0, 2));

DateTime 获取当前时间, 以微秒为单位

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// 输出当前时间, 以微秒为单位, 若直接将 $timeZone 作为 createFromFormat 的第三个参数是无效的, 问题是 microtime() 和 time()  返回的是当前时区的时间戳
// 参考 http://php.net/manual/zh/datetime.createfromformat.php#120552
$timeZone = new DateTimeZone(date_default_timezone_get() ? : 'Asia/Shanghai');
$ds = DateTime::createFromFormat('U.u', microtime(true))->setTimezone($timeZone);
var_dump($ds->format('Y-m-d H:i:s.u'));

删除不可见字符与BOM头

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// 删除ASCII码 0-31,127-255 字符
$string = preg_replace('/[\x00-\x1F\x7F-\xFF]/', '', $string);

// 删除ASCII码 0-31,127 字符
$string = preg_replace('/[\x00-\x1F\x7F]/', '', $string);

// 删除BOM,BOM的ASCII码为 239,187,191
$string = trim($string, "\xEF\xBB\xBF");

// IOS提交的不可见字符
$string = "‭1234567890‬";
var_dump(json_encode([$string]));
$string = preg_replace('/[\x7F-\xFF]/', '', $string);
var_dump(json_encode([$string]));

cURL 自定义 HEADER 参数

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<?php
$method = strtoupper($_SERVER['REQUEST_METHOD']);
if ($method == 'POST') {
    $postData = $_POST;
    $headers = [];
    $paramsArray = ['USERID', 'RANDOM'];
    foreach ($paramsArray as $param) {
        $headers[$param] = $_SERVER['HTTP_' . $param];
    }

    header('content-type:application/json;charset=utf8');
    die(json_encode([$postData, $headers]));
} else {
    $url = 'http://localhost:8080/index.php';
    $header = ['USERID:1', 'RANDOM:' . mt_rand(1, 1000)];
    $content = ['name' => 'test'];
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_HTTPHEADER, $header);
    curl_setopt($ch, CURLOPT_POST, true);
    curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($content));
    $response = curl_exec($ch);
    curl_close($ch);
    var_dump($response);
}

二维数组指定字段排序

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<?php
$array = [
    ['name' => 't1', 'val' => 1],
    ['name' => 't3', 'val' => 3],
    ['name' => 't2', 'val' => 2],
];
array_multisort($array, array_column($array, 'val'));
//array_multisort(array_column($array, 'val'), SORT_ASC, $array);
var_dump($array);

图片转换数据流

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<?php
$imgPath = './1.jpg';
if (file_exists($imgPath)) {
    $img = base64_encode(file_get_contents($imgPath));
    $img = 'data:image/jpg;base64,' . $img;
} else {
    $img = 'data:image/jpg;base64,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';
}
echo "<img src='{$img}' />";

HEADER 介绍

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<?php
header('HTTP/1.1 200 OK');                                              // ok 正常访问
header('HTTP/1.1 404 Not Found');                                       // 通知浏览器 页面不存在
header('HTTP/1.1 301 Moved Permanently');                               // 设置地址被永久的重定向 301
header('Location: http://www.ruonu.com/');                              // 跳转到一个新的地址
header('Refresh: 10; url=http://www.ruonu.com/');                       // 延迟转向 也就是隔几秒跳转
header('X-Powered-By: PHP/6.0.0');                                      // 修改 X-Powered-By信息
header('Content-language: en');                                         // 文档语言
header('Content-Length: 1234');                                         // 设置内容长度
header('Last-Modified: ' . gmdate('D, d M Y H:i:s', $time) . ' GMT');   // 告诉浏览器最后一次修改时间
header('HTTP/1.1 304 Not Modified');                                    // 告诉浏览器文档内容没有发生改变
 
###内容类型###
header('Content-Type: text/html; charset=utf-8');                       // 网页编码
header('Content-Type: text/plain');                                     // 纯文本格式
header('Content-Type: image/jpeg');                                     // JPG、JPEG
header('Content-Type: application/zip');                                // ZIP文件
header('Content-Type: application/pdf');                                // PDF文件
header('Content-Type: audio/mpeg');                                     // 音频文件
header('Content-type: text/css');                                       // css文件
header('Content-type: text/javascript');                                // js文件
header('Content-type: application/json');                               // json
header('Content-type: application/pdf');                                // pdf
header('Content-type: text/xml');                                       // xml
header('Content-Type: application/x-shockw**e-flash');                  // Flash动画
header('Content-Type: application/octet-stream');                       // .*( 二进制流, 不知道下载文件类型)
######
 
###声明一个下载的文件###
header('Content-Description:File');                                     // 描述
header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename="ITblog.zip"');
header('Content-Transfer-Encoding: binary');
readfile('test.zip');
######
 
###对当前文档禁用缓存###
header('Cache-Control: no-cache, no-store, max-age=0, must-revalidate');
header('Expires: Mon, 26 Jul 1997 05:00:00 GMT');
######
 
###显示一个需要验证的登陆对话框###
header('HTTP/1.1 401 Unauthorized');
header('WWW-Authenticate: Basic realm="Top Secret"');
######
 
 
###声明一个需要下载的xls文件###
header('Content-Disposition: attachment; filename=ithhc.xlsx');
header('Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');
header('Content-Length: '.filesize('./test.xls'));
header('Content-Transfer-Encoding: binary');
header('Cache-Control: must-revalidate');
header('Pragma: public');
readfile('./test.xls');
######
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