const BUFSIZE = 1024;
    const SHARE_IMG = "share_logo.jpg";

    public function download($src) {
        $url = parse_url($src);
        $host = $url['host'];
        $protocol = $url['scheme']; // http, https
        $uri = $url['path'];

        if (0==strncmp($protocol, "https", 5)) {
            $port = 443;
        } else {
            $port = 80;
        }
        $socket = fsockopen($host, $port, $errno, $errMsg);
        if (!$socket) {
            return ["errno" => $errno, "errMsg" => $errMsg, "data" => null];
        }
        fwrite($socket, sprintf("GET %s HTTP/1.1\r\n", $uri));
        fwrite($socket, "Host: ".$host."\r\n");
        fwrite($socket, "Connection: keep-alive\n\n");
        fwrite($socket, "Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9\r\n");
        fwrite($socket, "Accept-Encoding: gzip, deflate\r\n");
        fwrite($socket, "User-Agent: Socket_Backstage\r\n");
        fwrite($socket, "\r\n\r\n");

        // jump over http headers
        $header = "";
        while ($str = trim(fgets($socket, self::BUFSIZE))) {
            $header .= $str."\r\n";
        }
        Log::info($header);

        $dir = self::getDir();
        $path = $dir."/".self::SHARE_IMG;
        $outFile = fopen($path, "w");

        $bytesWritten = 0;
        while (!feof($socket)) {
            $s = fread($socket, self::BUFSIZE);
            $bytesWritten += fwrite($outFile, $s, strlen($s));
        }
        fclose($socket);
        fclose($outFile);
        return ["errno" => $errno, "errMsg" => $errMsg, "data" => ['bytesWritten' => $bytesWritten]];
    }

    private static function getDir() {
        $dir = app_path().'/../storage/app';
        $absDir = Str::absPath($dir);
        if (!is_dir($absDir)) {
            unlink($absDir);
        }
        if (!file_exists($absDir)) {
            mkdir($absDir, 0755);
        }
        return $absDir;
    }

    public function image() {
        $dir = self::getDir();
        $img = $dir."/".self::SHARE_IMG;
        $info = getimagesize($img);
        // 获取文件后缀
        $imgExt = image_type_to_extension($info[2], false);
        $fun = "imagecreatefrom".$imgExt;
        // 1.由文件或 URL 创建一个新图象。如:imagecreatefrompng ( string $filename )
        $imgInfo = $fun($img);
        //$mime = $info['mime'];
        $mime = image_type_to_mime_type(exif_imagetype($img)); //获取图片的 MIME 类型
        header('Content-Type:'.$mime);
        $quality = 100;
        // 输出质量,JPEG格式(0-100),PNG格式(0-9)
        if($imgExt == 'png') $quality = 9;
        $getImgInfo = "image{$imgExt}";
        //2.将图像输出到浏览器或文件。如: imagepng ( resource $image )
        $getImgInfo($imgInfo, null, $quality);
        imagedestroy($imgInfo);
    }

路径转化

PHP去掉路径中的 ./ ../ 相对路径，绝对路径