C++从http下载二进制文件

Question

C++从http下载二进制文件

我正在为我用c ++编写的第一个程序创建一个更新机制.理论是:

程序将其版本作为http标头发送到服务器php
服务器检查是否存在更高版本
如果是,则服务器将新二进制文件发送到客户端.

大多数都有效,但收到的二进制文件格式不正确.当我将格式错误的exe与工作exe进行比较时,我\r\n在编译的exe中有s的区别.好像\r是加倍了.

我下载的c ++代码:

void checkForUpdates () {
    SOCKET sock = createHttpSocket (); // creates the socket, nothing wrong here, other requests work

    char* msg = (char*)"GET /u/2 HTTP/1.1\r\nHost: imgup.hu\r\nUser-Agent: imgup uploader app\r\nVersion: 1\r\n\r\n";

    if (send(sock, msg, strlen(msg), 0) == SOCKET_ERROR) {
        error("send failed with error\n");
    }
    shutdown(sock, SD_SEND);

    FILE *fp = fopen("update.exe", "w");
    char answ[1024] = {};
    int iResult;
    bool first = false;
    do {
        if ((iResult = recv(sock, answ, 1024, 0)) < 0) {
            error("recv failed with error\n");
        }
        if (first) {
            info (answ); // debug purposes
            first = false;
        } else {
            fwrite(answ, 1, iResult, fp);
            fflush(fp);
        }
    } while (iResult > 0);
    shutdown(sock, SD_RECEIVE);

    if (closesocket(sock) == SOCKET_ERROR) {
        error("closesocket failed with error\n");
    }

    fclose(fp);

    delete[] answ;
}

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和我的PHP来处理请求

<?php
if (!function_exists('getallheaders')) {
    function getallheaders() {
        $headers = '';
        foreach ($_SERVER as $name => $value) {
            if (substr($name, 0, 5) == 'HTTP_') {
                $headers[str_replace(' ', '-', ucwords(strtolower(str_replace('_', ' ', substr($name, 5)))))] = $value;
            }
        }
        return $headers;
    }
}

$version = '0';
foreach (getallheaders() as $name => $value) {
    if (strtolower ($name) == 'version') {
        $version = $value;
        break;
    }
}

if ($version == '0') {
    exit('error');
}


if ($handle = opendir('.')) {
    while (false !== ($entry = readdir($handle))) {
        if ($entry != '.' && $entry != '..' && $entry != 'u.php') {
            if (intval ($entry) > intval($version)) {
                header('Content-Version: ' . $entry);
                header('Content-Length: ' . filesize($entry));
                header('Content-Type: application/octet-stream');
                echo "\r\n";
                ob_clean();
                flush();
                readfile($entry);
                exit();
            }
        }
    }
    closedir($handle);
}
echo 'error2';


?>

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注意我发送标题后刷新内容的方式,ob_clean(); flush();所以我不必用c ++解析它们.写入文件的第一个字节很好,所以我怀疑这里有什么问题.

另外,二进制文件的示例比较http://i.imgup.hu/meC16C.png

问题:http是否\r\n在二进制文件传输中转义？如果不是,导致此行为的原因是什么？如何解决此问题？