java - 如何使用 HTTP/2 over TLS 发送 HTTP 请求？ (Java 11 HttpClient)

Question

我正在尝试在 Java 应用程序中创建一个代理，该代理允许我修改 HTTP 请求的某些方面。

为此，我在端口 8080 上打开一个 ServerSocket，在该端口上的 Mozilla Firefox 中配置一个代理，并且对于每个连接，在单独的线程中执行 ServerSocket 的accept() 方法。到目前为止一切正常。

为了将请求从浏览器发送到相应的网站，我使用了 Java 11 中包含的 HttpClient 库。这是我使用该库的代码片段:

private void obtainResponse(Socket socket, IHttpRequest req, String uri) {

        HttpClient client = null;
        if (req.isSSL()) {
            SSLContext sslContext = ((SecureConnectionHandler)connHandler).createSSLContext( req.getHost() );
            client = HttpClient.newBuilder()
                    .connectTimeout(Duration.ofSeconds(30))
                    .priority(1)
                    .version(HttpClient.Version.HTTP_2)
                    .followRedirects(Redirect.NORMAL)
                    .sslContext( sslContext )
                    .build();
        }
        else
            client = HttpClient.newBuilder()
                    .connectTimeout(Duration.ofSeconds(30))
                    .priority(1)
                    .version(HttpClient.Version.HTTP_2)
                    .followRedirects(Redirect.NORMAL)
                    .build();

        String protocolAndHost = ((req.isSSL()) ? "https://" : "http://") + req.getHost();

        if (uri == null)
            uri = protocolAndHost + req.getRequestedResource();
        else {
            if (uri.startsWith("/"))
                uri = protocolAndHost + uri;
            System.out.println("Aqui:" + uri);
        }

        HttpRequest.Builder preRequest=null;
        if (req.getMethod().equalsIgnoreCase("GET")) {
            preRequest = HttpRequest.newBuilder()  // GET request!
                .uri(URI.create( uri ))
                .GET();
        }
        else if (req.getMethod().equalsIgnoreCase("POST")) {
            preRequest = HttpRequest.newBuilder()  // POST request!
            .uri(URI.create( uri ))
            .POST(BodyPublishers.ofString(req.getBody()));
        }

        for (Header header : req.getHeaders()) {
            if (!header.getKey().equalsIgnoreCase("Host") &&
                !header.getKey().equalsIgnoreCase("Connection") &&
                !header.getKey().equalsIgnoreCase("Content-Length") &&
                !header.getKey().equalsIgnoreCase("Upgrade") ) 
            {
                preRequest.setHeader(header.getKey(), header.getValues());
            }
        }
        HttpRequest request = preRequest.build();

        System.err.println("Request to: " + uri);

        HttpResponse<byte[]> response;
        try {
            response = client.sendAsync(request, BodyHandlers.ofByteArray())
                             .join();   
        } catch (CompletionException ce) {
            System.err.println("Address " + uri + " is unreachable!");
            return ;
        }

        HttpHeaders httpHeaders = response.headers();

        Optional<String> locationHeader = httpHeaders.firstValue("Location"); // When resource has been permanently moved

        if ( !locationHeader.isEmpty() ) {
            System.out.println("Moved permanently to " + locationHeader.get());
            obtainResponse( socket, req, locationHeader.get() );
        }
        else {
            Map<String, List<String>> headers = httpHeaders.map();

            String protocol = response.version().toString().replace("_", ".").replaceFirst("\\.", "/");

            int code = response.statusCode();

            String reasonPhrase = HttpStatus.getStatusText( code );

            var crlf = "\r\n";

            var responseString = protocol + " " + code + " " + reasonPhrase + crlf;

            for (String key : headers.keySet()) {
                responseString += key + ":";
                for (String valor : headers.get(key)) {
                    responseString += " " + valor;
                }
                responseString += crlf;
            }

            responseString += crlf; // espacio cabeceras y cuerpo

            writeResponse(socket, response.body(), responseString);
        }
    }


private void writeResponse(Socket socket, byte[] streamResponse, String responseHeaders) {
        OutputStream outputStream = null;
        try {
            outputStream = socket.getOutputStream(); 

            outputStream.write(responseHeaders.getBytes());
            outputStream.write(streamResponse);
            outputStream.flush();

        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } finally {
            try {
                if (!socket.isOutputShutdown()) {
                    socket.shutdownOutput();
                }
                outputStream.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        }
    }

注意:IHttpRequest 是我创建的一个类，其中包含从套接字收集的所有信息(目标主机、 header 、正文(如果存在)等)

到目前为止，我已经成功拦截了所有指向 HTTP 网站的请求。但是，我遇到了问题，例如 https://www.google.com/ ，它实现了HTTP/2协议(protocol)并使用了TLS。当我运行 Java 应用程序并访问之前的 Google 页面时，它没有向我显示网站，而是在浏览器中显示以下内容(忽略标题之间的空白):

HTTP/2 200 OK

:status: 200

alt-svc: quic = ":443"; ma = 2592000; v = "46,43,39"

cache-control: private

content-encoding: gzip

content-length: 46058

content-type: text/html; charset = UTF-8

date: Tue, 03 Sep 2019 09:47:34 GMT

Expires: Tue, 03 Sep 2019 09:47:34 GMT

p3p: CP = "This is not a P3P policy! See g.co/p3phelp for more info."

server: gws

set-cookie: 1P_JAR = 2019-09-03-09; expires = Thu, 03-Oct-2019 09:47:34 GMT; path = /; domain = .google.com; SameSite = none NID = 188 = XOJkffugf5G8rxNLov_iqqxo-Cq5RCvhwJPNu9tvtzLesZ4q8CE0IDVt9VgCEHZsw-AV0EYaaL8D4d_2Qwb6jXCcss7RydfV9PqQFemN_Ezz0kUjyseDDbJXfrHpmqPR6GIQCnR7bjukfasxg883K9fjnhAaqz6IpUYxoguZx-vazWc; expires = Wed, 04-Mar-2020 09:47:34 GMT; path = /; domain = .google.com; HttpOnly CONSENT = WP.27dd1a; expires = Fri, 01-Jan-2038 00:00:00 GMT; path = /; domain = .google.com

x-frame-options: SAMEORIGIN

x-xss-protection: 0

(↓↓ body ↓↓)

‹����� ÿÔ½ézâȲ (ú¿Ÿ‚ ¢ örÁ²À or PªÚ ° çyÜÞ¾ © $ Æ.ÞåžG¸ßýwþ® »™ š ¶« »× ùöíê ¢ ¤T '' '' ™ 'ß¿ († l / Æj ¢ or õ ßñ7¡ “QOLªV ÞU ¢ üø> Tm' ûÄ´T [L ^] îd * I7Õ Ùê Rçšb ÷ EE i²š¡ / ÜP iÃé0cÉDWE! ËsCò I ™ ZªI_ ‰) ## ™ '* & gš: ¦½ÒŽêê¸oŒ ‚™» † 9 $ vFQmU¶5c´Rˆ (Š © ZÖï 1L§ Üì ¦ÚUMS5W² Û $ # K'¶êæí FOWWrniCÒS- ò + Ú¨ · Åòõ¶ „÷ ñɲá 1 • 'ÙÐ

<< And much more information in form of bytes >>

你在我的代码中发现了什么奇怪的地方吗？我知道 HTTP/2 压缩了 Frames 中的 header ，但我假设 HTTPClient 在内部完成了...

如果您需要更多信息，请告诉我:)

提前谢谢您。

Answer 1

HTTP/2 协议(protocol)是二进制协议(protocol)。您发送回浏览器的是 HTTP/1.1 响应(即使 HttpClient 用于获取响应的协议(protocol)是 HTTP/2)。

但是 - 您的状态行是 HTTP/2 200 OK，您的浏览器无法理解。您需要将响应作为格式良好的 HTTP/1.1 响应发送。这包括过滤掉键以 ':' 开头的 header - 就像 ':status' 一样，因为这些是 HTTP/2 特定的响应 header 。另外，在不理解响应头的情况下转发回所有响应头可能根本行不通:编写完整的 HTTP 代理很困难。