springboot中controller层实现通用的透明代理

代理的要求:

• 透明
• 可更改请求,响应头,体
• 支持流式请求和流式响应

spring cloud gateway

首先想到api网关spring cloud gateway是否能用到controller层, 其实是有的:

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-gateway-mvc</artifactId>
            <version>3.1.6</version>
        </dependency>

    @PostMapping("/app-api/proxy/**")
    public ResponseEntity<String> proxyPath(ProxyExchange<String> proxy) throws Exception {
        System.out.println("proxyPath: "+proxy.path());
        ///app-api/chatgpt/chat-list/proxy/hello333
        String path = proxy.path("/app-api/proxy/");
        System.out.println("proxyPath2: "+path);
        //hello333
        //UnknownContentTypeException: no suitable HttpMessageConverter found for response type [?] and content type [text/html;charset=iso-8859-1]
        //Could not extract response: no suitable HttpMessageConverter found for response type [?] and content type [text/html;charset=UTF-8]

        //ResponseEntity.status()
        //  requestHeaders.remove("host");
        //        requestHeaders.remove("tenant-id");
        //proxy.post().getHeaders();
        return proxy.uri("https://xxx.yyy.zzz/" + path)
                .header("host","")
                //.headers(proxy.get().getHeaders())
                .post();
    }

上面的代码泛型为string,即响应会解析为string然后返回.

ResponseEntity 即返回streaming body.

但spring-cloud-gateway-mvc并不支持流式响应. 在官方issue里已有人咨询过.

ProxyExchange does not support streaming response (opens new window)

Streaming file download through spring-cloud-gateway can not open (opens new window)

okhttp

直接使用okhttp进行代理转发,通过okhttp来支持流式请求和流式响应:

舒坦

     okHttpClient = new OkHttpClient.Builder()
                .readTimeout(Duration.ofSeconds(50))
                .writeTimeout(Duration.ofSeconds(50))
                .connectTimeout(Duration.ofSeconds(50))
                .addNetworkInterceptor(new HttpLoggingInterceptor().setLevel(HttpLoggingInterceptor.Level.HEADERS))
                .build();


private void proxy(HttpServletRequest request,
                       Map<String, String> requestHeaders,
                       HttpServletResponse response, String url) throws IOException {
        String queryString = request.getQueryString();
        if (queryString != null) {
            url += "?" + queryString;
        }


        //if(request.)
        RequestBody requestBody = null;
        InputStream inputStream0 = request.getInputStream();
        if(inputStream0 != null){
            String type = request.getHeader("content-type");
            if(type ==null || type.isEmpty()){
                type = "application/octet-stream";
            }
           requestBody = new InputStreamRequestBody(MediaType.parse(type),inputStream0);
            //TODO inputStream.readAllBytes()是非stream操作, 如果是大文件上传,就会有性能问题和内存问题
           /* byte[] bytes = inputStream.readAllBytes();
            requestBody = RequestBody.create(bytes);*/
        }
        //todo 加上bare token

        Request okHttpRequest = new Request.Builder()
                .url(url)
                .method(request.getMethod(),requestBody)
                //.post(requestBody)
                .headers(Headers.of(requestHeaders))
                .build();

        try (Response okHttpResponse = okHttpClient.newCall(okHttpRequest).execute()) {

            // set response status code
            response.setStatus(okHttpResponse.code());
            // pass response headers
            for (Map.Entry<String, List<String>> entry : okHttpResponse.headers().toMultimap().entrySet()) {
                String key = entry.getKey();
                List<String> value = entry.getValue();
                ////access-control-allow-origin: *  : 会与外部重复,导致跨域问题,所以需要移除
                //todo
                if(!key.toLowerCase().startsWith("access-control")){
                    response.addHeader(key, value.get(0));
                }
            }
            if(!okHttpResponse.isSuccessful()){
                //todo
            }
            if(okHttpResponse.body() ==null){
                return;
            }

            // set response content type
            if( okHttpResponse.body().contentType() != null ){
                response.setContentType(okHttpResponse.body().contentType().toString());
            }

            // streaming response body
            try (InputStream inputStream = okHttpResponse.body().byteStream();
                 OutputStream outputStream = response.getOutputStream()) {
                ByteArrayOutputStream outputStream2 = new ByteArrayOutputStream();
                // 一个inputStream往两个outputStream里写
                OutputStream teeOutputStream = new TeeOutputStream(outputStream, outputStream2);

                byte[] buffer = new byte[512];
                int bytesRead;
                while ((bytesRead = inputStream.read(buffer)) != -1) {
                    teeOutputStream.write(buffer, 0, bytesRead);
                }
                teeOutputStream.flush();
                teeOutputStream.close();
                byte[] bytes = outputStream2.toByteArray();
                outputStream2.close();

                String json = new String(bytes,0,bytes.length,"UTF-8");
                //这里可以构建一个不影响流式响应的拦截/日志功能
                StaticLog.info(json);
            }
            //ClassCastException: class java.util.LinkedHashMap cannot be cast to class [B (java.util.LinkedHashMap and
            // [B are in module java.base of loader 'bootstrap')(String), java.lang.ClassCastException:
            // class java.util.LinkedHashMap cannot be cast to class [B (java.util.LinkedHashMap and [B are in module java.base of loader 'bootstrap')
        }catch (Throwable throwable){
            StaticLog.error(throwable);
            throw  throwable;
        }

调用

注意header的添加和移除.以及跨域头的重复问题

@PostMapping(value = "/app-api/proxyStream/**")
    @PreAuthenticated
    public void proxy(HttpServletRequest request,
                      @RequestHeader Map<String, String> requestHeaders,
                      HttpServletResponse response ) throws IOException {
        String url = request.getRequestURI();
        String path = url.substring(url.indexOf("/app-api/proxyStream/")+"/app-api/proxyStream/".length());
        StaticLog.debug("path---> "+path);
        StaticLog.debug("headers---> "+requestHeaders.toString());
        url = "https://yyy.xxx.zzz/"+ path;
        requestHeaders.remove("host");
        requestHeaders.remove("X-Real-IP");
        requestHeaders.remove("X-Forwarded-For");
        requestHeaders.remove("tenant-id");
        requestHeaders.remove("Referer");
        requestHeaders.remove("referer");
        requestHeaders.remove("Origin");
        requestHeaders.remove("origin");
        requestHeaders.remove("Authorization");
        requestHeaders.remove("authorization");
        requestHeaders.remove("device-id");
        requestHeaders.remove("language-id");
        requestHeaders.remove("language-id");
        requestHeaders.remove("version-name");
        requestHeaders.remove("version-code");
        requestHeaders.remove("device-type");
        requestHeaders.remove("accept-language");
        Iterator<String> iterator = requestHeaders.keySet().iterator();
        while (iterator.hasNext()){
            String next = iterator.next();
            if(next.startsWith("sec-")){
                iterator.remove();
            }
        }
        requestHeaders.put("user-agent","Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/112.0.0.0 Safari/537.36");
        StaticLog.info("headers after remove---> "+requestHeaders.toString());
        //{user-agent=navigation/1.0.07.1007 Dalvik/2.1.0 (Linux; U; Android 10; HRY-AL00a Build/HONORHRY-AL00a),
        // version-name=1.0.07, accept-encoding=gzip, device-id=eb791a8665fb5255,
        // version-code=1007, content-type=application/json, language-id=123, accept=application/json,*/*,
        // content-length=1802, app-version=1007, device-type=Android}

        //web:
        //{connection=keep-alive, content-length=99, sec-ch-ua="Chromium";v="112", "Google Chrome";v="112", "Not:A-Brand";v="99",
        // content-type=application/json, sec-ch-ua-mobile=?1, user-agent=Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7)
        // AppleWebKit/537.36 (KHTML, like Gecko) Chrome/112.0.0.0 Safari/537.36, sec-ch-ua-platform="Android", accept=*/*,
        // origin=http://localhost:57581, sec-fetch-site=same-site, sec-fetch-mode=cors, sec-fetch-dest=empty,
        // referer=http://localhost:57581/, accept-encoding=gzip, deflate, br, accept-language=zh-CN,zh;q=0.9}
        proxy(request, requestHeaders, response, url);
    }