我有一项任务是编写代理服务器。简单测试有效，但是当我将 firefox 配置为使用代理时，响应输入流从未准备好。你能帮忙吗？
ProxyServer(重要方法)
public void start() {
while (true) {
Socket serverSocket;
Socket clientSocket;
BufferedWriter toClient;
BufferedWriter toServer;
try {
//The client is meant to put data on the port, read the socket.
clientSocket = listeningSocket.accept();
Request request = new Request(clientSocket.getInputStream());
System.out.println("Accepted a request!\n" + request);
while(request.busy);
//Make a connection to a real proxy.
//Host & Port - should be read from the request
URL url = null;
try {
url = new URL(request.getRequestURL());
} catch (MalformedURLException e){
url = new URL("http:\\"+request.getRequestHost()+request.getRequestURL());
}
//remove entry from cache if needed
if (!request.getCacheControl().equals(CacheControl.CACHE) && cache.containsRequest(request)) {
cache.remove(request);
}
Response response = null;
if (request.getRequestType() == RequestType.GET && request.getCacheControl().equals(CacheControl.CACHE) && cache.containsRequest(request)) {
response = cache.get(request);
} else {
//Get the response from the destination
int remotePort = (url.getPort() == -1) ? 80 : url.getPort();
System.out.println("I am going to try to connect to: " + url.getHost() + " at port " + remotePort);
serverSocket = new Socket(url.getHost(), remotePort);
System.out.println("Connected.");
//write to the server - keep it open.
System.out.println("Writing to the server's buffer...");
toServer = new BufferedWriter(new OutputStreamWriter(serverSocket.getOutputStream()));
toServer.write(request.getFullRequest());
toServer.flush();
System.out.println("flushed.");
System.out.println("Getting a response...");
response = new Response(serverSocket.getInputStream());
System.out.println("Got a response!\n" + response);
//wait for the response
while(response.isBusy());
}
if (request.getRequestType() == RequestType.GET && request.getCacheControl().equals(CacheControl.CACHE)) {
cache.put(request, response);
}
response = filter.filter(response);
// Return the response to the client
toClient = new BufferedWriter(new OutputStreamWriter(clientSocket.getOutputStream()));
toClient.write(response.getFullResponse());
toClient.flush();
toClient.close();
} catch (IOException e) {
e.printStackTrace();
continue;
}
}
}
Response 和Request 类只是非常简单的 HTTP 请求/响应解析器。当我尝试通过代理加载网站时，我得到:
编辑 2
这是另一个尝试。我在 toClient.write(response.getFullResponse());
Accepted a request!
Request
==============================
GET http://t2.technion.ac.il/~srachum/ HTTP/1.1
Host: t2.technion.ac.il
User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:2.0) Gecko/20100101 Firefox/4.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-us,en;q=0.5
Accept-Encoding: gzip, deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 115
Proxy-Connection: keep-alive
I am going to try to connect to: t2.technion.ac.il at port 80
Connected.
Writing to the server's buffer...
flushed.
Getting a response...
Got a response!
Response
==============================
HTTP/1.1 200 OK
Date: Sat, 23 Apr 2011 15:54:08 GMT
Server: Apache/2.0.52 (Red Hat)
Last-Modified: Fri, 18 Mar 2011 23:45:24 GMT
ETag: "14928fc-877-49eca5f29cd00"
Accept-Ranges: bytes
Content-Length: 2167
Connection: close
Content-Type: text/html
X-Pad: avoid browser bug
<html>
...
</html>
I am going to write the following response:
HTTP/1.1 200 OK
Date: Sat, 23 Apr 2011 15:54:08 GMT
Server: Apache/2.0.52 (Red Hat)
Last-Modified: Fri, 18 Mar 2011 23:45:24 GMT
ETag: "14928fc-877-49eca5f29cd00"
Accept-Ranges: bytes
Content-Length: 2167
Connection: close
Content-Type: text/html
X-Pad: avoid browser bug
<html>
...
</html>
编辑 3:
请求
package cs236369.proxy;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import cs236369.proxy.types.CacheControl;
import cs236369.proxy.types.HttpPatterns;
import cs236369.proxy.types.RequestHeader;
import cs236369.proxy.types.RequestType;
public class Request {
private String fullRequest = "";
private BufferedReader reader;
private RequestHeader requestHeader;
private String requestHost;
boolean busy = true;
private CacheControl cacheControl = CacheControl.CACHE;
public CacheControl getCacheControl() {
return cacheControl;
}
Request(String request) {
this(new ByteArrayInputStream(request.getBytes()));
}
Request(InputStream input){
reader = new BufferedReader(new InputStreamReader(input));
try {
while(!reader.ready()); //wait for initialization.
String line;
while ((line = reader.readLine()) != null) {
fullRequest += "\r\n" + line;
if (HttpPatterns.CACHE_CONTROL.matches(line)) {
cacheControl = (CacheControl) HttpPatterns.RESPONSE_CODE.process(line);
} else if (HttpPatterns.REQUEST_HEADER.matches(line)) {
requestHeader = (RequestHeader) HttpPatterns.REQUEST_HEADER.process(line);
} else if (HttpPatterns.HOST.matches(line)) {
requestHost = (String) HttpPatterns.HOST.process(line);
}
}
fullRequest = "\r\n" + fullRequest.trim() + "\r\n\r\n";
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
busy = false;
}
public String getFullRequest() {
return fullRequest;
}
public RequestType getRequestType() {
return requestHeader.type;
}
public String getRequestURL() {
return requestHeader.url;
}
public String getRequestProtocol() {
return requestHeader.protocol;
}
public String getRequestHost() {
return requestHost;
}
public boolean isBusy() {
return busy;
}
@Override
public String toString() {
return "Request\n==============================\n" + fullRequest;
}
}
响应
package cs236369.proxy;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import cs236369.proxy.types.CacheControl;
import cs236369.proxy.types.HttpPatterns;
public class Response {
private String fullResponse = "";
private BufferedReader reader;
private boolean busy = true;
private int responseCode;
private CacheControl cacheControl;
public Response(String input) {
this(new ByteArrayInputStream(input.getBytes()));
}
public Response(InputStream input) {
reader = new BufferedReader(new InputStreamReader(input));
try {
while (!reader.ready());//wait for initialization.
String line;
while ((line = reader.readLine()) != null) {
fullResponse += "\r\n" + line;
if (HttpPatterns.RESPONSE_CODE.matches(line)) {
responseCode = (Integer) HttpPatterns.RESPONSE_CODE.process(line);
} else if (HttpPatterns.CACHE_CONTROL.matches(line)) {
cacheControl = (CacheControl) HttpPatterns.CACHE_CONTROL.process(line);
}
}
reader.close();
fullResponse = "\r\n" + fullResponse.trim() + "\r\n\r\n";
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
busy = false;
}
public CacheControl getCacheControl() {
return cacheControl;
}
public String getFullResponse() {
return fullResponse;
}
public boolean isBusy() {
return busy;
}
public int getResponseCode() {
return responseCode;
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result
+ ((fullResponse == null) ? 0 : fullResponse.hashCode());
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (!(obj instanceof Response))
return false;
Response other = (Response) obj;
if (fullResponse == null) {
if (other.fullResponse != null)
return false;
} else if (!fullResponse.equals(other.fullResponse))
return false;
return true;
}
@Override
public String toString() {
return "Response\n==============================\n" + fullResponse;
}
}
最佳答案
有一次我写了一个发送 HTTP 请求的程序……我的代码是这样的:
String host="www.google.com";
String request="GET / HTTP/1.0\r\nHost: "+host+"\r\nAccept-Encoding: gzip\r\n\r\n";
System.out.println(request);
Socket sock=new Socket(host,80);
InputStream inp=sock.getInputStream();
OutputStream outp=sock.getOutputStream();
outp.write(request.getBytes());
byte[] buff=new byte[999];
while(true){
int n=inp.read(buff);
if(n<0) break;
System.out.println(new String(buff,0,n));
}
inp.close();
outp.close();
sock.close();
此代码有效。乍一看，它看起来像你的。您可以尝试将两者结合起来，观察问题何时开始出现。也许您的 Response 解析器有问题？
附言您确定您从浏览器收到的原始请求以两个换行符结尾吗？在您发布的日志中，似乎只有一个空行...
编辑: 我编译了您的代码并稍作修改，它运行良好。我做的事情:
- 注释掉有关 CacheControl、过滤和 RequestHeader 的所有内容，因为我没有这些类的源代码；
- 添加了 URL 和主机的简单解析，因为没有它们就无法工作；
- 添加了一项检查以删除
Accept-Encoding，因为许多服务器使用的 gzip 在此程序中已损坏； - 添加了检查以在两次换行后停止解析请求。
此程序用作 Firefox 的代理服务器，并且可以很好地处理 HTML 代码。请编译我的版本并尝试它是否适合你。可能与 Firefox 设置有关？
请注意，此代理服务器正在破坏二进制数据，例如图像和 gzip 压缩的 HTML。这一定是InputStreamReader和OutputStreamWriter的使用引起的；它们将字节转换为字符，反之亦然，这对文本很有用，但对于二进制数据，您最好“按原样”使用 InputStream 和 OutputStream。
public class AmirRachum {
public static void main(String[] args) {
try{
int port=38824;
ServerSocket listeningSocket=new ServerSocket(port);
System.out.println("Socket created");
while (true) {
Socket serverSocket;
Socket clientSocket;
BufferedWriter toClient;
BufferedWriter toServer;
try {
//The client is meant to put data on the port, read the socket.
clientSocket = listeningSocket.accept();
Request request = new Request(clientSocket.getInputStream());
System.out.println("Accepted a request!\n" + request);
while(request.busy);
//Make a connection to a real proxy.
//Host & Port - should be read from the request
URL url = null;
try {
url = new URL(request.getRequestURL());
} catch (MalformedURLException e){
url = new URL("http:\\"+request.getRequestHost()+request.getRequestURL());
}
//remove entry from cache if needed
/* if (!request.getCacheControl().equals(CacheControl.CACHE) && cache.containsRequest(request)) {
cache.remove(request);
}*/
Response response = null;
/* if (request.getRequestType() == RequestType.GET && request.getCacheControl().equals(CacheControl.CACHE) && cache.containsRequest(request)) {
response = cache.get(request);
} else*/ {
//Get the response from the destination
int remotePort = (url.getPort() == -1) ? 80 : url.getPort();
System.out.println("I am going to try to connect to: " + url.getHost() + " at port " + remotePort);
serverSocket = new Socket(url.getHost(), remotePort);
System.out.println("Connected.");
//write to the server - keep it open.
System.out.println("Writing to the server's buffer...");
toServer = new BufferedWriter(new OutputStreamWriter(serverSocket.getOutputStream()));
toServer.write(request.getFullRequest());
toServer.flush();
System.out.println("flushed.");
System.out.println("Getting a response...");
response = new Response(serverSocket.getInputStream());
System.out.println("Got a response!\n" + response);
//wait for the response
while(response.isBusy());
}
/* if (request.getRequestType() == RequestType.GET && request.getCacheControl().equals(CacheControl.CACHE)) {
cache.put(request, response);
}
response = filter.filter(response);*/
// Return the response to the client
toClient = new BufferedWriter(new OutputStreamWriter(clientSocket.getOutputStream()));
toClient.write(response.getFullResponse());
toClient.flush();
toClient.close();
} catch (IOException e) {
e.printStackTrace();
continue;
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
public static class Request {
private String fullRequest = "";
private BufferedReader reader;
// private RequestHeader requestHeader;
private String requestHost;
private String requestURL;
boolean busy = true;
// private CacheControl cacheControl = CacheControl.CACHE;
/* public CacheControl getCacheControl() {
return cacheControl;
}*/
Request(String request) {
this(new ByteArrayInputStream(request.getBytes()));
}
Request(InputStream input){
reader = new BufferedReader(new InputStreamReader(input));
try {
while(!reader.ready()); //wait for initialization.
String line;
while ((line = reader.readLine()) != null) {
if(!line.startsWith("Accept-Encoding:")) fullRequest += "\r\n" + line;
/* if (HttpPatterns.CACHE_CONTROL.matches(line)) {
cacheControl = (CacheControl) HttpPatterns.RESPONSE_CODE.process(line);
} else if (HttpPatterns.REQUEST_HEADER.matches(line)) {
requestHeader = (RequestHeader) HttpPatterns.REQUEST_HEADER.process(line);
} else if (HttpPatterns.HOST.matches(line)) {
requestHost = (String) HttpPatterns.HOST.process(line);
}*/
if(line.startsWith("GET ")){requestURL=line.split(" ")[1];System.out.println("url \""+requestURL+"\"");}
if(line.startsWith("Host:")){requestHost=line.substring(6);System.out.println("Host \""+requestHost+"\"");}
if(line.length()==0){System.out.println("empty line");break;}
}
fullRequest = "\r\n" + fullRequest.trim() + "\r\n\r\n";
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
busy = false;
}
public String getFullRequest() {
return fullRequest;
}
/* public RequestType getRequestType() {
return requestHeader.type;
}*/
public String getRequestURL() {
return requestURL;
}
/* public String getRequestProtocol() {
return requestHeader.protocol;
}*/
public String getRequestHost() {
return requestHost;
}
public boolean isBusy() {
return busy;
}
//@Override
public String toString() {
return "Request\n==============================\n" + fullRequest;
}
}
public static class Response {
private String fullResponse = "";
private BufferedReader reader;
private boolean busy = true;
// private int responseCode;
// private CacheControl cacheControl;
public Response(String input) {
this(new ByteArrayInputStream(input.getBytes()));
}
public Response(InputStream input) {
reader = new BufferedReader(new InputStreamReader(input));
try {
while (!reader.ready());//wait for initialization.
String line;
while ((line = reader.readLine()) != null) {
fullResponse += "\r\n" + line;
/* if (HttpPatterns.RESPONSE_CODE.matches(line)) {
responseCode = (Integer) HttpPatterns.RESPONSE_CODE.process(line);
}/* else if (HttpPatterns.CACHE_CONTROL.matches(line)) {
cacheControl = (CacheControl) HttpPatterns.CACHE_CONTROL.process(line);
}*/
}
reader.close();
fullResponse = "\r\n" + fullResponse.trim() + "\r\n\r\n";
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
busy = false;
}
/* public CacheControl getCacheControl() {
return cacheControl;
}*/
public String getFullResponse() {
return fullResponse;
}
public boolean isBusy() {
return busy;
}
/* public int getResponseCode() {
return responseCode;
}*/
//@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result
+ ((fullResponse == null) ? 0 : fullResponse.hashCode());
return result;
}
//@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (!(obj instanceof Response))
return false;
Response other = (Response) obj;
if (fullResponse == null) {
if (other.fullResponse != null)
return false;
} else if (!fullResponse.equals(other.fullResponse))
return false;
return true;
}
//@Override
public String toString() {
return "Response\n==============================\n" + fullResponse;
}
}
}
关于java - 尝试创建代理，不起作用，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/5763704/