正如我在 a previous question 中所描述的那样，我有一个任务要写一个代理服务器。它现在部分工作，但我在处理 gzip 信息时仍然有问题。我将 HttpResponse 存储在一个字符串中，看来我无法使用 gzip 压缩的内容来做到这一点。但是， header 是我需要解析的文本，它们都来自同一个 InputStream。我的问题是，我必须做什么才能正确处理二进制响应，同时仍将 header 解析为字符串？
>> 在查看代码之前，请先查看下面的编辑。
这是 Response 类的实现:
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;
}
}
这里是HttpPatterns:
public enum HttpPatterns {
RESPONSE_CODE("^HTTP/1\\.1 (\\d+) .*$"),
CACHE_CONTROL("^Cache-Control: (\\w+)$"),
HOST("^Host: (\\w+)$"),
REQUEST_HEADER("(GET|POST) ([^\\s]+) ([^\\s]+)$"),
ACCEPT_ENCODING("^Accept-Encoding: .*$");
private final Pattern pattern;
HttpPatterns(String regex) {
pattern = Pattern.compile(regex);
}
public boolean matches(String expression) {
return pattern.matcher(expression).matches();
}
public Object process(String expression) {
Matcher matcher = pattern.matcher(expression);
if (!matcher.matches()) {
throw new RuntimeException("Called `process`, but the expression doesn't match. Call `matches` first.");
}
if (this == RESPONSE_CODE) {
return Integer.parseInt(matcher.group(1));
} else if (this == CACHE_CONTROL) {
return CacheControl.parseString(matcher.group(1));
} else if (this == HOST) {
return matcher.group(1);
} else if (this == REQUEST_HEADER) {
return new RequestHeader(RequestType.parseString(matcher.group(1)), matcher.group(2), matcher.group(3));
} else { //never happens
return null;
}
}
}
编辑
我尝试根据建议实现，但它不起作用，我变得绝望了。当我尝试查看图像时，我从浏览器收到以下消息:
The image “http://www.google.com/images/logos/ps_logo2.png” cannot be displayed because it contains errors.
这是日志:
Request
==============================
GET http://www.google.com/images/logos/ps_logo2.png HTTP/1.1
Host: www.google.com
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-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 115
Cookie: PREF=ID=31f95dd7f42dfc7d:TM=1303507626:LM=1303507626:S=D4kIZ6rGFrlOUWlm
Not Reading from the Cache!!!!
I am going to try to connect to: www.google.com at port 80
Connected.
Writing to the server's buffer...
flushed.
Getting a response...
Got a binary response!
contentLength = 26209; headers.length() = 312; responseLength = 12136; fullResponse length = 12136
Got a response!
Writing to the Cache!!!!
I am going to write the following response:
HTTP/1.1 200 OK
Content-Type: image/png
Last-Modified: Thu, 05 Aug 2010 22:54:44 GMT
Date: Wed, 04 May 2011 15:05:30 GMT
Expires: Wed, 04 May 2011 15:05:30 GMT
Cache-Control: private, max-age=31536000
X-Content-Type-Options: nosniff
Server: sffe
Content-Length: 26209
X-XSS-Protection: 1; mode=block
Response body is binary and was truncated.
Finished with request!
这是新的 Response 类:
public class Response {
private String headers = "";
private BufferedReader reader;
private boolean busy = true;
private int responseCode;
private CacheControl cacheControl;
private InputStream fullResponse;
private ContentEncoding encoding = ContentEncoding.TEXT;
private ContentType contentType = ContentType.TEXT;
private int contentLength;
public Response(String input) {
this(new ByteArrayInputStream(input.getBytes()));
}
public Response(InputStream input) {
ByteArrayOutputStream tempStream = new ByteArrayOutputStream();
InputStreamReader inputReader = new InputStreamReader(input);
try {
while (!inputReader.ready());
int responseLength = 0;
while (inputReader.ready()) {
tempStream.write(inputReader.read());
responseLength++;
}
/*
* Read the headers
*/
reader = new BufferedReader(new InputStreamReader(new ByteArrayInputStream(tempStream.toByteArray())));
while (!reader.ready());//wait for initialization.
String line;
while ((line = reader.readLine()) != null) {
headers += "\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);
} else if (HttpPatterns.CONTENT_ENCODING.matches(line)) {
encoding = (ContentEncoding) HttpPatterns.CONTENT_ENCODING.process(line);
} else if (HttpPatterns.CONTENT_TYPE.matches(line)) {
contentType = (ContentType) HttpPatterns.CONTENT_TYPE.process(line);
} else if (HttpPatterns.CONTENT_LENGTH.matches(line)) {
contentLength = (Integer) HttpPatterns.CONTENT_LENGTH.process(line);
} else if (line.isEmpty()) {
break;
}
}
InputStreamReader streamReader = new InputStreamReader(new ByteArrayInputStream(tempStream.toByteArray()));
while (!reader.ready());//wait for initialization.
//Now let's get the rest
ByteArrayOutputStream out = new ByteArrayOutputStream();
int counter = 0;
while (streamReader.ready() && counter < (responseLength - contentLength)) {
out.write((char) streamReader.read());
counter++;
}
if (encoding == ContentEncoding.BINARY || contentType == ContentType.BINARY) {
System.out.println("Got a binary response!");
while (streamReader.ready()) {
out.write(streamReader.read());
}
} else {
System.out.println("Got a text response!");
while (streamReader.ready()) {
out.write((char) streamReader.read());
}
}
fullResponse = new ByteArrayInputStream(out.toByteArray());
System.out.println("\n\ncontentLength = " + contentLength +
"; headers.length() = " + headers.length() +
"; responseLength = " + responseLength +
"; fullResponse length = " + out.toByteArray().length + "\n\n");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
busy = false;
}
这是 ProxyServer 类:
class ProxyServer {
public void start() {
while (true) {
Socket serverSocket;
Socket clientSocket;
OutputStreamWriter 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());
}
System.out.println(request);
//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)) {
System.out.println("Reading from the Cache!!!!");
response = cache.get(request);
} else {
System.out.println("Not Reading from the Cache!!!!");
//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.");
serverSocket.setSoTimeout(50000);
//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);
System.out.println("Got a response!\n");
//wait for the response
while(response.isBusy());
}
if (request.getRequestType() == RequestType.GET && request.getCacheControl().equals(CacheControl.CACHE) && response.getResponseCode() == 200) {
System.out.println("Writing to the Cache!!!!");
cache.put(request, response);
}
else System.out.println("Not Writing to the Cache!!!!");
response = filter.filter(response);
// Return the response to the client
toClient = new OutputStreamWriter(clientSocket.getOutputStream());
System.out.println("I am going to write the following response:\n" + response);
BufferedReader responseReader = new BufferedReader(new InputStreamReader(response.getFullResponse()));
while (responseReader.ready()) {
toClient.write(responseReader.read());
}
toClient.flush();
toClient.close();
clientSocket.close();
System.out.println("Finished with request!");
} catch (IOException e) {
e.printStackTrace();
continue;
}
}
}
}
我将不胜感激关于如何解决此问题的任何和所有反馈/见解/建议，并且当然更喜欢一些实际代码。
最佳答案
将其存储在一个字节数组中:
byte[] bufer = new byte[???];
更详细的过程:
- 为响应头创建一个足够大的缓冲区(如果更大则丢弃异常)。
- 读取字节到缓冲区，直到在缓冲区中找到
\r\n\r\n。您可以编写一个辅助函数，例如static int arrayIndexOf(byte[] haystack, int offset, int length, byte[] needle) - 当遇到 header 结尾时，创建一个 strinform 缓冲区的前 n 个字节。然后，您可以在此字符串上使用 RegEx(另请注意，RegEx 不是解析 HTTPeader 的最佳方法)。
- 请准备好缓冲区将包含 header 之后的附加数据，这些数据是响应正文的第一个字节。您必须将这些字节复制到输出流或输出文件或输出缓冲区。
- 阅读响应正文的其余部分。 (直到读取content-length 或关闭流)。
编辑:
您没有遵循我建议的这些步骤。 inputReader.ready() 是检测响应阶段的错误方法。无法保证 header 将在单个突发中发送。
我尝试用代码(arrayIndexOf 除外)函数编写原理图。
InputStream is;
// Create a buffer large enough for the response header (and drop exception if it is bigger).
byte[] headEnd = {13, 10, 13, 10}; // \r \n \r \n
byte[] buffer = new byte[10 * 1024];
int length = 0;
// Read bytes to the buffer until you find `\r\n\r\n` in the buffer.
int bytes = 0;
int pos;
while ((pos = arrayIndexOf(buffer, 0, length, headEnd)) == -1 && (bytes = is.read(buffer, length, buffer.length() - length)) > -1) {
length += bytes;
// buffer is full but have not found end siganture
if (length == buffer.length())
throw new RuntimeException("Response header too long");
}
// pos contains the starting index of the end signature (\r\n\r\n) so we add 4 bytes
pos += 4;
// When you encounter the end of header, create a strinform the first *n* bytes
String header = new String(buffer, 0, pos);
System.out.println(header);
// Be prepared that the buffer will contain additional data after the header
// ... so we process it
System.out.write(buffer, pos, length - pos);
// process the rest until connection is closed
while (bytes = is.read(buffer, 0, bufer.length())) {
System.out.write(buffer, 0, bytes);
}
arrayIndexOf 方法可能看起来像这样:(可能有更快的版本)
public static int arrayIndexOf(byte[] haystack, int offset, int length, byte[] needle) {
for (int i=offset; i<offset+length-nedle.length(); i++) {
boolean match = false;
for (int j=0; j<needle.length(); j++) {
match = haystack[i + j] == needle[j];
if (!match)
break;
}
if (match)
return i;
}
return -1;
}
关于java - 如何存储可能包含二进制数据的 Http Response？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/5777503/