如何從此示例HTTP請求獲取正文？

Question

我試圖找到最簡單的方法來解析Java中的RFC-822文檔。 假設我有一個存儲HTTP消息的消息隊列。 請求和響應。 因此，通過建立與端口80的套接字連接並從該端口發送/檢索消息，不能以“正常”方式檢索它們。

在下面的代碼中，我故意將“郵件”標頭與HTTP消息混合在一起。 這是為了表明兩者之間沒有太大區別。 但這不是重點。 這是代碼：

package httpexample;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import org.apache.http.Header;
import org.apache.http.HttpException;
import org.apache.http.HttpRequest;
import org.apache.http.impl.io.DefaultHttpRequestParser;
import org.apache.http.impl.io.HttpTransportMetricsImpl;
import org.apache.http.impl.io.SessionInputBufferImpl;
import org.apache.http.io.HttpMessageParser;
import org.apache.http.message.BasicHttpEntityEnclosingRequest;

public class HttpExample {

    // RFC 822

    public static void main(String[] args) throws IOException, HttpException {
        String str = "POST http://localhost:8080/foobar/1234567 HTTP/1.1\n" +
            "Message-ID: <19815303.1075861029555.JavaMail.ss@kk>\n" +
            "Date: Wed, 6 Mar 2010 12:32:20 -0800 (PST)\n" +
            "From: someone@someotherplace.com\n" +
            "To: someone@someplace.com\n" +
            "Subject: some subject\n" +
            "Mime-Version: 1.0\n" +
            "Content-Type: text/plain; charset=us-ascii\n" +
            "Content-Transfer-Encoding: 7bit\n" +
            "X-From: one, some <some.one@someotherplace.com>\n" +
            "X-To: one\n" +
            "X-cc: \n" +
            "X-bcc: \n" +
            "X-Origin: Bob-R\n" +
            "X-FileName: rbob (Non-Privileged).pst\n" +
            "\n" +
            "some message\n";
        ByteArrayInputStream fakeStream = new ByteArrayInputStream(
                str.getBytes());
        HttpTransportMetricsImpl metrics = new HttpTransportMetricsImpl();
        SessionInputBufferImpl inbuffer = new SessionInputBufferImpl(metrics, 1024);

        inbuffer.bind(fakeStream);
        HttpMessageParser<HttpRequest> requestParser =
                new DefaultHttpRequestParser(inbuffer);
        BasicHttpEntityEnclosingRequest request = (BasicHttpEntityEnclosingRequest)requestParser.parse();

        for (Header hdr : request.getAllHeaders()) {
            System.out.println(String.format("%-30s = %s", hdr.getName(), hdr.getValue()));
        }
        System.out.println(String.format("Request Line: %s", request.getRequestLine()));
        System.out.println(String.format("Body\n------------------\n%s",
                request.getEntity()));
    }

}

輸出看起來像這樣：

Message-ID                     = <19815303.1075861029555.JavaMail.ss@kk>
Date                           = Wed, 6 Mar 2010 12:32:20 -0800 (PST)
From                           = someone@someotherplace.com
To                             = someone@someplace.com
Subject                        = some subject
Mime-Version                   = 1.0
Content-Type                   = text/plain; charset=us-ascii
Content-Transfer-Encoding      = 7bit
X-From                         = one, some <some.one@someotherplace.com>
X-To                           = one
X-cc                           = 
X-bcc                          = 
X-Origin                       = Bob-R
X-FileName                     = rbob (Non-Privileged).pst
Request Line: POST http://localhost:8080/foobar/1234567 HTTP/1.1
Body
------------------
null

我想不通，是如何訪問消息的主體 。

我希望它的內容some message\\n

我在BasicHttpEntityEnclosingRequest中找不到任何可以提供此值的方法。 在較早的版本中，我使用了

HttpRequest request = requestParser.parse();

代替

BasicHttpEntityEnclosingRequest request = 
    (BasicHttpEntityEnclosingRequest) requestParser.parse();

我將其更改為BasicHttpEntityEnclosingRequest因為它具有getEntity方法。 但這返回null 。

所以我有點迷路。

我在哪里找到屍體？

Answer 1

我添加了Content-Length標頭，否則解析器將忽略POST正文。 我已經修改了您的代碼，現在它可以很好地解析主體了：

package org.apache.http.examples;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;

import org.apache.http.Header;
import org.apache.http.HttpException;
import org.apache.http.message.BasicHttpEntityEnclosingRequest;
import org.apache.http.util.EntityUtils;

public class HttpExample {

    // RFC 822

    public static void main(String[] args) throws IOException, HttpException {
        String str = "POST http://localhost:8080/foobar/1234567 HTTP/1.1\n" +
            "Message-ID: <19815303.1075861029555.JavaMail.ss@kk>\n" +
            "Date: Wed, 6 Mar 2010 12:32:20 -0800 (PST)\n" +
            "From: someone@someotherplace.com\n" +
            "To: someone@someplace.com\n" +
            "Subject: some subject\n" +
            "Mime-Version: 1.0\n" +
            "Content-Type: text/plain; charset=us-ascii\n" +
            "Content-Transfer-Encoding: 7bit\n" +
            "X-From: one, some <some.one@someotherplace.com>\n" +
            "X-To: one\n" +
            "X-cc: \n" +
            "X-bcc: \n" +
            "X-Origin: Bob-R\n" +
            "X-FileName: rbob (Non-Privileged).pst\n" +
            "Content-Length: 13\n" +
            "\n" +
            "some message\n";
        ByteArrayInputStream fakeStream = new ByteArrayInputStream(
                str.getBytes());

        BHttpConnectionBaseImpl b = new BHttpConnectionBaseImpl(fakeStream);

        BasicHttpEntityEnclosingRequest request1 = (BasicHttpEntityEnclosingRequest) b.receiveRequestHeader();
        b.receiveRequestEntity(request1);


        for (Header hdr : request1.getAllHeaders()) {
            System.out.println(String.format("%-30s = %s", hdr.getName(), hdr.getValue()));
        }
        System.out.println(String.format("Request Line: %s", request1.getRequestLine()));
        System.out.println(String.format("Body\n------------------\n%s",
                EntityUtils.toString( request1.getEntity() ) ));
    }

}

class BHttpConnectionBaseImpl extends  org.apache.http.impl.DefaultBHttpServerConnection{

    private InputStream inputStream;

    public BHttpConnectionBaseImpl(final InputStream inputStream) {
        super(4048);
        this.inputStream = inputStream;
        try {
            super.bind(new Socket());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Override
    protected InputStream getSocketInputStream(final Socket socket) throws IOException {
        return inputStream;
    }

    @Override
    protected OutputStream getSocketOutputStream(final Socket socket) throws IOException {
        return new ByteArrayOutputStream();
    }
}

POST正文的解析在org.apache.http.impl.BHttpConnectionBase.prepareInput(HttpMessage) ，無論其唯一的構造方法是受保護的並且需要很多參數。 子org.apache.http.impl.DefaultBHttpServerConnection有一個方便的公共構造函數，並在receiveRequestHeader()中進行頭解析。 我正在重載的方法需要繞過一些錯誤檢查，例如Socket == null並能夠從fakeStream讀取請求

盡管我尚未測試過，但另一種可行的方法是重寫Socket尤其是重寫其getInputStream()和getOutputStream() 。 然后創建DefaultBHttpServerConnection的實例並調用其bind方法。 其余應相同。

Answer 2

我認為問題可能在於您的消息標題不清楚主體的長度，因此接收方只是忽略了它。 HTTP規范定義了幾種有關如何傳達此信息的選項，但似乎沒有一個選項適用於此：

1. Content-Transfer-Encoding必須為Transfer-Encoding
2. 7bit不在標准選項之列 。
3. 當您使用str.getBytes() ，它將為您提供UTF-16字節，這不是在Content-Type聲明的us-ascii 。

因此，我會稍微更改您的請求：

1. 使用標題Content-Type: text/plain; charset=UTF-16 Content-Type: text/plain; charset=UTF-16
2. 刪除標題Content-Transfer-Encoding
3. 添加Content-Lenght: 28 （28是"some message\\n".getBytes().length() ）。

Answer 3

查看DefaultHttpRequestParser的源代碼，似乎它僅解析請求行和標頭，而不嘗試解析正文。

此主題正在討論同一主題。 解決方案的建議也很少。

Answer 4

通過覆蓋LineParser自定義解析頭：

inbuffer = new SessionInputBufferImpl(new HttpTransportMetricsImpl(), reqDataLength);
inbuffer.bind(input);
HttpMessageParser<org.apache.http.HttpRequest> requestParser = new DefaultHttpRequestParser(
                inbuffer,
                new LineParser(),
                new DefaultHttpRequestFactory(),
                MessageConstraints.DEFAULT
        );

獲取實體主體，如下所示：

        HttpEntityEnclosingRequest ereq = (HttpEntityEnclosingRequest) req;
        ContentLengthStrategy contentLengthStrategy =
                    StrictContentLengthStrategy.INSTANCE;
        long len = contentLengthStrategy.determineLength(req);
        InputStream contentStream = null;
        if (len == ContentLengthStrategy.CHUNKED) {
            contentStream = new ChunkedInputStream(buf);
        } else if (len == ContentLengthStrategy.IDENTITY) {
            contentStream = new IdentityInputStream(buf);
        } else {
            contentStream = new ContentLengthInputStream(buf, len);
        }
        BasicHttpEntity ent = new BasicHttpEntity();
        ent.setContent(contentStream);
        ereq.setEntity(ent);
        return ereq;