cloudstack/awsapi/src/com/cloud/bridge/service/S3RestServlet.java

// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.
package com.cloud.bridge.service;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.security.SignatureException;
import java.sql.SQLException;
import java.util.Enumeration;

import javax.inject.Inject;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.xml.bind.DatatypeConverter;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

import org.apache.axis2.AxisFault;
import org.apache.log4j.Logger;
import org.springframework.web.context.support.SpringBeanAutowiringSupport;
import org.w3c.dom.Document;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

import com.cloud.bridge.io.MultiPartDimeInputStream;
import com.cloud.bridge.model.SAcl;
import com.cloud.bridge.model.UserCredentialsVO;
import com.cloud.bridge.persist.dao.CloudStackConfigurationDao;
import com.cloud.bridge.persist.dao.UserCredentialsDao;
import com.cloud.bridge.service.controller.s3.S3BucketAction;
import com.cloud.bridge.service.controller.s3.S3ObjectAction;
import com.cloud.bridge.service.controller.s3.ServiceProvider;
import com.cloud.bridge.service.controller.s3.ServletAction;
import com.cloud.bridge.service.core.s3.S3AccessControlList;
import com.cloud.bridge.service.core.s3.S3AuthParams;
import com.cloud.bridge.service.core.s3.S3Engine;
import com.cloud.bridge.service.core.s3.S3Grant;
import com.cloud.bridge.service.core.s3.S3MetaDataEntry;
import com.cloud.bridge.service.core.s3.S3PutObjectRequest;
import com.cloud.bridge.service.core.s3.S3PutObjectResponse;
import com.cloud.bridge.service.exception.InvalidBucketName;
import com.cloud.bridge.service.exception.PermissionDeniedException;
import com.cloud.bridge.util.ConfigurationHelper;
import com.cloud.bridge.util.HeaderParam;
import com.cloud.bridge.util.RestAuth;
import com.cloud.bridge.util.S3SoapAuth;
import com.cloud.utils.db.DB;
import com.cloud.utils.db.Transaction;
import com.cloud.utils.db.TransactionLegacy;

public class S3RestServlet extends HttpServlet {
    private static final long serialVersionUID = -6168996266762804877L;
    public static final String ENABLE_S3_API = "enable.s3.api";
    private static boolean isS3APIEnabled = false;

    public static final Logger logger = Logger.getLogger(S3RestServlet.class);
    @Inject
    CloudStackConfigurationDao csDao;
    @Inject
    UserCredentialsDao ucDao;

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) {
        processRequest(req, resp, "GET");
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) {
        // -> DIME requests are authenticated via the SOAP auth mechanism
        String type = req.getHeader("Content-Type");
        if (null != type && type.equalsIgnoreCase("application/dime"))
            processDimeRequest(req, resp);
        else
            processRequest(req, resp, "POST");
    }

    @Override
    protected void doPut(HttpServletRequest req, HttpServletResponse resp) {
        processRequest(req, resp, "PUT");
    }

    @Override
    protected void doHead(HttpServletRequest req, HttpServletResponse resp) {
        processRequest(req, resp, "HEAD");
    }

    @Override
    protected void doOptions(HttpServletRequest req, HttpServletResponse resp) {
        processRequest(req, resp, "OPTIONS");
    }

    @Override
    protected void doDelete(HttpServletRequest req, HttpServletResponse resp) {
        processRequest(req, resp, "DELETE");
    }

    @Override
    public void init(ServletConfig config) throws ServletException {
        try {
            SpringBeanAutowiringSupport.processInjectionBasedOnServletContext(this, config.getServletContext());

            ConfigurationHelper.preConfigureConfigPathFromServletContext(config.getServletContext());
            // check if API is enabled
            String value = csDao.getConfigValue(ENABLE_S3_API);
            if (value != null) {
                isS3APIEnabled = Boolean.valueOf(value);
            }
            logger.info("S3Engine :: Configuration value is : " + value);

        } catch (Exception e) {
            throw new ServletException("Error initializing awsapi: " + e.getMessage());
        }

    }

    /**
     * POST requests do not get authenticated on entry.   The associated
     * access key and signature headers are embedded in the message not encoded
     * as HTTP headers.
     */
    private void processRequest(HttpServletRequest request, HttpServletResponse response, String method) {
        TransactionLegacy txn = TransactionLegacy.open("cloudbridge", TransactionLegacy.AWSAPI_DB, true);
        try {
            logRequest(request);

            // Our extensions to the S3 REST API for simple management actions
            // are conveyed with Request parameter "Action".
            // The present extensions are either to set up the user credentials
            // (see the cloud-bridge-register script for more detail) or
            // to report our version of this capability.
            // -> unauthenticated calls, should still be done over HTTPS
            String cloudAction = request.getParameter("Action");

            if (!isS3APIEnabled) {
                throw new RuntimeException("Amazon S3 API is disabled.");
            }

            if (null != cloudAction) {
                if (cloudAction.equalsIgnoreCase("SetUserKeys")) {
                    setUserKeys(request, response);
                    return;
                }

                if (cloudAction.equalsIgnoreCase("SetCertificate"))
                    // At present a noop
                    return;

                if (cloudAction.equalsIgnoreCase("CloudS3Version")) {
                    cloudS3Version(request, response);
                    return;
                }
            }

            txn.start();
            // -> authenticated calls
            if (!((method.equalsIgnoreCase("POST") && !(request.getQueryString().equalsIgnoreCase("delete"))))) {
                S3AuthParams params = extractRequestHeaders(request);
                authenticateRequest(request, params);
            }

            ServletAction action = routeRequest(request);
            if (action != null) {
                action.execute(request, response);
            } else {
                response.setStatus(404);
                endResponse(response, "File not found");
            }
            txn.close();
        } catch (InvalidBucketName e) {
            logger.error("Unexpected exception " + e.getMessage(), e);
            response.setStatus(400);
            endResponse(response, "Invalid Bucket Name - " + e.toString());
        } catch (PermissionDeniedException e) {
            logger.error("Unexpected exception " + e.getMessage(), e);
            response.setStatus(403);
            endResponse(response, "Access denied - " + e.toString());
        } catch (Throwable e) {
            logger.error("Unexpected exception " + e.getMessage(), e);
            response.setStatus(404);
            endResponse(response, "Bad request");

        } finally {

            try {
                response.flushBuffer();
            } catch (IOException e) {
                logger.error("Unexpected exception " + e.getMessage(), e);
            }
        }
    }

    /**
     * Provide an easy way to determine the version of the implementation running.
     *
     * This is an unauthenticated REST call.
     */
    private void cloudS3Version(HttpServletRequest request, HttpServletResponse response) {
        String version = new String("<?xml version=\"1.0\" encoding=\"utf-8\"?><CloudS3Version>1.04</CloudS3Version>");
        response.setStatus(200);
        endResponse(response, version);
    }

    /**
     * This request registers the user Cloud.com account holder to the S3 service.   The Cloud.com
     * account holder saves his API access and secret keys with the S3 service so that
     * each rest call he makes can be verified was originated from him.   The given API access
     * and secret key are saved into the "usercredentials" database table.
     *
     * This is an unauthenticated REST call.   The only required parameters are 'accesskey' and
     * 'secretkey'.
     *
     * To verify that the given keys represent an existing account they are used to execute the
     * Cloud.com's listAccounts API function.   If the keys do not represent a valid account the
     * listAccounts function will fail.
     *
     * A user can call this REST function any number of times, on each call the Cloud.com secret
     * key is simply over writes any previously stored value.
     *
     * As with all REST calls HTTPS should be used to ensure their security.
     */
    @DB
    private void setUserKeys(HttpServletRequest request, HttpServletResponse response) {
        String[] accessKey = null;
        String[] secretKey = null;

        try {
            // -> both these parameters are required
            accessKey = request.getParameterValues("accesskey");
            if (null == accessKey || 0 == accessKey.length) {
                response.sendError(530, "Missing accesskey parameter");
                return;
            }

            secretKey = request.getParameterValues("secretkey");
            if (null == secretKey || 0 == secretKey.length) {
                response.sendError(530, "Missing secretkey parameter");
                return;
            }
        } catch (Exception e) {
            logger.error("SetUserKeys exception " + e.getMessage(), e);
            response.setStatus(500);
            endResponse(response, "SetUserKeys exception " + e.getMessage());
            return;
        }

        try {
            // -> use the keys to see if the account actually exists
            //ServiceProvider.getInstance().getEC2Engine().validateAccount( accessKey[0], secretKey[0] );
            //UserCredentialsDaoImpl credentialDao = new UserCredentialsDao();
            TransactionLegacy txn = TransactionLegacy.open(TransactionLegacy.AWSAPI_DB);
            txn.start();
            UserCredentialsVO user = new UserCredentialsVO(accessKey[0], secretKey[0]);
            user = ucDao.persist(user);
            txn.commit();
            txn.close();
            //credentialDao.setUserKeys( accessKey[0], secretKey[0] );

        } catch (Exception e) {
            logger.error("SetUserKeys " + e.getMessage(), e);
            response.setStatus(401);
            endResponse(response, e.toString());
            return;
        }
        response.setStatus(200);
        endResponse(response, "User keys set successfully");
    }

    /**
     * We are using the S3AuthParams class to hide where the header values are coming
     * from so that the authenticateRequest call can be made from several places.
     */
    public static S3AuthParams extractRequestHeaders(HttpServletRequest request) {
        S3AuthParams params = new S3AuthParams();

        Enumeration headers = request.getHeaderNames();
        if (null != headers) {
            while (headers.hasMoreElements()) {
                HeaderParam oneHeader = new HeaderParam();
                String headerName = (String)headers.nextElement();
                oneHeader.setName(headerName);
                oneHeader.setValue(request.getHeader(headerName));
                params.addHeader(oneHeader);
            }
        }
        return params;
    }

    public static void authenticateRequest(HttpServletRequest request, S3AuthParams params) throws InstantiationException, IllegalAccessException, ClassNotFoundException,
        SQLException {
        RestAuth auth = new RestAuth(ServiceProvider.getInstance().getUseSubDomain());
        String AWSAccessKey = null;
        String signature = null;
        String authorization = null;

        // [A] Is it an annonymous request?
        if (null == (authorization = params.getHeader("Authorization"))) {
            UserContext.current().initContext();
            return;
        }

        // [B] Is it an authenticated request?
        int offset = authorization.indexOf("AWS");
        if (-1 != offset) {
            String temp = authorization.substring(offset + 3).trim();
            offset = temp.indexOf(":");
            AWSAccessKey = temp.substring(0, offset);
            signature = temp.substring(offset + 1);
        }

        // [C] Calculate the signature from the request's headers
        auth.setDateHeader(request.getHeader("Date"));
        auth.setContentTypeHeader(request.getHeader("Content-Type"));
        auth.setContentMD5Header(request.getHeader("Content-MD5"));
        auth.setHostHeader(request.getHeader("Host"));
        auth.setQueryString(request.getQueryString());
        auth.addUriPath(request.getRequestURI());

        // -> are their any Amazon specific (i.e. 'x-amz-' ) headers?
        HeaderParam[] headers = params.getHeaders();
        for (int i = 0; null != headers && i < headers.length; i++) {
            String headerName = headers[i].getName();
            String ignoreCase = headerName.toLowerCase();
            if (ignoreCase.startsWith("x-amz-"))
                auth.addAmazonHeader(headerName + ":" + headers[i].getValue());
        }

        UserInfo info = ServiceProvider.getInstance().getUserInfo(AWSAccessKey);
        if (info == null)
            throw new PermissionDeniedException("Unable to authenticate access key: " + AWSAccessKey);

        try {
            if (auth.verifySignature(request.getMethod(), info.getSecretKey(), signature)) {
                UserContext.current().initContext(AWSAccessKey, info.getSecretKey(), AWSAccessKey, info.getDescription(), request);
                return;
            }

        } catch (SignatureException e) {
            throw new PermissionDeniedException(e);

        } catch (UnsupportedEncodingException e) {
            throw new PermissionDeniedException(e);
        }
        throw new PermissionDeniedException("Invalid signature");
    }

    private ServletAction routeRequest(HttpServletRequest request) {
        //  URL routing for S3 REST calls.
        String pathInfo = request.getPathInfo();
        String bucketName = null;
        String key = null;

        String serviceEndpoint = ServiceProvider.getInstance().getServiceEndpoint();
        String host = request.getHeader("Host");

        // Check for unrecognized forms of URI information in request

        if ((pathInfo == null) || (pathInfo.indexOf('/') != 0))
            if ("POST".equalsIgnoreCase(request.getMethod()))
            // Case where request is POST operation with no pathinfo
            // This is the POST alternative to PUT described at s3.amazonaws.com API doc page 141
            {
                return routePlainPostRequest(request);
            }

        // Irrespective of whether the requester is using subdomain or full host naming of path expressions
        // to buckets, wherever the request is made up of a service endpoint followed by a /, in AWS S3 this always
        // conveys a ListAllMyBuckets command

        if ((serviceEndpoint.equalsIgnoreCase(host)) && (pathInfo.equalsIgnoreCase("/"))) {
            request.setAttribute(S3Constants.BUCKET_ATTR_KEY, "/");
            return new S3BucketAction();   // for ListAllMyBuckets
        }

        // Because there is a leading / at position 0 of pathInfo, now subtract this to process the remainder
        pathInfo = pathInfo.substring(1);

        if (ServiceProvider.getInstance().getUseSubDomain())

        {
            // -> verify the format of the bucket name
            int endPos = host.indexOf(ServiceProvider.getInstance().getMasterDomain());
            if (endPos > 0) {
                bucketName = host.substring(0, endPos);
                S3Engine.verifyBucketName(bucketName, false);
                request.setAttribute(S3Constants.BUCKET_ATTR_KEY, bucketName);
            } else
                request.setAttribute(S3Constants.BUCKET_ATTR_KEY, "");

            if (pathInfo == null || pathInfo.equalsIgnoreCase("/")) {
                return new S3BucketAction();
            } else {
                String objectKey = pathInfo.substring(1);
                request.setAttribute(S3Constants.OBJECT_ATTR_KEY, objectKey);
                return new S3ObjectAction();
            }
        }

        else

        {

            int endPos = pathInfo.indexOf('/');  // Subsequent / character?

            if (endPos < 1) {
                bucketName = pathInfo;
                S3Engine.verifyBucketName(bucketName, false);
                request.setAttribute(S3Constants.BUCKET_ATTR_KEY, bucketName);
                return new S3BucketAction();
            } else {
                bucketName = pathInfo.substring(0, endPos);
                key = pathInfo.substring(endPos + 1);
                S3Engine.verifyBucketName(bucketName, false);

                if (!key.isEmpty()) {
                    request.setAttribute(S3Constants.BUCKET_ATTR_KEY, bucketName);
                    request.setAttribute(S3Constants.OBJECT_ATTR_KEY, pathInfo.substring(endPos + 1));
                    return new S3ObjectAction();
                } else {
                    request.setAttribute(S3Constants.BUCKET_ATTR_KEY, bucketName);
                    return new S3BucketAction();
                }
            }
        }
    }

    public static void endResponse(HttpServletResponse response, String content) {
        try {
            byte[] data = content.getBytes();
            response.setContentLength(data.length);
            OutputStream os = response.getOutputStream();
            os.write(data);
            os.close();
        } catch (Throwable e) {
            logger.error("Unexpected exception " + e.getMessage(), e);
        }
    }

    public static void writeResponse(HttpServletResponse response, String content) throws IOException {
        byte[] data = content.getBytes();
        OutputStream os = response.getOutputStream();
        os.write(data);
    }

    public static void writeResponse(HttpServletResponse response, InputStream is) throws IOException {
        byte[] data = new byte[4096];
        int length = 0;
        while ((length = is.read(data)) > 0) {
            response.getOutputStream().write(data, 0, length);
        }
    }

    // Route for the case where request is POST operation with no pathinfo
    // This is the POST alternative to PUT described at s3.amazonaws.com API doc, Amazon Simple
    // Storage Service API Reference API Version 2006-03-01 page 141.
    // The purpose of the plain POST operation is to add an object to a specified bucket using HTML forms.

    private S3ObjectAction routePlainPostRequest(HttpServletRequest request) {
        // TODO - Remove the unnecessary fields below
        // Obtain the mandatory fields from the HTML form or otherwise fail with a logger message
        String keyString = request.getParameter("key");
        String metatagString = request.getParameter("x-amz-meta-tag");
        String bucketString = request.getParameter("Bucket");
        String aclString = request.getParameter("acl");
        String fileString = request.getParameter("file");

        String accessKeyString = request.getParameter("AWSAccessKeyId");
        String signatureString = request.getParameter("Signature");

        // Obtain the discretionary fields from the HTML form
        String policyKeyString = request.getParameter("Policy");
        String metauuidString = request.getParameter("x-amz-meta-uuid");
        String redirectString = request.getParameter("redirect");

        // if none of the above are null then ...
        request.setAttribute(S3Constants.BUCKET_ATTR_KEY, bucketString);
        request.setAttribute(S3Constants.OBJECT_ATTR_KEY, keyString);
        request.setAttribute(S3Constants.PLAIN_POST_ACCESS_KEY, accessKeyString);
        request.setAttribute(S3Constants.PLAIN_POST_SIGNATURE, signatureString);

        // -> authenticated calls
        try {
            // S3AuthParams params = extractRequestHeaders( request );
            S3AuthParams params = new S3AuthParams();
            HeaderParam headerParam1 = new HeaderParam("accessKey", accessKeyString);
            params.addHeader(headerParam1);
            HeaderParam headerParam2 = new HeaderParam("secretKey", signatureString);
            params.addHeader(headerParam2);
            authenticateRequest(request, params);
        } catch (Exception e) {
            logger.warn("Authentication details insufficient");
        }

        return new S3ObjectAction();

    }

    /**
     * A DIME request is really a SOAP request that we are dealing with, and so its
     * authentication is the SOAP authentication approach.   Since Axis2 does not handle
     * DIME messages we deal with them here.
     *
     * @param request
     * @param response
     */
    private void processDimeRequest(HttpServletRequest request, HttpServletResponse response) {
        S3PutObjectRequest putRequest = null;
        S3PutObjectResponse putResponse = null;
        int bytesRead = 0;

        S3Engine engine = new S3Engine();

        try {
            logRequest(request);

            MultiPartDimeInputStream ds = new MultiPartDimeInputStream(request.getInputStream());

            // -> the first stream MUST be the SOAP party
            if (ds.nextInputStream()) {
                //logger.debug( "DIME msg [" + ds.getStreamType() + "," + ds.getStreamTypeFormat() + "," + ds.getStreamId() + "]" );
                byte[] buffer = new byte[8192];
                bytesRead = ds.read(buffer, 0, 8192);
                //logger.debug( "DIME SOAP Bytes read: " + bytesRead );
                ByteArrayInputStream bis = new ByteArrayInputStream(buffer, 0, bytesRead);
                putRequest = toEnginePutObjectRequest(bis);
            }

            // -> we only need to support a DIME message with two bodyparts
            if (null != putRequest && ds.nextInputStream()) {
                InputStream is = ds.getInputStream();
                putRequest.setData(is);
            }

            // -> need to do SOAP level auth here, on failure return the SOAP fault
            StringBuffer xml = new StringBuffer();
            String AWSAccessKey = putRequest.getAccessKey();
            UserInfo info = ServiceProvider.getInstance().getUserInfo(AWSAccessKey);
            try {
                S3SoapAuth.verifySignature(putRequest.getSignature(), "PutObject", putRequest.getRawTimestamp(), AWSAccessKey, info.getSecretKey());

            } catch (AxisFault e) {
                String reason = e.toString();
                int start = reason.indexOf(".AxisFault:");
                if (-1 != start)
                    reason = reason.substring(start + 11);

                xml.append("<?xml version=\"1.0\" encoding=\"utf-8\"?>");
                xml.append("<soap:Envelope xmlns:soap=\"http://schemas.xmlsoap.org/soap/envelope/\" xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\" >\n");
                xml.append("<soap:Body>\n");
                xml.append("<soap:Fault>\n");
                xml.append("<faultcode>").append(e.getFaultCode().toString()).append("</faultcode>\n");
                xml.append("<faultstring>").append(reason).append("</faultstring>\n");
                xml.append("</soap:Fault>\n");
                xml.append("</soap:Body></soap:Envelope>");

                endResponse(response, xml.toString());
                return;
            }

            // -> PutObject S3 Bucket Policy would be done in the engine.handleRequest() call
            UserContext.current().initContext(AWSAccessKey, info.getSecretKey(), AWSAccessKey, "S3 DIME request", request);
            putResponse = engine.handleRequest(putRequest);

            xml.append("<?xml version=\"1.0\" encoding=\"utf-8\"?>");
            xml.append("<soap:Envelope xmlns:soap=\"http://schemas.xmlsoap.org/soap/envelope/\" xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\" xmlns:tns=\"http://s3.amazonaws.com/doc/2006-03-01/\">");
            xml.append("<soap:Body>");
            xml.append("<tns:PutObjectResponse>");
            xml.append("<tns:PutObjectResponse>");
            xml.append("<tns:ETag>\"").append(putResponse.getETag()).append("\"</tns:ETag>");
            xml.append("<tns:LastModified>").append(DatatypeConverter.printDateTime(putResponse.getLastModified())).append("</tns:LastModified>");
            xml.append("</tns:PutObjectResponse></tns:PutObjectResponse>");
            xml.append("</soap:Body></soap:Envelope>");

            endResponse(response, xml.toString());
        } catch (PermissionDeniedException e) {
            logger.error("Unexpected exception " + e.getMessage(), e);
            response.setStatus(403);
            endResponse(response, "Access denied");
        } catch (Throwable e) {
            logger.error("Unexpected exception " + e.getMessage(), e);
        } finally {
        }
    }

    /**
     * Convert the SOAP XML we extract from the DIME message into our local object.
     * Here Axis2 is not parsing the SOAP for us.   I tried to use the Amazon PutObject
     * parser but it keep throwing exceptions.
     *
     * @param putObjectInline
     * @return
     * @throws Exception
     */
    public static S3PutObjectRequest toEnginePutObjectRequest(InputStream is) throws Exception {
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        dbf.setNamespaceAware(true);

        DocumentBuilder db = dbf.newDocumentBuilder();
        Document doc = db.parse(is);
        Node parent = null;
        Node contents = null;
        NodeList children = null;
        String temp = null;
        String element = null;
        int count = 0;

        S3PutObjectRequest request = new S3PutObjectRequest();

        // [A] Pull out the simple nodes first
        NodeList part = getElement(doc, "http://s3.amazonaws.com/doc/2006-03-01/", "Bucket");
        if (null != part) {
            if (null != (contents = part.item(0)))
                request.setBucketName(contents.getFirstChild().getNodeValue());
        }
        part = getElement(doc, "http://s3.amazonaws.com/doc/2006-03-01/", "Key");
        if (null != part) {
            if (null != (contents = part.item(0)))
                request.setKey(contents.getFirstChild().getNodeValue());
        }
        part = getElement(doc, "http://s3.amazonaws.com/doc/2006-03-01/", "ContentLength");
        if (null != part) {
            if (null != (contents = part.item(0))) {
                String length = contents.getFirstChild().getNodeValue();
                if (null != length)
                    request.setContentLength(Long.decode(length));
            }
        }
        part = getElement(doc, "http://s3.amazonaws.com/doc/2006-03-01/", "AWSAccessKeyId");
        if (null != part) {
            if (null != (contents = part.item(0)))
                request.setAccessKey(contents.getFirstChild().getNodeValue());
        }
        part = getElement(doc, "http://s3.amazonaws.com/doc/2006-03-01/", "Signature");
        if (null != part) {
            if (null != (contents = part.item(0)))
                request.setSignature(contents.getFirstChild().getNodeValue());
        }
        part = getElement(doc, "http://s3.amazonaws.com/doc/2006-03-01/", "Timestamp");
        if (null != part) {
            if (null != (contents = part.item(0)))
                request.setRawTimestamp(contents.getFirstChild().getNodeValue());
        }
        part = getElement(doc, "http://s3.amazonaws.com/doc/2006-03-01/", "StorageClass");
        if (null != part) {
            if (null != (contents = part.item(0)))
                request.setStorageClass(contents.getFirstChild().getNodeValue());
        }
        part = getElement(doc, "http://s3.amazonaws.com/doc/2006-03-01/", "Credential");
        if (null != part) {
            if (null != (contents = part.item(0)))
                request.setCredential(contents.getFirstChild().getNodeValue());
        }

        // [B] Get a list of all 'Metadata' elements
        part = getElement(doc, "http://s3.amazonaws.com/doc/2006-03-01/", "Metadata");
        if (null != part) {
            count = part.getLength();
            S3MetaDataEntry[] metaEntry = new S3MetaDataEntry[count];

            for (int i = 0; i < count; i++) {
                parent = part.item(i);
                metaEntry[i] = new S3MetaDataEntry();

                // -> get a list of all the children elements of the 'Metadata' parent element
                if (null != (children = parent.getChildNodes())) {
                    int numChildren = children.getLength();
                    for (int j = 0; j < numChildren; j++) {
                        contents = children.item(j);
                        element = contents.getNodeName().trim();
                        if (element.endsWith("Name")) {
                            temp = contents.getFirstChild().getNodeValue();
                            if (null != temp)
                                metaEntry[i].setName(temp);
                        } else if (element.endsWith("Value")) {
                            temp = contents.getFirstChild().getNodeValue();
                            if (null != temp)
                                metaEntry[i].setValue(temp);
                        }
                    }
                }
            }
            request.setMetaEntries(metaEntry);
        }

        // [C] Get a list of all Grant elements in an AccessControlList
        part = getElement(doc, "http://s3.amazonaws.com/doc/2006-03-01/", "Grant");
        if (null != part) {
            S3AccessControlList engineAcl = new S3AccessControlList();

            count = part.getLength();
            for (int i = 0; i < count; i++) {
                parent = part.item(i);
                S3Grant engineGrant = new S3Grant();

                // -> get a list of all the children elements of the 'Grant' parent element
                if (null != (children = parent.getChildNodes())) {
                    int numChildren = children.getLength();
                    for (int j = 0; j < numChildren; j++) {
                        contents = children.item(j);
                        element = contents.getNodeName().trim();
                        if (element.endsWith("Grantee")) {
                            NamedNodeMap attbs = contents.getAttributes();
                            if (null != attbs) {
                                Node type = attbs.getNamedItemNS("http://www.w3.org/2001/XMLSchema-instance", "type");
                                if (null != type)
                                    temp = type.getFirstChild().getNodeValue().trim();
                                else
                                    temp = null;

                                if (null != temp && temp.equalsIgnoreCase("CanonicalUser")) {
                                    engineGrant.setGrantee(SAcl.GRANTEE_USER);
                                    engineGrant.setCanonicalUserID(getChildNodeValue(contents, "ID"));
                                } else
                                    throw new UnsupportedOperationException("Missing http://www.w3.org/2001/XMLSchema-instance:type value");
                            }
                        } else if (element.endsWith("Permission")) {
                            temp = contents.getFirstChild().getNodeValue().trim();
                            if (temp.equalsIgnoreCase("READ"))
                                engineGrant.setPermission(SAcl.PERMISSION_READ);
                            else if (temp.equalsIgnoreCase("WRITE"))
                                engineGrant.setPermission(SAcl.PERMISSION_WRITE);
                            else if (temp.equalsIgnoreCase("READ_ACP"))
                                engineGrant.setPermission(SAcl.PERMISSION_READ_ACL);
                            else if (temp.equalsIgnoreCase("WRITE_ACP"))
                                engineGrant.setPermission(SAcl.PERMISSION_WRITE_ACL);
                            else if (temp.equalsIgnoreCase("FULL_CONTROL"))
                                engineGrant.setPermission(SAcl.PERMISSION_FULL);
                            else
                                throw new UnsupportedOperationException("Unsupported permission: " + temp);
                        }
                    }
                    engineAcl.addGrant(engineGrant);
                }
            }
            request.setAcl(engineAcl);
        }
        return request;
    }

    /**
     * Have to deal with XML with and without namespaces.
     */
    public static NodeList getElement(Document doc, String namespace, String tagName) {
        NodeList part = doc.getElementsByTagNameNS(namespace, tagName);
        if (null == part || 0 == part.getLength())
            part = doc.getElementsByTagName(tagName);

        return part;
    }

    /**
     * Looking for the value of a specific child of the given parent node.
     *
     * @param parent
     * @param childName
     * @return
     */
    private static String getChildNodeValue(Node parent, String childName) {
        NodeList children = null;
        Node element = null;

        if (null != (children = parent.getChildNodes())) {
            int numChildren = children.getLength();
            for (int i = 0; i < numChildren; i++) {
                if (null != (element = children.item(i))) {
                    // -> name may have a namespace on it
                    String name = element.getNodeName().trim();
                    if (name.endsWith(childName)) {
                        String value = element.getFirstChild().getNodeValue();
                        if (null != value)
                            value = value.trim();
                        return value;
                    }
                }
            }
        }
        return null;
    }

    private void logRequest(HttpServletRequest request) {
        if (logger.isInfoEnabled()) {
            logger.info("Request method: " + request.getMethod());
            logger.info("Request contextPath: " + request.getContextPath());
            logger.info("Request pathInfo: " + request.getPathInfo());
            logger.info("Request pathTranslated: " + request.getPathTranslated());
            logger.info("Request queryString: " + request.getQueryString());
            logger.info("Request requestURI: " + request.getRequestURI());
            logger.info("Request requestURL: " + request.getRequestURL());
            logger.info("Request servletPath: " + request.getServletPath());
            Enumeration headers = request.getHeaderNames();
            if (headers != null) {
                while (headers.hasMoreElements()) {
                    Object headerName = headers.nextElement();
                    logger.info("Request header " + headerName + ":" + request.getHeader((String)headerName));
                }
            }

            Enumeration params = request.getParameterNames();
            if (params != null) {
                while (params.hasMoreElements()) {
                    Object paramName = params.nextElement();
                    logger.info("Request parameter " + paramName + ":" + request.getParameter((String)paramName));
                }
            }
            logger.info("- End of request -");
        }
    }
}