java.fedora.server.storage.DefaultExternalContentManager Maven / Gradle / Ivy

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The Fedora Client is a Java Library that allows API access to a Fedora Repository. The client is typically one part of a full Fedora installation.
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/*
 * -----------------------------------------------------------------------------
 *
 * License and Copyright: The contents of this file are subject to 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.fedora-commons.org/licenses.
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for
 * the specific language governing rights and limitations under the License.
 *
 * The entire file consists of original code.
 * Copyright © 2008 Fedora Commons, Inc.

 * 
Copyright © 2002-2007 The Rector and Visitors of the University of 
 * Virginia and Cornell University
 
 * All rights reserved.
 *
 * -----------------------------------------------------------------------------
 */
package fedora.server.storage;

import java.util.Hashtable;
import java.util.Map;

import org.apache.commons.httpclient.Header;

import org.apache.log4j.Logger;

import fedora.common.http.HttpInputStream;
import fedora.common.http.WebClient;
import fedora.server.Context;
import fedora.server.Module;
import fedora.server.Server;
import fedora.server.errors.GeneralException;
import fedora.server.errors.HttpServiceNotFoundException;
import fedora.server.errors.ModuleInitializationException;
import fedora.server.security.BackendPolicies;
import fedora.server.security.BackendSecurity;
import fedora.server.security.BackendSecuritySpec;
import fedora.server.storage.types.MIMETypedStream;
import fedora.server.storage.types.Property;
import fedora.server.utilities.ServerUtility;

/**
 *
 * Title: DefaultExternalContentManager.java
 * Description: Provides a mechanism to obtain external HTTP-accessible
 * content.
 *
 * @author [email protected]
 * @version $Id: DefaultExternalContentManager.java 6338 2007-12-05 19:29:11Z rwayland3 $
 */
public class DefaultExternalContentManager extends Module
    implements ExternalContentManager
{

  /** Logger for this class. */
  private static final Logger LOG = Logger.getLogger(
        DefaultExternalContentManager.class.getName());

  private String m_userAgent;
  private String fedoraServerHost;
  private String fedoraServerPort;
  private String fedoraServerRedirectPort;

  private WebClient m_http;

  /**
   *  Creates a new DefaultExternalContentManager.
   *
   * @param moduleParameters The name/value pair map of module parameters.
   * @param server The server instance.
   * @param role The module role name.
   * @throws ModuleInitializationException If initialization values are
   *         invalid or initialization fails for some other reason.
   */
  public DefaultExternalContentManager(Map moduleParameters,
                                       Server server, String role)
      throws ModuleInitializationException
  {
    super(moduleParameters, server, role);
  }

  /**
   * Initializes the Module based on configuration parameters. The
   * implementation of this method is dependent on the schema used to define
   * the parameter names for the role of
   * fedora.server.storage.DefaultExternalContentManager.
   *
   * @throws ModuleInitializationException If initialization values are
   *         invalid or initialization fails for some other reason.
   */
  public void initModule() throws ModuleInitializationException
  {
    try
    {
      Server s_server = this.getServer();
      m_userAgent=getParameter("userAgent");
      if (m_userAgent==null) {
        m_userAgent="Fedora";
      }

      fedoraServerPort = s_server.getParameter("fedoraServerPort");
      fedoraServerHost = s_server.getParameter("fedoraServerHost");
      fedoraServerRedirectPort = s_server.getParameter("fedoraRedirectPort");

      m_http = new WebClient();
      m_http.USER_AGENT = m_userAgent;

    } catch (Throwable th)
    {
      throw new ModuleInitializationException("[DefaultExternalContentManager] "
          + "An external content manager "
          + "could not be instantiated. The underlying error was a "
          + th.getClass().getName() + "The message was \""
          + th.getMessage() + "\".", getRole());
    }
  }              

    /**
     * Get a MIMETypedStream for the given URL.
     *
     * If user or password are null, basic authentication will 
     * not be attempted.
     */
    private MIMETypedStream get(String url,
                                String user,
                                String pass) throws GeneralException {
        LOG.debug("DefaultExternalContentManager.get(" + url + ")");
        try {
            HttpInputStream response = m_http.get(url, true, user, pass);
            String mimeType = response.getResponseHeaderValue("Content-Type",
                                                              "text/plain");
            Property[] headerArray = toPropertyArray(
                                         response.getResponseHeaders());
  		    return new MIMETypedStream(mimeType, response, headerArray);
        } catch (Exception e) {
            throw new GeneralException("Error getting " + url, e);
        }
    }

    /**
     * Convert the given HTTP Headers to an array of 
     * Property objects.
     */
    private static Property[] toPropertyArray(Header[] headers) {

        Property[] props = new Property[headers.length];
        for (int i = 0; i < headers.length; i++) {
            props[i] = new Property();
            props[i].name = headers[i].getName();
            props[i].value = headers[i].getValue();
        }
        return props;
    }

  /**
   * A method that reads the contents of the specified URL and returns the
   * result as a MIMETypedStream
   *
   * @param url The URL of the external content.
   * @return A MIME-typed stream.
   * @throws HttpServiceNotFoundException If the URL connection could not
   *         be established.
   */
  public MIMETypedStream getExternalContent(String url, Context context)
      throws GeneralException, HttpServiceNotFoundException {
  	LOG.debug("in getExternalContent(), url=" + url);
  	try {
  		String backendUsername = "";
  		String backendPassword = "";
  		boolean backendSSL = false;
  		String modURL = url;
		if (ServerUtility.isURLFedoraServer(modURL)) {
		    BackendSecuritySpec m_beSS;
		    BackendSecurity m_beSecurity = (BackendSecurity) getServer().getModule("fedora.server.security.BackendSecurity");
		    try {
		    	m_beSS = m_beSecurity.getBackendSecuritySpec();
		    } catch (Exception e) {
		    	throw new ModuleInitializationException("Can't intitialize BackendSecurity module (in default access) from Server.getModule", getRole());
		    }	            
		    Hashtable beHash = m_beSS.getSecuritySpec(BackendPolicies.FEDORA_INTERNAL_CALL);
		    backendUsername = (String) beHash.get("callUsername");
		    backendPassword = (String) beHash.get("callPassword");	            
		    backendSSL = new Boolean((String) beHash.get("callSSL")).booleanValue();
		    if (backendSSL) {
		    	if (modURL.startsWith("http:")) {
		    		modURL = modURL.replaceFirst("http:", "https:");
		    	}
		    	modURL = modURL.replaceFirst(":"+fedoraServerPort+"/", ":"+fedoraServerRedirectPort+"/");
		    }    
		}
		if (LOG.isDebugEnabled()) {
		   	LOG.debug("************************* backendUsername: "+backendUsername+ "     backendPassword: "+backendPassword+"     backendSSL: "+backendSSL);
		   	LOG.debug("************************* doAuthnGetURL: "+modURL);
		}

        return get(modURL, backendUsername, backendPassword);

  	} catch (GeneralException ge) {
        throw ge;
  	} catch (Throwable th) {
        // catch anything but generalexception
  		th.printStackTrace();
  		throw new HttpServiceNotFoundException("[DefaultExternalContentManager] "
  			+ "returned an error.  The underlying error was a "
			+ th.getClass().getName() + "  The message "
			+ "was  \"" + th.getMessage() + "\"  .  ");
  	}
  } 
  
}