org.openmrs.module.uiframework.ResourceServlet.java Source code

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Here is the source code for org.openmrs.module.uiframework.ResourceServlet.java

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/**
 * The contents of this file are subject to the OpenMRS Public License
 * Version 1.0 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://license.openmrs.org
 *
 * 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.
 *
 * Copyright (C) OpenMRS, LLC.  All Rights Reserved.
 */
package org.openmrs.module.uiframework;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.openmrs.ui.framework.resource.ResourceFactory;
import org.openmrs.util.OpenmrsUtil;

/**
 * Modeled after ModuleResourcesServlet in the OpenMRS 1.x web application, and used to provide access to
 * the {@link ResourceFactory} in a web context.
 */
public class ResourceServlet extends HttpServlet {

    private static final long serialVersionUID = 1L;
    private Log log = LogFactory.getLog(this.getClass());

    private Pattern pathPattern;

    public ResourceServlet() {
        pathPattern = Pattern.compile("/.+?/.+?/(.+?)/(.*)");
    }

    /**
     * Used for caching purposes 
     * 
     * @see javax.servlet.http.HttpServlet#getLastModified(javax.servlet.http.HttpServletRequest)
     */
    @Override
    protected long getLastModified(HttpServletRequest req) {
        File f = getFile(req);

        if (f == null)
            return super.getLastModified(req);

        return f.lastModified();
    }

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        log.debug("In service method for module servlet: " + request.getPathInfo());

        File f = getFile(request);
        if (f == null) {
            response.setStatus(HttpServletResponse.SC_NOT_FOUND);
            return;
        }

        response.setDateHeader("Last-Modified", f.lastModified());
        response.setContentLength(new Long(f.length()).intValue());
        String mimeType = getServletContext().getMimeType(f.getName());
        response.setContentType(mimeType);

        FileInputStream is = new FileInputStream(f);
        try {
            OpenmrsUtil.copyFile(is, response.getOutputStream());
        } finally {
            OpenmrsUtil.closeStream(is);
        }
    }

    /**
     * @param request
     * @return the requested file
     */
    protected File getFile(HttpServletRequest request) {
        ResourceFactory factory = ResourceFactory.getInstance();

        String path = request.getPathInfo();
        try {
            // path is like "/uiframework/resource/providerName/path/to/resource.png"
            // the first and second elements are this module's id and this servlet's name; we don't care about them
            Matcher matcher = pathPattern.matcher(path);
            if (!matcher.matches())
                throw new IllegalArgumentException("Pattern does not match");
            String providerName = matcher.group(1);
            String resourcePath = matcher.group(2);
            if ("*".equals(providerName))
                providerName = null;
            return factory.getResource(providerName, resourcePath);

        } catch (Exception ex) {
            if (log.isDebugEnabled())
                log.debug("Invalid resource path: " + path, ex);
            return null;
        }
    }
}