foam.nanos.servlet.ImageServlet.java Source code

Introduction

Here is the source code for foam.nanos.servlet.ImageServlet.java

Source

/**
 * @license
 * Copyright 2018 The FOAM Authors. All Rights Reserved.
 * http://www.apache.org/licenses/LICENSE-2.0
 */

package foam.nanos.servlet;

import foam.util.SafetyUtil;
import org.apache.commons.io.FilenameUtils;
import org.apache.commons.io.IOUtils;
import org.apache.commons.text.StringEscapeUtils;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

public class ImageServlet extends HttpServlet {
    protected static final int BUFFER_SIZE = 4096;
    protected static final String DEFAULT_EXT = "application/octet-stream";
    protected static final Map<String, String> EXTS = new HashMap<String, String>();

    static {
        EXTS.put("js", "application/javascript");
        EXTS.put("json", "application/json");
        EXTS.put("class", "application/java-vm");
        EXTS.put("xml", "application/xml");

        EXTS.put("gif", "image/gif");
        EXTS.put("png", "image/png");
        EXTS.put("svg", "image/svg+xml");

        EXTS.put("java", "text/x-java-source");
        EXTS.put("csv", "text/csv");
        EXTS.put("txt", "text/plain");
        EXTS.put("html", "text/html");
    }

    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        // get path
        String cwd = System.getProperty("user.dir");
        String[] paths = getServletConfig().getInitParameter("paths").split(":");
        String reqPath = req.getRequestURI().replaceFirst("/?images/?", "/");

        // enumerate each file path
        for (int i = 0; i < paths.length; i++) {
            File src = new File(cwd + "/" + paths[i] + reqPath);
            if (src.isFile() && src.canRead()
                    && src.getCanonicalPath().startsWith(new File(paths[i]).getCanonicalPath())) {
                String ext = EXTS.get(FilenameUtils.getExtension(src.getName()));
                try (BufferedInputStream is = new BufferedInputStream(new FileInputStream(src))) {
                    resp.setContentType(!SafetyUtil.isEmpty(ext) ? ext : DEFAULT_EXT);
                    resp.setHeader("Content-Disposition",
                            "filename=\"" + StringEscapeUtils.escapeHtml4(src.getName()) + "\"");
                    resp.setContentLengthLong(src.length());

                    IOUtils.copy(is, resp.getOutputStream());
                    return;
                }
            }
        }

        resp.sendError(resp.SC_NOT_FOUND);
    }
}