A servlet for serving static files

servlet/src/main/java/com/twelvemonkeys/servlet/StaticContentServlet.java

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+/*
+ * Copyright (c) 2011, Harald Kuhr
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name "TwelveMonkeys" nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package com.twelvemonkeys.servlet;
+
+import com.twelvemonkeys.io.FileUtil;
+
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * A minimal servlet that can serve static files. Also from outside the web application.
+ *
+ * @author <a href="mailto:harald.kuhr@gmail.com">Harald Kuhr</a>
+ * @author last modified by $Author: haraldk$
+ * @version $Id: StaticContentServlet.java,v 1.0 12.12.11 15:09 haraldk Exp$
+ *
+ * @see #setRoot(java.io.File)
+ */
+public final class StaticContentServlet extends HttpServlet {
+
+    private File root;
+
+    /**
+     * Configures the file system {@code root} for this servlet.
+     * If {@code root} is a directory, files will be served relative to the directory.
+     * If {@code root} is a file, only this file may be served
+     *
+     * @param root the file system root.
+     */
+    @InitParam(name = "root")
+    public void setRoot(final File root) {
+        this.root = root;
+    }
+
+    @Override
+    public void init() throws ServletException {
+        if (root == null) {
+            throw new ServletConfigException("File system root not configured, check 'root' init-param");
+        }
+        else if (!root.exists()) {
+            throw new ServletConfigException(
+                    String.format("File system root '%s' does not exist, check 'root' init-param", root.getAbsolutePath())
+            );
+        }
+
+        log(String.format("Serving %s '%s'", root.isDirectory() ? "files from directory" : "single file", root.getAbsolutePath()));
+    }
+
+    @Override
+    protected long getLastModified(final HttpServletRequest request) {
+        File file = findFileForRequest(request);
+
+        return file.exists() ? file.lastModified() : -1L;
+    }
+
+    @Override
+    protected void doGet(final HttpServletRequest request, final HttpServletResponse response) throws IOException {
+        File file = findFileForRequest(request);
+
+        if (file.isFile() && file.canRead()) {
+            // Normal file, all ok
+            response.setStatus(HttpServletResponse.SC_OK);
+            String contentType = getServletContext().getMimeType(file.getName());
+            response.setContentType(contentType != null ? contentType : "application/octet-stream");
+            if (file.length() <= Integer.MAX_VALUE) {
+                response.setContentLength((int) file.length());
+            }
+            else {
+                response.setHeader("Content-Length", String.valueOf(file.length()));
+            }
+            response.setDateHeader("Last-Modified", file.lastModified());
+
+            InputStream in = new FileInputStream(file);
+
+            try {
+                FileUtil.copy(in, response.getOutputStream());
+            }
+            finally {
+                in.close();
+            }
+        }
+        else {
+            if (file.exists()) {
+                // Attempted directory listing or non-readable file
+                response.sendError(HttpServletResponse.SC_FORBIDDEN, request.getRequestURI());
+            }
+            else {
+                // No such file
+                response.sendError(HttpServletResponse.SC_NOT_FOUND, request.getRequestURI());
+            }
+        }
+    }
+
+    private File findFileForRequest(final HttpServletRequest request) {
+        String relativePath = request.getPathInfo();
+
+        return relativePath != null ? new File(root, relativePath) : root;
+    }
+}

servlet/src/test/java/com/twelvemonkeys/servlet/StaticContentServletTestCase.java

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+/*
+ * Copyright (c) 2011, Harald Kuhr
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name "TwelveMonkeys" nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package com.twelvemonkeys.servlet;
+
+import org.junit.Test;
+
+import javax.servlet.ServletConfig;
+import javax.servlet.ServletContext;
+import javax.servlet.ServletException;
+import javax.servlet.ServletOutputStream;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.File;
+import java.io.IOException;
+import java.net.URISyntaxException;
+import java.net.URL;
+import java.util.Arrays;
+import java.util.Collections;
+
+import static org.mockito.Matchers.anyString;
+import static org.mockito.Mockito.*;
+
+
+/**
+ * StaticContentServletTestCase
+ *
+ * @author <a href="mailto:harald.kuhr@gmail.com">Harald Kuhr</a>
+ * @author last modified by $Author: haraldk$
+ * @version $Id: StaticContentServletTestCase.java,v 1.0 12.12.11 15:10 haraldk Exp$
+ */
+public class StaticContentServletTestCase {
+
+    private static final String IMAGE_RESOURCE = "/12monkeys-splash.png";
+
+    private static String getFileSystemRoot() {
+        File root = getResourceAsFile(IMAGE_RESOURCE).getParentFile();
+        return root.getAbsolutePath();
+    }
+
+    private static File getResourceAsFile(String resourceName) {
+        URL resource = StaticContentServletTestCase.class.getResource("/com/twelvemonkeys/servlet/image" + resourceName);
+
+        try {
+            return new File(resource.toURI());
+        }
+        catch (URISyntaxException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    @Test(expected = ServletException.class)
+    public void testBadInitNoRoot() throws ServletException {
+        StaticContentServlet servlet = new StaticContentServlet();
+        ServletConfig config = mock(ServletConfig.class);
+        when(config.getInitParameterNames()).thenReturn(Collections.enumeration(Collections.emptyList()));
+
+        servlet.init(config);
+    }
+
+    @Test(expected = ServletException.class)
+    public void testBadInit() throws ServletException {
+        StaticContentServlet servlet = new StaticContentServlet();
+        ServletConfig config = mock(ServletConfig.class);
+        when(config.getInitParameterNames()).thenReturn(Collections.enumeration(Arrays.asList("root")));
+        when(config.getInitParameter("root")).thenReturn("foo/bar");
+
+        servlet.init(config);
+    }
+
+    @Test
+    public void testNotFound() throws ServletException, IOException {
+        StaticContentServlet servlet = new StaticContentServlet();
+
+        ServletContext context = mock(ServletContext.class);
+        when(context.getServletContextName()).thenReturn("foo");
+        when(context.getMimeType(anyString())).thenReturn("image/jpeg");
+
+        ServletConfig config = mock(ServletConfig.class);
+        when(config.getInitParameterNames()).thenReturn(Collections.enumeration(Arrays.asList("root")));
+        when(config.getInitParameter("root")).thenReturn(getFileSystemRoot());
+        when(config.getServletContext()).thenReturn(context);
+
+        servlet.init(config);
+
+        HttpServletRequest request = mock(HttpServletRequest.class);
+        when(request.getMethod()).thenReturn("GET");
+        when(request.getPathInfo()).thenReturn("/missing.jpg");
+        when(request.getRequestURI()).thenReturn("/foo/missing.jpg");
+        when(request.getContextPath()).thenReturn("/foo");
+
+        HttpServletResponse response = mock(HttpServletResponse.class);
+
+        servlet.service(request, response);
+
+        verify(response).sendError(HttpServletResponse.SC_NOT_FOUND, "/foo/missing.jpg");
+    }
+
+    @Test
+    public void testDirectoryListingForbidden() throws ServletException, IOException {
+        StaticContentServlet servlet = new StaticContentServlet();
+
+        ServletContext context = mock(ServletContext.class);
+        when(context.getServletContextName()).thenReturn("foo");
+        when(context.getMimeType(anyString())).thenReturn("image/png");
+
+        ServletConfig config = mock(ServletConfig.class);
+        when(config.getInitParameterNames()).thenReturn(Collections.enumeration(Arrays.asList("root")));
+        when(config.getInitParameter("root")).thenReturn(getFileSystemRoot());
+        when(config.getServletContext()).thenReturn(context);
+
+        servlet.init(config);
+
+        HttpServletRequest request = mock(HttpServletRequest.class);
+        when(request.getMethod()).thenReturn("GET");
+        when(request.getPathInfo()).thenReturn("/");       // Attempt directory listing
+        when(request.getRequestURI()).thenReturn("/foo/"); // Attempt directory listing
+        when(request.getContextPath()).thenReturn("/foo");
+
+        ServletOutputStream stream = mock(ServletOutputStream.class);
+
+        HttpServletResponse response = mock(HttpServletResponse.class);
+        when(response.getOutputStream()).thenReturn(stream);
+
+        servlet.service(request, response);
+
+        verify(response).sendError(HttpServletResponse.SC_FORBIDDEN, "/foo/");
+    }
+
+    @Test
+    public void testGet() throws ServletException, IOException {
+        StaticContentServlet servlet = new StaticContentServlet();
+
+        ServletContext context = mock(ServletContext.class);
+        when(context.getServletContextName()).thenReturn("foo");
+        when(context.getMimeType(anyString())).thenReturn("image/png");
+
+        ServletConfig config = mock(ServletConfig.class);
+        when(config.getInitParameterNames()).thenReturn(Collections.enumeration(Arrays.asList("root")));
+        when(config.getInitParameter("root")).thenReturn(getFileSystemRoot());
+        when(config.getServletContext()).thenReturn(context);
+
+        servlet.init(config);
+
+        HttpServletRequest request = mock(HttpServletRequest.class);
+        when(request.getMethod()).thenReturn("GET");
+        when(request.getPathInfo()).thenReturn(IMAGE_RESOURCE);
+        when(request.getRequestURI()).thenReturn("/foo" + IMAGE_RESOURCE);
+        when(request.getContextPath()).thenReturn("/foo");
+
+        ServletOutputStream stream = mock(ServletOutputStream.class);
+
+        HttpServletResponse response = mock(HttpServletResponse.class);
+        when(response.getOutputStream()).thenReturn(stream);
+
+        servlet.service(request, response);
+
+        verify(response).setStatus(HttpServletResponse.SC_OK);
+//        verify(stream, atLeastOnce()).write((byte[]) any(), anyInt(), anyInt()); // Mockito bug?
+        verify(stream, times(51)).write((byte[]) any(), anyInt(), anyInt()); // This test is fragile, but the above throws exception..?
+        verify(stream, atLeastOnce()).flush();
+    }
+
+    @Test
+    public void testGetConfiguredForSingleFile() throws ServletException, IOException {
+        StaticContentServlet servlet = new StaticContentServlet();
+
+        ServletContext context = mock(ServletContext.class);
+        when(context.getServletContextName()).thenReturn("foo");
+        when(context.getMimeType(anyString())).thenReturn("text/plain");
+
+        ServletConfig config = mock(ServletConfig.class);
+        when(config.getInitParameterNames()).thenReturn(Collections.enumeration(Arrays.asList("root")));
+        when(config.getInitParameter("root")).thenReturn(getFileSystemRoot() + "/foo.txt");
+        when(config.getServletContext()).thenReturn(context);
+
+        servlet.init(config);
+
+        HttpServletRequest request = mock(HttpServletRequest.class);
+        when(request.getMethod()).thenReturn("GET");
+        when(request.getPathInfo()).thenReturn(null);
+        when(request.getRequestURI()).thenReturn("/foo");
+        when(request.getContextPath()).thenReturn("/foo");
+
+        ServletOutputStream stream = mock(ServletOutputStream.class);
+
+        HttpServletResponse response = mock(HttpServletResponse.class);
+        when(response.getOutputStream()).thenReturn(stream);
+
+        servlet.service(request, response);
+
+        verify(response).setStatus(HttpServletResponse.SC_OK);
+//        verify(stream, atLeastOnce()).write((byte[]) any(), anyInt(), anyInt()); // Mockito bug?
+        verify(stream, times(1)).write((byte[]) any(), anyInt(), anyInt()); // This test is fragile, but the above throws exception..?
+        verify(stream, atLeastOnce()).flush();
+    }
+
+    @Test
+    public void testGetNotModified() throws ServletException, IOException {
+        StaticContentServlet servlet = new StaticContentServlet();
+
+        ServletContext context = mock(ServletContext.class);
+        when(context.getServletContextName()).thenReturn("foo");
+        when(context.getMimeType(anyString())).thenReturn("image/png");
+
+        ServletConfig config = mock(ServletConfig.class);
+        when(config.getInitParameterNames()).thenReturn(Collections.enumeration(Arrays.asList("root")));
+        when(config.getInitParameter("root")).thenReturn(getFileSystemRoot());
+        when(config.getServletContext()).thenReturn(context);
+
+        servlet.init(config);
+
+        HttpServletRequest request = mock(HttpServletRequest.class);
+        when(request.getMethod()).thenReturn("GET");
+        when(request.getPathInfo()).thenReturn(IMAGE_RESOURCE);
+        when(request.getRequestURI()).thenReturn("/foo" + IMAGE_RESOURCE);
+        when(request.getContextPath()).thenReturn("/foo");
+        when(request.getDateHeader("If-Modified-Since")).thenReturn(getResourceAsFile(IMAGE_RESOURCE).lastModified());
+
+        ServletOutputStream stream = mock(ServletOutputStream.class);
+
+        HttpServletResponse response = mock(HttpServletResponse.class);
+        when(response.getOutputStream()).thenReturn(stream);
+
+        servlet.service(request, response);
+
+        verify(response).setStatus(HttpServletResponse.SC_NOT_MODIFIED);
+        verifyZeroInteractions(stream);
+    }
+
+    @Test
+    public void testHead() throws ServletException, IOException {
+        StaticContentServlet servlet = new StaticContentServlet();
+
+        ServletContext context = mock(ServletContext.class);
+        when(context.getServletContextName()).thenReturn("foo");
+        when(context.getMimeType(anyString())).thenReturn("image/png");
+
+        ServletConfig config = mock(ServletConfig.class);
+        when(config.getInitParameterNames()).thenReturn(Collections.enumeration(Arrays.asList("root")));
+        when(config.getInitParameter("root")).thenReturn(getFileSystemRoot());
+        when(config.getServletContext()).thenReturn(context);
+
+        servlet.init(config);
+
+        HttpServletRequest request = mock(HttpServletRequest.class);
+        when(request.getMethod()).thenReturn("HEAD");
+        when(request.getPathInfo()).thenReturn(IMAGE_RESOURCE);
+        when(request.getRequestURI()).thenReturn("/foo" + IMAGE_RESOURCE);
+        when(request.getContextPath()).thenReturn("/foo");
+
+        ServletOutputStream stream = mock(ServletOutputStream.class);
+
+        HttpServletResponse response = mock(HttpServletResponse.class);
+        when(response.getOutputStream()).thenReturn(stream);
+
+        servlet.service(request, response);
+
+        verify(response).setStatus(HttpServletResponse.SC_OK);
+        verifyZeroInteractions(stream);
+    }
+}