A servlet for serving static files

2026-04-04 00:00:01 -04:00 · 2012-06-21 10:45:06 +02:00
parent c7f6dedaa7
commit d84acbf4b3
2 changed files with 417 additions and 0 deletions
--- a/servlet/src/main/java/com/twelvemonkeys/servlet/StaticContentServlet.java
+++ b/servlet/src/main/java/com/twelvemonkeys/servlet/StaticContentServlet.java
@@ -0,0 +1,130 @@
+/*
+ * 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;
+    }
+}