GaeVfsServlet uploads files into the GAE virtual file system (GaeVFS)
* and then serves them out again. It can also be configured to optionally return
* directory listings of GaeVFS folders. Here's sample web.xml configuration
* for this servlet:
*
* <servlet>
*
* <servlet-name>gaevfs</servlet-name>
* <servlet-class>com.newatlanta.commons.vfs.provider.gae.GaeVfsServlet</servlet-class>
* <init-param>
* <param-name>dirListingAllowed</param-name>
* <param-value>true</param-value>
* </init-param>
* <init-param>
* <param-name>initDirs</param-name>
* <param-value>/gaevfs/images,/gaevfs/docs</param-value>
* </init-param>
* <init-param>
* <param-name>uploadRedirect</param-name>
* <param-value>/uploadComplete.jsp</param-value>
* </init-param>
* </servlet>
* <servlet-mapping>
* <servlet-name>gaevfs</servlet-name>
* <url-pattern>/gaevfs/*</url-pattern>
* </servlet-mapping>
*
* The <url-pattern> within the <servlet-mapping>
* element is very important
* because it determines which incoming requests get processed by this servlet.
* When uploading a file, be sure to specify a "path" form parameter that starts
* with this URL pattern. For example, if you upload a file named "picture.jpg"
* with a "path" of "/gaevfs/images", then the following URL will serve it:
*
* http://www.myhost.com/gaevfs/images/picture.jpg
* <url-pattern> to be whatever you want--and even
* specify multiple <url-pattern> elements--just make sure to
* specify the "path" form parameter correctly when uploading the file. See additional
* comments on the doPost() method.
*
* The "dirListingAllowed" <init-param> controls whether this servlet
* returns directory listings for GaeVFS folders. If false, then a FORBIDDEN
* error is returned for attempted directory listings. The default value is false.
*
* The "initDirs" <init-param> allows you to specify a comma-separated
* list of folders to create when this servlet initializes. This is merely for
* convenience and is entirely optional. (If you have directory listing enabled,
* then it's a good idea to create the top-level directory. Otherwise, you'll
* get a NOT_FOUND response when invoking this servlet on an empty
* file system, which might be confusing).
*
* The "uploadRedirect" <init-param> allows you to specify a page
* to use to create the response for a file upload. The default is to do a directory
* listing of the folder to which the file was uploaded, so you should specify
* "uploadRedirect" if you disable directory listings.
*
* @author Vince Bonfanti
*/
@SuppressWarnings("serial")
public class GaeVfsServlet extends HttpServlet {
private boolean dirListingAllowed;
private String uploadRedirect;
private int rootPathLen;
/**
* Initializes GaeVFS and processes <init-param> elements from
* web.xml.
*/
@Override
public void init() throws ServletException {
dirListingAllowed = Boolean.parseBoolean( getInitParameter( "dirListingAllowed" ) );
uploadRedirect = getInitParameter( "uploadRedirect" );
String rootPath = getServletContext().getRealPath( "/" );
rootPathLen = rootPath.length();
// for development on Windows
if ( System.getProperty( "os.name" ).startsWith( "Windows" ) ) {
rootPathLen++;
}
GaeVFS.setRootPath( rootPath );
try {
String initDirs = getInitParameter( "initDirs" );
if ( initDirs != null ) {
StringTokenizer st = new StringTokenizer( initDirs, "," );
while ( st.hasMoreTokens() ) {
FileObject fileObject = GaeVFS.resolveFile( "gae://" + st.nextToken() );
if ( !fileObject.exists() ) {
fileObject.createFolder();
}
}
}
} catch ( IOException e ) {
throw new ServletException( e );
} finally {
GaeVFS.clearFilesCache();
}
}
@Override
public void destroy() {
GaeVFS.close();
}
/**
* If a file is specified, return the file; if a folder is specified, then
* either return a listing of the folder, or FORBIDDEN, based on
* configuration.
*/
@Override
public void doGet( HttpServletRequest req, HttpServletResponse res ) throws ServletException, IOException {
System.out.println("get request");
try {
FileObject fileObject = GaeVFS.resolveFile( req.getRequestURI() );
if ( !fileObject.exists() ) {
res.sendError( HttpServletResponse.SC_NOT_FOUND );
return;
}
if ( fileObject.getType().hasChildren() ) { // it's a directory
if ( dirListingAllowed ) {
res.getWriter().write( getListHTML( fileObject ) );
res.flushBuffer();
} else {
res.sendError( HttpServletResponse.SC_FORBIDDEN, "Directory listing not allowed" );
}
return;
}
// it's file, return it
// the servlet MIME type is configurable via web.xml, check it first
String contentType = getServletContext().getMimeType( fileObject.getName().getBaseName() );
res.setContentType( contentType != null ? contentType
: fileObject.getContent().getContentInfo().getContentType() );
copyAndClose( fileObject.getContent().getInputStream(), res.getOutputStream() );
res.flushBuffer();
} finally {
GaeVFS.clearFilesCache();
}
}
/**
* Return the directory listing for the specified GaeVFS folder. Copied from:
*
* http://www.docjar.com/html/api/org/mortbay/util/Resource.java.html
*
* Modified to support GAE virtual file system.
*/
private String getListHTML( FileObject fileObject ) throws IOException {
String title = "Directory: " + getRelativePath( fileObject );
StringBuffer buf = new StringBuffer( 4096 );
buf.append( "
| Parent Directory | |||
| [empty directory] | |||
| Name | Size | Type | Date modified |
|---|---|---|---|
| " ); buf.append( StringEscapeUtils.escapeHtml( child.getName().getBaseName() ) ); if ( child.getType().hasChildren() ) { buf.append( '/' ); } buf.append( " | " ); if ( child.getType().hasContent() ) { buf.append( nfmt.format( child.getContent().getSize() ) ).append( " bytes" ); } buf.append( " | " ); buf.append( child.getType().getName() ); buf.append( " | " ); buf.append( dfmt.format( new Date( child.getContent().getLastModifiedTime() ) ) ); buf.append( " |