Example of Virtual File System as Grails Service

gistfile1.groovy

package com.example

import org.springframework.beans.factory.InitializingBean

import java.net.URLEncoder

import java.io.InputStream
import java.io.OutputStream
import java.io.ByteArrayOutputStream

import org.apache.commons.io.FileUtils
import org.apache.commons.vfs2.FileSystemManager
import org.apache.commons.vfs2.VFS
import org.apache.commons.vfs2.FileObject
import org.apache.commons.vfs2.FileSystemOptions
import org.apache.commons.vfs2.provider.ftp.FtpFileSystemConfigBuilder
import org.apache.commons.vfs2.Selectors
import org.apache.commons.vfs2.FileType

class VirtualFileSystemService implements InitializingBean {

	static transactional = false

	FileSystemManager vfs = VFS.getManager()
	FileSystemOptions vfsFileSystemOptions = new FileSystemOptions()

	void afterPropertiesSet() {
		// setup FTP file system options
		FtpFileSystemConfigBuilder.getInstance().setPassiveMode(vfsFileSystemOptions, true)
		FtpFileSystemConfigBuilder.getInstance().setUserDirIsRoot(vfsFileSystemOptions, true)
		FtpFileSystemConfigBuilder.getInstance().setDataTimeout(vfsFileSystemOptions, 180000)
	}

    boolean exists(Map settings, String container, String fileName) {
    	FileObject fo = resolveFile(settings, container, fileName)
    	boolean file_exists = fo?.exists() ?: false
    	fo.close()
    	return file_exists
    }

    List listFiles(Map settings, String container, String fileName) {
        List results = []
        FileObject fo = resolveFile(settings, container, fileName)
        if (!fo.exists()) return results

        List files = fo.getChildren()
        files.each {
            results << [
                type: (it.getType() == FileType.FOLDER) ? 'FOLDER' : 'FILE',
                name: it.getName().getBaseName(),
                size: (it.getType() == FileType.FILE) ? it.getContent().getSize() : 0
            ]
        }

        fo.close()
        return results
    }

    void delete(Map settings, String container, String fileName) {
    	FileObject fo = resolveFile(settings, container, fileName)
    	if (fo.exists() == true) fo.delete(Selectors.SELECT_ALL)
    	fo.close()
    }

    void rename(Map settings, String container, String fileName, String newFileName) {
        FileObject fo = resolveFile(settings, container, fileName)
        if (fo.exists() == false) return

        FileObject nfo = resolveFile(settings, container, newFileName)
        fo.doRename(nfo)
        fo.close()
        nfo.close()
    }

    void createDirectory(Map settings, String container, String fileName) {
        FileObject fo = resolveFile(settings, container, fileName)
        if (fo.exists() == true) return
        fo.createFolder()
        fo.close()
    }

    void upload(Map settings, String container, String fileName, InputStream data) {
    	log.debug("Save file ${fileName} to ${container}")

        FileObject pfo = resolveFile(settings, container, null)
        log.debug("Parent exists?: " + pfo.exists())

    	FileObject fo = resolveFile(settings, container, fileName)
    	if (fo.exists() == false) {
            try {
                fo.createFile()
            } catch (Exception e) {
                log.error(e)
                log.error(e.getMessage())
                throw e
            }
        } else {
            fo.delete()
            fo.createFile()
        }

    	long bytesCopied = org.apache.commons.io.IOUtils.copy(data, fo.content.outputStream)

    	log.debug("${bytesCopied} bytes uploaded.")
    	fo.close()
    }

    OutputStream download(Map settings, String container, String fileName) {
        FileObject fo = resolveFile(settings, container, fileName)
        if (fo.exists() == false) return null

        ByteArrayOutputStream outputStream = new ByteArrayOutputStream()
        org.apache.commons.io.IOUtils.copy(fo.content.inputStream, outputStream)
        fo.close()

        return outputStream
    }

    FileObject resolveFile(Map settings, String container, String fileName) {
    	// add any leading forward slash to container if not present
        if (!container.startsWith("/")) {
            container = "/" + container
        }
    	// remove any trailing slash from container if present
        if (container.endsWith("/")) {
            container = container.substring(0, container.length() -1)
        }
    	String path = "${container}/${fileName}"
        if (!fileName) path = "${container}"

        log.debug("resolving path for ftp://${URLEncoder.encode(settings['username'])}:${URLEncoder.encode(settings['password'])}@${settings['host']}${path}")
    	return vfs.resolveFile("ftp://${URLEncoder.encode(settings['username'])}:${URLEncoder.encode(settings['password'])}@${settings['host']}${path}", vfsFileSystemOptions)
    }
}