/* The contents of this file are subject to the license and copyright terms
* detailed in the license directory at the root of the source tree (also
* available online at http://fedora-commons.org/license/).
*/
package org.fcrepo.server.rest;
import java.io.File;
import java.util.Date;
import java.util.HashMap;
import java.util.Set;
import java.util.regex.Pattern;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.fcrepo.common.Constants;
import org.fcrepo.server.Context;
import org.fcrepo.server.Server;
import org.fcrepo.server.access.Access;
import org.fcrepo.server.errors.DatastreamNotFoundException;
import org.fcrepo.server.management.Management;
import org.fcrepo.server.storage.RDFRelationshipReader;
import org.fcrepo.server.storage.types.DatastreamDef;
import org.fcrepo.server.storage.types.MIMETypedStream;
import org.fcrepo.server.storage.types.Property;
import org.fcrepo.server.storage.types.RelationshipTuple;
/**
* Helper class to manage getting filenames for datastreams and adding content
* disposition headers to force downloading of datastream disseminations
*
* @author Stephen Bayliss
* @version $Id$
*/
public class DatastreamFilenameHelper {
private static final Logger logger =
LoggerFactory.getLogger(DatastreamFilenameHelper.class);
// configures behaviour from fedora.fcfg
protected static String m_datastreamContentDispositionInlineEnabled;
protected static String m_datastreamFilenameSource;
protected static String m_datastreamExtensionMappingLabel;
protected static String m_datastreamExtensionMappingId;
protected static String m_datastreamExtensionMappingRels;
protected static String m_datastreamExtensionMappingDefault;
protected static String m_datastreamDefaultFilename;
protected static String m_datastreamDefaultExtension;
// TODO: in the future this could be (in) a Fedora object. For now it's a file in the server config directory
private static String DATASTREAM_MAPPING_SOURCE_FILE = "mime-to-extensions.xml";
// uri used to assert the download filename name
protected static String FILENAME_REL = Constants.MODEL.DOWNLOAD_FILENAME.uri;
// characters that we don't allow in filenames.
// main: \ / * ? < > : | "
// other characters that can cause problems: ; , % # $
protected static Pattern ILLEGAL_FILENAME_REGEX= Pattern.compile("[\\\\/\\*\\?<>:\\|\";,%#\\$]+");
protected Management m_apiMService;
protected Access m_apiAService;
// MIMETYPE-to-extensions mappings
protected static HashMap<String, String> m_extensionMappings;
/**
* Read configuration information from fedora.fcfg
*
* @param fedoraServer
* @param management
* @param access
*/
public DatastreamFilenameHelper(Server fedoraServer, Management management, Access access) {
m_datastreamContentDispositionInlineEnabled = fedoraServer.getParameter("datastreamContentDispositionInlineEnabled");
m_datastreamFilenameSource = fedoraServer.getParameter("datastreamFilenameSource");
m_datastreamExtensionMappingLabel = fedoraServer.getParameter("datastreamExtensionMappingLabel");
m_datastreamExtensionMappingId = fedoraServer.getParameter("datastreamExtensionMappingId");
m_datastreamExtensionMappingRels = fedoraServer.getParameter("datastreamExtensionMappingRels");
m_datastreamExtensionMappingDefault = fedoraServer.getParameter("datastreamExtensionMappingDefault");
m_datastreamDefaultFilename = fedoraServer.getParameter("datastreamDefaultFilename");
m_datastreamDefaultExtension = fedoraServer.getParameter("datastreamDefaultExtension");
m_apiMService = management;
m_apiAService = access;
}
/**
* Get the file extension for a given MIMETYPE from the extensions mappings
*
* @param MIMETYPE
* @return
* @throws Exception
*/
private static final String getExtension(String MIMETYPE) throws Exception {
if (m_extensionMappings == null) {
m_extensionMappings = readExtensionMappings(Server.FEDORA_HOME + "/server/" + Server.CONFIG_DIR + "/" + DATASTREAM_MAPPING_SOURCE_FILE);
}
String extension = m_extensionMappings.get(MIMETYPE);
if (extension != null) {
return extension;
} else {
return "";
}
}
/**
* Read the extensions mappings from config file
*
* @returns new HashMap of mime-types to extensions mappings
* @throws Exception
*/
private static synchronized final HashMap<String, String> readExtensionMappings(String mappingFile) throws Exception {
HashMap<String, String> extensionMappings = new HashMap<String, String>();
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
Document doc = factory.newDocumentBuilder().parse(new File(mappingFile));
Element root = doc.getDocumentElement();
// "mime-mapping" elements are children of root
NodeList mappingNodes = root.getChildNodes();
for (int i = 0; i < mappingNodes.getLength(); i++) {
Node mappingNode = mappingNodes.item(i);
// check it's a mime-mapping element
if (mappingNode.getNodeType() == Node.ELEMENT_NODE && mappingNode.getNodeName().equals("mime-mapping")) {
// look for child elements "extension" and "mime-type" and get values from text nodes
String extension = null;
String mimeType = null;
NodeList nl = mappingNode.getChildNodes();
for (int j = 0; j < nl.getLength(); j++) {
Node n = nl.item(j);
if (n.getNodeType() == Node.ELEMENT_NODE) {
// assuming here that extension and mime-type nodes only have text content (no attrs etc)
if (n.getNodeName().equals("extension")) {
extension = n.getFirstChild().getNodeValue();
} else {
if (n.getNodeName().equals("mime-type")) {
mimeType = n.getFirstChild().getNodeValue();
}
}
}
}
// if we've got an extension and mime-type, and it's not in the list, add it.
if (extension != null && mimeType != null) {
if (!extensionMappings.containsKey(mimeType)) {
extensionMappings.put(mimeType, extension);
} else {
logger.warn("Duplicate extension " + extension + " found for mime-type " + mimeType + " in " + mappingFile);
}
} else {
logger.warn("Element mime-mapping is missing child elements mime-type and/or extension in " + mappingFile);
}
}
}
return extensionMappings;
}
/**
* Add a content disposition header to a MIMETypedStream based on configuration preferences.
* Header by default specifies "inline"; if download=true then "attachment" is specified.
*
* @param context
* @param pid
* @param dsID
* @param download
* true if file is to be downloaded
* @param asOfDateTime
* @param stream
* @throws Exception
*/
public final void addContentDispositionHeader(Context context, String pid, String dsID, String download, Date asOfDateTime, MIMETypedStream stream) throws Exception {
String headerValue = null;
String filename = null;
// is downloading requested?
if (download != null && download.equals("true")) {
// generate an "attachment" content disposition header with the filename
filename = getFilename(context, pid, dsID, asOfDateTime, stream.MIMEType);
headerValue="attachment; filename=\"" + filename + "\"";
} else {
// is the content disposition header enabled in the case of not downloading?
if (m_datastreamContentDispositionInlineEnabled.equals("true")) {
// it is... generate the header with "inline"
filename = getFilename(context, pid, dsID, asOfDateTime, stream.MIMEType);
headerValue="inline; filename=\"" + filename + "\"";
}
}
// create content disposition header to add
Property[] header = { new Property ("content-disposition", headerValue) };
// add header to existing headers if present, or set this as the new header if not
if (stream.header != null) {
Property headers[] = new Property[stream.header.length + 1];
System.arraycopy(stream.header, 0, headers, 0, stream.header.length);
headers[headers.length - 1] = header[0];
stream.header = headers;
} else {
stream.header = header;
}
}
/**
* Generate a filename and extension for a datastream based on configuration preferences.
* Filename can be based on a definition in RELS-INT, the datastream label or
* the datastream ID. These sources can be specified in order of preference together with
* using a default filename. The extension is based on a mime-type-to-extension mapping
* configuration file; alternatively if the filename determined already includes an extension
* that can be specified instead.
*
* @param context
* @param pid
* @param dsid
* @param asOfDateTime
* @param MIMETYPE
* @return
* @throws Exception
*/
private final String getFilename(Context context, String pid, String dsid, Date asOfDateTime, String MIMETYPE) throws Exception {
String filename = "";
String extension = "";
// check sources in order
for (String source : m_datastreamFilenameSource.split(" ")) {
// try and get filename and extension from specified source
if (source.equals("rels")) {
filename = getFilenameFromRels(context, pid, dsid, MIMETYPE);
if (!filename.equals(""))
extension = getExtension(filename, m_datastreamExtensionMappingRels, MIMETYPE);
} else {
if (source.equals("id")) {
filename = getFilenameFromId(pid, dsid, MIMETYPE);
if (!filename.equals(""))
extension = getExtension(filename, m_datastreamExtensionMappingId, MIMETYPE);
} else {
if (source.equals("label")) {
filename = getFilenameFromLabel(context, pid, dsid, asOfDateTime, MIMETYPE);
if (!filename.equals(""))
extension = getExtension(filename, m_datastreamExtensionMappingLabel, MIMETYPE);
} else {
logger.warn("Unknown datastream filename source specified in datastreamFilenameSource in fedora.fcfg: " + source + ". Please specify zero or more of: rels id label");
}
}
}
// if we've got one by here, quit loop
if (!filename.equals(""))
break;
}
// if not determined from above use the default
if (filename.equals("")) {
filename = m_datastreamDefaultFilename;
extension = getExtension(m_datastreamDefaultFilename, m_datastreamExtensionMappingDefault, MIMETYPE);
}
// clean up filename - remove illegal chars
if (extension.equals("")) {
return ILLEGAL_FILENAME_REGEX.matcher(filename).replaceAll("");
} else {
return ILLEGAL_FILENAME_REGEX.matcher(filename + "." + extension).replaceAll("");
}
}
/**
* Get datastream filename as defined in RELS-INT
*
* @param context
* @param pid
* @param dsid
* @param MIMETYPE
* @return
* @throws Exception
*/
private final String getFilenameFromRels(Context context, String pid, String dsid, String MIMETYPE) throws Exception {
String filename = "";
// read rels directly from RELS-INT - can't use Management.getRelationships as this requires auth
MIMETypedStream relsInt;
try {
relsInt = m_apiAService.getDatastreamDissemination(context, pid, "RELS-INT", null);
} catch (DatastreamNotFoundException e) {
return ""; // no RELS-INT - so no filename
}
Set<RelationshipTuple> relsIntTuples = RDFRelationshipReader.readRelationships(relsInt.getStream());
// find the tuple specifying the filename
int matchingTuples = 0;
for ( RelationshipTuple tuple : relsIntTuples ) {
if (tuple.subject.equals(Constants.FEDORA.uri + pid + "/" + dsid) && tuple.predicate.equals(FILENAME_REL)) {
// use the first found relationship by default (report warning later if there are more)
if (matchingTuples == 0) {
if (tuple.isLiteral) {
filename = tuple.object;
} else {
logger.warn("Object " + pid + " datastream " + dsid + " specifies a filename which is not a literal in RELS-INT");
filename = "";
}
}
matchingTuples++;
}
}
if (matchingTuples > 1) {
logger.warn("Object " + pid + " datastream " + dsid + " specifies more than one filename in RELS-INT.");
}
return filename;
}
/**
* Get filename based on datastream label
*
* @param context
* @param pid
* @param dsid
* @param asOfDateTime
* @param MIMETYPE
* @return
* @throws Exception
*/
private final String getFilenameFromLabel(Context context, String pid, String dsid, Date asOfDateTime, String MIMETYPE) throws Exception {
// can't get datastream label directly from datastream as this is an API-M call
// instead get list of datastream defs, as these contain labels
DatastreamDef[] datastreams = m_apiAService.listDatastreams(context, pid, asOfDateTime);
String filename = "";
for ( DatastreamDef datastream : datastreams) {
if (datastream.dsID.equals(dsid)) {
filename = datastream.dsLabel;
break;
}
}
return filename;
}
/**
* Get filename from datastream id
*
* @param pid
* @param dsid
* @param MIMETYPE
* @return
* @throws Exception
*/
private static final String getFilenameFromId(String pid, String dsid, String MIMETYPE) throws Exception {
return dsid;
}
/**
* Get a filename extension for a datastream based on mime-type to extension mapping.
* mappingType may be:
* <li>never: never look up extension
* <li>ifmissing: if the given filename already contains an extension return nothing,
* otherwise look up an extension
* <li>always: always look up an extension
*/
private static final String getExtension(String filename, String mappingType, String MIMETYPE) throws Exception {
String extension = "";
if (mappingType.equals("never")) {
extension = "";
} else {
// if mapping specifies ifmissing and filename contains an extension; extension is "" (filename already contains the extension)
if (mappingType.equals("ifmissing") && filename.contains(".")) {
extension = "";
} else {
// oth
if (mappingType.equals("ifmissing") || mappingType.equals("always")) {
// look up extension from mapping
extension = getExtension(MIMETYPE);
// if not found in mappings, use the default
if (extension.equals(""))
extension = m_datastreamDefaultExtension;
} else {
// unknown mapping type
logger.warn("Unknown extension mapping type specified in fedora.fcfg");
extension = m_datastreamDefaultExtension;
}
}
}
return extension;
}
}