Java tutorial
/** * The contents of this file are subject to the license and copyright * detailed in the LICENSE and NOTICE files at the root of the source * tree and available online at * * http://www.dspace.org/license/ */ package org.dspace.app.dav; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import java.sql.SQLException; import java.util.ArrayList; import java.util.List; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.commons.codec.binary.Base64; import org.apache.log4j.Logger; import org.dspace.authorize.AuthorizeException; import org.dspace.authorize.AuthorizeManager; import org.dspace.content.Bitstream; import org.dspace.content.BitstreamFormat; import org.dspace.content.Bundle; import org.dspace.content.Item; import org.dspace.core.Constants; import org.dspace.core.Context; import org.dspace.core.LogManager; import org.dspace.core.Utils; import org.jdom.Element; import org.jdom.Namespace; /** * This defines the behavior of DSpace "resources" in the WebDAV interface; it * maps DAV operations onto DSpace object. */ class DAVBitstream extends DAVDSpaceObject { /** log4j category. */ private static Logger log = Logger.getLogger(DAVBitstream.class); /** The item. */ private Item item = null; /** The bitstream. */ private Bitstream bitstream = null; /** The Constant BITSTREAM_INLINE_THRESHOLD. * The longest bitstream that should be rendered "inline" (base64) * see makeXmlBitstream */ private static final int BITSTREAM_INLINE_THRESHOLD = 2000; /** The Constant getcontentlengthProperty. */ private static final Element getcontentlengthProperty = new Element("getcontentlength", DAV.NS_DAV); /** The Constant getcontenttypeProperty. */ private static final Element getcontenttypeProperty = new Element("getcontenttype", DAV.NS_DAV); /** The Constant sourceProperty. */ private static final Element sourceProperty = new Element("source", DAV.NS_DSPACE); /** The Constant descriptionProperty. */ private static final Element descriptionProperty = new Element("description", DAV.NS_DSPACE); /** The Constant formatProperty. */ private static final Element formatProperty = new Element("format", DAV.NS_DSPACE); /** The Constant format_descriptionProperty. */ private static final Element format_descriptionProperty = new Element("format_description", DAV.NS_DSPACE); /** The Constant checksumProperty. */ private static final Element checksumProperty = new Element("checksum", DAV.NS_DSPACE); /** The Constant checksum_algorithmProperty. */ private static final Element checksum_algorithmProperty = new Element("checksum_algorithm", DAV.NS_DSPACE); /** The Constant sequence_idProperty. */ private static final Element sequence_idProperty = new Element("sequence_id", DAV.NS_DSPACE); /** The Constant bundleProperty. */ private static final Element bundleProperty = new Element("bundle", DAV.NS_DSPACE); /** The all props. */ private static List<Element> allProps = new ArrayList<Element>(commonProps); static { allProps.add(getcontentlengthProperty); allProps.add(getcontenttypeProperty); allProps.add(sourceProperty); allProps.add(descriptionProperty); allProps.add(formatProperty); allProps.add(format_descriptionProperty); allProps.add(checksumProperty); allProps.add(checksum_algorithmProperty); allProps.add(sequence_idProperty); allProps.add(bundleProperty); allProps.add(handleProperty); } /** * Instantiates a new DAV bitstream. * This gets called by matchResourceURI, for /retrieve_<dbid> format * * @param context the context * @param request the request * @param response the response * @param pathElt the path elt * @param bitstream the bitstream */ protected DAVBitstream(Context context, HttpServletRequest request, HttpServletResponse response, String pathElt[], Bitstream bitstream) { super(context, request, response, pathElt, bitstream); this.bitstream = bitstream; this.type = TYPE_BITSTREAM; } /** * Instantiates a new DAV bitstream. * * @param context the context * @param request the request * @param response the response * @param pathElt the path elt * @param item the item * @param bitstream the bitstream */ protected DAVBitstream(Context context, HttpServletRequest request, HttpServletResponse response, String pathElt[], Item item, Bitstream bitstream) { super(context, request, response, pathElt, bitstream); this.bitstream = bitstream; this.type = TYPE_BITSTREAM; this.item = item; } /** * Make bitstream path element with filename extension, if given. * * @param sid the sid * @param ext the ext * * @return bitstream path element */ protected static String getPathElt(int sid, String ext) { return "bitstream_" + String.valueOf(sid) + (ext == null ? "" : "." + ext); } /** * Attempt to locate Bitstream object from URI. pathElt is * "bitstream_{sid}.ext" or "retrieve_{db-id}.ext" * * @param context the context * @param item the item * @param pathElt the path elt * * @return the bitstream found (any errors throw an exception) * * @throws SQLException the SQL exception * @throws DAVStatusException the DAV status exception */ protected static Bitstream findBitstream(Context context, Item item, String pathElt) throws SQLException, DAVStatusException { try { // get rid of extension, if any, e.g. ".pdf" int dot = pathElt.indexOf('.'); String strId = (dot >= 0) ? pathElt.substring(0, dot) : pathElt; Bitstream result = null; if (strId.startsWith("bitstream_")) { strId = strId.substring(10); result = getBitstreamBySequenceID(item, Integer.parseInt(strId)); } else if (strId.startsWith("retrieve_")) { strId = strId.substring(9); result = Bitstream.find(context, Integer.parseInt(strId)); } else { throw new DAVStatusException(HttpServletResponse.SC_BAD_REQUEST, "Unrecognized bitstream URI format."); } if (result == null) { throw new DAVStatusException(HttpServletResponse.SC_NOT_FOUND, "No bitstream at this sequence ID: " + pathElt); } return result; } catch (NumberFormatException nfe) { throw new DAVStatusException(HttpServletResponse.SC_BAD_REQUEST, "Invalid Bitstream Sequence ID in URI: " + pathElt, nfe); } } /** * Find bitstream with matching sequence id. * * @param item the item * @param sid the sid * * @return bitstream, or null if none found. * * @throws SQLException the SQL exception */ protected static Bitstream getBitstreamBySequenceID(Item item, int sid) throws SQLException { Bundle[] bundles = item.getBundles(); for (Bundle element : bundles) { Bitstream[] bitstreams = element.getBitstreams(); for (Bitstream element0 : bitstreams) { if (sid == element0.getSequenceID()) { return element0; } } } return null; } /* (non-Javadoc) * @see org.dspace.app.dav.DAVResource#getAllProperties() */ @Override protected List<Element> getAllProperties() { return allProps; } /* (non-Javadoc) * @see org.dspace.app.dav.DAVResource#children() */ @Override protected DAVResource[] children() throws SQLException { return new DAVResource[0]; } /* (non-Javadoc) * @see org.dspace.app.dav.DAVDSpaceObject#propfindInternal(org.jdom.Element) */ @Override protected Element propfindInternal(Element property) throws SQLException, AuthorizeException, IOException, DAVStatusException { String value = null; /* * FIXME: This implements permission check that really belongs in * business logic. Although communities and collections don't check for * read auth, Bitstream may contain sensitive data and should always * check for READ permission. */ AuthorizeManager.authorizeAction(this.context, this.bitstream, Constants.READ); // displayname - title or handle. if (elementsEqualIsh(property, displaynameProperty)) { value = this.bitstream.getName(); if (value == null) { value = makeDisplayname(); } } else if (elementsEqualIsh(property, getcontentlengthProperty)) { value = String.valueOf(this.bitstream.getSize()); } else if (elementsEqualIsh(property, getcontenttypeProperty)) { value = this.bitstream.getFormat().getMIMEType(); } else if (elementsEqualIsh(property, sourceProperty)) { value = this.bitstream.getSource(); } else if (elementsEqualIsh(property, descriptionProperty)) { value = this.bitstream.getDescription(); } else if (elementsEqualIsh(property, formatProperty)) { BitstreamFormat bsf = this.bitstream.getFormat(); value = bsf == null ? null : bsf.getShortDescription(); } else if (elementsEqualIsh(property, format_descriptionProperty)) { value = this.bitstream.getFormatDescription(); } else if (elementsEqualIsh(property, checksumProperty)) { value = this.bitstream.getChecksum(); } else if (elementsEqualIsh(property, checksum_algorithmProperty)) { value = this.bitstream.getChecksumAlgorithm(); } else if (elementsEqualIsh(property, sequence_idProperty)) { int sid = this.bitstream.getSequenceID(); if (sid >= 0) { value = String.valueOf(sid); } } else if (elementsEqualIsh(property, bundleProperty)) { Bundle bn[] = this.bitstream.getBundles(); if (bn != null && bn.length > 0) { value = bn[0].getName(); } } else { return super.propfindInternal(property); } // value was set up by "if" clause: if (value == null) { throw new DAVStatusException(HttpServletResponse.SC_NOT_FOUND, "Not found."); } Element p = new Element(property.getName(), property.getNamespace()); p.setText(filterForXML(value)); return p; } /* (non-Javadoc) * @see org.dspace.app.dav.DAVResource#proppatchInternal(int, org.jdom.Element) */ @Override protected int proppatchInternal(int action, Element prop) throws SQLException, AuthorizeException, IOException, DAVStatusException { Namespace ns = prop.getNamespace(); String propName = prop.getName(); boolean nsDspace = ns != null && ns.equals(DAV.NS_DSPACE); String newValue = (action == DAV.PROPPATCH_REMOVE) ? null : prop.getText(); // displayname - arbitrary string if (elementsEqualIsh(prop, displaynameProperty)) { this.bitstream.setName(newValue); } else if (nsDspace && propName.equals("description")) { this.bitstream.setDescription(newValue); } else if (nsDspace && propName.equals("source")) { this.bitstream.setSource(newValue); } else if (nsDspace && propName.equals("format_description")) { this.bitstream.setUserFormatDescription(newValue); } else if (nsDspace && propName.equals("format")) { if (action == DAV.PROPPATCH_REMOVE) { throw new DAVStatusException(DAV.SC_CONFLICT, "The format property cannot be removed."); } BitstreamFormat bsf = BitstreamFormat.findByShortDescription(this.context, newValue); if (bsf == null) { throw new DAVStatusException(DAV.SC_CONFLICT, "Cannot set format, no such Bitstream Format: " + newValue); } this.bitstream.setFormat(bsf); } else { throw new DAVStatusException(DAV.SC_CONFLICT, "The " + prop.getName() + " property cannot be changed."); } // this assumes we got through an IF clause and changed something: this.bitstream.update(); return HttpServletResponse.SC_OK; } /* (non-Javadoc) * @see org.dspace.app.dav.DAVResource#get() */ @Override protected void get() throws SQLException, AuthorizeException, IOException, DAVStatusException { if (this.bitstream == null) { throw new DAVStatusException(HttpServletResponse.SC_NOT_FOUND, "Bitstream not found, URI=\"" + hrefURL() + "\""); } else { if (this.item != null) { log.info(LogManager.getHeader(this.context, "DAV GET Bitstream", "item handle=" + this.item.getHandle() + ", bitstream_id=" + this.bitstream.getID())); } // Set the response MIME type this.response.setContentType(this.bitstream.getFormat().getMIMEType()); // Response length this.response.setHeader("Content-Length", String.valueOf(this.bitstream.getSize())); // Pipe the bits InputStream is = this.bitstream.retrieve(); Utils.bufferedCopy(is, this.response.getOutputStream()); is.close(); this.response.getOutputStream().flush(); } } /* (non-Javadoc) * @see org.dspace.app.dav.DAVResource#put() */ @Override protected void put() throws SQLException, AuthorizeException, IOException, DAVStatusException { throw new DAVStatusException(HttpServletResponse.SC_NOT_IMPLEMENTED, "PUT is not implemented for Bitstream (yet?)."); } /* (non-Javadoc) * @see org.dspace.app.dav.DAVResource#copyInternal(org.dspace.app.dav.DAVResource, int, boolean, boolean) */ @Override protected int copyInternal(DAVResource destination, int depth, boolean overwrite, boolean keepProperties) throws DAVStatusException, SQLException, AuthorizeException, IOException { throw new DAVStatusException(HttpServletResponse.SC_NOT_IMPLEMENTED, "COPY method not implemented."); } /** * Make a default name to go in properties' displayname Should be last path * element of canonical resource URI. * * @return name string */ private String makeDisplayname() { String ext[] = this.bitstream.getFormat().getExtensions(); String prefix = (this.item == null) ? "retrieve_" + String.valueOf(this.bitstream.getID()) : "bitstream_" + String.valueOf(this.bitstream.getSequenceID()); return prefix + (ext.length > 0 ? ext[0] : ""); } /** * Match the URIs this subclass understands and return the corresponding * resource. * * @param context the context * @param request the request * @param response the response * @param pathElt the path elt * * @return the DAV resource * * @throws DAVStatusException the DAV status exception * @throws SQLException the SQL exception */ protected static DAVResource matchResourceURI(Context context, HttpServletRequest request, HttpServletResponse response, String pathElt[]) throws DAVStatusException, SQLException { /** * Match URI /retrieve_<DbId> NOTE: This is an evil kludge to get raw * bitstreams by DB ID, required to implement link form of * <dspace:bitstream> element in properties. The "logo" of Community or * Collection is a loose bitstream not connected to any Item, so it can * only be identified by a direct database-ID reference. Ugh. */ if (pathElt[0].startsWith("retrieve_")) { Bitstream bs = findBitstream(context, null, pathElt[0]); return new DAVBitstream(context, request, response, pathElt, bs); } return null; } /** * Returns an XML representation of a bitstream -- either inline content or * a link reference. The XML looks like: * * <pre> * <dspace:bitstream> * <dspace:link href="url-to-bitstream"> * </dspace:bitstream> * ...or... * <dspace:bitstream> * <dspace:content contenttype="image/gif" contentlength="299" contentencoding="base64"> * ...text of base64.. * </dspace:content> * </dspace:bitstream> * NOTE: contentlength is the DECODED length of the content. * </pre> * * Used by the "logo" property on collections and communities. * * @param bitstream the bitstream * @param resource the resource * * @return the element * * @throws AuthorizeException the authorize exception * @throws SQLException the SQL exception * @throws IOException Signals that an I/O exception has occurred. */ protected static Element makeXmlBitstream(Bitstream bitstream, DAVResource resource) throws AuthorizeException, SQLException, IOException { Element b = new Element("bitstream", DAV.NS_DSPACE); long length = bitstream.getSize(); BitstreamFormat bf = bitstream.getFormat(); if (length > BITSTREAM_INLINE_THRESHOLD) { Element e = new Element("link", DAV.NS_DSPACE); e.setAttribute("href", resource.hrefPrefix() + "retrieve_" + String.valueOf(bitstream.getID())); b.addContent(e); } else { Element e = new Element("content", DAV.NS_DSPACE); if (bf != null) { e.setAttribute("contenttype", bf.getMIMEType()); } e.setAttribute("contentlength", String.valueOf(length)); e.setAttribute("contentencoding", "base64"); b.addContent(e); // write encoding of bitstream contents ByteArrayOutputStream baos = new ByteArrayOutputStream((int) length); Utils.copy(bitstream.retrieve(), baos); e.setText(new String(Base64.encodeBase64(baos.toByteArray()))); } return b; } /** * Extract bitstream from the XML representation, i.e. * * <pre> * <dspace:bitstream> * <dspace:content contenttype="image/gif" * contentlength="299" * contentencoding="base64"> * ...text of base64.. * </dspace:content> * </dspace:bitstream> * </pre> * * In the above format, contenttype and contentencoding attributes of * content are REQUIRED. * * @param context the context * @param xb the xb * * @return inputstream of the contents of the data, or null on error. */ protected static InputStream getXmlBitstreamContent(Context context, Element xb) { Element c = xb.getChild("content", DAV.NS_DSPACE); if (c != null) { String enc = c.getAttributeValue("contentencoding"); if (enc != null && enc.equals("base64")) { byte value[] = Base64.decodeBase64(c.getText().getBytes()); return new ByteArrayInputStream(value); } } return null; } /** * Get the content-type from an XML-encoded bitstream. * * @param context required for reading the DB. * @param xb XML bitstream representation in JDOM. * * @return First BitstreamFormat matching content-type string, or null if * none. * * @throws SQLException the SQL exception */ protected static BitstreamFormat getXmlBitstreamFormat(Context context, Element xb) throws SQLException { Element c = xb.getChild("content", DAV.NS_DSPACE); if (c != null) { String ctype = c.getAttributeValue("contenttype"); if (ctype != null) { BitstreamFormat af[] = BitstreamFormat.findAll(context); for (BitstreamFormat element : af) { if (ctype.equals(element.getMIMEType())) { return element; } } } } return null; } /* (non-Javadoc) * @see org.dspace.app.dav.DAVResource#deleteInternal() */ @Override protected int deleteInternal() throws DAVStatusException, SQLException, AuthorizeException, IOException { throw new DAVStatusException(HttpServletResponse.SC_NOT_IMPLEMENTED, "DELETE method not implemented for BitStream."); } /* (non-Javadoc) * @see org.dspace.app.dav.DAVResource#mkcolInternal(java.lang.String) */ @Override protected int mkcolInternal(String waste) throws DAVStatusException, SQLException, AuthorizeException, IOException { throw new DAVStatusException(HttpServletResponse.SC_METHOD_NOT_ALLOWED, "MKCOL method not allowed for BitStream."); } }