Metacat

    public InputStream read(String docid, String username, String[] groups)

        throws InsufficientKarmaException, ParseLSIDException,

        PropertyNotFoundException, McdbException, SQLException, 

        ClassNotFoundException, IOException

    {

        logMetacat.debug("MetacatHandler.read() called.");

        InputStream fileInputStream = null;

        File tmpDir = null;

        // be sure we have a local ID from an LSID

        if (docid.startsWith("urn:")) {

          try {

            docid = LSIDUtil.getDocId(docid, true);                 

          } catch ( ParseLSIDException ple ) {

            logMetacat.debug("There was a problem parsing the LSID. The " +

                             "error message was: " + ple.getMessage());

            throw ple;

          }

        }

        // accomodate old clients that send docids without revision numbers

        docid = appendRev(docid);

        DocumentImpl doc = new DocumentImpl(docid, false);

        //check the permission for read

        if (!DocumentImpl.hasReadPermission(username, groups, docid)) {

            throw new InsufficientKarmaException(

              "User " + username +

              " does not have permission" +

              " to read the document with the docid " + docid);

        }

        // deal with data or metadata cases

        if (doc.getRootNodeID() == 0) {

          // this is a data file

          // get the path to the file to read

          try {

            String filepath = PropertyService.getProperty("application.datafilepath");

            // ensure it is a directory path

            if ( !(filepath.endsWith("/")) ) {

                filepath += "/";

            }

            String filename = filepath + docid;

            fileInputStream = (InputStream) readFromFilesystem(filename);

          } catch ( PropertyNotFoundException pnf ) {

            logMetacat.debug("There was a problem finding the " +

                             "application.datafilepath property. The error " + 

                             "message was: " + pnf.getMessage());

            throw pnf;

          } // end try()

        } else {

          // this is an metadata document

          // get a temporary file handle to write to as an OutputStream

          try {

            tmpDir = new File(PropertyService.getProperty("application.tempDir"));

          } catch ( PropertyNotFoundException pnfe ) {

            logMetacat.debug("There was a problem getting the" + 

                             "application.tempDir property. Using /tmp " + 

                             "instead. The error was: " + pnfe.getMessage());

            tmpDir = new File("/tmp");

          } //end try()

          Date d = new Date();

          final File outputFile = new File(tmpDir, "metacat.output." + d.getTime());

          OutputStream out = new FileOutputStream(outputFile);

          // Try to get the metadata file from disk. If it isn't

          // found, create it from the db and write it to disk then.

          try {

              doc.toXml(out, username, groups, true);

          } catch (McdbException e) {

              // any exceptions in reading the xml from disc, and we go back to the

              // old way of creating the xml directly.

              logMetacat.error("MetaCatServlet.readFromMetacat() " +

                "- could not read from document file " + 

                docid + ": " + e.getMessage());

              e.printStackTrace(System.out);

              doc.toXmlFromDb(out, username, groups, true);

          }

          // set the input stream

          fileInputStream = new FileInputStream(outputFile);

          //set a timer to clean up the temp files

          Timer t = new Timer();

          TimerTask tt = new TimerTask() {

              @Override

              public void run()

              {

                  outputFile.delete();

              }

          };

          // destroy the file after 30 minutes (possibly large files)

          t.schedule(tt, 18000000);

        }

        return fileInputStream;

    }