content: /*
   *  Licensed under the Apache License, Version 2.0 (the "License");
   *  you may not use this file except in compliance with the License.
   *  You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   *  Unless required by applicable law or agreed to in writing, software
   *  distributed under the License is distributed on an "AS IS" BASIS,
   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the License for the specific language governing permissions and
   *  limitations under the License.
   *
   *  See the NOTICE file distributed with this work for additional
   *  information regarding copyright ownership.
   */
  
  package org.seaborne.delta.server.http;
  
  import java.io.FileNotFoundException ;
  import java.io.IOException;
  import java.io.InputStream ;
  import java.nio.file.Files ;
  import java.nio.file.NoSuchFileException ;
  import java.nio.file.Path ;
  import java.nio.file.Paths ;
  
  import jakarta.servlet.http.HttpServletRequest;
  import jakarta.servlet.http.HttpServletResponse;
  
  import org.apache.commons.io.IOUtils ;
  import org.apache.jena.atlas.lib.IRILib ;
  import org.apache.jena.atlas.web.ContentType ;
  import org.apache.jena.riot.RDFLanguages ;
  import org.apache.jena.web.HttpSC ;
  import org.seaborne.delta.Delta;
  import org.seaborne.delta.DeltaNotFoundException ;
  import org.seaborne.delta.Id ;
  import org.seaborne.delta.link.DeltaLink;
  import org.seaborne.delta.server.local.DataSource;
  import org.slf4j.Logger ;
  
  /** Data over HTTP. */
  public class S_FetchData extends HttpOperationBase {
      static private Logger LOG = Delta.getDeltaLogger("Data") ;
  
      public S_FetchData(DeltaLink engine) {
          super(engine);
      }
  
      // Fetch a file
      @Override
      protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {
          doCommon(req, resp);
      }
  
      @Override
      protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws IOException {
          doCommon(req, resp);
      }
  
      @Override
      protected void validateAction(Args httpArgs) {
      }
  
      @Override
      protected void executeAction(DeltaAction action) throws IOException {
          LOG.info("GET "+action.getURL());
          Id dsRef = Id.fromString(action.httpArgs.datasourceName);
          String filenameIRI = determineData(action, dsRef);
          ContentType ct = RDFLanguages.guessContentType(filenameIRI) ;
          String fn = IRILib.IRIToFilename(filenameIRI);
          Path path = Paths.get(fn);
          try ( InputStream in = Files.newInputStream(path) ) {
              action.response.setStatus(HttpSC.OK_200);
              action.response.setContentType(ct.getContentTypeStr());
              IOUtils.copy(in, action.response.getOutputStream());
          } catch (NoSuchFileException | FileNotFoundException ex) {
              throw new DeltaNotFoundException(action.getURL());
          }
      }
  
      /** Decide which data to return.
       *  Default is the initial data for a {@link DataSource}.
       */
      protected String determineData(DeltaAction action, Id dsRef) {
          return action.dLink.initialState(dsRef);
      }
  
      @Override
      protected String getOpName() {
          return "data";
      }
  }