restconf/restconf-nb/src/main/java/org/opendaylight/restconf/nb/rfc8040/streams/SSEStreamService.java

   1 /*
   2  * Copyright (c) 2020 Lumina Networks, Inc. All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8 package org.opendaylight.restconf.nb.rfc8040.streams;
   9
  10 import static java.util.Objects.requireNonNull;
  11
  12 import java.io.UnsupportedEncodingException;
  13 import javax.ws.rs.BadRequestException;
  14 import javax.ws.rs.GET;
  15 import javax.ws.rs.NotFoundException;
  16 import javax.ws.rs.Path;
  17 import javax.ws.rs.PathParam;
  18 import javax.ws.rs.Produces;
  19 import javax.ws.rs.core.Context;
  20 import javax.ws.rs.core.MediaType;
  21 import javax.ws.rs.core.UriInfo;
  22 import javax.ws.rs.sse.Sse;
  23 import javax.ws.rs.sse.SseEventSink;
  24 import javax.xml.xpath.XPathExpressionException;
  25 import org.opendaylight.restconf.api.QueryParameters;
  26 import org.opendaylight.restconf.server.api.EventStreamGetParams;
  27 import org.opendaylight.restconf.server.spi.RestconfStream;
  28 import org.opendaylight.restconf.server.spi.RestconfStream.EncodingName;
  29 import org.slf4j.Logger;
  30 import org.slf4j.LoggerFactory;
  31
  32 /**
  33  * Access to notification streams via Server-Sent Events.
  34  */
  35 @Path("/")
  36 // FIXME: integrate this service into JaxRsRestconf once we remove support for WebSockets
  37 public final class SSEStreamService {
  38     private static final Logger LOG = LoggerFactory.getLogger(SSEStreamService.class);
  39
  40     private final RestconfStream.Registry streamRegistry;
  41     private final PingExecutor pingExecutor;
  42     private final int maximumFragmentLength;
  43     private final int heartbeatInterval;
  44
  45     SSEStreamService(final RestconfStream.Registry streamRegistry, final PingExecutor pingExecutor,
  46             final StreamsConfiguration configuration) {
  47         this.streamRegistry = requireNonNull(streamRegistry);
  48         this.pingExecutor = requireNonNull(pingExecutor);
  49         heartbeatInterval = configuration.heartbeatInterval();
  50         maximumFragmentLength = configuration.maximumFragmentLength();
  51     }
  52
  53     /**
  54      * Attach to a particular notification stream.
  55      *
  56      * @param streamName path to target
  57      */
  58     @GET
  59     @Path("/{encodingName:[a-zA-Z]+}/{streamName:.+}")
  60     @Produces(MediaType.SERVER_SENT_EVENTS)
  61     public void getSSE(@PathParam("encodingName") final EncodingName encodingName,
  62             @PathParam("streamName") final String streamName, @Context final UriInfo uriInfo,
  63             @Context final SseEventSink sink, @Context final Sse sse) {
  64         final var stream = streamRegistry.lookupStream(streamName);
  65         if (stream == null) {
  66             LOG.debug("Listener for stream with name {} was not found.", streamName);
  67             throw new NotFoundException("No such stream: " + streamName);
  68         }
  69
  70         final EventStreamGetParams getParams;
  71         try {
  72             getParams = EventStreamGetParams.of(QueryParameters.ofMultiValue(uriInfo.getQueryParameters()));
  73         } catch (IllegalArgumentException e) {
  74             throw new BadRequestException(e.getMessage(), e);
  75         }
  76
  77         LOG.debug("Listener for stream with name {} has been found, SSE session handler will be created.", streamName);
  78         // FIXME: invert control here: we should call 'listener.addSession()', which in turn should call
  79         //        handler.init()/handler.close()
  80         final var handler = new SSESender(pingExecutor, sink, sse, stream, encodingName, getParams,
  81             maximumFragmentLength, heartbeatInterval);
  82
  83         try {
  84             handler.init();
  85         } catch (UnsupportedEncodingException e) {
  86             throw new NotFoundException("Unsupported encoding " + encodingName.name(), e);
  87         } catch (IllegalArgumentException | XPathExpressionException e) {
  88             throw new BadRequestException(e.getMessage(), e);
  89         }
  90     }
  91 }