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 com.google.common.collect.ImmutableMap;
  13 import java.io.UnsupportedEncodingException;
  14 import javax.ws.rs.BadRequestException;
  15 import javax.ws.rs.GET;
  16 import javax.ws.rs.NotFoundException;
  17 import javax.ws.rs.Path;
  18 import javax.ws.rs.PathParam;
  19 import javax.ws.rs.Produces;
  20 import javax.ws.rs.core.Context;
  21 import javax.ws.rs.core.MediaType;
  22 import javax.ws.rs.core.UriInfo;
  23 import javax.ws.rs.sse.Sse;
  24 import javax.ws.rs.sse.SseEventSink;
  25 import javax.xml.xpath.XPathExpressionException;
  26 import org.opendaylight.restconf.nb.rfc8040.ReceiveEventsParams;
  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 final class SSEStreamService {
  37     private static final Logger LOG = LoggerFactory.getLogger(SSEStreamService.class);
  38
  39     private final RestconfStream.Registry streamRegistry;
  40     private final PingExecutor pingExecutor;
  41     private final int maximumFragmentLength;
  42     private final int heartbeatInterval;
  43
  44     SSEStreamService(final RestconfStream.Registry streamRegistry, final PingExecutor pingExecutor,
  45             final StreamsConfiguration configuration) {
  46         this.streamRegistry = requireNonNull(streamRegistry);
  47         this.pingExecutor = requireNonNull(pingExecutor);
  48         heartbeatInterval = configuration.heartbeatInterval();
  49         maximumFragmentLength = configuration.maximumFragmentLength();
  50     }
  51
  52     /**
  53      * Attach to a particular notification stream.
  54      *
  55      * @param streamName path to target
  56      */
  57     @GET
  58     @Path("/{encodingName:[a-zA-Z]+}/{streamName:.+}")
  59     @Produces(MediaType.SERVER_SENT_EVENTS)
  60     public void getSSE(@PathParam("encodingName") final EncodingName encodingName,
  61             @PathParam("streamName") final String streamName, @Context final UriInfo uriInfo,
  62             @Context final SseEventSink sink, @Context final Sse sse) {
  63         final var stream = streamRegistry.lookupStream(streamName);
  64         if (stream == null) {
  65             LOG.debug("Listener for stream with name {} was not found.", streamName);
  66             throw new NotFoundException("No such stream: " + streamName);
  67         }
  68
  69         final var queryParameters = ImmutableMap.<String, String>builder();
  70         for (var entry : uriInfo.getQueryParameters().entrySet()) {
  71             final var values = entry.getValue();
  72             switch (values.size()) {
  73                 case 0:
  74                     // No-op
  75                     break;
  76                 case 1:
  77                     queryParameters.put(entry.getKey(), values.get(0));
  78                     break;
  79                 default:
  80                     throw new BadRequestException(
  81                         "Parameter " + entry.getKey() + " can appear at most once in request URI");
  82             }
  83         }
  84
  85         final ReceiveEventsParams params;
  86         try {
  87             params = ReceiveEventsParams.ofQueryParameters(queryParameters.build());
  88         } catch (IllegalArgumentException e) {
  89             throw new BadRequestException(e.getMessage(), e);
  90         }
  91
  92         LOG.debug("Listener for stream with name {} has been found, SSE session handler will be created.", streamName);
  93         // FIXME: invert control here: we should call 'listener.addSession()', which in turn should call
  94         //        handler.init()/handler.close()
  95         final var handler = new SSESender(pingExecutor, sink, sse, stream, encodingName, params,
  96             maximumFragmentLength, heartbeatInterval);
  97
  98         try {
  99             handler.init();
 100         } catch (UnsupportedEncodingException e) {
 101             throw new NotFoundException("Unsupported encoding " + encodingName.name(), e);
 102         } catch (IllegalArgumentException | XPathExpressionException e) {
 103             throw new BadRequestException(e.getMessage(), e);
 104         }
 105     }
 106 }