77 lines
2.2 KiB
C
77 lines
2.2 KiB
C
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// Copyright 2017-2018 The NATS Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include <nats.h>
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static void
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onMsg(natsConnection *nc, natsSubscription *sub, natsMsg *msg, void *closure)
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{
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printf("Received msg: %s - %.*s\n",
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natsMsg_GetSubject(msg),
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natsMsg_GetDataLength(msg),
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natsMsg_GetData(msg));
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// Sends a reply
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if (natsMsg_GetReply(msg) != NULL)
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{
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natsConnection_PublishString(nc, natsMsg_GetReply(msg),
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"here's some help");
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}
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// Need to destroy the message!
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natsMsg_Destroy(msg);
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// Notify the main thread that we are done.
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*(bool *)(closure) = true;
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}
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int main(int argc, char **argv)
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{
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natsConnection *conn = NULL;
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natsSubscription *sub = NULL;
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natsStatus s;
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volatile bool done = false;
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printf("Listening for requests on subject 'help'\n");
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// Creates a connection to the default NATS URL
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s = natsConnection_ConnectTo(&conn, NATS_DEFAULT_URL);
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if (s == NATS_OK)
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{
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// Creates an asynchronous subscription on subject "help",
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// waiting for a request. If a message arrives on this
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// subject, the callback onMsg() will be invoked and it
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// will send a reply.
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s = natsConnection_Subscribe(&sub, conn, "help", onMsg, (void*) &done);
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}
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if (s == NATS_OK)
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{
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for (;!done;) {
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nats_Sleep(100);
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}
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}
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// Anything that is created need to be destroyed
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natsSubscription_Destroy(sub);
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natsConnection_Destroy(conn);
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// If there was an error, print a stack trace and exit
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if (s != NATS_OK)
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{
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nats_PrintLastErrorStack(stderr);
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exit(2);
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}
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return 0;
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}
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