jinterop/gorecv/gorecv.go

   1 //
   2 // Copyright © 2011-2016 Guy M. Allard
   3 //
   4 // Licensed under the Apache License, Version 2.0 (the "License");
   5 // you may not use this file except in compliance with the License.
   6 // You may obtain a copy of the License at
   7 //
   8 //     http://www.apache.org/licenses/LICENSE-2.0
   9 //
  10 // Unless required by applicable law or agreed to in writing, software
  11 // distributed under the License is distributed on an "AS IS" BASIS,
  12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13 // See the License for the specific language governing permissions and
  14 // limitations under the License.
  15 //
  16
  17 /*
  18 A message receiver, to demonstrate JMS interoperability.
  19 */
  20 package main
  21
  22 import (
  23         "log"
  24         "net"
  25         "os"
  26         //
  27         "github.com/gmallard/stompngo"
  28 )
  29
  30 var (
  31         exampid = "gorecv: "
  32         ll      = log.New(os.Stdout, "GOJRCV ", log.Ldate|log.Lmicroseconds|log.Lshortfile)
  33         nmsgs   = 1
  34 )
  35
  36 // Connect to a STOMP 1.2 broker, receive some messages and disconnect.
  37 func main() {
  38         ll.Println(exampid + "starts ...")
  39
  40         // Set up the connection.
  41         n, e := net.Dial("tcp", "localhost:61613")
  42         if e != nil {
  43                 ll.Fatalln(e) // Handle this ......
  44         }
  45         ll.Println(exampid + "dial complete ...")
  46         ch := stompngo.Headers{"login", "userr", "passcode", "passw0rd",
  47                 "host", "localhost", "accept-version", "1.2"}
  48         conn, e := stompngo.Connect(n, ch)
  49         if e != nil {
  50                 ll.Fatalln(e) // Handle this ......
  51         }
  52         ll.Println(exampid + "stomp connect complete ...")
  53
  54         // Setup Headers ...
  55         id := stompngo.Uuid() // Use package convenience function for unique ID
  56         sbh := stompngo.Headers{"destination", "/queue/allards.queue",
  57                 "id", id} // subscribe/unsubscribe headers
  58
  59         // Subscribe
  60         sc, e := conn.Subscribe(sbh)
  61         if e != nil {
  62                 ll.Fatalln(e) // Handle this ...
  63         }
  64         ll.Println(exampid + "stomp subscribe complete ...")
  65
  66         var md stompngo.MessageData
  67         // Read data from the returned channel
  68         for i := 1; i <= nmsgs; i++ {
  69                 select {
  70                 case md = <-sc:
  71                 case md = <-conn.MessageData:
  72                         // A RECEIPT or ERROR frame is unexpected here
  73                         ll.Fatalln(exampid, md) // Handle this
  74                 }
  75                 ll.Println(exampid + "channel read complete ...")
  76                 // MessageData has two components:
  77                 // a) a Message struct
  78                 // b) an Error value.  Check the error value as usual
  79                 if md.Error != nil {
  80                         ll.Fatalln(md.Error) // Handle this
  81                 }
  82                 //
  83                 ll.Printf("Frame Type: %s\n", md.Message.Command) // Should be MESSAGE
  84                 wh := md.Message.Headers
  85                 for j := 0; j < len(wh)-1; j += 2 {
  86                         ll.Printf("Header: %s:%s\n", wh[j], wh[j+1])
  87                 }
  88                 ll.Printf("Payload: %s\n", string(md.Message.Body)) // Data payload
  89         }
  90         // It is polite to unsubscribe, although unnecessary if a disconnect follows.
  91         // With Stomp 1.1+, the same unique ID is required on UNSUBSCRIBE.  Failure
  92         // to provide it will result in an error return.
  93         e = conn.Unsubscribe(sbh) // Same headers as Subscribe
  94         if e != nil {
  95                 ll.Fatalln(e) // Handle this ...
  96         }
  97         ll.Println(exampid + "stomp unsubscribe complete ...")
  98
  99         // Disconnect from the Stomp server
 100         dh := stompngo.Headers{}
 101         e = conn.Disconnect(dh)
 102         if e != nil {
 103                 ll.Fatalln(e) // Handle this ......
 104         }
 105         ll.Println(exampid + "stomp disconnect complete ...")
 106         // Close the network connection
 107         e = n.Close()
 108         if e != nil {
 109                 ll.Fatalln(e) // Handle this ......
 110         }
 111         ll.Println(exampid + "network close complete ...")
 112
 113         ll.Println(exampid + "ends ...")
 114 }