// Get retrieves a message from the server via a JSON api.
func (client *Client) Get() (*api.GetMessageResponse, error) {
request := api.GetMessageRequest{Mailbox: client.Mailbox}
request.Sign(client.AccessKeyName, client.AccessKey)
var response api.GetMessageResponse
err := client.request("get", request, &response)
if err != nil {
return nil, err
}
if !response.IsEmpty() {
if !response.Validate(client.AccessKey) {
return nil, errors.New("Could not validate the server's signature")
}
}
return &response, nil
}
// getMessage is used by clients to poll for mailbox messages. This method will
// search the database for messages for the given mailbox. If the mailbox is
// empty and long_polling is enabled it will create a channel and add it to
// pollingChannels. It will then wait for a message to be pushed to that
// channel. It will then continue to output that message. Messages are pushed by
// the putMessage method.
func getMessage(w http.ResponseWriter, r *http.Request) {
if !EnableLongPolling {
time.Sleep(ThrottleDelay)
}
var request api.GetMessageRequest
err := readRequest(r, &request)
if err != nil {
sendError(w, err.Error())
return
}
mb, err := mailbox.Find(request.Mailbox)
if err != nil {
sendError(w, err.Error())
return
}
if mb == nil {
log.Warnf("Could not find a mailbox named '%s'", request.Mailbox)
sendError(w, fmt.Sprintf("Mailbox %s not found.", request.Mailbox))
return
}
log.Debugf("Message request from %s", mb.Id)
accessKey, err := mailbox.FindKeyByName(request.AccessKeyName)
if accessKey == nil {
log.Warnf("Could not find an access key named '%s'", request.AccessKeyName)
sendError(w, "Access key is invalid")
return
}
if !request.Validate(accessKey.Secret) {
log.Warnf(fmt.Sprintf("Signature for %s invalid", mb.Id))
sendError(w, "Signature is invalid")
return
}
if !accessKey.CanGet(mb) {
sendError(w, "Not allowed to get messages from this mailbox.")
return
}
if err := mb.Checkin(r.RemoteAddr, request.Version); err != nil {
sendError(w, err.Error())
return
}
msg, err := mb.GetMessage()
if err != nil {
sendError(w, err.Error())
log.Errorf("Error retrieving messages: %s", err.Error())
return
}
if EnableLongPolling == true && msg == nil {
if _, ok := pollingChannels[mb.Id]; ok {
delete(pollingChannels, mb.Id)
}
// Create a channel for the client. This channel has a message pushed to it
// from the putMessage function. When a message gets delivered.
pollingChannels[mb.Id] = make(chan *mailbox.Message)
timeout := make(chan bool, 1)
// This goroutine will create a timeout to close the long polling connection
// and force the client to reconnect.
go func() {
// Randomize the polling timeout in order to stagger client reconnects.
sleepTime := rand.Intn(500) + 200
time.Sleep(time.Duration(sleepTime) * time.Second)
timeout <- true
}()
// Wait for either a timeout or a message to be sent to a channel.
select {
case m := <-pollingChannels[mb.Id]:
msg = m
case <-timeout:
response := api.GetMessageResponse{}
response.Sign(accessKey.Name, accessKey.Secret)
writeResponse(&w, response)
delete(pollingChannels, mb.Id)
return
}
delete(pollingChannels, mb.Id)
}
if msg == nil {
writeResponse(&w, nil)
return
}
dep, err := msg.GetDeployment()
if err != nil {
sendError(w, err.Error())
return
}
response := api.GetMessageResponse{
Message: msg.Id,
Body: msg.Body,
CreatedAt: msg.CreatedAt,
ReceiveCount: msg.ReceiveCount,
Deployment: msg.Deployment,
Asset: dep.Asset,
}
response.Sign(accessKey.Name, accessKey.Secret)
log.Infof("Delivering message %s to %s", response.Message, mb.Id)
writeResponse(&w, response)
}