subscribe
The subscribe
command is the primary way to retrieve messages from the AMPS processing stream. A client can issue a subscribe
command on a topic to receive all published messages to that topic in the future. Additionally, content filtering can be used to choose which messages the client is interested in receiving.
Header Fields
Options Field
The following table contains a list of the Options
available and their definitions when used in the AMPS subscribe
command.
Returns
A subscribe
command returns the following command types:
It is possible to specify a processed
acknowledgment be sent back to the client that issued the subscribe
command. Within this processed
acknowledgment, a client can get back the result of placing the subscription (success or failure) and the SubscriptionId
, which uniquely identifies the subscription within AMPS. Keeping track of the SubscriptionId
is useful for unsubscribing from subscriptions and issuing SOW queries.
The following table contains a list of the supported acknowledgment messages available to the subscribe
command.
Errors
Any errors that occur during this command will be returned in the status of a processed
acknowledgment and logged to the log file. Regardless of success or failure, the processed acknowledgment will only be returned if requested by including processed
in the AckType
field.
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