Data retrieval in subscription mode – 2N Helios IP HTTP API v2.6 User Manual
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In the
mode, 2N
Helios IP sends events to the subscriber in the form of
Subscription
®
Notify messages.
In the
mode, the client sends the GetMessages request to retrieve the log
PullPoint
data.
Data Retrieval in Subscription Mode
To retrieve events from 2N® Helios IP in the Subscription mode, subscribe via the
command, specifying the type of events to be retrieved, the HTTP sending
Subscribe
address and the subscription time.
If the subscription is successful, 2N® Helios IP sends the
includin
SubscribeResponse
g the Subscription Id for subsequent communication with 2N® Helios IP.
Now 2N® Helios IP starts sending
messages to the specified HTTP address.
Notify
Events are sent at the moment of rise without delay. In your Subscribe request, you
can specify the maximum count of events to be sent within one Notify message.
The subscription time is limited (as specified in the Subscribe request). When the
subscription time expires, you will be unsubscribed automatically. To extend the
subscription time, send the
request before expiry. 2N® Helios IP will reply with
Renew
the
message.
RenewResponse
Send the
request to unsubscribe explicitly. 2N® Helios IP will reply with
Unsubscribe
the
message.
UnsubscribeResponse
If there is a firewall or NAT between you and 2N® Helios IP, the Subscription mode
may not be convenient. The Notify messages are delivered only if the network
elements are properly configured.
The figure below shows the status diagram and typical client - 2N® Helios IP message
sequence.