Understanding how to design and
arrange BizTalk messaging settings is an absolutely critical part of
designing any BizTalk solution, let alone a service-oriented one.
Earlier in this
crash-course on BizTalk Server, we discussed the BizTalk messaging
architecture and its foundation in a publish and subscribe routing
model. One of the most important parts of a messaging configuration is
enabling the receipt of new messages. Without the ability to absorb
messages, there's not much else to talk about. In BizTalk Server,
messages are brought onboard through the combination of receive ports
and receive locations.
Receive ports can be configured from within the BizTalk Server
Administration Console. New receive ports support both "one-way" or
"two-way" message exchange patterns. On the lefthand side of a receive
port configuration, there are a series of vertically arranged tabs that
display different sets of properties. Choosing the Receive Locations
tab enables us to create the actual receive location which defines the
URI that BizTalk will monitor for inbound messages. In the Transport
section of a receive location's primary configuration pane, we can
choose from the list of available BizTalk adapters. Once an adapter is
chosen from the list, the Configure button next to the selected transport type becomes
active. For a receive location exploiting the FILE adapter,
"configuration" requires entering a valid file path into the Receive folder property.
The next step in configuring BizTalk messaging is to create a subscriber
for the data that is published by this receiving interface. BizTalk send ports are
an example of a subscriber in a messaging solution. Much like receive
locations, send ports allow you to choose a BizTalk adapter and
configure the transmission URI for the message. However, simply
configuring a URI does not complete a send port configuration, as we
must pinpoint what type of message this subscriber is interested in. On
the left side of a send port configuration window, there is a vertical
set of tabs. The Filters tab is where we can set up specific interest criteria for this
send port. For example, we could define a subscription that listens for
all messages of a particular type that reach the MessageBox.
A send port can be
in three distinct states. By default, a send port is unenlisted. This means that the port has not registered its
particular subscription with BizTalk, and would not pull any messages
from the MessageBox. A send port may also be enlisted, which is associated with ports that have
registered subscriptions but are not processing messages. In this case,
the messages targeted for this port stay in a queue until the port is
placed in the final state, Started. A
started port has its subscriptions active in the MessageBox and is
heartily processing all the messages it cares about.
The BizTalk Server messaging
engine is the heart and soul of a BizTalk solution. Here we saw how to
create new input interfaces, and define subscribers for the published
data.
