Mule requester is a Mule module that allows resources like files, messages, and emails to be requested at any point in a Mule flow. This provides more flexibility than only being able to request resources through message sources. The mule requester can consume messages from a queue on demand, such as after an HTTP request, rather than immediately. It provides reusable functionality for common use cases like loading a file in the middle of a flow or consuming messages from a queue at a specific point. The module is reusable, simple to use, can be installed in MuleStudio, and used with Maven. It supports expressions and automatic transformation of the requested resource to the specified return type.

1. Mule requester
Presented By
Sindhu VL

2. What is mule requester?
• As its name may hint, its goal is to allow the
request of a resource at any point in a flow.
• This resource can be a file, a message (from
VM, JMS, AMQP, etc.), an e-mail, etc.
• It’s intended for resources that originally could
only be requested by message sources.

3. • If we want to consume messages from a queue on demand,
i.e. not consuming the message as soon as it’s put on the
queue but at a later stage, when a user calls an HTTP
inbound endpoint, for example.
• We cannot achieve this by using a JMS inbound endpoint,
since it will consume the message as soon as it’s put on the
queue.
• Thinking about a way of doing this, we could have a
stopped flow and activate it on demand but this would
cause the consumption of more than one message or a
clumsy implementation that would pick a message and stop
the flow again.
• Another option would be to use a component but this
would have to deal with the specifics of the transport,
leading to either one implementation per transport type or
a big component handling all the transports.

4. Example flow :

5. Some of its more common use cases
are :
• Load a file in the middle of a flow for
processing.
• Consume messages (one, N, all) from a queue
in the middle of a flow.
• Pull messages from a mail server on demand,
to use its data in an enricher for example.

6. Why releasing it as a Mule module?
• It’s reusable
• It’s simple
• It can be easily installed in MuleStudio
• It can be used with Maven

7. •Following the first example, let’s show a more complex one: consuming all the
messages from a queue on demand. Let’s assume that the use case is to get all those
messages after a user called an inbound HTTP endpoint (it could be any other kind of
Mule endpoint, e.g. Quartz).
First we have the flow with the starting entry point:

8. Flow reference :

9. This flow does all the magic:
• First it requests a message from the queue ‘input’.
• If there is a message, it processes it (just logs the
payload in the example) and calls the same flow again,
to allow the processing of the next messages in queue.
• Otherwise, if there is no pending message in the
queue, it just logs the queue has been emptied and
finishes.
• This configuration also contains another example that
shows how to consume a file based on an expression
after calling an HTTP inbound endpoint.

10. Key feature of the module :
• Expressions support
• Possibility of throwing an exception if the
requested resource is null
• Automatic transformer: the return type of the
requester resource can be set to any type and
Mule will automatically try to transform it

11. ThankYou!!!!!!!!!!!!!