This document discusses the mule requester component in MuleSoft. The mule requester allows resources like files, messages, and emails to be requested on demand within a Mule flow. This is useful for consuming messages from queues when needed rather than as soon as they are available. The document provides an example flow that uses a mule requester to consume all messages from a queue after an HTTP request is received. It notes that the mule requester is reusable, simple, and can be installed via Maven. Key features include support for expressions and automatic transformation of response types.

1. 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!!!!!!!!!!!!!