Mule Connectors - Part_1

1. Mule ESB - Connectors

2. File Connector
 The File connector allows Mule application to exchange files with a File system.
 It can be implemented as an inbound or an outbound endpoint.

3. File as an Inbound Endpoint
 If the File component is placed at the beginning of the flow, then it acts as an
inbound endpoint, which triggers the flow whenever it receives an incoming
file.
 File endpoint can be configured by providing the values on the fields of the
General tab of Properties editor.

5. Some of the important fields used for inbound endpoint configuration are :-
 Display Name – It is the general endpoint name.
 Path – This is the location of the file which is transferred into the flow.
 Move to Pattern – This is the pattern to be used when moving the file according to the
Move to Directory property
 Move to Directory – This is used to save a copy of the file on the Host machine when the
file is being dispatched to the next element.
 Polling Frequency – It checks how often the endpoint should check for the incoming
messages.
 File Age – Sets a minimum period a file must wait before it is processed.

6. File as an Outbound Endpoint
 If the File building block is placed at the middle or the end of the flow, then it acts
as the outbound endpoint, passing files to the connected file system.
 File outbound endpoint can also be configured just like inbound endpoint.

8. Some of the important fields used for outbound endpoint configuration are :-
 Path – For an outbound endpoint, this would be the directory on the connected file
system to which the file currently in the flow is written.
 File Name/Pattern – This property specifies a file name or pattern for naming files that
are sent from the File endpoint to the connected file system. If not set, it follows the
same pattern as the incoming files.

9. Advanced Tab fields
Apart from the configuration for Inbound and outbound properties in General Tab, there are
fields that could b configured in Advanced Tab as well. Some of the main fields are :-
 Address – To enter the address of the endpoint.
 Connector Endpoint – To add a new connection configuration or to edit an existing one.
 Comparator – To sort the incoming files
 Reverse Order – To reverse the normal comparison order

11. Connector Syntax
 A typical syntax for an inbound endpoint configured for reading files can be given
as :-
 <file:connector name = “input” fileAge = “500” autoDelete = “true”
pollingFrequency = “100” moveToDirectory = “/backup” />

12. Transformers for File
File Component includes several transformers for transforming the content of the file :-
 File to Byte Array Transformer – This element configures a transformer that reads
the content of a java.io.File into a byte array
 File to String Transformer - This element configures a transformer that reads the
content of a java.io.File into a String

13. Database Connector
 The Database connector allows to connect with almost any JDBC relational
database.
 Using Database connector, we can run diverse SQL operations on our database like
Select, Insert, Update, Delete, and even stored procedures.
 Database connector helps us perform pre defined as well as parametrized queries
and even DDL requests.

15. Configuration for Database Connector
To use Database connector, the basic configuration required is :-
 A database driver is required to connect with the database
 Configure a global database element where we can define the database’s location
and connection details, and advanced connection parameters like connection
pooling.
 Configure the database element in the mule flow which contains the query and the
reference to the Database Global element.

17. The Database connector provides out of the box support for 3 databases :
 MySQL
 Oracle
 Derby
For those databases, where Out of the box support is not provided, a Generic DB
Configuration is provided, and the driver can be added to the project.

18. Configuration Fields
Some of the important fields which should be configured are :-
 Database URL – To define the details of the Database to be connected with.
 Required Dependencies – To add the driver required.
 Enable Datasense(Optional) – It enables Mule to make use of message metadata at
run time.
 Connection Timeout – To define the amount of time the connection should remain
active.
 Config Reference – To identify any Global element if present
 Operation – To instruct the application for the type of operation to be performed
on the database.

19.  Type – To define the type of SQL statement we wish to use to submit queries to a
database :
 Parametrized – Mule replaces all MEL expressions inside the query with “?” to create
a prepared statement, then evaluates the MEL expressions.
E.g:- insert into employees where name = #[message.payload.name]
 Dynamic – Mule replaces all MEL expressions in the query with the result of the
expression evaluation, then sends the results to the database.
E.g:- select * from #[tablename]
 From Template- It enables to define a query once globally and then reuse the query
multiple times in the same application.

21.  Bulk Updates – The Database connector can run multiple SQL statements in bulk mode.
The individual SQL statements must be separated by semicolons and line breaks.
 Instead of writing a statement directly, we can also refer a file which contains multiple
statements with semicolons and line breaks.
 We can not perform Select operation as a part of bulk update, only Insert, Update and
Delete.

22. Using Mule with Web Services
Mule ESB allows different integration scenarios using web services :-
 Consuming existing web services.
 Building web services and exposing them to other applications.
 Creating a proxy/gateway to existing web services.

23. Web Service consumer
 While developing our applications, whenever we need to consume some external
SOAP services to acquire data, we can use a Web Service consumer.
 Using the information contained in service’s WSDL, this connector enables us to
configure a few details in order to establish the connection.
 The Web service consumer interfaces only with the SOAP services and not with the
REST.

24. To use the Web service consumer, we need to carry out the following 3 tasks :-
 Add the WSDL file of the service we need to consume.
 Embed a web service consumer in our Mule Flow.
 Configure the Global web service consumer element in which we reference the
service’s WSDL, enable Datasense and apply any security settings that the service
provider demands.

26. The studio auto populates the values of the fields in the Properties editor of the Web
service consumer :-
 Connector Configuration – With the name of the Global Web service consumer that we
just created.
 Operation – With the name of an operation that the Web service supports for its
consumers.

27. Building Web Services with CXF
Mule provides 3 ways to create web services :-
 Use the JAX WS front end to build a code first web service.
 Use the JAX WS front end to build a WSDL first web service.
 Creating a web service from simple POJOs.

28. To begin with writing a code first web service, the steps to be followed are :-
 We begin with writing the service interface. For example
package org.example;
import javax.jws.WebService;
@WebService
public interface HelloWorld {
String sayHi(String text);
}

29. The implementation for the above class may look like:-
package org.example;
import javax.jws.WebService;
@WebService(endpointInterface = “org.example.HelloWorld”,
serviceName = “HelloWorld”)
public class HelloWorldImpl implements HelloWorld {
public String sayHi(String text){
return “Hello ” + text;
}
}

30. Use case:

31. Once the application is deployed, we can generate the WSDL by appending ?wsdl at
the end of the end point URL.
 For e.g. http://localhost:8081/hello?wsdl
 This displays the WSDL generated by CXF

32. REST Component
 REST relies on HTTP for transport and uses HTTP methods to perform operations
on remote services.
 Mule ESB can be configured as a RESTful service endpoint. It provides a built-in
REST component based on the Jersey project.
 Mule ESB can be used as a publisher as well as consumer of RESTful Web Services.

33. Consuming a REST API
 We can consume a REST API from within a Mule application, by configuring an
HTTP Request Connector.
 A basic Mule application setup to consume a REST API contains :-
• One or more message processors configured to build the request.
• An HTTP request connector configured to call the REST API.
• One or more processors configured to accept and process the response.

35.  If a RAML file exists that describes the API we want to consume, then we can simply
reference it in the HTTP connector and it will expose the structure of the API at design
time.
 If we don’t have a RAML file, then we need to be aware of the structure of the API,
including any authentication requirements, the name of the resources we want to
access, and the methods supported for each resource.
 Some of the important information required are :-
• Authentication
• Base URL
• The type of input API expects (JSON, XML . . . . . etc)
• The type of output API produces.
• Error codes if any

36. Configuration
The first thing to be configured is the Global Connector element by providing the
basic information like
• Connector name
• Host
• Port
• Base Path
• API Configuration (if RAML is available)

38. Thank Q