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Reusing Mediation Sequences¶

What you'll build¶

In this sample scenario, you will use a Sequence Template and reuse it in multiple places of the medation flow. You can reuse the mediation flow that was defined in the Exposing Several Services as a Single Service tutorial and then replace its sections with the sequence template . See Creating Templates for details on how to work with templates using WSO2 Integration Studio.

Let's get started!¶

Step 1: Set up the workspace¶

Set up WSO2 Integration Studio as follows:

Download the relevant WSO2 Integration Studio based on your operating system. The path to the extracted/installed folder is referred to as MI_TOOLING_HOME throughout this tutorial.
If you did not try the Exposing Several Services as a Single Service tutorial yet:
1. Download the pre-packaged project.
2. Open WSO2 Integration Studio and go to File -> Import.
3. Select Existing WSO2 Projects into workspace under the WSO2 category, click Next, and then upload the pre-packaged project.

Optionally, you can set up the CLI tool for artifact monitoring. This will later help you get details of the artifacts that you deploy in your Micro Integrator.

Go to the WSO2 Micro Integrator website.
Click Download -> Other Resources and click CLI Tooling to download the tool.
Extract the downloaded ZIP file. This will be your MI_CLI_HOME directory.
Export the MI_CLI_HOME/bin directory path as an environment variable. This allows you to run the tool from any location on your computer using the mi command. Read more about the CLI tool.

Step 2: Develop the integration artifacts¶

Create a Sequence Template¶

Once you have imported the ESB project as described above, the project directory will appear with the artifacts as shown below.
Right-click on SampleServices and navigate to New -> Template . The New Template Artifact dialog will open.
Select the Create a New Template and click Next.

Enter the following details and click Finish.

Parameter	Description
Template Name	HospitalRoutingSeq
Template Type	Sequence Template

The template artifact will open in the canvas as shown below.
Open the Properties tab of the sequence template by clicking on the canvas (outside the sequence box).
Click the icon to start adding parameters .
In the Template Parameter dialog that opens, enter 'sethospital' as the parameter name and click Finish .
Add a Log mediator to the sequence template as shown below. This will print a message indicating to which hospital a requested message is routed.
Open the Properties tab of the log mediator and specify the following:

Property Description

Log Category INFO

Log Level CUSTOM

Click the icon to start defining a property. Then add the following details for the property:

Property Name	Description
Name	message
Type	EXPRESSION
Property Expression	`fn:concat('Routing to ', get-property('Hospital'))`

We select EXPRESSION because the required properties for the log message must be extracted from the request, which we can do using an XPath expression.

Add a Property mediator just after the Log mediator to store the value for uri.var.hospital.

With the Property mediator selected, access the Properties tab and enter the information given below:

Property	Description
Property Name	Select New Property
New Property Name	uri.var.hospital
Property Data Type	Select STRING
Property Action	Select set
Value Type	Select EXPRESSION
Value Expression	`$func:sethospital`
Description	Set Hospital Variable

Update the mediation flow¶

Open the design view of the HealthcareAPI.xml and delete 'GrandOak' Log mediator by right clicking the mediator and selecting Delete from Model.
Delete the 'Set Hospital Variable' Property mediator.
Add a Call Template mediator to the sequence as shown below.
Open the Properties tab of the Call Template mediator and select ' HospitalRoutingSeq' from the list of available templates.

Click the icon to start adding parameters. Enter the following parameter details and click Finish .

Parameter	Description
Parameter Name	sethospital
Parameter Type	value
Value/Expression	grandoaks

Repeat the above steps to add Call Templates for 'Clemency' and 'Pine Valley' hospitals. Add clemency and pinevalley as the respective parameter values.

Save the configuration.

After completion, your API will be similar to this.

<?xml version="1.0" encoding="UTF-8"?>
<api context="/healthcare" name="HealthcareAPI" xmlns="http://ws.apache.org/ns/synapse">
    <resource methods="GET" uri-template="/querydoctor/{category}">
        <inSequence>
            <log description="Request Log" level="custom">
                <property name="Log Property message" value="&quot;Welcome to HealthcareService&quot;"/>
            </log>
            <send>
                <endpoint key="QueryDoctorEP"/>
            </send>
        </inSequence>
        <outSequence>
            <send/>
        </outSequence>
        <faultSequence/>
    </resource>
    <resource methods="POST" uri-template="/categories/{category}/reserve">
        <inSequence>
            <property description="Get Hospital" expression="json-eval($.hospital)" name="Hospital" scope="default" type="STRING"/>
            <property description="Get Card Number" expression="json-eval($.cardNo)" name="card_number" scope="default" type="STRING"/>
            <datamapper config="gov:datamapper/RequestMapping.dmc" inputSchema="gov:datamapper/RequestMapping_inputSchema.json" inputType="JSON" outputSchema="gov:datamapper/RequestMapping_outputSchema.json" outputType="JSON" xsltStyleSheet="gov:datamapper/RequestMapping_xsltStyleSheet.xml"/>
            <switch source="get-property('Hospital')">
                <case regex="grand oak community hospital">
                    <call-template target="HospitalRoutingSeq">
                        <with-param name="sethospital" value="grandoaks"/>
                    </call-template>
                    <call>
                        <endpoint key="GrandOakEP"/>
                    </call>
                </case>
                <case regex="clemency medical center">
                    <call-template target="HospitalRoutingSeq">
                        <with-param name="sethospital" value="Clemency"/>
                    </call-template>
                    <call>
                        <endpoint key="ClemencyEP"/>
                    </call>
                </case>
                <case regex="pine valley community hospital">
                    <call-template target="HospitalRoutingSeq">
                        <with-param name="sethospital" value="Pine Valley"/>
                    </call-template>
                    <call>
                        <endpoint key="PineValleyEP"/>
                    </call>
                </case>
                <default>
                    <log description="Fault Log" level="custom">
                        <property expression="fn:concat('Invalid hospital - ', get-property('Hospital'))" name="message"/>
                    </log>
                    <respond/>
                </default>
            </switch>
            <property description="Get Appointment Number" expression="json-eval($.appointmentNumber)" name="uri.var.appointment_id" scope="default" type="STRING"/>
            <property description="Get Doctor Details" expression="json-eval($.doctor)" name="doctor_details" scope="default" type="STRING"/>
            <property description="Get Patient Details" expression="json-eval($.patient)" name="patient_details" scope="default" type="STRING"/>
            <call>
                <endpoint key="ChannelingFeeEP"/>
            </call>
            <property description="Get Actual Fee" expression="json-eval($.actualFee)" name="actual_fee" scope="default" type="STRING"/>
            <payloadFactory media-type="json">
                <format>{"appointmentNumber":$1, "doctor":$2, "patient":$3, "fee":$4, "confirmed":"false", "card_number":"$5"}</format>
                <args>
                    <arg evaluator="xml" expression="$ctx:uri.var.appointment_id"/>
                    <arg evaluator="xml" expression="$ctx:doctor_details"/>
                    <arg evaluator="xml" expression="$ctx:patient_details"/>
                    <arg evaluator="xml" expression="$ctx:actual_fee"/>
                    <arg evaluator="xml" expression="$ctx:card_number"/>
                </args>
            </payloadFactory>
            <call>
                <endpoint key="SettlePaymentEP"/>
            </call>
            <respond/>
        </inSequence>
        <outSequence/>
        <faultSequence/>
    </resource>
</api>

Step 3: Package the artifacts¶

Package the artifacts in your composite application project (SampleServicesCompositeApplication project) to be able to deploy the artifacts in the server.

Open the pom.xml file in the composite application project POM editor.
Ensure that the following artifacts are selected in the POM file.
- HealthcareAPI
- HospitalRoutingSeq
Save the project.

Step 4: Build and run the artifacts¶

To test the artifacts, deploy the packaged artifacts in the embedded Micro Integrator:

Right-click the composite application project and click Export Project Artifacts and Run.
In the dialog that opens, select the artifacts that you want to deploy.
Click Finish. The artifacts will be deployed in the embedded Micro Integrator and the server will start. See the startup log in the Console tab.

Step 5: Testing the use case¶

Let's test the use case by sending a simple client request that invokes the service.

Start the backend service¶

Download the JAR file of the back-end service from here.
Open a terminal, navigate to the location where your saved the back-end service.
Execute the following command to start the service:
```
java -jar Hospital-Service-2.0.0-EI7.jar
```

Get details of deployed artifacts (Optional)¶

Let's use the CLI Tool to find the URL of the REST API (that is deployed in the Micro integrator) to which you will send a request.

Tip

Be sure to set up the CLI tool for your work environment as explained in the first step of this tutorial.

Open a terminal and execute the following command to start the tool:
```
mi
```
Log in to the CLI tool. Let's use the server administrator user name and password:
```
mi remote login admin admin
```
You will receive the following message: Login successful for remote: default!
Execute the following command to find the APIs deployed in the server:
```
mi api show
```
You will receive the following information:

NAME : HealthcareAPI
URL : http://localhost:8290/healthcare

Similarly, you can get details of Connectors as well as other artifacts deployed in the server. Read more about using the CLI tool.

Send the client request¶

Let's send a simple request to invoke the service. You can use the embedded HTTP Client of WSO2 Integration Studio as follows:

Open the HTTP Client of WSO2 Integration Studio.

Tip

If you don't see the HTTP Client tab, go to Window -> Show View - Other and select HTTP Client to enable the client.

Enter the request information as given below and click the Send icon ().

Method	`POST`
Headers	`Content-Type=application/json`
URL	`http://localhost:8290/healthcare/categories/surgery/reserve`
Body	`{ "name": "John Doe", "dob": "1940-03-19", "ssn": "234-23-525", "address": "California", "phone": "8770586755", "email": "[email protected]", "doctor": "thomas collins", "hospital": "grand oak community hospital", "cardNo": "7844481124110331", "appointment_date": "2025-04-02" }` This JSON payload contains details of the appointment reservation, which includes patient details, doctor, hospital, and data of appointment.

If you want to send the client request from your terminal:

Install and set up cURL as your REST client.

Create a JSON file names request.json with the following request payload.

{
 "name": "John Doe",
 "dob": "1940-03-19",
 "ssn": "234-23-525",
 "address": "California",
 "phone": "8770586755",
 "email": "[email protected]",
 "doctor": "thomas collins",
 "hospital": "grand oak community hospital",
 "cardNo": "7844481124110331",
 "appointment_date": "2025-04-02"
}

Open a command line terminal and execute the following command from the location where the request.json file you created is saved:

curl -v -X POST --data @request.json http://localhost:8290/healthcare/categories/surgery/reserve --header "Content-Type:application/json"

Analyze the response¶

You will see the response received to your HTTP Client:

{"appointmentNo":2,"doctorName":"thomas collins","patient":"John Doe","actualFee":7000.0,"discount":20,"discounted":5600.0,"paymentID":"cc7e4c23-a66d-4d60-8b72-2cf9143c6335","status":"Settled"}

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Property	Description
Log Category	INFO
Log Level	CUSTOM