MuleSoft Mastery: From Zero to Hero | Ch.02

📥 HTTP Listener  →  ⚡ Set Payload (DataWeave JSON greeting)  →  📝 Logger
GET /hello?name=Maria

<!-- Mule Database Connector -->
<dependency>
  <groupId>org.mule.connectors</groupId>
  <artifactId>mule-db-connector</artifactId>
  <version>1.14.0</version>
  <classifier>mule-plugin</classifier>
</dependency>

<!-- H2 in-memory driver — zero install -->
<dependency>
  <groupId>com.h2database</groupId>
  <artifactId>h2</artifactId>
  <version>2.2.224</version>
</dependency>

# HTTP Listener
http.host=0.0.0.0
http.port=8081

# Database — H2 in-memory, zero install
db.url=jdbc:h2:mem:customerdb;DB_CLOSE_DELAY=-1;MODE=MySQL
db.driver=org.h2.Driver
db.user=sa
db.password=

<flow name="init-db-flow">
  <scheduler>
    <scheduling-strategy>
      <fixed-frequency frequency="999999" timeUnit="DAYS" />
    </scheduling-strategy>
  </scheduler>

  <db:execute-ddl config-ref="H2_Config">
    <db:sql><![CDATA[
      CREATE TABLE IF NOT EXISTS customers (
        id    INT AUTO_INCREMENT PRIMARY KEY,
        name  VARCHAR(100) NOT NULL,
        email VARCHAR(150) NOT NULL,
        city  VARCHAR(100)
      )
    ]]></db:sql>
  </db:execute-ddl>

  <db:insert config-ref="H2_Config">
    <db:sql><![CDATA[
      MERGE INTO customers (id, name, email, city) KEY(id) VALUES
        (1, 'Alice Dupont',  'alice@example.com',  'Paris'),
        (2, 'Bob Martin',    'bob@example.com',    'Lyon'),
        (3, 'Claire Bernard','claire@example.com', 'Marseille')
    ]]></db:sql>
  </db:insert>

  <logger level="INFO" message="✅ Database initialized" />
</flow>

<flow name="get-customer-by-id-flow">
  <http:listener config-ref="HTTP_Listener_config"
                 path="/customers/{id}"
                 allowedMethods="GET">
    <http:response statusCode="#[vars.httpStatus default 200]"/>
  </http:listener>

  <db:select config-ref="H2_Config">
    <db:sql>SELECT id, name, email, city FROM customers WHERE id = :id</db:sql>
    <db:input-parameters>#[{ id: attributes.uriParams.id as Number }]</db:input-parameters>
  </db:select>

  <choice>
    <when expression="#[!isEmpty(payload)]">
      <ee:transform>
        <ee:message>
          <ee:set-payload><![CDATA[%dw 2.0
output application/json
---
{
  id:    payload[0].id,
  name:  payload[0].name,
  email: payload[0].email,
  city:  payload[0].city
}]]></ee:set-payload>
        </ee:message>
      </ee:transform>
    </when>
    <otherwise>
      <set-variable variableName="httpStatus" value="404"/>
      <ee:transform>
        <ee:message>
          <ee:set-payload><![CDATA[%dw 2.0
output application/json
---
{
  error:   "Not Found",
  message: "No customer found with id = " ++ attributes.uriParams.id
}]]></ee:set-payload>
        </ee:message>
      </ee:transform>
    </otherwise>
  </choice>
</flow>

<flow name="create-customer-flow">
  <http:listener config-ref="HTTP_Listener_config"
                 path="/customers" allowedMethods="POST">
    <http:response statusCode="#[vars.httpStatus default 201]"/>
  </http:listener>

  <!-- 🔑 SAVE PAYLOAD FIRST — the DB call will overwrite it -->
  <set-variable variableName="requestBody" value="#[payload]"/>

  <db:insert config-ref="H2_Config" autoGenerateKeys="true">
    <db:sql>
      INSERT INTO customers (name, email, city)
      VALUES (:name, :email, :city)
    </db:sql>
    <db:input-parameters>#[{
      name:  vars.requestBody.name,
      email: vars.requestBody.email,
      city:  vars.requestBody.city default null
    }]</db:input-parameters>
  </db:insert>

  <ee:transform>
    <ee:message>
      <ee:set-payload><![CDATA[%dw 2.0
output application/json
---
{
  id:    payload.generatedKeys.id,
  name:  vars.requestBody.name,
  email: vars.requestBody.email,
  city:  vars.requestBody.city default null
}]]></ee:set-payload>
    </ee:message>
  </ee:transform>
</flow>

# List all customers — 200 OK
curl -s http://localhost:8081/customers | jq
# → [{"id":1,"name":"Alice Dupont","email":"...","city":"Paris"}, …]

# Get one — 200 OK
curl -s http://localhost:8081/customers/2 | jq
# → {"id":2,"name":"Bob Martin","email":"bob@example.com","city":"Lyon"}

# Get missing — 404 Not Found
curl -s -i http://localhost:8081/customers/999
# → HTTP/1.1 404 Not Found
#   {"error":"Not Found","message":"No customer found with id = 999"}

# Create — 201 Created
curl -s -X POST http://localhost:8081/customers \
  -H "Content-Type: application/json" \
  -d '{"name":"Eve Morel","email":"eve@example.com","city":"Nice"}' | jq
# → {"id":4,"name":"Eve Morel","email":"...","city":"Nice"}

# Update — 200 OK
curl -s -X PUT http://localhost:8081/customers/1 \
  -H "Content-Type: application/json" \
  -d '{"name":"Alice DUPONT","email":"alice@example.com","city":"Paris"}'

# Delete — 204 No Content (no body)
curl -s -i -X DELETE http://localhost:8081/customers/3

<!-- Count after DB select -->
<logger level="INFO"
        message="#['Found: ' ++ sizeOf(payload) ++ ' rows']"/>

<!-- Full payload as readable JSON (works for any Java object) -->
<logger level="DEBUG"
        message="#[write(payload,'application/json')]"/>

<!-- All variables at once -->
<logger level="DEBUG"
        message="#[write(vars,'application/json')]"/>