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"GraphQL Made Easy With Ballerina"
"Securing Microservices with JWT"
"Connecting to and using Google's Cloud SQL with Ballerina"
"How to Create a REST API--Spring Boot and Ballerina"
"An Introduction to Pub/Sub in Ballerina"
Hello, world. A Ballerina application can have:
Both of these are considered as entry points for program execution.
Service
import ballerina/http;
# A service representing a network-accessible API
# bound to port `9090`.
service /hello on new http:Listener(9090) {
# A resource representing an invokable API method
# accessible at `/hello/sayHello`.
#
# + return - A string payload which eventually becomes
# the payload of the response
resource function get sayHello() returns string {
return "Hello Ballerina!";
}
}
Run it:
$ bal run hello_service.bal
Compiling source
hello_service.bal
Running executable
[ballerina/http] started HTTP/WS listener 0.0.0.0:9090
Or, build it into a JAR:
$ bal build -o my_first_service.jar hello_service.bal
Compiling source
hello_service.bal
Generating executable
my_first_service.jar
$ bal run my_first_service.jar
[ballerina/http] started HTTP/WS listener 0.0.0.0:9090
Client
Either approach, hit it from curl:
$ curl http://localhost:9090/hello/sayHello
Hello Ballerina!
... or build a Ballerina client:
import ballerina/http;
import ballerina/io;
public function main() returns @tainted error? {
// Add the relevant endpoint URL to perform the invocation.
http:Client helloClient = check new("http://localhost:9090/hello");
// Perform a `GET` request to the `hello` service. If successful,
// the remote call would return an `http:Response` or the payload
// (if the `targetType` defaultable parameter is configured).
// Otherwise an `error` on failure.
http:Response helloResp = check helloClient->get("/sayHello");
// Retrieve the payload as a `string` and print it if the
// response of the remote call is successful.
io:println(check helloResp.getTextPayload());
}
$ bal run hello_client.bal
Hello Ballerina!
Last modified 21 December 2022