HTTP Hello World - Get

Function that prints "Hello world!" in response to a GET request.

Explore further

For detailed documentation that includes this code sample, see the following:

Code sample

C#

To authenticate to Cloud Run functions, set up Application Default Credentials. For more information, see Set up authentication for a local development environment. 

using Google.Cloud.Functions.Framework;
using Microsoft.AspNetCore.Http;
using System.Threading.Tasks;

namespace HelloWorld;

public class Function : IHttpFunction
{
    public async Task HandleAsync(HttpContext context)
    {
        await context.Response.WriteAsync("Hello World!", context.RequestAborted);
    }
}

Go

To authenticate to Cloud Run functions, set up Application Default Credentials. For more information, see Set up authentication for a local development environment. 


// Package helloworld provides a set of Cloud Functions samples.
package helloworld

import (
	"fmt"
	"net/http"

	"github.com/GoogleCloudPlatform/functions-framework-go/functions"
)

func init() {
	functions.HTTP("HelloGet", helloGet)
}

// helloGet is an HTTP Cloud Function.
func helloGet(w http.ResponseWriter, r *http.Request) {
	fmt.Fprint(w, "Hello, World!")
}

Java

To authenticate to Cloud Run functions, set up Application Default Credentials. For more information, see Set up authentication for a local development environment. 


package functions;

import com.google.cloud.functions.HttpFunction;
import com.google.cloud.functions.HttpRequest;
import com.google.cloud.functions.HttpResponse;
import java.io.BufferedWriter;
import java.io.IOException;

public class HelloWorld implements HttpFunction {
  // Simple function to return "Hello World"
  @Override
  public void service(HttpRequest request, HttpResponse response)
      throws IOException {
    BufferedWriter writer = response.getWriter();
    writer.write("Hello World!");
  }
}

Kotlin

import com.google.cloud.functions.HttpFunction
import com.google.cloud.functions.HttpRequest
import com.google.cloud.functions.HttpResponse
import java.io.IOException
import java.util.logging.Logger

class HelloWorld : HttpFunction {
    // Simple function to return "Hello World"
    @Throws(IOException::class)
    override fun service(request: HttpRequest, response: HttpResponse) {
        response.writer.write("Hello World!")
    }
}

Node.js

To authenticate to Cloud Run functions, set up Application Default Credentials. For more information, see Set up authentication for a local development environment. 

const functions = require('@google-cloud/functions-framework');

// Register an HTTP function with the Functions Framework that will be executed
// when you make an HTTP request to the deployed function's endpoint.
functions.http('helloGET', (req, res) => {
  res.send('Hello World!');
});

PHP

To authenticate to Cloud Run functions, set up Application Default Credentials. For more information, see Set up authentication for a local development environment. 


use Psr\Http\Message\ServerRequestInterface;

function helloGet(ServerRequestInterface $request): string
{
    return 'Hello, World!' . PHP_EOL;
}

Python

To authenticate to Cloud Run functions, set up Application Default Credentials. For more information, see Set up authentication for a local development environment. 

import functions_framework

@functions_framework.http
def hello_get(request):
    """HTTP Cloud Function.
    Args:
        request (flask.Request): The request object.
        <https://flask.palletsprojects.com/en/1.1.x/api/#incoming-request-data>
    Returns:
        The response text, or any set of values that can be turned into a
        Response object using `make_response`
        <https://flask.palletsprojects.com/en/1.1.x/api/#flask.make_response>.
    Note:
        For more information on how Flask integrates with Cloud
        Functions, see the `Writing HTTP functions` page.
        <https://cloud.google.com/functions/docs/writing/http#http_frameworks>
    """
    return "Hello World!"

Ruby

To authenticate to Cloud Run functions, set up Application Default Credentials. For more information, see Set up authentication for a local development environment. 

require "functions_framework"

FunctionsFramework.http "hello_get" do |_request|
  # The request parameter is a Rack::Request object.
  # See https://www.rubydoc.info/gems/rack/Rack/Request

  # Return the response body as a string.
  # You can also return a Rack::Response object, a Rack response array, or
  # a hash which will be JSON-encoded into a response.
  "Hello World!"
end

What's next

To search and filter code samples for other Google Cloud products, see the Google Cloud sample browser.