Quick start

Prerequisites

• PHP 7.0 or higher, PECL, Composer
• grpc extension, protocol buffers compiler: for installation instructions, see the gRPC PHP readme.

Get the example code

The example code is part of the grpc repo.

1. Clone the grpc repo and its submodules:

   $ git clone --recurse-submodules -b v1.38.0 https://github.com/grpc/grpc
   

2. Change to the quick start example directory:

   $ cd grpc/examples/php
   

3. Install the grpc composer package:

   $ ./greeter_proto_gen.sh
   $ composer install
   

Run the example

1. Launch the a quick start server: for example, follow the instructions given in the Quick start for Node.

2. From the examples/php directory, run the PHP client:

   $ ./run_greeter_client.sh
   

Congratulations! You’ve just run a client-server application with gRPC.

Update the gRPC service

Now let’s look at how to update the application with an extra method on the server for the client to call. Our gRPC service is defined using protocol buffers; you can find out lots more about how to define a service in a .proto file in Basics tutorial. For now all you need to know is that both the server and the client “stub” have a SayHello RPC method that takes a HelloRequest parameter from the client and returns a HelloResponse from the server, and that this method is defined like this:

// The greeting service definition.
service Greeter {
  // Sends a greeting
  rpc SayHello (HelloRequest) returns (HelloReply) {}
}

// The request message containing the user's name.
message HelloRequest {
  string name = 1;
}

// The response message containing the greetings
message HelloReply {
  string message = 1;
}

Let’s update this so that the Greeter service has two methods. Edit examples/protos/helloworld.proto and update it with a new SayHelloAgain method, with the same request and response types:

// The greeting service definition.
service Greeter {
  // Sends a greeting
  rpc SayHello (HelloRequest) returns (HelloReply) {}
  // Sends another greeting
  rpc SayHelloAgain (HelloRequest) returns (HelloReply) {}
}

// The request message containing the user's name.
message HelloRequest {
  string name = 1;
}

// The response message containing the greetings
message HelloReply {
  string message = 1;
}

Remember to save the file!

Regenerate gRPC code

Next we need to update the gRPC code used by our application to use the new service definition. From the grpc root directory:

$ protoc --proto_path=examples/protos \
  --php_out=examples/php \
  --grpc_out=examples/php \
  --plugin=protoc-gen-grpc=bins/opt/grpc_php_plugin \
  ./examples/protos/helloworld.proto

or running the helper script under the grpc/example/php directory if you build grpc-php-plugin by source:

$ ./greeter_proto_gen.sh

This regenerates the protobuf files, which contain our generated client classes, as well as classes for populating, serializing, and retrieving our request and response types.

Update and run the application

We now have new generated client code, but we still need to implement and call the new method in the human-written parts of our example application.

Update the server

In the same directory, open greeter_server.js. Implement the new method like this:

function sayHello(call, callback) {
  callback(null, {message: 'Hello ' + call.request.name});
}

function sayHelloAgain(call, callback) {
  callback(null, {message: 'Hello again, ' + call.request.name});
}

function main() {
  var server = new grpc.Server();
  server.addProtoService(hello_proto.Greeter.service,
                         {sayHello: sayHello, sayHelloAgain: sayHelloAgain});
  server.bind('0.0.0.0:50051', grpc.ServerCredentials.createInsecure());
  server.start();
}
...

Update the client

In the same directory, open greeter_client.php. Call the new method like this:

$request = new Helloworld\HelloRequest();
$request->setName($name);
list($reply, $status) = $client->SayHello($request)->wait();
$message = $reply->getMessage();
list($reply, $status) = $client->SayHelloAgain($request)->wait();
$message = $reply->getMessage();

Run!

Just like we did before, from the examples/node/dynamic_codegen directory:

1. Run the server:

   $ node greeter_server.js
   

2. From another terminal, from the examples/php directory, run the client:

   $ ./run_greeter_client.sh
   

What’s next

• Learn how gRPC works in Introduction to gRPC and Core concepts.
• Work through the Basics tutorial.
• Explore the API reference.