gRPC on Android TakuSemba CyberAgent.Inc 

@takusemba https://github.com/TakuSemba 

Droidcon SF 

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What’s gRPC? 

gRPC ɾProtocol Buffers ɾRemote Procedure Call ɾHTTP/2 

ɾProtocol Buffers ɾRemote Procedure Call ɾHTTP/2 gRPC 

ɾProtocol Buffers ɾRemote Procedure Call ɾHTTP/2 gRPC 

What’s Protocol Buffers? 

ɾBinary based transmission Protocol Buffers ɾAvailable for many languages ɾFaster than Json 

ɾBinary based transmission ɾAvailable for many languages ɾFaster than Json Protocol Buffers 

ɾBinary based transmission ɾAvailable for many languages ɾFaster than Json Protocol Buffers 

Protocol BuffersͰͷ௨৴͸jsonͱൺ΂ͯૣ͍ͷ͔ IUUQTRJJUBDPNUBLVTFNCBJUFNTGFBCEBEDFEEC 

Let’s gRPC 

message CoffeeRequest { string name = 1; } Request //coffee.proto 

message CoffeeResponse { int32 price = 1; string name = 2; string message = 3; } Response //coffee.proto 

service Coffee { rpc Order (CoffeeRequest) returns (CoffeeResponse) {} } Service //coffee.proto 

Service service Coffee { rpc Order (CoffeeRequest) returns (CoffeeResponse) {} } service Coffee { rpc Order (stream CoffeeRequest) returns (CoffeeResponse) {} } service Coffee { rpc Order (CoffeeRequest) returns (stream CoffeeResponse) {} } service Coffee { rpc Order (stream CoffeeRequest) returns (stream CoffeeResponse) {} } 

syntax = "proto3"; option java_package = "com.takusemba.grpc.android.protos"; option go_package = "protos"; package Coffee; message CoffeeRequest { string name = 1; } message CoffeeResult { string message = 1; } service Coffee { rpc Order (CoffeeRequest) returns (CoffeeResult) {} } //coffee.proto 

->% curl -OL https://github.com/google/protobuf/releases/download/v3.5.0/ protobuf-java-3.5.0.tar.gz ->% tar -zxvf protobuf-java-3.5.0.tar.gz ->% cd protobuf-3.5.0 ->% ./configure ->% make ->% sudo make install ->% protoc —version // -> libprotoc 3.5.0 :) //protoc 

->% git clone [email protected]:grpc/grpc-java.git ->% cd grpc-java ->% git checkout -b v1.7.0 ->% cd compiler ->% make ->% ../gradlew java_pluginExecutable ->% cp build/exe/java_plugin/protoc-gen-grpc-java /usr/local/bin //protoc-gen-grpc-java 

->% protoc coffee.proto --grpc-java_out=lite:. --java_out=. --plugin=protoc-gen- grpc-java=/usr/local/bin/protoc-gen-grpc-java //generate proto files for client ->% protoc --go_out=plugins=grpc:. coffee.proto //generate proto files for server Generate Proto Files 

Generate Proto Files 

gRPC on Android classpath 'com.google.protobuf:protobuf-gradle-plugin:0.8.2' implementation "io.grpc:grpc-okhttp:1.7.0" implementation "io.grpc:grpc-protobuf:1.7.0" implementation "io.grpc:grpc-stub:1.7.0" implementation "javax.annotation:javax.annotation-api:1.2" //build.gradle //app/build.gradle 

gRPC on Android val channel = ManagedChannelBuilder.forAddress("10.0.2.2", 8080) .usePlaintext(true) .build() val stub = CoffeeGrpc.newBlockingStub(channel) val request = CoffeeOuterClass.CoffeeRequest.newBuilder() .setName(“hot coffee") .build() Single .create { it.onSuccess(stub.order(request)) }.subscribeOn(Schedulers.io()) .observeOn(AndroidSchedulers.mainThread()) .subscribe( { /** do something */ }, { /** error handling */ } ) 

gRPC on Android val channel = ManagedChannelBuilder.forAddress("10.0.2.2", 8080) .usePlaintext(true) .build() val stub = CoffeeGrpc.newBlockingStub(channel) val request = CoffeeOuterClass.CoffeeRequest.newBuilder() .setName(“hot coffee") .build() Single .create { it.onSuccess(stub.order(request)) }.subscribeOn(Schedulers.io()) .observeOn(AndroidSchedulers.mainThread()) .subscribe( { /** do something */ }, { /** error handling */ } ) 

gRPC on Android val channel = ManagedChannelBuilder.forAddress("10.0.2.2", 8080) .usePlaintext(true) .build() val stub = CoffeeGrpc.newBlockingStub(channel) val request = CoffeeOuterClass.CoffeeRequest.newBuilder() .setName(“hot coffee") .build() Single .create { it.onSuccess(stub.order(request)) }.subscribeOn(Schedulers.io()) .observeOn(AndroidSchedulers.mainThread()) .subscribe( { /** do something */ }, { /** error handling */ } ) 

gRPC on Android val channel = ManagedChannelBuilder.forAddress("10.0.2.2", 8080) .usePlaintext(true) .build() val stub = CoffeeGrpc.newBlockingStub(channel) val request = CoffeeOuterClass.CoffeeRequest.newBuilder() .setName(“hot coffee") .build() Single .create { it.onSuccess(stub.order(request)) }.subscribeOn(Schedulers.io()) .observeOn(AndroidSchedulers.mainThread()) .subscribe( { /** do something */ }, { /** error handling */ } ) 

Demo 

gRPC on Android https://github.com/takusemba https://twitter.com/takusemba