Creating .proto File for Messages and Services
Explore how to create .proto files that define gRPC services and messages, including the syntax, Java options, and message structures needed to implement FTP service RPCs. Understand message components like MetaData and FileChunk, define request and response formats, and use features such as oneof and enums to organize your Protobuf definitions for Java client and server code generation.
As discussed previously, in gRPC, the .proto files are used to define the structure of the services and messages exchanged between clients and servers. After defining the .proto file, we will generate Java code from it in order to implement gRPC clients and servers in Java.
FTP service .proto file
In the ftp-service-proto project created in the Configuring Protobuf in Java lesson, we will create a .proto file for the FTP service. First, we need to create a directory named proto in src/main. This is the source root path for the .proto file specified in the <configuration> section of the protobuf-maven-plugin. (Since this project will only contain the proto file, we can delete the java directory from src/main.)
Inside the proto directory, create a file named ftp_service.proto. In this file, we will specify the RPCs that our FTP service will expose, along with the request and response messages. ...