Fully understand the use of Protobuf in GO

I. Environment configuration

1. Download the installation package of the corresponding version
2. Run the go env command to check your go path address and create a bin folder under the go path directory
3, unzip the downloads from the first point and copy the protoc under bin to the bin folder under go path
4. Check whether the installation is successful
```
# check version
protoc --version
# Check common commands
protoc
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```
Currently, only these languages are supported

5. Configure to support go language and depend on package address

go get -u github.com/golang/protobuf/proto
go get -u github.com/golang/protobuf/protoc-gen-go
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Second, the test`probuf`turn`go`code

1. Write simple Proto files

// helloWorld.proto

// Version, just stick to 3
syntax = "proto3";
// Convert to the package name of go, preceding. Output in the current directory
option go_package = ".; profile";

message HelloWorld {
  string name = 1;
  int64 age = 2;
  double fee = 3;
  bool isLogin = 4;
}
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2. Run commands to convert the proto file to the go file

#Protoc -i =.[current directory] --go_out=plugins= GRPC :.[current directory] File name
protoc -I=. --go_out=plugins=grpc:. helloWorld.proto
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Three, test,

1. Direct output

package main

import (
	"fmt"
	"go_demo/01.protobuf/proto"
)

func main(a) {
	hello := proto.HelloWorld{
		Name:    "Zhang",
		Age:     14,
		Fee:     20.9,
		IsLogin: false,
	}
	fmt.Println(&hello)
}
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Other data types

1. Compound data types, in fact, are nested data

.message Location {
  double latitude = 1;
  double longitude = 2;
}
message HelloWorld {
  string name = 1;
  // Note that this location has nothing to do with the position, only the number behind it
  Location location = 5;
  int64 age = 2;
  double fee = 3;
  bool isLogin = 4;
}
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2. List data types

message Location {
  double latitude = 1;
  double longitude = 2;
}
message HelloWorld {
  string name = 1;
  Location location = 5;
  int64 age = 2;
  double fee = 3;
  bool isLogin = 4;
  repeated Location locationList = 6;
}
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3. Enumeration types

// Define an enumeration type
enum HelloStatus {
  NO_PAY = 0;
  PAY = 1;
}
message HelloWorld {
  string name = 1;
  Location location = 5;
  int64 age = 2;
  double fee = 3;
  bool isLogin = 4;
  repeated Location locationList = 6;
  HelloStatus status = 7;
}
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4, import another file

A similar type is used in multiple proto files. You don’t need to define a type in each proto file. You just need to define a common type and import it in other files

// base.proto
syntax = "proto3";

message Empty {}
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syntax = "proto3";
import "base.proto";
option go_package=".; proto";

service Hello {
  rpc SayHello(Empty) returns (Empty);
}
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5. Introduce built-in packages

syntax = "proto3";
import "google/protobuf/empty.proto";
option go_package=".; proto";

service Hello {
  rpc SayHello(google.protobuf.Empty) returns (google.protobuf.Empty);
}
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6. About other built-in

7. Map type

message HelloWorld {... map<string.string> mp = 8;
}
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8. Built-in time types

syntax = "proto3";
import "google/protobuf/timestamp.proto";

message HelloWorld {... google.protobuf.Timestamp addTime =9;
}
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9. Assignment

func main(a) {
	var hello = proto.HelloWorld{
		Name:    "Zhang",
		Age:     14,
		Fee:     20.9,
		IsLogin: false,
		Location: &proto.Location{
			Latitude:  30,
			Longitude: 100,
		},
		LocationList: []*proto.Location{
			{
				Latitude:  100,
				Longitude: 10,
			},
		},
    Status: profile.HelloStatus_NO_PAY,
	}
	fmt.Println(&hello)
}
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10. Assignment of time

import (
	"google.golang.org/protobuf/types/known/timestamppb"
	"time"
)

var hello = profile.HelloWorld{
  ...
  AddTime: timestamppb.New(time.Now()),
}
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5. Other outputs

1. Use proto.Marshal to output the binary

var hell1 profile.HelloWord
err = proto.Unmarshal(b, &hell1)
fmt.Println(&hello)
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2. Output JSON

var hell1 profile.HelloWord
b, err = json.Marshal(&hell1)
fmt.Printf("%s\n", b)
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Realize data interaction between client and server

1. Define a proto file

// Version, just stick to 3
syntax = "proto3";
// Convert to the package name of go, preceding. Output in the current directory
option go_package = ".; profile";

message Location {
  double latitude = 1;
  double longitude = 2;
}
message HelloWorld {
  string name = 1;
  Location location = 5;
  int64 age = 2;
  double fee = 3;
  bool isLogin = 4;
  repeated Location locationList = 6;
}

message GetHelloRequest {
  string id = 1;
}

message GetHelloResponse {
  string id = 1;
  HelloWorld helloWorld = 2;
}
// The service must be defined
service HelloService {
  rpc GetHello(GetHelloRequest) returns (GetHelloResponse);
}
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2. Run the command to generate the go file and view the service you define

func (c *helloServiceClient) GetHello(ctx context.Context, in *GetHelloRequest, opts ... grpc.CallOption) (*GetHelloResponse, error) {
	out := new(GetHelloResponse)
	err := c.cc.Invoke(ctx, "/HelloService/GetHello", in, out, opts...)
	iferr ! =nil {
		return nil, err
	}
	return out, nil
}
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3. Define server-side methods

type Service struct{}func (*Service) GetHello(ctx context.Context, req *profile.GetHelloRequest) (*profile.GetHelloResponse, error) {
	return &profile.GetHelloResponse{
		Id: req.Id,
		HelloWorld: &profile.HelloWorld{
			Name:    "Zhang",
			Age:     20,
			Fee:     100,
			IsLogin: true,
			Location: &profile.Location{
				Longitude: 100,
				Latitude:  10,
			},
			LocationList: []*profile.Location{
				{
					Longitude: 10,
					Latitude:  100,},},},},nil
}
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4. Start the server-side method

func main(a) {
	listen, err := net.Listen("tcp".": 9000")
	iferr ! =nil {
		log.Fatalf("Server startup failure :%v", err)
	}
	// Start the service
	service :=grpc.NewServer()
  // Service is custom from above
	profile.RegisterHelloServiceServer(service, &Service{})
	log.Fatal(service.Serve(listen))
}
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5. Start the client

package main

import (
	"context"
	"fmt"
	"go_demo/01.protobuf/profile"
	"google.golang.org/grpc"
	"log"
)

func main(a) {
	conn, err := grpc.Dial("localhost:9000", grpc.WithInsecure())
	iferr ! =nil {
		log.Fatalf("Error connecting server: %v", err)
	}

	client := profile.NewHelloServiceClient(conn)
	response, err := client.GetHello(context.Background(), &profile.GetHelloRequest{
		Id: "1001",})iferr ! =nil {
		log.Fatalf("Connection service error :%v", err)
	}
	fmt.Println(response)
}
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Seven,`protobuf`convert`http`request

1. Transform the proTO file before

syntax = "proto3";
// Add this
package collect;
option go_package = ".; profile";
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2. Create a YAML file in the same proto directory

# the helloWorld. Yaml files
type: google.api.Service
config_version: 3

http:
  rules:
    - selector: collect.HelloService.GetHello
      get: /hello/{id}
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3. Install dependency packages

go get -u github.com/grpc-ecosystem/grpc-gateway/v2/protoc-gen-grpc-gateway
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4. Modify the command

#It's the same order as before
protoc -I=. --go_out=plugins=grpc,paths=source_relative:. helloWorld.proto
#A helloWorld.pb.gw.go file is generated
protoc -I=. --grpc-gateway_out=paths=source_relative,grpc_api_configuration=helloWorld.yaml:. helloWorld.proto
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5. Since there are too many commands to remember, create a gen.sh file in the directory, put the two commands in it, and execute them when necessary
```
sh ./gen.sh
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```
6. The service layer of GRPC is the same as above

7. Define the HTTP client

package main

import (
	"context"
	"github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
	"go_demo/01.protobuf/profile"
	"google.golang.org/grpc"
	"log"
	"net/http"
)

func main(a) {
	c := context.Background()
	c, cancel := context.WithCancel(c)
	defer cancel()

	mux := runtime.NewServeMux()
	err := profile.RegisterHelloServiceHandlerFromEndpoint(
		c,
		mux,
		"localhost:9000".// GRPC server address
		[]grpc.DialOption{grpc.WithInsecure()},
	)
	iferr ! =nil {
		log.Fatalf("Error connecting GRPC: %v", err)
	}
	err = http.ListenAndServe(": 8080", mux)
	iferr ! =nil {
		log.Fatalf("Listening error: %v", err)
	}
}
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8, directly enter http://localhost:8080/hello/123 in your browser

Processing the data structure of the back end back to the front end

There are two problems

1. We originally defined the age field as an integer and returned the character type to the front end
We should return an enumerated value, not a string

The solution

1. Change the datatype of the age field from INT64 to int32

2. The state enumeration type is modified via the HTTP client

.var mux = runtime.NewServeMux(
  runtime.WithMarshalerOption(
    runtime.MIMEWildcard,
    &runtime.JSONPb{
      MarshalOptions: protojson.MarshalOptions{
        UseEnumNumbers: true.// Enumeration field values use numbers
        UseProtoNames:  true,
      },
      UnmarshalOptions: protojson.UnmarshalOptions{
        DiscardUnknown: true.// Ignore the nonexistent poroto field sent by client},},),)...Copy the code

Fully understand the use of Protobuf in GO

I. Environment configuration

Second, the testprobufturngocode

Three, test,

Other data types

5. Other outputs

Realize data interaction between client and server

Seven,protobufconverthttprequest

Processing the data structure of the back end back to the front end

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