gRPC 消息类型转换

依旧是 protoreflect 包的使用

使用例：

package main

import (
    "fmt"
    "path/filepath"
    "stgrpc/log"
    "sync"

    "github.com/golang/protobuf/proto"
    "github.com/golang/protobuf/ptypes"
    "github.com/jhump/protoreflect/desc"
    "github.com/jhump/protoreflect/desc/protoparse"
    "github.com/jhump/protoreflect/dynamic"
)

var (
    globalProtoMap map[string]*desc.FileDescriptor
    IsCached       = true
    lk             sync.RWMutex
)

func init() {
    globalProtoMap = make(map[string]*desc.FileDescriptor)
}

func getProto(path string) *desc.FileDescriptor {
    lk.Lock()
    defer lk.Unlock()

    if IsCached {
        fd, ok := globalProtoMap[path]
        if ok {
            log.Debugf("getProto path:%v cached \n", path)
            return fd
        }
    }
    p := protoparse.Parser{}
    fds, err := p.ParseFiles(path)
    if err != nil {
        log.Error("getProto ParseFiles error:", err)
        return nil
    }

    log.Debug("JsonToPb fd", fds[0])
    fd := fds[0]

    if IsCached {
        globalProtoMap[path] = fd
    }

    return fd
}

// JsonToPb 传入 proto 文件的 path, proto 中对应的 message.name，js 的原始数据
// 返回生成的 proto.Marshal 的 []byte
// example:
// path := "$PROTOPATH/hello.proto"
// messageName "hello.HelloRequest"
// JsonToPb(path,"hello.HelloRequest", []byte(`{"name":"John"}`)
func JsonToPb(protoPath, messageName string, jsonStr []byte) ([]byte, error) {
    log.Debug("JsonToPb protoPath", protoPath)

    fd := getProto(protoPath)

    msg := fd.FindMessage(messageName)

    dymsg := dynamic.NewMessage(msg)
    err := dymsg.UnmarshalJSON(jsonStr)

    if err != nil {
        log.Error("JsonToPb UnmarshalJSON error:", err)
        return nil, nil
    }

    log.Debug("JsonToPb UnmarshalJSON dymsg", dymsg)

    any, err := ptypes.MarshalAny(dymsg)
    if err != nil {
        log.Error("JsonToPb MarshalAny error:", err)
        return nil, nil
    }
    log.Debug("JsonToPb marshal any", any.Value)
    return any.Value, nil
}

// PbToJson 传入 proto 的 byte 数据，返回它对应的 json 数据
// example:
// path := "$PROTOPATH/helloworld.proto"
// messageName "hello.HelloRequest"
// jsonByte, err := PbToJson(path, messageName, pbByte)
func PbToJson(protoPath, messageName string, protoData []byte) ([]byte, error) {
    log.Debug("PbToJson protoPath", protoPath)
    fd := getProto(protoPath)
    msg := fd.FindMessage(messageName)
    dymsg := dynamic.NewMessage(msg)

    err := proto.Unmarshal(protoData, dymsg)
    log.Debug("PbToJson Unmarshal err:", err)

    jsonByte, err := dymsg.MarshalJSON()
    return jsonByte, err
}

// 使用例
func main() {
    path, _ := filepath.Abs("./tests/hello.proto")
    fmt.Println(JsonToPb(path, "hello.HelloRequest", []byte(`{"name":"John"}`)))
}