使用 Node.js 中的 gRPC 从 Redis 中读取数据

需要三个东西：配置文件、服务器程序和客户端程序。

设定文件

redis_read.proto
与此相同
使用 Python 的 gRPC 读取 Redis 数据（读取）

服务器程序

#! /usr/bin/node
// ---------------------------------------------------------------
//  redis_read_server.js
//
//                  Feb/08/2020
// ---------------------------------------------------------------
var PROTO_PATH = 'redis_read.proto'

var grpc = require('grpc')

var protoLoader = require('@grpc/proto-loader')
var packageDefinition = protoLoader.loadSync(
    PROTO_PATH,
    {keepCase: true,
     longs: String,
     enums: String,
     defaults: true,
     oneofs: true
    });
var redis_read_proto = grpc.loadPackageDefinition(packageDefinition).redis_read

// ---------------------------------------------------------------
function redis_read_proc(key_in,callback)
{
    const redis = require ("redis")
    const client = redis.createClient (6379,'localhost')

client.get (key_in, function (err, reply)
    {
    if (err)
        {
        console.log("Get error: " + err)
            }
     else if (reply != null)
        {
        const str_json = reply
        const data = JSON.parse(str_json)

        var out_str = key_in + "\t"
        out_str  += data.name + "\t"
        out_str += data.population + "\t"
        out_str += data.date_mod
        console.log (out_str)
    callback(null, {str_json: str_json})
        }

    client.quit()
    })
}

// ---------------------------------------------------------------
function RedisRead(call, callback) {
    console.error("*** RedisDelete ***")
    const key_in = call.request.key
    const str_out = 'RedisDelete ' + key_in
    console.error(str_out)
    redis_read_proc(key_in,callback)
//  callback(null, {key: key_in})
}

// ---------------------------------------------------------------
function main() {
    var server = new grpc.Server()
    server.addService(redis_read_proto.Greeter.service, {RedisRead: RedisRead })
    server.bind('0.0.0.0:50051', grpc.ServerCredentials.createInsecure())
    server.start()
}

// ---------------------------------------------------------------
main()
// ---------------------------------------------------------------

客户端程序

#! /usr/bin/node
// ---------------------------------------------------------------
//  redis_read_client.js
//
//                      Feb/08/2020
// ---------------------------------------------------------------
var PROTO_PATH = 'redis_read.proto'

var grpc = require('grpc');
var protoLoader = require('@grpc/proto-loader');
var packageDefinition = protoLoader.loadSync(
    PROTO_PATH,
    {keepCase: true,
     longs: String,
     enums: String,
     defaults: true,
     oneofs: true
    });
var redis_read_proto = grpc.loadPackageDefinition(packageDefinition).redis_read

// ---------------------------------------------------------------
function main() {
  var client = new redis_read_proto.Greeter('localhost:50051',
                                       grpc.credentials.createInsecure())

    var key_in = process.argv[2]
    client.RedisRead({key: key_in}, function(err, response) {
//    console.log('str_json:', response.str_json)

    const data = JSON.parse(response.str_json)
    var out_str = data.name + "\t"
    out_str += data.population + "\t"
    out_str += data.date_mod
    console.log (out_str)
  })

}

// ---------------------------------------------------------------
main()
// ---------------------------------------------------------------

服务器程序的启动

export NODE_PATH=/usr/lib/node_modules
./redis_read_server.js

客户端程序的执行

$ export NODE_PATH=/usr/lib/node_modules
$ ./redis_read_client.js t1852
敦賀  41295   2003-5-10