Couchase Node Js sdk 连接

Question

我正在尝试连接我的 couchbase 服务器，但是当我尝试在我的 express.js 应用程序的 app.js 上创建连接实例时，我收到警告消息。

这里是app.js

const express = require('express');
const bodyParser = require('body-parser');
const couchbase = require('couchbase');

const app = express();
const userRoutes = require('./routes/route');


app.use(bodyParser.json());
app.use(bodyParser.urlencoded({extended: true}));

//COUCHBASE CONNECTION
const cluster = couchbase.connect('couchbase://localhost', {username: 'admin', password: '5121451214'},(err,cluster) => { 
    const bucket =  cluster.bucket('test_data_bucket');
    module.exports.bucket = bucket;
}); 



app.use('/',userRoutes);

app.listen(process.env.port || 3000);

console.log('Web Server is listening at port '+ (process.env.port || 3000));

这是我的 AutherModel

const N1qlQuery = require('couchbase').N1qlQuery;
const data_bucket = require('../app').bucket;


function AuthorModel (){}

AuthorModel.getAll = function (callback)
{
    data_bucket.get('invoice_32212100000218', (err, res) => {
        if(error)
        {
            return callback(error,null);
        }

        callback(null,res);
    });
}


module.exports.AuthorModel = AuthorModel;

当我运行节点 app.js 收到此错误时

node:2410417) Warning: Accessing non-existent property 'bucket' of module exports inside circular dependency
(Use `node --trace-warnings ...` to show where the warning was created)

//修改后的结果

connection.js

const couchbase = require('couchbase');

//COUCHBASE CONNECTION
couchbase.connect('couchbase://localhost', {username: 'admin', password: '5121451214'},(err,cluster) => {
  const bucket =  cluster.bucket('test_data_bucket');
  const defautScope = bucket.scope('_default');
  const defaultCollection = defautScope.collection('_default');

  module.exports.bucket = bucket;
  module.exports.cluster = cluster;
  module.exports.defaultCollection = defaultCollection;
});

author.js 型号

 const connection = require('../config/connection');
    
    const data_bucket = connection.bucket;
    const data_cluster = connection.cluster;
    const data_collection = connection.defaultCollection;
    
    
    module.exports = {
        getUsers  ()
        {
            const data = data_collection.get('invoice_32212100000218', (err, res) => {
                console.log(res);
            });
    
            return 'Hello from express';
        }
     }

得到这个错误

TypeError: Cannot read properties of undefined (reading 'get')

Answer 1

循环依赖警告可能是因为您正在从 app.js 导出存储桶，在您的模型中需要它，它也可能包含在 app.js 的某处，形成循环依赖。

为了解决这个问题，我建议将连接代码移到一个单独的文件中，这样您就可以在模型和路线中需要的任何地方使用它。

重要说明：如果您使用的是 Node.js SDK 3.0 或更高版本，您需要在集合级对象上调用 .get() ，而不是在桶上。您可以轻松地从连接代码中导出所需的集合。请参阅以下连接文件示例，它使用默认范围和集合：

// connection.js
const couchbase = require('couchbase')

//COUCHBASE CONNECTION
const cluster = couchbase.connect('couchbase://localhost', {username: 'admin', password: '5121451214'},(err,cluster) => {
  const bucket =  cluster.bucket('test_data_bucket');
  const defautScope = bucket.scope('_default');
  const defaultCollection = defautScope.collection('_default')

  module.exports.bucket = bucket;
  module.exports.cluster = cluster;
  module.exports.defaultCollection = defaultCollection;
});

然后您可以轻松地在模型中要求 connection.js 并根据需要获取存储桶、集群或集合级别的对象：

const connection = require('../connection');

const data_bucket = connection.bucket;
const data_cluster = connection.cluster;
const data_collection = connection.defaultCollection;

Couchase Node Js sdk 连接

Couchase Node Js sdk connection

node.js

express

couchbase