使用node.js访问MongoDB

10 月 ago

新, 韵

2 minutes

如果使用Mongodb客户端进行连接的话

使用cfenv，在本地环境中通过vcap-local.json读取服务资格证书，在CF容器环境中通过环境变量获取证书信息的代码。完整的代码可以在https://github.com/IBM-Bluemix/compose-mongodb-helloworld-nodejs/blob/master/server.js中找到。

//var appenv = cfenv.getAppEnv();                                                                                                        
var vcapLocal = require("./vcap-local.json");
var appEnvOpts = vcapLocal ? { vcap: vcapLocal} : {}

//var appenv = cfenv.getAppEnv();
var appenv = cfenv.getAppEnv(appEnvOpts);

如果使用Mongoose进行连接

在本地环境中，同样需要使用vcap-local.json文件来读取服务凭证信息，在容器环境中，需要使用环境变量来导入这些凭证信息。连接成功后，将显示数据库列表。

#!/usr/bin/env node

var mongoose = require('mongoose');
var assert = require('assert');
var cfenv = require("cfenv");

var svc = 'compose-for-mongodb';
var vcapLocal = require("./vcap-local.json");
var appEnvOpts = vcapLocal ? { vcap: vcapLocal} : {};
var appenv = cfenv.getAppEnv(appEnvOpts);
var services = appenv.services;
var mongodb_services = services["compose-for-mongodb"];
var credentials = mongodb_services[0].credentials;
var ca = [new Buffer(credentials.ca_certificate_base64, 'base64')];

var options = {
    mongos: {
    ssl: true,
    sslValidate: true,
    sslCA: ca,
    poolSize: 1,
    reconnectTries: 1
    }
};

// コールバック　エラー時
mongoose.connection.on('error',function (err) {
  console.log('Mongoose default connection error: ' + err);
});

// コールバック  セッション確立時
mongoose.connection.on('open', function (err) {
  console.log("=== Connected to mongodb on Compose ===" );
  assert.equal(null, err);
  mongoose.connection.db.listCollections().toArray(function(err, collections) {
     assert.equal(null, err);
     collections.forEach(function(collection) {
       console.log(collection);
     });
     mongoose.connection.db.close();
     process.exit(0);
  });
});

// 接続
mongoose.connect(credentials.uri, options);

vcap-local.json -> 本地的vcap.json配置文件

在Bluemix门户上，将credentials部分替换为显示的服务资格信息进行使用。

imac:mongodb_mongoose maho$ cat vcap-local.json 
{
 "services": {
  "compose-for-mongodb": [
   {
    "credentials": {
     "ca_certificate_base64": "LS0tLS1CRUdJTiBDRVJUSUZJQ0FURS0tLS0tCk1JSURlekNDQW1PZ0F3SUJBZ0lFV1ZOZ0tEQU5CZ2txaGtpRzl3MEJBUTBGQURBL01UMH
<省略>
RkpObnVXQ01Fa2lZdVZoZDJoN21nekFVM2VlNVV3bmF6WHRlQT09Ci0tLS0tRU5EIENFUlRJRklDQVRFLS0tLS0K",
     "db_type": "mongodb",
     "deployment_id": "******************:",
     "maps": [],
     "name": "**************************",
     "uri": "mongodb://*****:***********@sl-us-south-1-portal.3.dblayer.com:17599,sl-us-south-1-portal.4.dblayer.com:17599/admin?ssl=true",
     "uri_cli": "mongo --ssl --sslAllowInvalidCertificates sl-us-south-1-portal.3.dblayer.com:17599/admin -u admin -p ***************"
    },
    "label": "compose-for-mongodb",
    "name": "Compose for MongoDB-no",
    "plan": "Standard",
    "provider": null,
    "syslog_drain_url": null,
    "tags": [
     "big_data",
     "data_management",
     "ibm_created"
    ],
    "volume_mounts": []
   }
  ]
 }
}

总结

使用Mongodb时，我担心无法在本地环境中连接，但问题已经解决了。太好了（笑）

请提供相关资料

GitHub IBM-Bluemix/compose-mongodb-helloworld-nodejs https://github.com/IBM-Bluemix/compose-mongodb-helloworld-nodejs

Hosted MongoDB https://www.compose.com/mongodb