节点- Postgres驱动程序安装与节点-postgres
节点- Postgres驱动程序安装与节点-postgres
提问于 2017-10-09 12:10:00
我正在尝试集成节点-postgres驱动程序，并学习做一个简单的CRUD操作。在我的app.js中，我做这样的事情：
...
var postgres = require('./adapters/postgres')
var postClient = new postgres(conf);
...
postClient.connect(function (dbconn) {
app.dbconn = dbconn;
app.conf = conf;
console.log("************************************************************");
console.log(new Date() + ' | CRUD Server Listening on ' + conf['web']['port']);
console.log("************************************************************");
server.listen(conf['web']['port']);
var Routes = require('./routes/http-routes');
new Routes(app);
});在我的adapters/postgres.js文件中，我有以下内容：
const Client = require('pg');
const postClient = new Client(conf)({
host: conf['postgres'].host,
port: conf['postgres'].port,
dbname: conf['postgres'].dbname,
username: conf['postgres'].username,
password: conf['postgres'].password,
dbconn: null,
});
module.exports = postClient;
postClient.prototype.connect = function (cbk) {
var self = this;
client.connect(function (err, db) {
console.log(new Date() + " | Postgres Server Connection Establised...");
console.log(new Date() + " | Current database: ", db.databaseName);
if (!err) {
console.log(new Date() + " | Postgres Server Authenticated...");
self.dbconn = db;
cbk(db);
} else {
console.log(new Date() + " | Postgres Server Error in connection...");
console.log(err);
self.dbconn = db;
cbk(db);
}
});
};使用上面的代码，我一直得到这个错误：ReferenceError: conf is not defined，所以我将它添加为var conf = require('../config/conf');。这不是一个合适的解决方案，因为我想从app.js中传递它。接下来，即使添加了这些内容，我仍然会得到以下错误：TypeError: Client is not a constructor。有人能指导修复这两种错误吗？
回答 1
Stack Overflow用户
回答已采纳
发布于 2017-10-13 09:53:09
导出接受配置对象并返回客户端实例的工厂函数。Client不是pg中的默认导出，因此需要取消结构。
const { Client } = require('pg');
const createPgClient = (conf) => {
const pgClient = new Client(conf)({
host: conf['postgres'].host,
port: conf['postgres'].port,
dbname: conf['postgres'].dbname,
username: conf['postgres'].username,
password: conf['postgres'].password,
dbconn: null,
});
pgClient.prototype.connect = function (callback) {
client.connect()
.then(() => {
console.log(new Date() + " | Postgres Server Authenticated...");
})
.catch((err) => {
console.log(new Date() + " | Postgres Server Error in connection...");
console.log(err);
})
.finally(()=> {
self.dbconn = this;
callback(this);
});
};
return pgClient;
};
module.exports = createPgClient;在app.js中使用这个工厂函数来创建一个客户端。
const createPgClient = require('./adapters/postgres')
cont pgClient = createPgClient(conf);
pg.connect(function (dbconn) {
app.dbconn = dbconn;
app.conf = conf;
console.log("************************************************************");
console.log(new Date() + ' | CRUD Server Listening on ' + conf['web']['port']);
console.log("************************************************************");
server.listen(conf['web']['port']);
const Routes = require('./routes/http-routes');
new Routes(app);
});页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/46646127
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