如何为我的整个Node.js应用程序使用相同的MySQL连接? [英] How do I use the same MySQL connection(s) for my entire Node.js app?
问题描述
我有一个 app.js
。我从那里运行我的整个应用程序。
I have an app.js
. I run my entire app from there.
在app.js内部,我需要
许多包含代码的文件。
Inside app.js, I require
many files that have code in it.
对于这些文件中的每一个,我这样做:
For each of these files, I do this:
var mysql = require('mysql');
var mclient = mysql.createConnection({
host: settings.MYSQL.HOST,
user: settings.MYSQL.USER,
password: settings.MYSQL.PASSWORD,
database: settings.MYSQL.DB,
});
基本上,我为每个文件启动一个新连接。
Essentially, I am initiating a new connection for every file.
我希望我的app.js建立一个连接,然后在require行期间将其传递给每个文件。如何将连接传递给它们以便这些文件可以使用它?
I want my app.js to make ONE connection, and then pass it to every file during the require line. How can I pass the connection to them so those files can use it?
(或者如何将连接池传递给它们?)
(Or how can I pass a pool of connections to them?)
推荐答案
你可以创建一个单独的模块,称之为 mysqlLib.js
,它将负责创建一个池和返回的连接:
You can create a separate module, call it mysqlLib.js
that will be responsible for creating a pool and returning connections:
var mysql = require("mysql");
var pool = mysql.createPool(/* credentials go here */);
exports.getConnection = function(callback) {
pool.getConnection(function(err, conn) {
if(err) {
return callback(err);
}
callback(err, conn);
});
};
在任何需要mysql连接的模块/文件中,你可以这样做:
and in any module/file that needs a mysql connection, you can do this:
var mysqlLib = require("mysqlLib");
mysqlLib.getConnection(function(err, mclient) {
//do queries that you need
});
require()
的方式有效, mysqlLib.js
中的代码只会运行一次,因此即使 require(mysqlLib.js} $ c,也只会创建一个池在多个文件中调用$ c>。请参阅node.js文档的此部分模块缓存的解释。
The way require()
works, the code in mysqlLib.js
will only be run once so only one pool will be created even if require("mysqlLib.js"}
is called in multiple files. See this section of the node.js docs for an explanation of module cacheing.
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