使用Bluebird手动实现pg.connect [英] Manually promisifying pg.connect with Bluebird

问题描述

我想使node-postgres的pg.connect方法与回调中提供的内部connection.query方法一致.

I want to promisify node-postgres' pg.connect method along with the inner connection.query method provided in the callback.

我可以.promisify后者，但是我需要手动实现第一个(如果我在这里遗漏了一些东西，请解释).

I can .promisify the latter, but I need to implement the first one manually (if I'm missing something here, please explain).

问题是，我不确定此代码是否正确或应该改进?该代码正在运行，我只想知道我是否按预期使用了Bluebird.

The thing is, I'm not sure if this code is correct or should be improved? The code is working, I just want to know if I'm using Bluebird as meant.

// aliases
var asPromise = Promise.promisify;

// save reference to original method
var connect = pg.connect.bind(pg);

// promisify method
pg.connect = function (data) {
  var deferred = Promise.defer();

  connect(data, function promisify(err, connection, release) {
    if (err) return deferred.reject(err);

    // promisify query factory
    connection.query = asPromise(connection.query, connection);

    // resolve promised connection
    deferred.resolve([connection,release]);
  });

  return deferred.promise;
};

推荐答案

丢掉所有可怕的回调代码，然后在应用程序初始化的某个位置进行操作:

Throw all that horrible callback code away, then do this somewhere in your application initialization:

var pg = require("pg");
var Promise = require("bluebird");

Object.keys(pg).forEach(function(key) {
    var Class = pg[key];
    if (typeof Class === "function") {
        Promise.promisifyAll(Class.prototype);
        Promise.promisifyAll(Class);
    }
})
Promise.promisifyAll(pg);

以后在任何可以使用pg模块的地方都可以使用它，就像它被设计为使用promises开头一样.

Later in anywhere you can use the pg module as if it was designed to use promises to begin with:

// Later
// Don't even need to require bluebird here
var pg = require("pg");
// Note how it's the pg API but with *Async suffix
pg.connectAsync(...).spread(function(connection, release) {
     return connection.queryAsync("...")
         .then(function(result) {
            console.log("rows", result.rows);
         })
         .finally(function() {
            // Creating a superfluous anonymous function cos I am
            // unsure of your JS skill level
            release();
         });
});

这篇关于使用Bluebird手动实现pg.connect的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！