Express.js-添加响应主体

问题描述

我想在Express.js的响应对象中添加一个body属性，该属性将在每次send method is called时调用，我通过添加以下代码作为中间件来做到这一点，

I would like to add a body property to Express.js' response object, which will be called every time the send method is called,I do it by adding the following code as a middleware,

但由于某种原因，当我调用res.send时，此函数被调用两次(一次是body为object，第二次是同一对象，而是字符串)1.为什么叫两次?2.为什么以及何时将其转换为字符串?

but for some reason, when I call res.send this function is called twice (once when body is object and in the 2nd time the same object butas a string )1.why is it being called twice?2.why and when is it being converted to string?

   applicationsRouter.use(function (req, res, next) {
        var send = res.send;
        res.send = function (body) {
            res.body = body
            send.call(this, body);
        };
        next();
    });

推荐答案

您可能正在使用类似这样的东西:

You are probably using something like this:

res.send({ foo : 'bar' });

换句话说，您要将对象传递给res.send.

In other words, you're passing an object to res.send.

这将执行以下操作:

• 使用对象作为参数调用res.send
• res.send 检查参数类型，然后看到它是一个对象，并将其传递给res.json
• res.json将对象转换为JSON字符串，然后再次调用res.send，但这一次使用JSON字符串作为参数

• call res.send with the object as argument
• res.send checks the argument type and sees that it's an object, which it passed to res.json
• res.json converts the object to a JSON string, and calls res.send again, but this time with the JSON string as argument

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