NodeJS：验证请求类型（检查JSON或HTML） [英] NodeJS : Validating request type (checking for JSON or HTML)

问题描述

我想检查客户端请求的类型是JSON还是HTML，因为我希望我的路由满足人机和机器的需求。

I would like to check if the type that is requested by my client is JSON or HTML, as I want my route to satisfy both human and machine needs.

我已阅读Express 3文档：

I have read the Express 3 documentation at:

http://expressjs.com/api.html

有两种方法 req.accepts（）和 req.is（），使用如下：

And there are two methods req.accepts() and req.is(), used like this:

req.accepts('json') 

或

req.accepts('html') 

由于这些都不行，所以我尝试使用：

Since these are not working as they should, I tried using:

var requestType = req.get('content-type');

或

var requestType = req.get('Content-Type');

requestType 总是未定义 ...

使用此线程的建议：

Express.js检查请求类型。 is（）不工作

也不起作用。我究竟做错了什么？

does not work either. what am I doing wrong?

编辑1 ：我检查过正确的客户端HTML协商。这是我的两个不同的请求标头（从调试器检查器获取）：

Edit 1: I have checked for correct client HTML negotiation. Here are my two different request headers (taken from the debugger inspector):

HTML：接受：text / html ，application / xhtml + xml，application / xml; q = 0.9，* / *; q = 0.8

JSON：接受：application / json，text / javascript，* / *; q = 0.01

---

（感谢Bret）：

---

Solution (thanks to Bret):

原来我指定了接受标题错误，而 * / *

Turns out I was specifying the Accept headers wrong, and the */* was the issue. Here is the code that works!

//server (now works)
var acceptsHTML = req.accepts('html');
var acceptsJSON = req.accepts('json');

if(acceptsHTML)  //will be null if the client does not accept html
{}

我正在使用JSTREE，一个使用jQuery Ajax调用的jQuery插件。传递给Ajax调用的参数在ajax字段中，我已经用一个完整的headers对象替换了accept参数。现在它的工作原理，并且应该解决问题，当你使用纯粹的jQuery，如果它应该发生。

I am using JSTREE, a jQuery plugin that uses jQuery Ajax calls underneath). The parameters passed to the Ajax call are in the "ajax" field, and I have replaced the "accepts" parameter with a complete "headers" object. Now it works, and should solve the problem when you are using plain jQuery if it should ever occur.

//client 

.jstree({
            // List of active plugins
            "plugins" : [
                "themes","json_data","ui","crrm","cookies","dnd","search","types","hotkeys","contextmenu"
            ],

            "json_data" : {
                "ajax" : {
                    // the URL to fetch the data
                    "url" : function(n) {
                        var url = n.attr ? IDMapper.convertIdToPath(n.attr("id")) : "<%= locals.request.protocol + "://" + locals.request.get('host') + locals.request.url %>";
                        return url;
                    },
                    headers : {
                        Accept : "application/json; charset=utf-8",
                        "Content-Type": "application/json; charset=utf-8"
                    }
                }
            }
        })

推荐答案

var requestType = req.get（'Content-Type'）; 绝对有效，如果一个内容类型实际上在请求中指定（我只是re - 一分钟前验证）。如果没有定义content-type，那么它将是未定义的。请记住，通常只有POST和PUT请求将指定内容类型。其他请求（如GET）通常会指定接受类型的列表，但这显然不一样。

var requestType = req.get('Content-Type'); definitely works if a content-type was actually specified in the request (I just re-verified this a minute ago). If no content-type is defined, it will be undefined. Keep in mind that typically only POST and PUT requests will specify a content type. Other requests (like GET) will often specify a list of accepted types, but that's obviously not the same thing.

编辑：

好的，我现在更了解你的问题。你正在谈论接受：标题，而不是内容类型。

Okay, I understand your question better now. You're talking about the Accept: header, not content-type.

发生了什么：注意 * / *; q = 0.8 在列表接受类型的末尾？这基本上说我会接受任何东西。因此，由于技术上它是一个被接受的内容， req.accepts（'json'）总是返回json

Here's what's happening: notice the */*;q=0.8 at the end of listed accept types? That essentially says "I'll accept anything." Therefore, req.accepts('json') is always going to return "json" because technically it's an accepted content type.

我想你想要看是否明确列出了 application / json ，如果是，在json中回应，否则在html中回复。这可以通过几种方式完成：

I think what you want is to see if application/json is explicitly listed, and if so, respond in json, otherwise respond in html. This can be done a couple of ways:

// a normal loop could also be used in place of array.some()
if(req.accepted.some(function(type) {return type.value === 'application/json';}){
    //respond json
} else {
    //respond in html
}

或使用简单的正则表达式：如果（/ application \ / json; /。test（req.get（'accept'）））{

or using a simple regular expression:

if(/application\/json;/.test(req.get('accept'))) {
    //respond json
} else {
    //respond in html
}

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