PHP Determines whether a request is an AJAX request or a normal request

In the PHP program, how to determine whether a Web request is an AJAX request or a normal request? We often have a problem with the project, in the browser directly input my Ajax submitted address, the browser can directly request the data and print the data on the page. In terms of procedural rigor and security, I think it's very bad.

But because of the limited level, this problem until today to be solved by me, I hereby leave the article for those who need to learn.

First, the principle: When sending Ajax requests, we can create custom header headers by XMLHttpRequest This object, if you are using native Ajax methods, that is, Ajax methods that are not packaged with jquery or other JS frameworks, So the code is as follows:

Xmlhttprequest.setrequestheader ("Request_type", "Ajax");

Also through the $.ajax () method of the jquery wrapper, we can easily create our custom header header information before we send the AJAX request, as shown in the following example:

$.ajax ({
	type: "Get",
	Url:base_url + ' php_check_ajax_request/get_user_list.html ',
	beforesend:function (XMLHttpRequest) {
		Xmlhttprequest.setrequestheader ("Request_type", "Ajax");
	},
	success:function (data) {
		$ ("#user_ List "). HTML (data);
		$tip. Hide ();
		$button. attr (' disabled ', true);
	}
);

There is one sentence in the above code:

Xmlhttprequest.setrequestheader ("Request_type", "Ajax");

This code is to create a custom variable "Request_type" into header header information. This variable receives variables in PHP as follows:

$_server[' Http_request_type ']

So for the questions that are raised in this article, we can do the following to determine the type of request that the user sent.

<?php
if (isset ($_server[' Http_request_type ')) && $_server[' http_request_type '] = = "Ajax") {
	// Ajax Submit
}else{
	//non-AJAX submission
}

What needs to be explained is that the "request_type" variable value is our custom, you can also customize, such as "Test", "Is_ajax" and so on.

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