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How to obtain the submitted data in the parsing order of PHP variables, this article introduces the corresponding analysis and solution in detail, hoping to help more partners who want to solve this problem to find a more simple and feasible method.

The study of PHP can not be limited to a few concepts in books. We also need to continue to understand deeply from practice. Let's introduce the practice of parsing order of PHP variables. The story begins with a somewhat weird BUG, where an ad submission function that is not frequently used in the background sometimes inexplicably causes errors in the URL of the submitted link.

Because the link URL of the submission was not informed after the submission, this BUG has been alive to this day. However, this BUG does not appear in every commit, and after several tests, it is found that it only occurs when it is committed several times in a row. Due to the complexity of the submitted form, the input is divided into several parts, so it is suspected that an error occurred in the middle link.

The process of troubleshooting starts with var_dump ($_ REQUEST) in each process, so the error is found on the second consecutive submission, and the $_ REQUEST array changes during the submission of * * forms to the second form. At this point, we need to take another look at the $_ REQUEST array:

The manual contains variables that are submitted to the script through the GET,POST and COOKIE mechanisms, so the array is not trusted. By decomposing var_dump ($_ REQUEST) into var_dump ($_ POST), var_dump ($_ GET) and var_dump ($_ COOKIE), the problem is clearer. Originally, in order to save the value among multiple page forms, COOKIE was tried. Although the expire item is not set, the COOKIE is destroyed at the end of the SESSION, but if multiple advertisements are submitted continuously in a session, the value of the form POST will be overwritten by the value previously stored in COOKIE. The reason why only part of the error is that the COOKIE variable name is prefixed when saving to COOKIE, except for the variable url, which still uses the same variable name.

The problem is found, but there is a new question, the same variable name, why COOKIE overrides POST instead of the other way around? So it's time to finally come to the variables_order setting item in the title, which is as follows in php.ini:

This directive describes the order in which PHP registers GET, POST, Cookie

Environment and Built-in variables (G, P, C, E & S respectively, often

Referred to as EGPCS or GPC). Registration is done from left to right, newer

Values override older values.

This setting describes the order of PHP parsing variables, including the $_ GET,$_POST,$_COOKIE,$_ENV, $_ SERVER array.

The parsing order is from left to right, and then the new values overwrite the old ones. The default setting is EGPCS (Environment,GET,POST,Cookie,Server).

Setting it to "GP" causes PHP to completely ignore the environment variables, cookies and server variables, and overwrite the variables of the GET method with the variables of the POST method.

Conclusion:

As stated in the manual, $_ REQUEST is an untrusted array. To avoid similar problems, you should explicitly use the $_ POST or $_ GET array when getting the submitted value.

In special cases, you can always get the submission data you want by adjusting the variables_order settings.

The answer to the question about how to obtain the submitted data in the parsing order of PHP variables is shared here. I hope the above content can be of some help to you. If you still have a lot of doubts to be solved, you can follow the industry information channel for more related knowledge.

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