PHP WeChat payment notification processing method implementation method

This article is a supplement to the previous article. The main reason is that there is no official demo about notifications. It is really difficult to cross the river by touching stones. It is convenient for everyone to develop and release it for everyone to see

The implementation of the notification mechanism only has official documentation and no demo code. For those who have never done it before, it will take a lot of time to test. Judging from what the document says, the structure of the data notified each time by WeChat is relatively complex. It is a multi-segment data. In addition to fetching the POST data, other data must also be fetched. This first involves a question about the values ​​​​of php://input and $_POST. A few simple points are as follows: 1. When the Content-Type value is application/x-www-form-urlencoded, PHP will fill in the corresponding data of the http request body into the array $_POST, and the data filled in the $_POST array will be parsed by urldecode() the result of. (Actually, in addition to the Content-Type, there is also multipart/form-data indicating that the data is form data, which we will introduce later)

2. php://input data, as long as the Content-Type is not multipart/form-data (this condition will be introduced later). Then the php://input data is consistent with the http entity body part of the data. The length of this partially consistent data is specified by Content-Length.

3. Only when the Content-Type is application/x-www-form-urlencoded and the submission method is the POST method, the $_POST data and the php://input data are "consistent" (with quotation marks, indicating that their formats are inconsistent, content is consistent). Otherwise, they are inconsistent.

4, php://input cannot read $_GET data. This is because the $_GET data is written in the PATH field of the http request header as query_path, rather than in the body part of the http request. Helps us understand why the xml_rpc server reads data through file_get_contents(‘php://input’, ‘r’). Instead of reading from $_POST, it is precisely because the data specification of xml_rpc is xml and its Content-Type is text/xml.

5. php://input encounters multipart/form-data, please check RFC1867 for its description. multipart/form-data also means submitting form data using the POST method. It is also accompanied by file upload, so it will be different from the application/x-www-form-urlencoded data format. It will be passed to the server in a more reasonable and efficient data format. When Content-Type is multipart/form-data, even if there is data in the HTTP request body, php://input is empty. At this time, PHP will not fill in the data into the php://input stream. Therefore, it is certain: php://input cannot be used to read enctype=multipart/form-data data.

6. When the Content-Type is application/x- www-form-urlencoded, php://input and $_POST data are "consistent". When it is other Content-Type, php://input and $_POST Data data is inconsistent. Because only when the Content-Type is application/x-www-form-urlencoded or multipart/form-data, PHP will fill in the corresponding part of the body data in the http request packet into the $_POST global variable. In other cases, PHP ignores both. Except that php://input is empty when the data type is multipart/form-data, it may not be empty in other situations. The meaning of so many words paraphrased above is that these two methods must be used to read the data sent by WeChat. Get $POST first. This is a regular payment notification message, in the form of: