We often need to deal with character sets when database connections, especially when the data stored in the database contains non-ASCII characters, making sure the character set is set correctly. The mysqli::get_charset function is used to obtain the character set (charset) used by the current database connection. However, some developers find that the returned character set is always latin1 when using this function, even if they have set other character sets (such as UTF-8) when connecting to the database. So, why does this happen? What exactly went wrong?

The header() function is used to send raw HTTP header information. These headers can control the behavior of the browser, such as setting page redirection. Page redirection is usually used when you need to direct the user to a different page, such as redirecting to the user's homepage after logging in, or to a new page under certain conditions.

When a browser accesses a web page, the server first establishes communication with the browser through the HTTP protocol. This process involves sending HTTP header information and subsequent HTML content. HTTP header information not only contains basic information of the web page (such as content type, character set, etc.), but also determines how the browser handles the page display, cache, jump and other behaviors.

In PHP development, mysqli_result is a common function for processing database query results. After executing the query through mysqli_query, we can use mysqli_result to get the query results. Although this function is widely used in different database operations, its performance may vary when processing data of different field types. This article will explore the performance differences of mysqli_result when processing data of different field types, helping developers better optimize query efficiency.

str_split is a very practical function that can cut a string into multiple substrings. If you want to cut the string by every two characters, you can do it by setting the second parameter of the function. This article will explain in detail how to use the str_split function to achieve this goal.

In PHP development, the mysqli extension is a widely used database interface that allows developers to interact with data through a MySQL database. In order to ensure the correct storage and query of data, the setting of the character set is a very important part. In some cases, when we use the mysqli::get_charset function to view the current character set, we may find that the displayed character set is different from the character set you set. Why is this? We will discuss this in this article.

In PHP array operations, array_flip() and array_values() are two very powerful functions. When you are dealing with arrays that are confusing, irregular, or need to be reconstructed, the combination of these two functions can bring unexpected efficiency gains.

In PHP programming, constants are identifiers that cannot be changed during execution and are often used for declarations of configuration parameters or fixed values. When we are developing large applications or debugging third-party libraries, we sometimes need to detect which constants are defined or modified in a certain piece of code. At this time, the get_defined_constants() function comes in handy.

When developing using MySQL databases, mysqli_result is a commonly used class that provides encapsulation of query results, allowing developers to extract data in the result set through a series of fetch_* methods. However, many developers encounter a problem when using these methods: after multiple calls to the fetch_* method, the query results seem to "disappear" and cannot be accessed again. What's going on? Let's take a deeper look.

In PHP, a constant is an identifier that will not be modified and is usually used to hold values ​​that remain unchanged during the run of the program. For debugging or learning purposes, we sometimes need to view all the constants defined in the current script. Fortunately, PHP provides a built-in function get_defined_constants() that can get information about all available constants at once.

In large PHP projects, the management of constants is an issue that cannot be ignored. Too many hard-coded constants are not only difficult to maintain, but are also not conducive to switching configurations between different environments. This article will explore how to build a flexible and centralized constant management mechanism through PHP's get_defined_constants() function combined with environment variable constants (such as .env files or server environment variables) to improve the maintainability and configurability of the project.

When developing PHP applications, character encoding settings of databases are a very important aspect. Correct character encoding settings can ensure accurate storage and correct display of data. In MySQL, character set selection often affects the behavior when querying, inserting, and updating data. If the character encoding of the database connection is incorrect, it may cause garbled code problems and even affect the stability of the application. To check and set the correct character encoding, PHP provides the mysqli::get_charset method to get the currently connected character set.

When building high-performance and flexible network services, PHP is not limited to building web applications, it also has the ability to handle underlying network communications. Through PHP's Socket extension, we can create a server-side program based on a custom protocol. This article will provide an in-depth introduction to how to implement a custom protocol server using socket_accept(), including basic principles and complete examples.

In PHP development, the date_sunset() function is a very useful tool that can get the sunset time at a specified location. The return value of this function is a UNIX timestamp (i.e. the number of seconds since January 1, 1970) and we usually need to convert it to a readable date-time format. In this article, we will explore how to correctly convert integer timestamps from date_sunset() output.

The curl_share_init() function is used to initialize a shared cURL handle, which can share certain resources, such as cookies or caches in multiple cURL sessions. This function is especially useful, and can effectively reduce unnecessary resource overhead when you want to reuse certain resources in multiple cURL requests.

curl_share_init is a function in the PHP cURL extension that allows multiple cURL handles to share the same resource. Specifically, using curl_share_init can allow multiple cURL requests to share data connections, cookie information, DNS resolution cache, etc. In this way, duplicate network connection overhead can be effectively reduced and performance can be improved, especially when handling a large number of concurrent requests.

The file_get_contents() function is used to read files or get content from a URL. When you need to request remote resources through the HTTP protocol, file_get_contents() can combine a stream context to set the context options for the request. We can use the stream_context_get_options() function to view the configuration information of the current stream context, and then understand how the request is sent.

PHP's header() function is a very common function, which is used to send raw HTTP header information to the client browser. Through this function, developers can control the header information of the page response, thereby affecting the behavior of the browser. For example, it can be used to set redirects, modify content types, control caches, etc.

How to set the JSON response header with the header function and return data with the AJAX call?