In PHP file handling, fopen() and rewind() are two fundamental yet crucial functions, especially when dealing with large files or scenarios where you need to read file content repeatedly. Many beginners often face issues such as "empty content on read" or "incorrect pointer position" when using these two functions. This article will provide a detailed explanation of how to properly use rewind() to reset the file pointer after opening a file with fopen().

In daily PHP development, file reading is a very basic but extremely important operation. PHP provides a variety of ways to read files. Fopen and fgets (often called getLine) can achieve more flexible, memory-friendly line-by-line reading operations, which are ideal for handling large files or log files.

Stream filters provide a very powerful and flexible way to handle file streams or other types of data streams. Through the flow filter, we can process and modify the input data in real time. In this article, we will explore in detail how to use the stream_get_filters function in conjunction with fopen to implement the function of a stream filter.