The difference between stream_get_line and fgets and the comparison of usage scenarios

How fgets() works

fgets() is the most commonly used function to read a row of data. Its definition is as follows:

 fgets(resource $handle, ?int $length = null): string|false

• $handle is an open file pointer (as obtained with fopen() ).

• $length is the optional maximum read length (including line breaks). If not specified, fgets() will be read until the end of the line ( \n ) or the end of the file.

Features:

• Automatically ends with a newline character ( \n ).

• Contains newlines in the returned string.

• Suitable for reading "standard line format".

• Unable to customize line ending characters.

Example:

 $handle = fopen("https://gitbox.net/data.txt", "r");
while (($line = fgets($handle)) !== false) {
    echo $line;
}
fclose($handle);

How stream_get_line() works

stream_get_line() is a more underlying and flexible reading function, defined as follows:

 stream_get_line(resource $handle, int $length, string $ending = ""): string|false

• $length is the maximum number of bytes to be read.

• $ending is a custom line ending character (optional).

Features:

• The ending character itself is not returned.

• Allow custom line ending characters (such as "\r\n" commonly used in HTTP headers).

• Not suitable for reading binary data blocks containing line breaks.

• The return content does not include line ending characters, so it is more suitable for scenarios where data structures are precisely controlled.

Example:

 $handle = fopen("https://gitbox.net/api/stream", "r");
while (($line = stream_get_line($handle, 1024, "\r\n")) !== false) {
    echo $line . PHP_EOL;
}
fclose($handle);

Summary of the difference

Each suitable use scenario

fgets() is suitable for:

• Read local log files or configuration files.

• Quickly read text data organized by row.

• When writing scripts to process standard input or file input.

stream_get_line() is suitable for:

• Read segmented data in network protocols such as HTTP or SMTP.

• Controls row read behavior (excluding ending symbols).

• Build your own parser (such as custom protocols, stream data cut based on line ending characters).