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English
In PHP, Streams is one of the core mechanisms for handling files, network connections, input and output operations. PHP provides a powerful stream processing interface, making it more flexible and efficient to operate streaming data. Especially when you need to filter and process data in a stream, the two functions stream_get_filters and stream_filter_append will be very useful tools.
The stream_get_filters function returns an array containing all available stream filter names. A stream filter is a mechanism for processing data in a stream, which allows us to read, write, or modify the data of a stream in different ways.
$filters = stream_get_filters();
print_r($filters);
The above code will list all registered stream filters. You can use these filters to process streaming data differently, such as converting data encoding, encryption, compression, etc.
The stream_filter_append function allows us to append a filter to a specified stream. With this function, we can apply filters to the open stream to process the data in the stream in real time. The syntax of this function is as follows:
stream_filter_append($stream, $filtername, $read_write = STREAM_FILTER_READ, $params = null);
$stream : The stream resource that requires additional filters.
$filtername : The name of the filter.
$read_write : Specifies whether the filter is applied to a read stream, a write stream, or both.
$params : Extra parameters passed to the filter.
When you need to efficiently process stream data in PHP, stream_get_filters and stream_filter_append work together, allowing you to select the right filter according to different needs and apply it to the open stream.
Here is an example of using stream_get_filters and stream_filter_append to process file streams:
<?php
// Get all available stream filters
$filters = stream_get_filters();
echo "Available filters:\n";
print_r($filters);
// Open a file stream
$file = fopen('example.txt', 'r+');
if (!$file) {
die('Unable to open the file');
}
// Convert data to uppercase（Assume this filter exists）
$filter_name = 'string.toupper';
// Check if the filter exists
if (in_array($filter_name, $filters)) {
// Attach filter to file stream
stream_filter_append($file, $filter_name, STREAM_FILTER_READ);
echo "Filters have been added '$filter_name' Attach to file stream\n";
} else {
echo "Filter '$filter_name' Does not exist\n";
}
// Read file data and output
while (($line = fgets($file)) !== false) {
echo $line;
}
// Close the file stream
fclose($file);
?>
In the above code, we first use stream_get_filters to get all available stream filters, and then check if a filter named string.toupper exists. If the filter exists, we append it to the file stream using stream_filter_append to convert all data in the file into capital letters.
Through stream filters, we can modify data in real time during streaming data processing without loading the entire data into memory, which is especially efficient for processing large amounts of data. For example, when processing large files, using stream filters can read and process data line by line, avoiding loading the entire file into memory at once, saving memory and improving processing efficiency.
Stream filters can be applied not only to file streams, but also to other streams such as network connections. Assuming you need to read data from a network stream and transmit it encryptedly, you can do this:
<?php
// Open one to gitbox.net Network connection
$fp = fopen("tcp://gitbox.net:80", "r+");
if (!$fp) {
die("Unable to connect to the server");
}
// 添加加密Filter
$filter_name = 'mcrypt.des';
stream_filter_append($fp, $filter_name, STREAM_FILTER_READ);
// Read encrypted data
$data = fread($fp, 1024);
echo "Encrypted data: " . $data;
// Close the connection
fclose($fp);
?>
In this example, we open a TCP connection to gitbox.net and apply an encryption filter to the stream. This ensures data security when performing network data transmission.
Through the combination of stream_get_filters and stream_filter_append , PHP developers can flexibly and efficiently process streaming data, which can significantly improve the performance and reliability of the program whether it is file processing or network data transmission.
