PHP流上下文 - >在这种情况下如何使用？

Question

I have a system that stores user comments in its own individual json file. I use scandir(); on the directory which gets all files and folders, but how do I limit it to json files, I don't want other files such as "." and ".." in the array because I need an accurate count.

I checked out the info on php.net but couldn't figure it out, perhaps you know of a resource you can point me toward, or which function to use.

Answer 1

This is a lovely example where the PHP library comes to the rescue. FilterIterator is a class that you extend and override its accept method to use only the files you want. In this case we use a standard FilesystemIterator to iterate over a directory. You could also use a RecursiveDirectoryIterator if you want to search for json files in sub-directories. This example iterates over json files in the current directory:

class StorageFilterIterator extends FilterIterator {

    function accept() {
        $item = $this->getInnerIterator()->current();
        return $item->isFile() && $item->getExtension() === 'json';
    }

}

$storageFiles = new StorageFilterIterator(new FilesystemIterator(__DIR__));

foreach ($storageFiles as $item) {
    echo $item;
}

getExtension exists in PHP >= 5.3.6

---

Another lesser-known part of the Standard PHP Library (SPL) is iterator_to_array . So if you want all of the items in an array instead of just iterating over them, you can do the following:

$storageFiles = iterator_to_array(
    new StorageFilterIterator(new FilesystemIterator(__DIR__))
);

Answer 2

There are no stream context parameters that will help you filter out the types of files.

Assuming that your JSON files are saved with the .json extension, you just have to filter out the array based on the file extensions.

You can use readdir() to build a list of files, or simply loop over the results you get from scandir and create a new array from that.

Here is an example using readdir :

$files = array();
$dh = opendir($path);
while (($file = readdir($dh) !== false) {
    if (pathinfo($path . '/' . $file, PATHINFO_EXTENSION) !== 'json') continue;
    $files[] = $path . '/' . $file;
}

closedir($dh);

// $files now has an array of json files