layout: default title: CSV document interoperability description: A Stream filter to improve RFC4180 compliance around CSV fields - deprecated feature

RFC4180 Field compliance

The RFC4180Field class enables to work around the following bugs in PHP's native CSV functions:

bug #43225: fputcsv incorrectly handles cells ending in \ followed by "
bug #55413: str_getcsv doesn't remove escape characters
bug #74713: CSV cell split after fputcsv() + fgetcsv() round trip.
bug #38301: field enclosure behavior in fputcsv (since version 9.1.0)

When using this stream filter you can easily create or read a RFC4180 compliant CSV document using League\Csv connections objects.

With CSV objects

public static RFC4180Field::addTo(AbstractCsv $csv, string $whitespace_replace = ''): AbstractCsv

The RFC4180Field::addTo method will register the stream filter if it is not already the case and add the stream filter to the CSV object using the following properties:

the CSV enclosure property;
the CSV escape property;
the CSV stream filter mode;

use League\Csv\RFC4180Field;
use League\Csv\Writer;

$writer = Writer::from('php://temp', 'r+');
$writer->setNewline("\r\n"); //RFC4180 Line feed
RFC4180Field::addTo($writer); //adding the stream filter to fix field formatting
$writer->insertAll($iterable_data);
$writer->output('mycsvfile.csv'); //outputting a RFC4180 compliant CSV Document

When the $whitespace_replace sequence is different from the empty space and does not contain:

one of the current CSV control characters;
a character that can trigger field enclosure;

its value will be used to:

prevent fputcsv default behavior of always using enclosure when a whitespace is found in a record field

use League\Csv\RFC4180Field;
use League\Csv\Writer;

$writer = Writer::from('php://temp', 'r+');
RFC4180Field::addTo($writer, "\0");
$writer->insertOne(['foo bar', 'bar']);
echo $writer->getContent(); //display 'foo bar,bar' instead of '"foo bar",bar'

use League\Csv\RFC4180Field;
use League\Csv\Writer;

$writer = Writer::from('php://temp', 'r+');
RFC4180Field::addTo($writer, 'fo'); //incorrect sequence this will alter your CSV
$writer->insertOne(['foo bar', 'bar']);
echo $writer->getContent(); //display ' o bar,baz' instead of 'foo bar,baz'

On Records Insertion

On Records Extraction

Conversely, to read a RFC4180 compliant CSV document, when using the League\Csv\Reader object, you just need to add the League\Csv\RFC4180Field stream filter as shown below:

use League\Csv\Reader;
use League\Csv\RFC4180Field;

//the current CSV is ISO-8859-15 encoded with a ";" delimiter
$csv = Reader::from('/path/to/rfc4180-compliant.csv', 'r');
RFC4180Field::addTo($csv); //adding the stream filter to fix field formatting

foreach ($csv as $record) {
    //do something meaningful here...
}

With PHP streams

public static RFC4180Field::register(): void
public static RFC4180Field::getFiltername(): string

To use this stream filter outside League\Csv objects you need to:

register the stream filter using RFC4180Field::register.
use RFC4180Field::getFiltername with one of PHP's attaching stream filter functions with the correct arguments as shown below:

use League\Csv\RFC4180Field;

RFC4180Field::register();

$resource = fopen('/path/to/my/file', 'r');
$filter = stream_filter_append($resource, RFC4180Field::getFiltername(), STREAM_FILTER_READ, [
    'enclosure' => '"',
    'escape' => '\\',
    'mode' => STREAM_FILTER_READ,
]);

while (false !== ($record = fgetcsv($resource))) {
    //$record is correctly parsed
}

Csv Laravel Package