The League of Extraordinary Packages

Our Packages:

Presented by The League of Extraordinary Packages

Getting Started

Connections Settings

Inserting Records

Selecting Records

Interoperability

Converting Records

Upgrading Guide

Writer connection

<?php

class Writer extends AbstractCsv
{
    public function addFormatter(callable $callable): Writer
    public function addValidator(callable $callable, string $validatorName): Writer
    public function getFlushThreshold(): ?int
    public function getNewline(): string
    public function insertAll(iterable $records): int
    public function insertOne(array $record): int
    public function setFlushThreshold(?int $threshold): self
    public function setNewline(string $sequence): self
}

The League\Csv\Writer class extends the general connections capabilities to create or update a CSV document.

When inserting records into a CSV document using League\Csv\Writer, first insert all the data that need to be inserted before starting manipulating the CSV. If you manipulate your CSV document before insertion, you may change the file cursor position and erase your data.

Inserting records

<?php

public Writer::insertOne(array $record): int
public Writer::insertAll(iterable $records): int

Writer::insertOne inserts a single record into the CSV document while Writer::insertAll adds several records. Both methods returns the length of the written data.

Writer::insertOne takes a single argument, an array which represents a single CSV record. Writer::insertAll takes a single argument a PHP iterable which contains a collection of CSV records.

<?php

use League\Csv\Writer;

$records = [
    [1, 2, 3],
    ['foo', 'bar', 'baz'],
    ['john', 'doe', 'john.doe@example.com'],
];

$writer = Writer::createFromPath('/path/to/saved/file.csv', 'w+');
$writer->insertOne(['john', 'doe', 'john.doe@example.com']);
$writer->insertAll($records); //using an array
$writer->insertAll(new ArrayIterator($records)); //using a Traversable object

In the above example, all CSV records are saved to /path/to/saved/file.csv

If the record can not be inserted into the CSV document a League\Csv\CannotInsertRecord exception is thrown. This exception extends League\Csv\Exception and adds the ability to get the record on which the insertion failed.

<?php

use League\Csv\CannotInsertRecord;
use League\Csv\Writer;

$records = [
    [1, 2, 3],
    ['foo', 'bar', 'baz'],
    ['john', 'doe', 'john.doe@example.com'],
];

try {
    $writer = Writer::createFromPath('/path/to/saved/file.csv', 'r');
    $writer->insertAll($records);
} catch (CannotInsertRecord $e) {
    $e->getRecords(); //returns [1, 2, 3]
}

Handling newline

Because PHP’s fputcsv implementation has a hardcoded \n, we need to be able to replace the last LF code with one supplied by the developper for more interoperability between CSV packages on different platforms. The newline sequence will be appended to each newly inserted CSV record.

Description

<?php

public Writer::setNewline(string $sequence): self
public Writer::getNewline(void): string

Example

<?php

use League\Csv\Writer;

$writer = Writer::createFromFileObject(new SplFileObject());
$newline = $writer->getNewline(); // equals "\n";
$writer->setNewline("\r\n");
$newline = $writer->getNewline(); // equals "\r\n";
$writer->insertOne(["one", "two"]);
echo $writer->getContent(); // displays "one,two\r\n";

The default newline sequence is \n;

If you are using a non seekable CSV document, changing the newline character will trigger an exception.

Flushing the buffer

For advanced usages, you can now manually indicates when flushing mechanism occurs while adding new content to your CSV document.

Description

<?php

public Writer::setFlushThreshold(?int $treshold): self
public Writer::getFlushThreshold(void): ?int

By default, getFlushTreshold returns null.

Writer::insertAll always flush its buffer when all records are inserted regardless of the threshold value.

If set to null the inner flush mechanism of PHP's fputcsv will be used.

Records filtering

<?php

public Writer::addFormatter(callable $callable): Writer
public Writer::addValidator(callable $callable, string $validatorName): Writer

Sometimes you may want to format and/or validate your records prior to their insertion into your CSV document. the Writer class provides a formatter and a validator mechanism to ease these operations.

Writer::addFormatter

Record Formatter

A formatter is a callable which accepts an single CSV record as an array on input and returns an array representing the formatted CSV record according to its inner rules.

<?php

function(array $record): array

Adding a Formatter to a Writer object

You can attach as many formatters as you want to the Writer class using the Writer::addFormatter method. Formatters are applied following the First In First Out rule.

<?php

use League\Csv\Writer;

$formatter = function (array $row): array {
    return array_map('strtoupper', $row);
};
$writer = Writer::createFromFileObject(new SplTempFileObject());
$writer->addFormatter($formatter);
$writer->insertOne(['john', 'doe', 'john.doe@example.com']);

$writer->getContent();
//will display something like JOHN,DOE,JOHN.DOE@EXAMPLE.COM

Writer::addValidator

Record Validator

A validator is a callable which takes single CSV record as an array as its sole argument and returns a boolean to indicate if it satisfies the validator inner rules.

<?php

function(array $record): bool

The validator must return true to validate the submitted record.

Any other expression, including thruthy ones like yes, 1,… will make the insertOne method throw an League\Csv\CannotInsertRecord.

Adding a Validator to a Writer object

As with the formatter capabilities, you can attach as many validators as you want using the Writer::addValidator method. Validators are applied following the First In First Out rule.

The CSV record is checked against your supplied validators after it has been formatted.

Writer::addValidator takes two (2) required parameters:

On failure a League\Csv\CannotInsertRecord exception is thrown.
This exception will give access to:

<?php

use League\Csv\Writer;
use League\Csv\CannotInsertRecord;

$writer->addValidator(function (array $row): bool {
    return 10 == count($row);
}, 'row_must_contain_10_cells');

try {
    $writer->insertOne(['john', 'doe', 'john.doe@example.com']);
} catch (CannotInsertRecord $e) {
    echo $e->getName(); //display 'row_must_contain_10_cells'
    $e->getData();//will return the invalid data ['john', 'doe', 'john.doe@example.com']
}