FILTERS.md

Filters

The filters can be a really powerful option when parsing a file. They can be used to validate file contents before ingesting them into the system, for manipulating the data by removing or adding characters, adding in other data so that it works better in a database, or creating an object from the field.

NOTE: Filters do not work with Maps

Customers.csv

So given the file below

ID	Name	Phone	Address
1	George Jetson	+1 (234) 456-7890	123 Main St, Anytown, ST 12345 US
2	Fred Flintstone	+1 1-1	1 Rocky Rd, Stonetown, CV 1 MINE

Once you open the file you need to add the filter with a callback method.

$reader = new Reader('/path/to/file.csv');
$filter = new Filter('Phone', [Employee::class, 'stripPhone']);
$reader->addFilter($filter);

Then you'll need to add the callback method to the appropriate class (making sure it is callable from the CSVReader class).

class Employee
{
    public static function stripPhone($val): string
    {
        return preg_replace("/[^0-9\+]/", "", $val);
    }

If you follow the above it will return

+1234567890
+111

If the data that you want to 'objectify' is all in one column you can use this to parse that data and turn it into an object. Example, address data. Your file has customer address data in one field (if the data is in separate fields you'll need to use a Link). In this case, you are adding a filter to an existing column header, so when calling that field, it will

First you need to create the Address class and the method you want to use to parse the data.

class Address 
{
    public static function fromCSV(string $data): Address
    {
        $me = new static();
        
        // you'll want to do some validation on the address

        // explode the string into an array
        $add_arr = explode(',', $data);
        
        // first element in the array is the street address
        $me->add = $add_arr[0];
        
        // second element is the city
        $me->city = trim($add_arr[1]);
        
        // third element needs to be split on a space to get the state, zip, and country
        $szc = explode(' ', $add_arr[2]); 
        $me->state = trim($szc[0]);
        $me->zip = trim($szc[1]);
        $me->country = trim($szc[2]);

        return $me;
    }
    ...

Then add the Address object within your Customer class.

class Customer
{
    public Address $address;
    ...
}

Then you'll just need to open the file with the reader, add the filter (before reading), and then where you need it, read the Address property.

// opening the customer file
$reader = new Reader('/path/to/customer.csv');
// add the filter (must be done prior to reading)
$filter = new Filter('Address', [Address::class, 'fromCSV']);
$reader->addFilter($filter);
...
// create the customer and read the address
$customer = new Customer();
$customer->address = $reader->Address;