# Recipes

These are some suggestions and ideas for when building your own protocols using the
various protocol classes.

## Marshalling objects

You can use the beforePackCb and afterUnpackCb to serialize and unserialize parameters
as desired. Consider the security implications of this before you do anything stupid
though, as a spoofed frame could have unexpected consequences when unserialized.

```php
$proto = new JsonProtocol(
    beforePackCb: function (array $frame): array {
        $frame['obj'] = serialize($frame['obj']);
        return $frame;
    },
    afterUnpackCb: function (array $frame): array {
        $frame['obj'] = unserialize($frame['obj]);
        return $frame;
    },
);
```

## Building line-based messages

By using the `beforePackCb` callback, you can take messages in a structured format
and return them as a list for line-based protocols. You can do the same in reverse
with the `afterUnpackCb` callback.

```php
$proto = new LineProtocol(
    beforePackCb: function (array $frame): array {
        switch ($frame['cmd']) {
            case 'search':
                return [ "search", $frame['query'] ];
            // ..
        }
    },
    afterUnpackCb: function (array $frame): array {
        switch ($frame[0]) {
            case 'search':
                return [ 'cmd' => $frame[0], 'query' => $frame[1] ];
            // ..
        }
    }
)
```