NAME

Protocol::HAP::Store::File - the store contract over files

SYNOPSIS

    use Protocol::HAP::Store::File;
    my $store = Protocol::HAP::Store::File->new(
        path   => '/var/db/openhapd',
        logger => $logger,
    );
    $store->save_pairing('controller-id', $ltpk, 1);
    my $pairings = $store->load_pairings;

DESCRIPTION

This module is the durable implementation of the store contract that Protocol/HAP/Store.pod documents. The state lives in one directory and survives a restart, which is what a paired accessory needs: a controller that sees "c#" go backwards drops the accessory.

The tier holds a sans-IO engine, and this module writes files. That is the point. Sans-IO describes Protocol::HAP::Server, and the store is the injected seam that keeps the engine pure.

CONSTRUCTOR

new(%args)

"path": The state directory. The argument is required, and "new" dies without it. The caller owns the location, because a default path is host policy. "new" creates the directory with mode 0700 when it is absent.
"logger": A logger with "debug", "info", "warning", and "error". The default is "Protocol::HAP->null_logger", which drops every message.

FILES

Every write applies the mode at the open, before the first byte. A "chmod" after the write leaves a window in which the identity of the accessory is world-readable.

<path>/accessory_ltsk: The long-term secret key of the accessory, mode 0600.
<path>/accessory_ltpk: The long-term public key of the accessory, mode 0644.
<path>/pairings.db: One line for each paired controller, mode 0600. The format is "controller_id:ltpk_hex:permissions". One process owns the store, so a read takes no lock.
<path>/state.json: The configuration number, the configuration digest, and the counter of pairing failures, mode 0600. The write goes through a sibling temporary file and a rename, so a reader sees the old content or the new content. A missing or corrupt file gives empty state, because a state file that a crash truncated must not stop the daemon that would rewrite it.