A simple static PHP class which can be used to interface with the omnicha.in API. Wallet support will be implemented later in another class named OmnichainWallet.

omnichain.php

<?php

class Omnichain {
    private static $baseurl = "https://omnicha.in/api/";

    // Returns an array of general information about the network such
    // as difficulty, network hashrate, total block count etc.
    public static function getInfo() {
        return self::call("getinfo");
    }

    // Returns the balance of a given address as a floating point number.
    // Returns 0 on unseen addresses, throws exception on invalid addresses.
    public static function getBalance($address) {
        $data = array("address" => $address);
        $response = self::call("getbalance", $data);
        return $response['balance'];
    }

    // Checks whether or not an address is valid.
    // Returns a boolean value.
    public static function checkAddress($address) {
        $data = array("address" => $address);
        $response = self::call("checkaddress", $data);
        return $response['isvalid'];
    }

    // Validate a message signed using an Omnicoin address.
    // Returns true if the signature is valid, false if invalid.
    public static function verifyMessage($address, $message, $signature) {
        $data = array(
            "address" => $address,
            "message" => $message,
            "signature" => $signature,
        );

        $response = self::call("verifymessage", $data);
        return $response['isvalid'];
    }

    // Fetches the numbers needed to draw charts for the same things as getInfo().
    public static function getCharts() {
        return self::call("getcharts");
    }

    // Get a list of the 100 richest addresses, including their amount, value in USD,
    // vanity name and the percentage of all coins in circulation owned by it.
    public static function getRichList() {
        return self::call("getrichlist")['richlist'];
    }

    // Get statistics about Omnichain's online wallet service, currently the amount of
    // registered users and their cumulative balance.
    public static function getWalletStatistics() {
        return self::call("getwstats");
    }

    // Call a remote method on the API, decode the response.
    // Throws OmnichainException on error.
    private static function call($method, $data = null) {
        // Build the request URL
        $url = self::$baseurl . "?method=" . $method;
        if($data !== null) {
            $url .= "&" . http_build_query($data);
        }

        // Set up cURL
        $ch = curl_init($url);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt($ch, CURLOPT_TIMEOUT, 10);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);

        // Execute request
        $output = curl_exec($ch);
        curl_close($ch);

        // Parse response
        $response = json_decode($output, true);

        // Throw a checked exception on error
        if($response['error'] === true) {
            throw new OmnichainException($response['error_info']);
        }

        return $response['response'];
    }
}

class OmnichainException extends Exception {

}