snippet to connect to the Ravelry API

RavelryClientSignin.java

	private String createShopSearchQuery() throws NoSuchAlgorithmException, InvalidKeyException, UnsupportedEncodingException {
		String jsonAction = "http://api.ravelry.com/shops/search.json?";
		DateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'hh:mm:ss.SSSZ");
		Calendar now = Calendar.getInstance();
		String timestamp = df.format(now.getTime());
		String searchTerm = "yarn"; 
		int shop_type_id = 1;
		
		String query = jsonAction;
		query += "access_key=" + urlEncode(ACCESS_KEY);
		query += "&query=" + urlEncode(searchTerm);
		query += "&shop_type_id=" + shop_type_id;
		query += "&timestamp=" + urlEncode(timestamp);		

		Mac mac = Mac.getInstance("HmacSHA256");
		mac.init(new SecretKeySpec(SECRET_KEY.getBytes(), mac.getAlgorithm()));
		byte[] signature = mac.doFinal(query.getBytes());
		
		byte[] encryptedSignature = Base64.encodeBase64(signature);
		
		query += "&signature=" + urlEncode(new String(encryptedSignature));
		return query;
	}
	
	private String urlEncode(String param) throws UnsupportedEncodingException {
		return URLEncoder.encode(param, "UTF-8");
	}