I am in the process of (re-)enabling NYCT Subway GTFS-rt on my client side. I am already covering several other GTFS-rt feeds, e.g. BART, without problem.
The account that I signed up for years ago has been wiped, along with the API key I received at the time. So I signed up for a new developer account and received a new API key. This authorizes my requests: Adding the API key in the request header, I receive a response code 200 as opposed to 403 when it is missing. So far so good.
The response content however is not GTFS-rt; I receive (ResponseId and HostId edited):
<?xml version="1.0" encoding="UTF-8"?>
<Error><Code>NoSuchKey</Code><Message>The specified key does not exist.</Message><Key>nyct/gtfs1</Key><RequestId>GS ... C</RequestId><HostId>H4cZJOX7 ... pSHDWBRooTHxc9A=</HostId></Error>
I let this sit overnight in case my new registration needed time to propagate, but no luck. Here is a Java code snippet for calling GTFS-rt APIs; this works for all other GTFS-rt feeds that I cover (edited for clarity):
URL url = new URL(requestString);
URLConnection connection = url.openConnection();
HttpURLConnection httpConnection = (HttpURLConnection)connection;
String authToken = "__ my key __";
InputStream ins = httpConnection.getInputStream();
String result = IOUtils.toString(ins, StandardCharsets.UTF_8);
# result as posted above "
The specified key does not exist."