// 1. Create the input
// 1.1 Create a protocol buffer
// 1.2 Create the query params
// 2. Create a connection
// 3. Do the annotation
// This method has two contracts:
// 1. It should call the two relevant callbacks
// 2. It must not throw an exception
/// <summary>Actually try to perform the annotation on the server side.</summary>
/// <remarks>
/// Actually try to perform the annotation on the server side.
/// This is factored out so that we can retry up to 3 times.
/// </remarks>
/// <param name="annotation">The annotation we need to fill.</param>
/// <param name="backend">The backend we are querying against.</param>
/// <param name="serverURL">The URL of the server we are hitting.</param>
/// <param name="message">The message we are sending the server (don't need to recompute each retry).</param>
/// <param name="tries">The number of times we've tried already.</param>
private void DoAnnotation(Annotation annotation, StanfordCoreNLPClient.Backend backend, URL serverURL, byte[] message, int tries)
{
try
{
// 1. Set up the connection
URLConnection connection = serverURL.OpenConnection();
// 1.1 Set authentication
if (apiKey != null && apiSecret != null)
{
string userpass = apiKey + ":" + apiSecret;
string basicAuth = "Basic " + Sharpen.Runtime.GetStringForBytes(Base64.GetEncoder().Encode(Sharpen.Runtime.GetBytesForString(userpass)));
connection.SetRequestProperty("Authorization", basicAuth);
}
// 1.2 Set some protocol-independent properties
connection.SetDoOutput(true);
connection.SetRequestProperty("Content-Type", "application/x-protobuf");
connection.SetRequestProperty("Content-Length", int.ToString(message.Length));
connection.SetRequestProperty("Accept-Charset", "utf-8");
connection.SetRequestProperty("User-Agent", typeof(StanfordCoreNLPClient).FullName);
switch (backend.protocol)
{
case "https":
case "http":
{
// 1.3 Set some protocol-dependent properties
((HttpURLConnection)connection).SetRequestMethod("POST");
break;
}
default:
{
throw new InvalidOperationException("Haven't implemented protocol: " + backend.protocol);
}
}
// 2. Annotate
// 2.1. Fire off the request
connection.Connect();
connection.GetOutputStream().Write(message);
connection.GetOutputStream().Flush();
// 2.2 Await a response
// -- It might be possible to send more than one message, but we are not going to do that.
Annotation response = serializer.Read(connection.GetInputStream()).first;
// 2.3. Copy response over to original annotation
foreach (Type key in response.KeySet())
{
annotation.Set(key, response.Get(key));
}
}
catch (Exception t)
{
// 3. We encountered an error -- retry
if (tries < 3)
{
log.Warn(t);
DoAnnotation(annotation, backend, serverURL, message, tries + 1);
}
else
{
throw new Exception(t);
}
}
}