namespace AustinHarris.JsonRpc
{
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using Newtonsoft.Json;
using System.Threading.Tasks;
using System.Collections.Concurrent;
using Newtonsoft.Json.Linq;
public class Handler
{
#region Members
//private static Handler current;
private static ConcurrentDictionary _sessionHandlers;
private static string _defaultSessionId;
#endregion
#region Constructors
static Handler()
{
//current = new Handler(Guid.NewGuid().ToString());
_defaultSessionId = Guid.NewGuid().ToString();
_sessionHandlers = new ConcurrentDictionary();
_sessionHandlers[_defaultSessionId]= new Handler(_defaultSessionId);
}
private Handler(string sessionId)
{
SessionId = sessionId;
this.MetaData = new SMD();
this.Handlers = new Dictionary();
}
#endregion
#region Properties
///
/// Returns the SessionID of the default session
///
///
public static string DefaultSessionId() { return _defaultSessionId; }
///
/// Gets a specific session
///
/// The sessionId of the handler you want to retrieve.
///
public static Handler GetSessionHandler(string sessionId)
{
return _sessionHandlers.GetOrAdd(sessionId, new Handler(sessionId));
}
///
/// gets the default session
///
/// The default Session Handler
public static Handler GetSessionHandler()
{
return GetSessionHandler(_defaultSessionId);
}
///
/// Removes and clears the Handler with the specific sessionID from the registry of Handlers
///
///
public static void DestroySession(string sessionId)
{
Handler h;
_sessionHandlers.TryRemove(sessionId,out h);
h.Handlers.Clear();
h.MetaData.Services.Clear();
}
///
/// Removes and clears the current Handler from the registry of Handlers
///
public void Destroy()
{
DestroySession(SessionId);
}
///
/// Gets the default session handler
///
public static Handler DefaultHandler { get { return GetSessionHandler(_defaultSessionId); } }
///
/// The sessionID of this Handler
///
public string SessionId { get; private set; }
private static ConcurrentDictionary RpcContexts = new ConcurrentDictionary();
private static ConcurrentDictionary RpcExceptions = new ConcurrentDictionary();
///
/// Provides access to a context specific to each JsonRpc method invocation.
/// Warning: Must be called from within the execution context of the jsonRpc Method to return the context
///
///
public static object RpcContext()
{
if (Task.CurrentId == null)
return null;
if (RpcContexts.ContainsKey(Task.CurrentId.Value) == false)
return null;
return RpcContexts[Task.CurrentId.Value];
}
///
/// Allows you to set the exception used in in the JsonRpc response.
/// Warning: Must be called from within the execution context of the jsonRpc method.
///
///
public static void RpcSetException(JsonRpcException exception)
{
if (Task.CurrentId != null)
RpcExceptions[Task.CurrentId.Value] = exception;
else
throw new InvalidOperationException("This method is only valid when used within the context of a method marked as a JsonRpcMethod, and that method must of been invoked by the JsonRpc Handler.");
}
private void RemoveRpcException()
{
if (Task.CurrentId != null)
{
var id = Task.CurrentId.Value;
RpcExceptions[id] = null;
JsonRpcException va;
RpcExceptions.TryRemove(id, out va);
}
}
private AustinHarris.JsonRpc.PreProcessHandler externalPreProcessingHandler;
private Func externalErrorHandler;
private Func parseErrorHandler;
private Dictionary Handlers { get; set; }
#endregion
///
/// This metadata contains all the types and mappings of all the methods in this handler. Warning: Modifying this directly could cause your handler to no longer function.
///
public SMD MetaData { get; set; }
#region Public Methods
///
/// Registers a jsonRpc method name (key) to be mapped to a specific function
///
/// The Method as it will be called from JsonRpc
/// The method that will be invoked
///
public bool Register(string key, Delegate handle)
{
var result = false;
if (!this.Handlers.ContainsKey(key))
{
this.Handlers.Add(key, handle);
}
return result;
}
public void UnRegister(string key)
{
this.Handlers.Remove(key);
MetaData.Services.Remove(key);
}
///
/// Invokes a method to handle a JsonRpc request.
///
/// JsonRpc Request to be processed
/// Optional context that will be available from within the jsonRpcMethod.
///
public JsonResponse Handle(JsonRequest Rpc, Object RpcContext = null)
{
AddRpcContext(RpcContext);
var preProcessingException = PreProcess(Rpc, RpcContext);
if (preProcessingException != null)
{
return new JsonResponse() { Error = preProcessingException,
Id = Rpc.Id };
}
SMDService metadata = null;
Delegate handle = null;
var haveDelegate = this.Handlers.TryGetValue(Rpc.Method, out handle);
var haveMetadata = this.MetaData.Services.TryGetValue(Rpc.Method, out metadata);
if (haveDelegate == false || haveMetadata == false || metadata == null || handle == null)
{
return new JsonResponse() { Result = null, Error = new JsonRpcException(-32601, "Method not found", "The method does not exist / is not available."), Id = Rpc.Id };
}
if (Rpc.Params is ICollection == false)
{
return new JsonResponse()
{
Result = null,
Error = new JsonRpcException(-32602,
"Invalid params", "The number of parameters could not be counted"),
Id = Rpc.Id
};
}
bool isJObject = Rpc.Params is Newtonsoft.Json.Linq.JObject;
bool isJArray = Rpc.Params is Newtonsoft.Json.Linq.JArray;
object[] parameters = null;
bool expectsRefException = false;
var metaDataParamCount = metadata.parameters.Count(x => x != null);
var getCount = Rpc.Params as ICollection;
var loopCt = getCount.Count;
var paramCount = loopCt;
if (paramCount == metaDataParamCount - 1 && metadata.parameters[metaDataParamCount-1].ObjectType.Name.Contains(typeof(JsonRpcException).Name))
{
paramCount++;
expectsRefException = true;
}
parameters = new object[paramCount];
if (isJArray)
{
var jarr = ((Newtonsoft.Json.Linq.JArray)Rpc.Params);
//var loopCt = jarr.Count;
//var pCount = loopCt;
//if (pCount == metaDataParamCount - 1 && metadata.parameters[metaDataParamCount].GetType() == typeof(JsonRpcException))
// pCount++;
//parameters = new object[pCount];
for (int i = 0; i < loopCt; i++)
{
parameters[i] = CleanUpParameter(jarr[i], metadata.parameters[i]);
}
}
else if (isJObject)
{
var jo = Rpc.Params as Newtonsoft.Json.Linq.JObject;
//var loopCt = jo.Count;
//var pCount = loopCt;
//if (pCount == metaDataParamCount - 1 && metadata.parameters[metaDataParamCount].GetType() == typeof(JsonRpcException))
// pCount++;
//parameters = new object[pCount];
var asDict = jo as IDictionary;
for (int i = 0; i < loopCt; i++)
{
if (asDict.ContainsKey(metadata.parameters[i].Name) == false)
{
return new JsonResponse()
{
Error = ProcessException(Rpc,
new JsonRpcException(-32602,
"Invalid params",
string.Format("Named parameter '{0}' was not present.",
metadata.parameters[i].Name)
))
,Id = Rpc.Id
};
}
parameters[i] = CleanUpParameter(jo[metadata.parameters[i].Name], metadata.parameters[i]);
}
}
// Optional Parameter support
// check if we still miss parameters compared to metadata which may include optional parameters.
// if the rpc-call didn't supply a value for an optional parameter, we should be assinging the default value of it.
if (parameters.Length < metaDataParamCount && metadata.defaultValues.Length > 0) // rpc call didn't set values for all optional parameters, so we need to assign the default values for them.
{
var paramIndex = parameters.Length; // the index we should start storing default values of optional parameters.
var missingParamsCount = metaDataParamCount - parameters.Length; // the amount of optional parameters without a value set by rpc-call.
Array.Resize(ref parameters, parameters.Length + metadata.defaultValues.Length); // resize the array to include all optional parameters.
// we need to add in reverse order as parameters can appear after all required parameters.
// as some of the optional parameters could already have assigned their values in rpc-call,
// by starting from the end we can make sure we only add the required default values.
for (int k = missingParamsCount; k > 0; k--)
{
var optionalParamIndex = k - 1; // the index of the optional parameter we will be currently setting a default value.
parameters[paramIndex] = metadata.defaultValues[optionalParamIndex].Value; // set the default value for the optional parameter that rpc-call didn't set a value for.
paramIndex++;
paramCount++; // we need to increase the paramCount by one each time we add default-value for an optional parameter that rpc-call didn't set a value for.
}
}
if (parameters.Length != metaDataParamCount)
{
return new JsonResponse()
{
Error = ProcessException(Rpc,
new JsonRpcException(-32602,
"Invalid params",
string.Format("Expecting {0} parameters, and received {1}",
metadata.parameters.Length,
parameters.Length)
)),
Id = Rpc.Id
};
}
try
{
var results = handle.DynamicInvoke(parameters);
var last = parameters.Length>0 ? parameters[paramCount - 1]:null;
JsonRpcException contextException;
if (Task.CurrentId.HasValue && RpcExceptions.TryRemove(Task.CurrentId.Value, out contextException))
{
return new JsonResponse() { Error = ProcessException(Rpc, contextException), Id = Rpc.Id };
}
if (expectsRefException && last != null && last is JsonRpcException)
{
return new JsonResponse() { Error = ProcessException(Rpc, last as JsonRpcException), Id = Rpc.Id };
}
return new JsonResponse() { Result = results };
}
catch (Exception ex)
{
if (ex is TargetParameterCountException)
{
return new JsonResponse() { Error = ProcessException(Rpc, new JsonRpcException(-32602, "Invalid params", ex)) };
}
// We really dont care about the TargetInvocationException, just pass on the inner exception
if (ex is JsonRpcException)
{
return new JsonResponse() { Error = ProcessException(Rpc, ex as JsonRpcException) };
}
if (ex.InnerException != null && ex.InnerException is JsonRpcException)
{
return new JsonResponse() { Error = ProcessException(Rpc, ex.InnerException as JsonRpcException) };
}
else if (ex.InnerException != null)
{
return new JsonResponse() { Error = ProcessException(Rpc, new JsonRpcException(-32603, "Internal Error", ex.InnerException)) };
}
return new JsonResponse() { Error = ProcessException(Rpc, new JsonRpcException(-32603, "Internal Error", ex)) };
}
finally
{
RemoveRpcContext();
}
}
private void AddRpcContext(object RpcContext)
{
if (Task.CurrentId != null)
RpcContexts[Task.CurrentId.Value] = RpcContext;
}
private void RemoveRpcContext()
{
if (Task.CurrentId != null)
{
var id = Task.CurrentId.Value;
RpcContexts[id] = null;
object va;
RpcContexts.TryRemove(id, out va);
}
}
private JsonRpcException ProcessException(JsonRequest req,JsonRpcException ex)
{
if(externalErrorHandler!=null)
return externalErrorHandler(req,ex);
return ex;
}
internal JsonRpcException ProcessParseException(string req,JsonRpcException ex)
{
if (parseErrorHandler != null)
return parseErrorHandler(req, ex);
return ex;
}
internal void SetErrorHandler(Func handler)
{
externalErrorHandler = handler;
}
internal void SetParseErrorHandler(Func handler)
{
parseErrorHandler = handler;
}
#endregion
private object CleanUpParameter(object p, SMDAdditionalParameters metaData)
{
var bob = p as JValue;
//if (bob != null && (bob.Value == null || bob.Value.GetType() == metaData.ObjectType))
if (bob != null && (bob.Value == null || metaData.ObjectType.IsAssignableFrom(bob.Value.GetType())))
{
return bob.Value;
}
var paramI = p;
try
{
return Newtonsoft.Json.JsonConvert.DeserializeObject(paramI.ToString(), metaData.ObjectType);
}
catch (Exception ex)
{
// no need to throw here, they will
// get an invalid cast exception right after this.
}
return paramI;
}
private JsonRpcException PreProcess(JsonRequest request, object context)
{
if (externalPreProcessingHandler == null)
return null;
return externalPreProcessingHandler(request, context);
}
internal void SetPreProcessHandler(AustinHarris.JsonRpc.PreProcessHandler handler)
{
externalPreProcessingHandler = handler;
}
}
}