public bool TryGetInvocationContext(HttpRequestMessage request, out InvocationContext context)
{
context = new InvocationContext();
// Required properties
context.ConnectionId = request.Headers.GetValues(Constants.AsrsConnectionIdHeader).FirstOrDefault();
if (string.IsNullOrEmpty(context.ConnectionId))
{
return(false);
}
context.Hub = request.Headers.GetValues(Constants.AsrsHubNameHeader).FirstOrDefault();
context.Category = request.Headers.GetValues(Constants.AsrsCategory).FirstOrDefault();
context.Event = request.Headers.GetValues(Constants.AsrsEvent).FirstOrDefault();
// Optional properties
if (request.Headers.TryGetValues(Constants.AsrsUserId, out var values))
{
context.UserId = values.FirstOrDefault();
}
if (request.Headers.TryGetValues(Constants.AsrsClientQueryString, out values))
{
context.Query = SignalRTriggerUtils.GetQueryDictionary(values.FirstOrDefault());
}
if (request.Headers.TryGetValues(Constants.AsrsUserClaims, out values))
{
context.Claims = SignalRTriggerUtils.GetClaimDictionary(values.FirstOrDefault());
}
context.Headers = SignalRTriggerUtils.GetHeaderDictionary(request.Headers);
return(true);
}
// The algorithm is defined in spec: Hex_encoded(HMAC_SHA256(access-key, connection-id))
public bool ValidateSignature(HttpRequestMessage request, string accessToken)
{
if (!_validateSignature)
{
return(true);
}
if (!string.IsNullOrEmpty(accessToken) &&
request.Headers.TryGetValues(Constants.AsrsSignature, out var values))
{
var signatures = SignalRTriggerUtils.GetSignatureList(values.FirstOrDefault());
if (signatures == null)
{
return(false);
}
using (var hmac = new HMACSHA256(Encoding.UTF8.GetBytes(accessToken)))
{
var hashBytes = hmac.ComputeHash(Encoding.UTF8.GetBytes(request.Headers.GetValues(Constants.AsrsConnectionIdHeader).First()));
var hash = "sha256=" + BitConverter.ToString(hashBytes).Replace("-", "");
return(signatures.Contains(hash, StringComparer.OrdinalIgnoreCase));
}
}
return(false);
}
internal SignalRTriggerAttribute GetParameterResolvedAttribute(SignalRTriggerAttribute attribute, ParameterInfo parameterInfo)
{
//TODO: AutoResolve more properties in attribute
var hubName = attribute.HubName;
var category = attribute.Category;
var @event = attribute.Event;
var parameterNames = attribute.ParameterNames ?? Array.Empty <string>();
var connectionStringSetting = attribute.ConnectionStringSetting;
// We have two models for C#, one is function based model which also work in multiple language
// Another one is class based model, which is highly close to SignalR itself but must keep some conventions.
var method = (MethodInfo)parameterInfo.Member;
var declaredType = method.DeclaringType;
string[] parameterNamesFromAttribute;
if (declaredType != null && IsServerlessHub(declaredType))
{
// Class based model
if (!string.IsNullOrEmpty(hubName) ||
!string.IsNullOrEmpty(category) ||
!string.IsNullOrEmpty(@event) ||
parameterNames.Length != 0)
{
throw new ArgumentException($"{nameof(SignalRTriggerAttribute)} must use parameterless constructor in class based model.");
}
parameterNamesFromAttribute = method.GetParameters().Where(IsLegalClassBasedParameter).Select(p => p.Name).ToArray();
hubName = declaredType.Name;
category = GetCategoryFromMethodName(method.Name);
@event = GetEventFromMethodName(method.Name, category);
connectionStringSetting = SignalRTriggerUtils.GetConnectionNameFromAttribute(declaredType) ?? attribute.ConnectionStringSetting;
}
else
{
parameterNamesFromAttribute = method.GetParameters().
Where(p => p.GetCustomAttribute <SignalRParameterAttribute>(false) != null).
Select(p => p.Name).ToArray();
if (parameterNamesFromAttribute.Length != 0 && parameterNames.Length != 0)
{
throw new InvalidOperationException(
$"{nameof(SignalRTriggerAttribute)}.{nameof(SignalRTriggerAttribute.ParameterNames)} and {nameof(SignalRParameterAttribute)} can not be set in the same Function.");
}
// If we aren't using the class-based model, make sure we resolve binding expressions for attribute properties here.
hubName = _nameResolver.ResolveWholeString(hubName);
category = _nameResolver.ResolveWholeString(category);
@event = _nameResolver.ResolveWholeString(@event);
}
parameterNames = parameterNamesFromAttribute.Length != 0
? parameterNamesFromAttribute
: parameterNames;
return(new SignalRTriggerAttribute(hubName, category, @event, parameterNames)
{
ConnectionStringSetting = connectionStringSetting
});
}
public Task <IListener> CreateListenerAsync(ListenerFactoryContext context)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
// It's not a real listener, and it doesn't need a start or close.
_dispatcher.Map((_attribute.HubName, _attribute.Category, _attribute.Event),
new ExecutionContext {
Executor = context.Executor, AccessKey = SignalRTriggerUtils.GetAccessKey(_attribute.ConnectionStringSetting)
});
return(Task.FromResult <IListener>(new NullListener()));
}
// The algorithm is defined in spec: Hex_encoded(HMAC_SHA256(access-key, connection-id))
public bool ValidateSignature(HttpRequestMessage request, AccessKey[] accessKeys)
{
if (!_validateSignature)
{
return(true);
}
if (accessKeys is null)
{
throw new ArgumentNullException(nameof(accessKeys));
}
foreach (var accessKey in accessKeys)
{
// Skip validation for aad access key.
if (accessKey is AadAccessKey)
{
return(true);
}
var accessToken = accessKey.Value;
if (!string.IsNullOrEmpty(accessToken) &&
request.Headers.TryGetValues(Constants.AsrsSignature, out var values))
{
var signatures = SignalRTriggerUtils.GetSignatureList(values.FirstOrDefault());
if (signatures == null)
{
continue;
}
using (var hmac = new HMACSHA256(Encoding.UTF8.GetBytes(accessToken)))
{
var hashBytes = hmac.ComputeHash(Encoding.UTF8.GetBytes(request.Headers.GetValues(Constants.AsrsConnectionIdHeader).First()));
var hash = "sha256=" + BitConverter.ToString(hashBytes).Replace("-", "");
if (signatures.Contains(hash, StringComparer.OrdinalIgnoreCase))
{
return(true);
}
else
{
continue;
}
}
}
}
return(false);
}