// merge with prev method InvokeResolverAsync
private object InvokeResolverFunc(FieldContext fieldContext)
{
var propReader = fieldContext.MappedField.Resolver.ResolverFunc;
var entity = fieldContext.CurrentParentScope.Entity;
var result = propReader(entity);
return(result);
}
internal static void ThrowRequestCancelled(this FieldContext fieldContext)
{
var reqCtx = (RequestContext)fieldContext.RequestContext;
var err = new GraphQLError($"Request cancelled",
fieldContext.GetFullRequestPath(), fieldContext.SelectionField.SourceLocation, type: "Cancel");
reqCtx.AddError(err);
throw new AbortRequestException();
}
internal static void ThrowObjectCountExceededQuota(this FieldContext fieldContext)
{
var reqCtx = (RequestContext)fieldContext.RequestContext;
var quota = reqCtx.Quota;
var err = new GraphQLError($"Output object count exceeded maximum ({quota.MaxOutputObjects}) allowed by quota.",
fieldContext.GetFullRequestPath(), fieldContext.SelectionField.SourceLocation, type: "Quota");
reqCtx.AddError(err);
throw new AbortRequestException();
}
internal static void ThrowFieldDepthExceededQuota(this FieldContext fieldContext)
{
var reqCtx = (RequestContext)fieldContext.RequestContext;
var quota = reqCtx.Quota;
var sourceLoc = fieldContext.SourceLocation;
var err = new GraphQLError($"Query depth exceeded maximum ({quota.MaxDepth}) allowed by quota.",
fieldContext.GetFullRequestPath(), sourceLoc, type: "Quota");
reqCtx.AddError(err);
throw new AbortRequestException();
}
private async Task ExecuteMappedSelectionSubsetAsync(MappedSelectionSubSet mappedSubSet, IList <ObjectTypeDef> possibleTypes,
IList <OutputObjectScope> parentScopes)
{
foreach (var mappedItem in mappedSubSet.MappedItems)
{
if (mappedItem.Item.OnExecuting(_requestContext, out var args) && args.Skip)
{
continue;
}
// if it is a fragment spread, make recursive call to process fragment fields
if (mappedItem.Item.Kind == SelectionItemKind.FragmentSpread)
{
var mappedSpread = (MappedFragmentSpread)mappedItem;
var objTypeDef = mappedSubSet.Mapping.TypeDef;
var fragmSelSubset = mappedSpread.Spread.Fragment.SelectionSubset;
var entType = mappedSubSet.Mapping.EntityType;
var mappedFragmSubset = GetMappedSubset(fragmSelSubset, possibleTypes, entType, mappedSpread.Spread);
await ExecuteMappedSelectionSubsetAsync(mappedFragmSubset, possibleTypes, parentScopes); //call self recursively
continue;
}
// It is a plain field
var mappedField = (MappedSelectionField)mappedItem;
var fieldContext = new FieldContext(_requestContext, this, mappedField, parentScopes);
var selFieldKey = mappedField.Field.Key;
// Process each scope for the field
foreach (var scope in parentScopes)
{
if (fieldContext.BatchResultWasSet && scope.ContainsKey(selFieldKey))
{
continue;
}
fieldContext.SetCurrentParentScope(scope);
var fldDef = fieldContext.FieldDef;
object result = await InvokeResolverAsync(fieldContext);
// if batched result was not set, save value in scope
if (!fieldContext.BatchResultWasSet)
{
scope.SetValue(selFieldKey, result);
}
} //foreach scope
// if there are any non-null object-type results, add this field context to this special list
// to execute selection subsets in the next round.
if (mappedField.Field.SelectionSubset != null && fieldContext.AllResultScopes.Count > 0)
{
_executedObjectFieldContexts.Add(fieldContext);
}
} //foreach mappedItem
} //method
private object InvokeFieldReader(FieldContext fieldContext, object parent)
{
try {
var reader = fieldContext.FieldDef.Reader;
var result = reader(parent);
return(result);
} catch (TargetInvocationException tex) {
// sync call goes here
var origExc = tex.InnerException ?? tex;
fieldContext.AddError(origExc, ErrorCodes.ResolverError);
throw new AbortRequestException();
}
}
public static void AddError(this FieldContext fieldContext, Exception exc, string errorType)
{
var reqCtx = (RequestContext)fieldContext.RequestContext;
var path = fieldContext.GetFullRequestPath();
var err = new GraphQLError(exc.Message, path, fieldContext.SelectionField.SourceLocation, type: errorType);
var withDet = reqCtx.Server.Settings.Options.IsSet(GraphQLServerOptions.ReturnExceptionDetails);
if (withDet)
{
err.Extensions["Details"] = exc.ToText();
}
reqCtx.AddError(err, exc);
}
private async Task <object> InvokeResolverAsync(FieldContext fieldContext)
{
try {
// Invoke resolver
object result;
object convResult;
if (fieldContext.MappedField.Resolver.ResolverFunc != null)
{
result = InvokeResolverFunc(fieldContext);
}
else
{
result = await InvokeResolverMethodAsync(fieldContext);
}
// if it was batch result set, and result is null, lookup result from current scope
// we still need to return real result
if (result == null && fieldContext.BatchResultWasSet)
{
var fldKey = fieldContext.MappedField.Field.Key;
fieldContext.CurrentParentScope.TryGetValue(fldKey, out convResult); // value already converted
}
else
{
convResult = fieldContext.ConvertToOutputValue(result);
}
// check for null in non-null field
if (convResult == null && fieldContext.FieldDef.TypeRef.IsNotNull)
{
var selFld = fieldContext.MappedField.Field;
_requestContext.AddError($"Server error: resolver for non-nullable field '{selFld.Key}' returned null.",
selFld, ErrorCodes.ServerError);
}
return(convResult);
} catch (TargetInvocationException tex) {
// sync call goes here
var origExc = tex.InnerException;
if (origExc is AbortRequestException)
{
throw origExc;
}
AddError(fieldContext, origExc, ErrorCodes.ResolverError);
Fail(); // throws
return(null); //never happens
} catch (AbortRequestException) {
throw;
} catch (Exception ex) {
AddError(fieldContext, ex, ErrorCodes.ResolverError);
Fail();
return(null); //never happens
}
}
public void AddError(FieldContext fieldContext, Exception ex, string errorType)
{
_failed = true;
// fire event
var eventArgs = new OperationErrorEventArgs(_requestContext, this._mappedOpField.Field, ex);
_requestContext.Server.Events.OnOperationError(eventArgs);
if (eventArgs.Exception == null)
{
return; // event handler cleared error
}
// add error
fieldContext.AddError(ex, errorType);
}
private async Task ExecuteObjectsSelectionSubsetAsync(IList <OutputObjectScope> parentScopes,
ObjectTypeDef objTypeDef, SelectionSubset subSet)
{
var outItemSet = subSet.MappedItemSets.FirstOrDefault(fi => fi.ObjectTypeDef == objTypeDef);
var mappedFields = _requestContext.GetIncludedMappedFields(outItemSet);
// init scopes
foreach (var scope in parentScopes)
{
scope.Init(objTypeDef, mappedFields);
}
for (int fldIndex = 0; fldIndex < mappedFields.Count; fldIndex++)
{
var mappedField = mappedFields[fldIndex];
var returnsComplexType = mappedField.FieldDef.Flags.IsSet(FieldFlags.ReturnsComplexType);
var fieldContext = new FieldContext(_requestContext, this, mappedField, fldIndex, parentScopes);
foreach (var scope in fieldContext.AllParentScopes)
{
if (fieldContext.BatchResultWasSet && scope.HasValue(fldIndex))
{
continue;
}
fieldContext.CurrentScope = scope;
object result = null;
switch (mappedField.FieldDef.ExecutionType)
{
case FieldExecutionType.Reader:
result = InvokeFieldReader(fieldContext, fieldContext.CurrentScope.Entity);
break;
case FieldExecutionType.Resolver:
result = await InvokeResolverAsync(fieldContext);
break;
}
var outValue = fieldContext.ConvertToOuputValue(result);
if (!fieldContext.BatchResultWasSet)
{
scope.SetValue(fldIndex, outValue);
}
} //foreach scope
// if there are any non-null object-type results, add this field context to this special list
// to execute selection subsets in the next round.
if (returnsComplexType && fieldContext.AllResultScopes.Count > 0)
{
_executedObjectFieldContexts.Add(fieldContext);
}
} //foreach fldIndex
} //method
public async Task ExecuteOperationFieldAsync()
{
try {
if (_mappedOpField.Field.OnExecuting(_requestContext, out var args) && args.Skip)
{
Result = DBNull.Value; // it's a signal to skip value in output
return;
}
var opFieldContext = new FieldContext(_requestContext, this, _mappedOpField);
opFieldContext.SetCurrentParentScope(_parentScope);
// We do not save result in parent top-level context: we maybe executing in parallel with other top-level fields;
// we need synchronization(lock), and also op fields might finish out of order. So we save result in a field, and
// RequestHandler will save all results from executers in proper order.
//_parentScope.SetValue(_mappedOpField.Field.Key, opOutValue); -- do not do this
this.Result = await InvokeResolverAsync(opFieldContext);
// for fields returning objects, save for further processing of results
if (opFieldContext.MappedField.Field.SelectionSubset != null)
{
_executedObjectFieldContexts.Add(opFieldContext);
}
// process object field results until no more
while (_executedObjectFieldContexts.Count > 0)
{
if (_requestContext.CancellationToken.IsCancellationRequested)
{
opFieldContext.ThrowRequestCancelled();
}
// save current list, create new one in the field
var oldFieldContexts = _executedObjectFieldContexts;
_executedObjectFieldContexts = new List <FieldContext>();
foreach (var fldCtx in oldFieldContexts)
{
await ExecuteFieldSelectionSubsetAsync(fldCtx);
}
}//while
} finally {
// notify resolvers about end request
if (_resolverInstances.Count > 0)
{
foreach (var resObj in _resolverInstances)
{
(resObj as IResolverClass)?.EndRequest(_requestContext);
}
}
}
}
private async Task <object> InvokeResolverAsync(FieldContext fieldContext)
{
try {
if (fieldContext.ResolverClassInstance == null)
{
AssignResolverClassInstance(fieldContext);
}
if (fieldContext.ArgValues == null)
{
BuildResolverArguments(fieldContext);
}
// we might have encountered errors when evaluating args; if so, abort all
this.AbortIfFailed();
// set current parentEntity arg
if (fieldContext.Flags.IsSet(FieldFlags.HasParentArg))
{
fieldContext.ArgValues[1] = fieldContext.CurrentScope.Entity;
}
var resolver = fieldContext.FieldDef.Resolver;
var result = resolver.Method.Invoke(fieldContext.ResolverClassInstance, fieldContext.ArgValues);
if (fieldContext.Flags.IsSet(FieldFlags.ReturnsTask))
{
result = await UnwrapTaskResultAsync(fieldContext, (Task)result);
}
Interlocked.Increment(ref _requestContext.Metrics.ResolverCallCount);
// Note: result might be null, but batched result might be set.
return(result);
} catch (TargetInvocationException tex) {
// sync call goes here
var origExc = tex.InnerException;
if (origExc is AbortRequestException)
{
throw origExc;
}
fieldContext.AddError(origExc, ErrorCodes.ResolverError);
Fail();
return(null); //never happens
} catch (AbortRequestException) {
throw;
} catch (Exception ex) {
fieldContext.AddError(ex, ErrorCodes.ResolverError);
Fail();
return(null); //never happens
}
}
private object SafeEvaluateArg(FieldContext fieldContext, MappedArg arg)
{
try {
var value = arg.Evaluator.GetValue(_requestContext);
var convValue = _requestContext.ValidateConvert(value, arg.ArgDef.TypeRef, arg.Anchor);
return(convValue);
} catch (AbortRequestException) {
return(null);
} catch (InvalidInputException bvEx) {
_requestContext.AddInputError(bvEx);
_failed = true;
return(null); //continue evaluating args; it will be aborted after all args are done
} catch (Exception ex) {
_requestContext.AddInputError($"Failed to evaluate argument {arg.ArgDef.Name}: {ex.Message}", arg.Anchor);
_failed = true;
return(null); // continue to next arg
}
}
private void BuildResolverArguments(FieldContext fieldContext)
{
var mappedArgs = fieldContext.MappedField.Field.MappedArgs;
var argValues = new List <object>();
// special arguments: context, parent
argValues.Add(fieldContext);
if (!fieldContext.FieldDef.Flags.IsSet(FieldFlags.Static))
{
argValues.Add(fieldContext.CurrentParentScope.Entity);
}
//regular arguments
for (int i = 0; i < mappedArgs.Count; i++)
{
var arg = mappedArgs[i];
var argValue = SafeEvaluateArg(fieldContext, arg);
argValues.Add(argValue);
}
fieldContext.ArgValues = argValues.ToArray();
}
public async Task ExecuteOperationFieldAsync()
{
try {
var opFieldContext = new FieldContext(_requestContext, this, _operationField, _fieldIndex);
opFieldContext.CurrentScope = _parentScope;
var result = await InvokeResolverAsync(opFieldContext);
var opOutValue = opFieldContext.ConvertToOuputValue(result);
_parentScope.SetValue(_fieldIndex, opOutValue);
// for fields returning objects, save for further processing of results
if (opFieldContext.Flags.IsSet(FieldFlags.ReturnsComplexType))
{
_executedObjectFieldContexts.Add(opFieldContext);
}
// process object field results until no more
while (_executedObjectFieldContexts.Count > 0)
{
if (_requestContext.CancellationToken.IsCancellationRequested)
{
opFieldContext.ThrowRequestCancelled();
}
// save current list, create new one in the field
var oldFieldContexts = _executedObjectFieldContexts;
_executedObjectFieldContexts = new List <FieldContext>();
foreach (var fldCtx in oldFieldContexts)
{
await ExecuteFieldSelectionSubsetAsync(fldCtx);
}
}//while
} finally {
// notify resolvers about end request
if (_resolverInstances.Count > 0)
{
foreach (var resObj in _resolverInstances)
{
(resObj as IResolverClass)?.EndRequest(_requestContext);
}
}
}
}
// gets cached resolver class instance or creates new one
private void AssignResolverClassInstance(FieldContext fieldCtx, FieldResolverInfo fieldResolver)
{
var resClassType = fieldResolver.ResolverMethod.ResolverClass.Type;
object resInstance = null;
if (_resolverInstances.Count == 1 && _resolverInstances[0].GetType() == resClassType) // fast track
{
resInstance = _resolverInstances[0];
}
else
{
resInstance = _resolverInstances.FirstOrDefault(r => r.GetType() == resClassType);
}
if (resInstance == null)
{
resInstance = Activator.CreateInstance(resClassType);
if (resInstance is IResolverClass iRes)
{
iRes.BeginRequest(_requestContext);
}
_resolverInstances.Add(resInstance);
}
fieldCtx.ResolverClassInstance = resInstance;
}
internal static void ThrowFatal(this FieldContext fieldContext, string message)
{
throw new FatalServerException(message);
}
