// Mutation should be null UNLESS adding a mutation at the schema level
internal GraphQLFieldBuilder <TContext, TField> AddFieldInternal <TArgs, TField>(string name, Func <TArgs, Expression <Func <TContext, TEntity, TField> > > exprFunc)
{
var field = GraphQLField.New(_schema, name, exprFunc, typeof(TField), _type);
_type.OwnFields.Add(field);
return(new GraphQLFieldBuilder <TContext, TField>(field));
}
// Mutation should be null UNLESS adding a mutation at the schema level
internal GraphQLFieldBuilder <TContext, TField> AddListMutationInternal <TArgs, TField, TMutReturn>(string name, Func <TArgs, TMutReturn, Expression <Func <TContext, TEntity, IEnumerable <TField> > > > exprFunc, Func <TContext, TArgs, TMutReturn> mutation)
{
var field = GraphQLField.NewMutation(_schema, name, exprFunc, typeof(IEnumerable <TField>), _type, mutation);
_type.OwnFields.Add(field);
return(new GraphQLFieldBuilder <TContext, TField>(field));
}
public GraphQLFieldBuilder <TContext, TField> AddPostField <TField>(string name, Func <TField> fieldFunc)
{
var field = GraphQLField.Post(_schema, name, fieldFunc);
_type.OwnFields.Add(field);
return(new GraphQLFieldBuilder <TContext, TField>(field));
}
private static Type GetFieldPropertyType(GraphQLField field)
{
return(field.Type.TypeKind == TypeKind.SCALAR
? (field.IsList
? typeof(IEnumerable <>).MakeGenericType(field.Type.CLRType)
: TypeHelpers.MakeNullable(field.Type.CLRType))
: typeof(object));
}
// unsafe generic magic to create a GQLField instance
private GraphQLField CreateGenericField(PropertyInfo prop)
{
// build selector expression, e.g.: (db, p) => p.Id
var entityParam = Expression.Parameter(typeof(TEntity), "p");
var memberExpr = Expression.MakeMemberAccess(entityParam, prop);
var lambda = Expression.Lambda(memberExpr, GraphQLSchema <TContext> .DbParam, entityParam);
// build args func wrapping selector expression, e.g. o => (db, p) => p.Id
var objectParam = Expression.Parameter(typeof(object), "o");
var argsExpr = Expression.Lambda(Expression.Quote(lambda), objectParam);
var exprFunc = argsExpr.Compile();
return(GraphQLField.New(_schema, prop.Name.ToCamelCase(), (Func <object, LambdaExpression>)exprFunc, prop.PropertyType, _type));
}
public static object Execute
(GraphQLSchema <TContext> schema, TContext context, GraphQLField field, ExecSelection <Info> query)
{
var mutReturn = field.RunMutation(context, query.Arguments.Values());
var queryableFuncExpr = field.GetExpression(query.Arguments.Values(), mutReturn);
var replaced = (LambdaExpression)ParameterReplacer.Replace(queryableFuncExpr, queryableFuncExpr.Parameters[0], GraphQLSchema <TContext> .DbParam);
// sniff queryable provider to determine how selector should be built
var dummyQuery = replaced.Compile().DynamicInvoke(context, null);
var queryType = dummyQuery.GetType();
var expressionOptions = schema.GetOptionsForQueryable(queryType);
if (expressionOptions.UseBaseType)
{
queryType = queryType.BaseType;
expressionOptions = schema.GetOptionsForQueryable(queryType);
}
var queryExecSelections = query.Selections.Values();
var selector = GetSelector(schema, field.Type, queryExecSelections, expressionOptions);
if (field.ResolutionType != ResolutionType.Unmodified)
{
var selectorExpr = Expression.Quote(selector);
// TODO: This should be temporary - queryable and enumerable should both work
var body = replaced.Body;
if (body.NodeType == ExpressionType.Convert)
{
body = ((UnaryExpression)body).Operand;
}
var call = Expression.Call(typeof(Queryable), "Select", new[] { field.Type.CLRType, field.Type.QueryType }, body, selectorExpr);
var expr = Expression.Lambda(call, GraphQLSchema <TContext> .DbParam);
var transformed = expr.Compile().DynamicInvoke(context);
object results;
switch (field.ResolutionType)
{
case ResolutionType.Unmodified:
throw new Exception("Queries cannot have unmodified resolution. May change in the future.");
case ResolutionType.ToList:
var list = GenericQueryableCall <IEnumerable <object> >(transformed, q => q.ToList());
results = list.Select(o => MapResults(o, queryExecSelections, schema)).ToList();
break;
case ResolutionType.FirstOrDefault:
var fod = GenericQueryableCall(transformed, q => q.FirstOrDefault());
results = MapResults(fod, queryExecSelections, schema);
break;
case ResolutionType.First:
var first = GenericQueryableCall(transformed, q => q.FirstOrDefault());
results = MapResults(first, queryExecSelections, schema);
break;
default:
throw new ArgumentOutOfRangeException();
}
return(results);
}
else
{
var invocation = Expression.Invoke(selector, replaced.Body);
var expr = Expression.Lambda(invocation, GraphQLSchema <TContext> .DbParam);
var result = expr.Compile().DynamicInvoke(context);
return(MapResults(result, queryExecSelections, schema));
}
}
internal GraphQLFieldBuilder(GraphQLField field)
{
_field = field;
}