private Expression VisitOrderAscendingMethod(Expression m)
{
void InspectOrdering(Expression e)
{
MethodCallExpression o = e as MethodCallExpression ?? throw new AuthenticationException($"Invalid expression type {e.GetType().Name}");
Expression lambdaBody = o.GetLambdaBody();
switch (o.Method.Name)
{
case "OrderBy":
Visit(o.Arguments[0]);
_sb.Append("\"sort\":[");
Visit(lambdaBody);
break;
case "OrderByDescending":
throw new InvalidOperationException("Cannot order in different directions.");
case "ThenBy":
InspectOrdering(o.Arguments[0]);
Visit(lambdaBody);
break;
default:
return;
}
_sb.Append(",");
}
InspectOrdering(m);
_sb.Length--;
_sb.Append("],");
return(m);
}
private Expression VisitSelectMethod(MethodCallExpression m)
{
Visit(m.Arguments[0]);
_sb.Append("\"fields\":[");
Expression lambdaBody = m.GetLambdaBody();
if (lambdaBody is NewExpression n)
{
foreach (Expression a in n.Arguments)
{
Visit(a);
_sb.Append(",");
}
_sb.Length--;
}
else if (lambdaBody is MemberExpression mb)
{
Visit(mb);
}
else
{
throw new NotSupportedException($"The expression of type {lambdaBody} is not supported in the Select method.");
}
_sb.Append("],");
return(m);
}
private Expression VisitAllMethod(MethodCallExpression m)
{
_sb.Append("{");
Visit(m.Arguments[0]);
_sb.Append(":{\"$allMatch\":");
Expression lambdaBody = m.GetLambdaBody();
Visit(lambdaBody);
_sb.Append("}}");
return(m);
}
private Expression VisitWhereMethod(MethodCallExpression m)
{
Visit(m.Arguments[0]);
_sb.Append("\"selector\":");
Expression lambdaBody = m.GetLambdaBody();
Visit(lambdaBody);
_sb.Append(",");
_isSelectorSet = true;
return(m);
}
