private static Expression BindArgument(Expression sourceExpression, ParameterModel parameter, string name)
{
var key = name ?? parameter.Name;
var type = Nullable.GetUnderlyingType(parameter.ParameterType) ?? parameter.ParameterType;
var valueArg = Expression.Convert(
Expression.MakeIndex(sourceExpression,
sourceExpression.Type.GetProperty("Item"),
new[] {
Expression.Constant(key)
}),
typeof(string));
MethodInfo parseMethod = (from m in type.GetMethods(BindingFlags.Public | BindingFlags.Static)
let parameters = m.GetParameters()
where m.Name == "Parse" && parameters.Length == 1 && parameters[0].ParameterType == typeof(string)
select m).FirstOrDefault();
Expression expr = null;
if (parseMethod != null)
{
expr = Expression.Call(parseMethod, valueArg);
}
else if (parameter.ParameterType != valueArg.Type)
{
// Convert.ChangeType()
expr = Expression.Call(ChangeTypeMethodInfo, valueArg, Expression.Constant(type));
}
else
{
expr = valueArg;
}
if (expr.Type != parameter.ParameterType)
{
expr = Expression.Convert(expr, parameter.ParameterType);
}
// property[key] == null ? default : (ParameterType){Type}.Parse(property[key]);
expr = Expression.Condition(
Expression.Equal(valueArg, Expression.Constant(null)),
Expression.Default(parameter.ParameterType),
expr);
return(expr);
}
private static Expression BindBody(Expression httpBody, ParameterModel parameter)
{
// Hard coded to JSON (and JSON.NET at that!)
// Also this is synchronous, good luck generating async anything
// new JsonSerializer().Deserialize(
// new JsonTextReader(
// new HttpRequestStreamReader(
// context.Request.Body, Encoding.UTF8)), p.ParameterType);
//
var streamReaderCtor = typeof(HttpRequestStreamReader).GetConstructor(new[] { typeof(Stream), typeof(Encoding) });
var streamReader = Expression.New(streamReaderCtor, httpBody, Expression.Constant(Encoding.UTF8));
var textReaderCtor = typeof(JsonTextReader).GetConstructor(new[] { typeof(TextReader) });
var textReader = Expression.New(textReaderCtor, streamReader);
Expression expr = Expression.Call(JsonDeserializeMethodInfo.MakeGenericMethod(parameter.ParameterType), textReader);
return(expr);
}