private static void NotNullExpression(Attribute.Selector selector)
{
if (string.IsNullOrWhiteSpace(selector.Expression))
{
throw new ArgumentException($"Expression of {selector} should not be null/empty");
}
}
/// <summary>
/// 构造方法
/// </summary>
public Model()
{
var type = typeof(T);
TypeName = type.FullName;
var entitySelector =
type.GetCustomAttributes(typeof(EntitySelector), true).FirstOrDefault() as EntitySelector;
int take = 0;
bool takeFromHead = true;
Attribute.Selector selector = null;
if (entitySelector != null)
{
take = entitySelector.Take;
takeFromHead = entitySelector.TakeFromHead;
selector = new Attribute.Selector {
Expression = entitySelector.Expression, Type = entitySelector.Type
};
}
var followSelectors = type.GetCustomAttributes(typeof(FollowSelector), true).Select(x => (FollowSelector)x)
.ToList();
var sharedValueSelectors = type.GetCustomAttributes(typeof(ValueSelector), true)
.Select(x => (ValueSelector)x).ToList();
var properties = type.GetProperties(BindingFlags.Instance | BindingFlags.Public);
var valueSelectors = new HashSet <ValueSelector>();
foreach (var property in properties)
{
var valueSelector = property.GetCustomAttributes(typeof(ValueSelector), true).FirstOrDefault() as ValueSelector;
if (valueSelector == null)
{
continue;
}
if (string.IsNullOrWhiteSpace(valueSelector.Name))
{
valueSelector.Name = property.Name;
}
valueSelector.Formatters = property.GetCustomAttributes(typeof(Formatter.Formatter), true)
.Select(p => (Formatter.Formatter)p).ToArray();
valueSelector.PropertyInfo = property;
valueSelector.NotNull = property.GetCustomAttributes(typeof(Required), false).Any();
valueSelectors.Add(valueSelector);
}
Selector = selector;
ValueSelectors = valueSelectors;
FollowSelectors = new HashSet <FollowSelector>(followSelectors);
ShareValueSelectors = new HashSet <ValueSelector>(sharedValueSelectors);
Take = take;
TakeFromHead = takeFromHead;
}
/// <summary>
/// 把 BaseSelector 转换成真正的查询器
/// </summary>
/// <param name="selector">BaseSelector</param>
/// <returns>查询器</returns>
public static ISelector ToSelector(this Attribute.Selector selector)
{
if (selector != null)
{
var expression = selector.Expression;
switch (selector.Type)
{
case SelectorType.Css:
{
NotNullExpression(selector);
return(Selectors.Css(expression));
}
case SelectorType.JsonPath:
{
NotNullExpression(selector);
return(Selectors.JsonPath(expression));
}
case SelectorType.Regex:
{
NotNullExpression(selector);
if (string.IsNullOrEmpty(selector.Arguments))
{
return(Selectors.Regex(expression));
}
if (int.TryParse(selector.Arguments, out var group))
{
return(Selectors.Regex(expression, group));
}
throw new ArgumentException($"Regex argument should be a number set to group: {selector}");
}
case SelectorType.XPath:
{
NotNullExpression(selector);
return(Selectors.XPath(expression));
}
default:
{
throw new NotSupportedException($"{selector} unsupported");
}
}
}
return(null);
}
