/// <inheritdoc />
public async Task <Expression <Func <TEntity, bool> > > ParseAsync(string filterExpression, bool unquote = true, ICustomFilterConvertersRunner <TEntity> customFilterConverterRunner = null)
{
var rootFilter = await ParseAsFilterAsync(filterExpression, unquote, customFilterConverterRunner);
var starter = PredicateBuilder.New <TEntity>();
starter.Start(rootFilter);
return(starter);
}
/// <inheritdoc />
public async Task <Expression <Func <TEntity, bool> > > ParseAsync(NameValueCollection parameters, bool unquote, ICustomFilterConvertersRunner <TEntity> customFilterConverterRunner = null)
{
if (parameters == null || parameters.Count == 0)
{
return(null);
}
var filterString = parameters.Get("$filter", string.Empty);
if (string.IsNullOrWhiteSpace(filterString))
{
return(null);
}
return(await ParseAsync(filterString, unquote, customFilterConverterRunner));
}
/// <inheritdoc />
public async Task <Filter <TEntity> > ParseAsFilterAsync(string filterExpression, bool unquote = true, ICustomFilterConvertersRunner <TEntity> customFilterConverterRunner = null)
{
var trimmedfilterExpression = filterExpression.Trim();
if (trimmedfilterExpression.Length > 2 && unquote)
{
trimmedfilterExpression = trimmedfilterExpression.Unquote(1).Trim();
}
var state = new ParserState <TEntity>(trimmedfilterExpression);
for (state.CharIndex = 0; state.CharIndex < state.FilterString.Length; state.CharIndex++)
{
_ActionDictionary.GetValueOrDefault(state.Char).Invoke(state);
}
state.LastApply(); // Final apply required to get the last value.
var rootFilter = state.CurrentFilter;
while (rootFilter.Parent != null)
{
rootFilter = rootFilter.Parent;
}
if (customFilterConverterRunner != null)
{
rootFilter = await customFilterConverterRunner.ConvertAsync(rootFilter);
}
return(rootFilter);
}
