public Expression CreateStringPropertyCompareExpressionHelper(StringBuilder builder, ParameterExpression elementParm, ParameterExpression keyValueParm, ParameterExpression valueParm)
{
var str = builder.ToString().Trim();
if (!str.StartsWith(".") && !str.StartsWith("#"))
{
return(elementParm.CreateStringPropertyCompareExpression(builder.ToString(), "TagName", PredicateBuilder.StringTransform.ToLowerInvariant, PredicateBuilder.StringComparison.Equals));
}
var keyCompareValue = string.Empty;
if (str.StartsWith("#"))
{
keyCompareValue = "id";
}
else if (str.StartsWith("."))
{
keyCompareValue = "class";
}
var keyCompareExpression = keyValueParm.CreateStringPropertyCompareExpression(
keyCompareValue,
"Key",
PredicateBuilder.StringTransform.ToLowerInvariant,
PredicateBuilder.StringComparison.Equals);
var valueCompareExpression = keyValueParm.CreateStringPropertyCompareExpression(
str.Substring(1),
valueParm,
PredicateBuilder.StringTransform.ToLowerInvariant,
PredicateBuilder.StringComparison.Equals);
var valuesCompareExpression = keyValueParm.CreateKeyValueBoolExpression <string>(
valueParm,
valueCompareExpression,
PredicateBuilder.EnumerableMethodName.Any);
return(Expression.AndAlso(keyCompareExpression, valuesCompareExpression));
}
public IEnumerable <Expression> ParseHtmlQuery(ParameterExpression elementParm, ParameterExpression keyValueParm, ParameterExpression valueParm, string htmlQueryString)
{
var expressions = new List <Expression>();
Expression expression = null;
var builder = new StringBuilder();
using (var stream = new MemoryStream(Encoding.Default.GetBytes(htmlQueryString ?? string.Empty)))
{
using (var reader = new StreamReader(stream))
{
while (reader.Peek() != -1)
{
if (reader.Peek() == '[')
{
reader.Read();
var str = GetNestedElement(reader, new[] { ']' });
var delimitors = new[] { "*=", "~=", "^=", "|=", "$=", "!=", "=" };
var values = new List <string>();
if (delimitors.Any(str.Contains))
{
var delimitor = delimitors.First(str.Contains);
values.AddRange(str.Split(new[] { delimitor }, StringSplitOptions.RemoveEmptyEntries));
values = values.Select(v => v.Trim()).ToList();
values[1] = values[1].Substring(1, values[1].Length - 2); // removes parenthesis surrounding value
values.Add(delimitor);
}
if (!values.Any())
{
expression = keyValueParm.CreateStringPropertyCompareExpression(str, "Key", PredicateBuilder.StringTransform.ToLowerInvariant, PredicateBuilder.StringComparison.Equals);
}
else
{
var keyExpression = keyValueParm.CreateStringPropertyCompareExpression(values.First(), "Key", PredicateBuilder.StringTransform.ToLowerInvariant, PredicateBuilder.StringComparison.Equals);
Expression valueExpression;
var enumerableMethodName = PredicateBuilder.EnumerableMethodName.Any;
if (values.Last() == "|=")
{
var valueExpression1 = keyValueParm.CreateStringPropertyCompareExpression(values[1], valueParm, PredicateBuilder.StringTransform.None, PredicateBuilder.StringComparison.Equals);
var valueExpression2 = keyValueParm.CreateStringPropertyCompareExpression(values[1] + "-", valueParm, PredicateBuilder.StringTransform.None, PredicateBuilder.StringComparison.StartsWith);
valueExpression = Expression.OrElse(valueExpression1, valueExpression2);
}
else
{
var stringComparison = PredicateBuilder.StringComparison.Equals;
switch (values.Last())
{
case "!=":
stringComparison = PredicateBuilder.StringComparison.NotEquals;
break;
case "$=":
stringComparison = PredicateBuilder.StringComparison.EndsWith;
break;
case "^=":
stringComparison = PredicateBuilder.StringComparison.StartsWith;
break;
case "*=":
stringComparison = PredicateBuilder.StringComparison.Contains;
break;
case "~=":
stringComparison = PredicateBuilder.StringComparison.Equals;
break;
}
if (stringComparison == PredicateBuilder.StringComparison.NotEquals)
{
valueExpression = Expression.Not(keyValueParm.CreateStringPropertyCompareExpression(values[1], valueParm, PredicateBuilder.StringTransform.None, PredicateBuilder.StringComparison.Equals));
}
else
{
valueExpression = keyValueParm.CreateStringPropertyCompareExpression(values[1], valueParm, PredicateBuilder.StringTransform.None, stringComparison);
}
}
if (values.Last() == "!=")
{
var valuesExpression = keyValueParm.CreateKeyValueBoolExpression <string>(valueParm, valueExpression, enumerableMethodName);
var expression2 = Expression.OrElse(Expression.Not(keyExpression), valuesExpression);
expression = Expression.OrElse(Expression.Not(elementParm.CreateAnyExpression()), expression2);
}
else
{
var valuesExpression = keyValueParm.CreateKeyValueBoolExpression <string>(valueParm, valueExpression, enumerableMethodName);
expression = Expression.AndAlso(keyExpression, valuesExpression);
}
}
}
else if (reader.Peek() == ':')
{
var str = GetNestedElement(reader, new[] { ' ', ',', '.', '>', '+', '~', '#' });
}
else if (reader.Peek() == ',')
{
reader.Read();
expression = builder.ToString().Trim().Length > 0 ? CreateStringPropertyCompareExpressionHelper(builder, elementParm, keyValueParm, valueParm) : expression;
builder = new StringBuilder();
var expression1 = ParseHtmlQuery(elementParm, keyValueParm, valueParm, reader.ReadToEnd());
expression = Expression.OrElse(expression, expression1.First());
}
else if (reader.Peek() == ' ')
{
var delimitors = new[] { '*', '~', '^', '|', '$', '!', '=', ' ', ',', '.', '>', '+', '~', '#' };
reader.Read();
if (!delimitors.Any(d => d == reader.Peek()))
{
if (builder.ToString().Trim().Length > 0)
{
expression = CreateStringPropertyCompareExpressionHelper(builder, elementParm, keyValueParm, valueParm);
builder = new StringBuilder();
}
expressions.Add(expression);
expression = ParseHtmlQuery(elementParm, keyValueParm, valueParm, reader.ReadToEnd()).First();
}
}
else
{
builder.Append((char)reader.Read());
}
}
if (builder.ToString().Trim().Length > 0)
{
expression = CreateStringPropertyCompareExpressionHelper(builder, elementParm, keyValueParm, valueParm);
}
}
}
expressions.Add(expression);
return(expressions);
}