/// <summary>
/// Check if a target directive exists among the set of given cache control directives.
/// </summary>
/// <param name="cacheControlDirectives">
/// The <see cref="StringValues"/> containing the set of cache control directives.
/// </param>
/// <param name="targetDirectives">
/// The target cache control directives to look for.
/// </param>
/// <returns>
/// <code>true</code> if <paramref name="targetDirectives"/> is contained in <paramref name="cacheControlDirectives"/>;
/// otherwise, <code>false</code>.
/// </returns>
public static bool ContainsCacheDirective(StringValues cacheControlDirectives, string targetDirectives)
{
if (StringValues.IsNullOrEmpty(cacheControlDirectives) || string.IsNullOrEmpty(targetDirectives))
{
return(false);
}
for (var i = 0; i < cacheControlDirectives.Count; i++)
{
// Trim leading white space
var current = HttpRuleParser.GetWhitespaceLength(cacheControlDirectives[i], 0);
while (current < cacheControlDirectives[i].Length)
{
var initial = current;
var tokenLength = HttpRuleParser.GetTokenLength(cacheControlDirectives[i], current);
if (tokenLength == targetDirectives.Length &&
string.Compare(cacheControlDirectives[i], current, targetDirectives, 0, tokenLength, StringComparison.OrdinalIgnoreCase) == 0)
{
// Token matches target value
return(true);
}
current = AdvanceCacheDirectiveIndex(current + tokenLength, cacheControlDirectives[i]);
// Ensure index was advanced
if (current <= initial)
{
Debug.Assert(false, $"Index '{nameof(current)}' not advanced, this is a bug.");
return(false);
}
}
}
return(false);
}
public static bool TryParseDate(StringSegment input, out DateTimeOffset result)
{
return(HttpRuleParser.TryStringToDate(input, out result));
}
