// Internal for unit testing purposes only.
private int GetDefaultTeaserLength(ExcerptTruncationMode mode)
{
switch (mode)
{
case ExcerptTruncationMode.Length:
return(defaultLengthAbsolute);
case ExcerptTruncationMode.Character:
return(defaultLengthCharacters);
case ExcerptTruncationMode.Word:
default:
return(defaultLengthWords);
}
}
// Internal for unit testing purposes only.
private string TruncatePost(ExcerptTruncationMode mode, string content, int length, bool isRightToLeftLanguage = false)
{
var truncateFrom = isRightToLeftLanguage ? TruncateFrom.Left : TruncateFrom.Right;
switch (mode)
{
case ExcerptTruncationMode.Length:
return(content.Truncate(length, terminator, Truncator.FixedLength, truncateFrom));
case ExcerptTruncationMode.Character:
return(content.Truncate(length, terminator, Truncator.FixedNumberOfCharacters, truncateFrom));
case ExcerptTruncationMode.Word:
default:
return(content.Truncate(length, terminator, Truncator.FixedNumberOfWords, truncateFrom));
}
}
//private string GetModeDescription(ExcerptTruncationMode mode)
//{
// switch (mode)
// {
// case ExcerptTruncationMode.Length:
// return "string length";
// case ExcerptTruncationMode.Character:
// return "letters or digits";
// case ExcerptTruncationMode.Word:
// default:
// return "words";
// }
//}
private int GetContentLength(string html, ExcerptTruncationMode mode)
{
if (string.IsNullOrEmpty(html))
{
return(0);
}
switch (mode)
{
case ExcerptTruncationMode.Length:
return(html.Length);
case ExcerptTruncationMode.Character:
return(html.ToCharArray().Count(char.IsLetterOrDigit));
case ExcerptTruncationMode.Word:
default:
return(html.Split((char[])null, StringSplitOptions.RemoveEmptyEntries).Count());
}
}
/// <summary>
/// this is an expensive method as often many retries ar eneeded to produce a valid html fragment.
/// therefore this should not be used for dynamic excerpt generation.
/// Excerpt should be generated and saved when content is edited.
/// </summary>
/// <param name="truncationMode"></param>
/// <param name="truncationLength"></param>
/// <param name="html"></param>
/// <param name="languageCode"></param>
/// <returns></returns>
public ExcerptResult GenerateExcerpt(
ExcerptTruncationMode truncationMode,
int truncationLength,
string html,
//string cacheKey,
//string slug,
string languageCode //,
//bool logWarnings = true
)
{
var result = new ExcerptResult();
if (string.IsNullOrWhiteSpace(html))
{
result.HtmlContent = html;
result.DidTruncate = false;
return(result);
}
// Try to get language metadata
var cultureInfo = CultureInfo.InvariantCulture;
if (!string.IsNullOrEmpty(languageCode))
{
try
{
cultureInfo = new CultureInfo(languageCode);
}
catch (CultureNotFoundException) { }
}
var contentLength = GetContentLength(html, truncationMode);
if (contentLength <= truncationLength)
{
result.HtmlContent = html;
result.DidTruncate = false;
return(result);
}
//if (_cache != null)
//{
// var cachedTeaser = _cache.GetTeaser(cacheKey);
// if (!string.IsNullOrEmpty(cachedTeaser))
// {
// result.Content = cachedTeaser;
// result.DidTruncate = true;
// return result;
// }
//}
var isRightToLeftLanguage = cultureInfo.TextInfo.IsRightToLeft;
// Get global teaser settings.
var truncationLengthToUse = truncationLength <= 0 ? GetDefaultTeaserLength(truncationMode) : truncationLength;
// Truncate the raw content first. In general, Humanizer is smart enough to ignore tags, especially if using word truncation.
var text = TruncatePost(truncationMode, html, truncationLengthToUse, isRightToLeftLanguage);
// Don't leave dangling <p> tags.
HtmlNode.ElementsFlags["p"] = HtmlElementFlag.Closed;
//var modeDesc = GetModeDescription(truncationMode);
//if we get bad output try increasing the allowed length unti it is valid
while (!IsValidMarkup(text) && truncationLengthToUse <= contentLength)
{
truncationLengthToUse += 1;
//if (_log != null && logWarnings)
//{
// _log.LogWarning($"teaser truncation for post {slug}, produced invalid html, so trying again and increasing the truncation length to {truncationLengthToUse} {modeDesc}. You should re-publish this post to create a persistent teaser.");
//}
text = TruncatePost(truncationMode, html, truncationLengthToUse, isRightToLeftLanguage);
}
if (!IsValidMarkup(text))
{
//if (_log != null)
//{
// _log.LogError($"failed to create valid teaser for post {slug}, so returning full content");
//}
result.HtmlContent = html;
result.DidTruncate = false;
return(result);
}
//if (_cache != null)
//{
// _cache.AddToCache(text, cacheKey);
//}
var doc = new HtmlDocument();
doc.LoadHtml(text);
result.HtmlContent = doc.DocumentNode.InnerHtml;
result.DidTruncate = true;
return(result);
}
