/// <summary>
/// Detect the mime type of file based by content with a fallback way by its extension
/// </summary>
/// <returns>instance of MimeMagicResult</returns>
public static MimeMagicResult FindMimeType(this byte[] contentBytes, string filename = "")
{
var result = new MimeMagicResult()
{
MimeType = "application/octet-stream"
};
var watch = new Stopwatch();
watch.Start();
Initialize();
try
{
var contentString = Encoding.UTF7.GetString(contentBytes, 0, Math.Min(_bufferLength, contentBytes.Length));
var extension = "*" + Path.GetExtension(filename);
// first, check all the base types
var mimes = _allTypes;
do
{
// let's try to find by content
var found = mimes.Find(mime =>
{
return(EvaluateSingleMimeByContent(contentString, mime, result));
});
// fallback to its extension
if (found == null)
{
found = mimes.Find(mime =>
{
return(EvaluateSingleMimeByExtension(extension, mime, result));
});
}
// is there any sub type for this type
mimes = _allTypes.Where(p => p.SubClassOf != null && p.SubClassOf.Type == found?.Type).ToList();
// set the result
if (found != null)
{
result.Acronym = string.IsNullOrEmpty(found?.ExpandedAcronym) ? found?.Comment : found.ExpandedAcronym;
result.MimeType = found?.Type;
}
}while (mimes != null && mimes.Count > 0);
return(result);
}
finally
{
watch.Stop();
result.ElapsedtimeInMS = (int)watch.ElapsedMilliseconds;
}
}
private static bool EvaluateSingleMimeByExtension(string extension, MimeType mime, MimeMagicResult diagnostic)
{
var matching = false;
// fallback to the file extension.
if (!matching)
{
matching = mime.Globs.Any(ext => extension.Equals(ext.Pattern));
if (matching)
{
diagnostic.FoundByExtension = true;
}
}
return(matching);
}
/// <summary>
/// According to its name
/// </summary>
private static bool EvaluateSingleMimeByContent(string content, MimeType mime, MimeMagicResult diagnostic)
{
var matching = false;
// try to find the magic in the content
if (mime.Magic != null && mime.Magic.Matches != null && mime.Magic.Matches.Count > 0)
{
matching = mime.Magic.Matches.Any(child => EvaluateSingleMatchRecursively(content, child));
if (matching)
{
diagnostic.FoundByContent = true;
}
}
return(matching);
}