Extract Metadata From OTF File In C#

// Extract OTF metadata properties by various criteria

// Construct Metadata passing OTF path
using (var metadata = new GroupDocs.Metadata.Metadata("input.otf"))
{
    // extract all metadata properties that fall into a particular category
    var properties = metadata.FindProperties(
      p => p.Tags.Any(t => t.Category == GroupDocs.Metadata.Tagging.Tags.Content));
    // iterate over all properties and display
    foreach (var property in properties)
    {
        Console.WriteLine("{0} = {1}", property.Name, property.Value);
    }

    // extract all properties having a specific type and value
    var year = DateTime.Today.Year;
    properties = metadata.FindProperties(
      p => p.Value.Type == GroupDocs.Metadata.Common.MetadataPropertyType.DateTime && 
      p.Value.ToStruct(DateTime.MinValue).Year == year);

    // display all datetime properties with the year value equal to the current year
    foreach (var property in properties)
    {
        Console.WriteLine("{0} = {1}", property.Name, property.Value);
    }

    // extract all properties having names matching the specified regex
    const string pattern = "^author|company|(.+date.*)$";
    var regex = new System.Text.RegularExpressions.Regex(pattern, 
      System.Text.RegularExpressions.RegexOptions.IgnoreCase);
    properties = metadata.FindProperties(p => regex.IsMatch(p.Name));

    // display properties whose names match the following pattern
    foreach (var property in properties)
    {
        Console.WriteLine("{0} = {1}", property.Name, property.Value);
    }
}