/// <summary>
/// Generic Helper Function which Resolves Uri References against a Base Uri
/// </summary>
/// <param name="uriref">Uri Reference to resolve</param>
/// <param name="baseUri">Base Uri to resolve against</param>
/// <returns>Resolved Uri as a String</returns>
/// <exception cref="RdfParseException">RDF Parse Exception if the Uri cannot be resolved for a know reason</exception>
/// <exception cref="UriFormatException">Uri Format Exception if one/both of the URIs is malformed</exception>
public static String ResolveUri(String uriref, String baseUri)
{
if (!baseUri.Equals(String.Empty))
{
if (uriref.Equals(String.Empty))
{
//Empty Uri reference refers to the Base Uri
return(UriFactory.Create(Tools.FixMalformedUriStrings(baseUri)).AbsoluteUri);
}
else
{
//Resolve the Uri by combining the Absolute/Relative Uri with the in-scope Base Uri
Uri u = new Uri(Tools.FixMalformedUriStrings(uriref), UriKind.RelativeOrAbsolute);
if (u.IsAbsoluteUri)
{
//Uri Reference is an Absolute Uri so no need to resolve against Base Uri
return(u.AbsoluteUri);
}
else
{
Uri b = UriFactory.Create(Tools.FixMalformedUriStrings(baseUri));
//Check that the Base Uri is valid for resolving Relative URIs
//If the Uri Reference is a Fragment ID then Base Uri validity is irrelevant
//We have to use ToString() here because this is a Relative URI so AbsoluteUri would be invalid here
if (u.ToString().StartsWith("#"))
{
return(Tools.ResolveUri(u, b).AbsoluteUri);
}
else if (Tools.IsValidBaseUri(b))
{
return(Tools.ResolveUri(u, b).AbsoluteUri);
}
else
{
throw new RdfParseException("Cannot resolve a URI since the Base URI is not a valid for resolving Relative URIs against");
}
}
}
}
else
{
if (uriref.Equals(String.Empty))
{
throw new RdfParseException("Cannot use an Empty URI to refer to the document Base URI since there is no in-scope Base URI!");
}
try
{
return(new Uri(Tools.FixMalformedUriStrings(uriref), UriKind.Absolute).AbsoluteUri);
}
#if PORTABLE
catch (FormatException)
#else
catch (UriFormatException)
#endif
{
throw new RdfParseException("Cannot resolve a Relative URI Reference since there is no in-scope Base URI!");
}
}
}
