How to use .NET Uri within VBScript

Question

I have a .NET assembly which is built to expose COM interop. A simple code sample is:

namespace ClassLibraryWithUri
{
    [ComVisible(true)]
    public class UriGenerator
    {
        public UriGenerator()
        { }

        public Uri GetUri()
        {
            return new Uri("http://www.google.com");
        }
    }
}

then I try to consume within Visual Basic script:

dim myObj
Set myObj = WScript.CreateObject("UriGenerator.UriGenerator")
Dim myUri
Set myUri = myObj.GetUri()
Dim url 
Set url = myUri.ToString()
WScript.Echo(url)

but I get error: Microsoft VBScript runtime error: Object required, at the line Set url = myUri.ToString()

My question is: why? Are Uri supported? I have not found anything on google and on Stack OVerflow Am I doing something wrong?

Thanks for your help.

Answer 1

I believe you'll have to create a COM wrapper class for .NET's Uri class in order for this to work. I was curious as to the effort it would take, and I wrote the following. This is more or less what you'll have to do. Everywhere you want to use a URI in your public interface, use IUri as defined below.

// COM doesn't have constructors, so in order to create Url objects from COM clients, you need a factory
[ComVisible(true)]
public interface IUriFactory
{
    IUri Create1(string uriString);
    IUri Create2(string uriString, UriKind uriKind);
    IUri Create3(IUri baseUri, string relativeUri);
    IUri Create4(IUri baseUri, IUri relativeUri);
}

[ComVisible(true)]
public interface IUri
{
    string GetComponents(UriComponents components, UriFormat format);
    string GetLeftPart(UriPartial part);
    bool IsBaseOf(IUri uri);
    bool IsWellFormedOriginalString();
    IUri MakeRelativeUri(IUri uri);
    string ToString();
    string AbsolutePath { get; }
    string AbsoluteUri { get; }
    string Authority { get; }
    string DnsSafeHost { get; }
    string Fragment { get; }
    string Host { get; }
    UriHostNameType HostNameType { get; }
    bool IsAbsoluteUri { get; }
    bool IsDefaultPort { get; }
    bool IsFile { get; }
    bool IsLoopback { get; }
    bool IsUnc { get; }
    string LocalPath { get; }
    string OriginalString { get; }
    string PathAndQuery { get; }
    int Port { get; }
    string Query { get; }
    string Scheme { get; }
    string[] Segments { get; }
    bool UserEscaped { get; }
    string UserInfo { get; }
}

[ComVisible(true)]
public enum UriKind
{
    RelativeOrAbsolute = System.UriKind.RelativeOrAbsolute,
    Absolute = System.UriKind.Absolute,
    Relative = System.UriKind.Relative,
}

[ComVisible(true)]
public enum UriComponents
{
    Scheme = System.UriComponents.Scheme,
    UserInfo = System.UriComponents.UserInfo,
    Host = System.UriComponents.Host,
    Port = System.UriComponents.Port,
    Path = System.UriComponents.Path,
    Query = System.UriComponents.Query,
    Fragment = System.UriComponents.Fragment,
    StrongPort = System.UriComponents.StrongPort,
    NormalizedHost = System.UriComponents.NormalizedHost,
    KeepDelimiter = System.UriComponents.KeepDelimiter,
    SerializationInfoString = System.UriComponents.SerializationInfoString,
    AbsoluteUri = Fragment | Query | Path | Port | Host | UserInfo | Scheme,
    HostAndPort = StrongPort | Host,
    StrongAuthority = HostAndPort | UserInfo,
    SchemeAndServer = Port | Host | Scheme,
    HttpRequestUrl = SchemeAndServer | Query | Path,
    PathAndQuery = Query | Path,
}

[ComVisible(true)]
public enum UriFormat
{
    UriEscaped = System.UriFormat.UriEscaped,
    Unescaped = System.UriFormat.Unescaped,
    SafeUnescaped = System.UriFormat.SafeUnescaped,
}

[ComVisible(true)]
public enum UriPartial
{
    Scheme = System.UriPartial.Scheme,
    Authority = System.UriPartial.Authority,
    Path = System.UriPartial.Path,
    Query = System.UriPartial.Query,
}

[ComVisible(true)]
public enum UriHostNameType
{
    Unknown = System.UriHostNameType.Unknown,
    Basic = System.UriHostNameType.Basic,
    Dns = System.UriHostNameType.Dns,
    IPv4 = System.UriHostNameType.IPv4,
    IPv6 = System.UriHostNameType.IPv6,
}

[ComVisible(true)]
public class UriFactory : IUriFactory
{
    public IUri Create1(string uriString){ return new Uri(new System.Uri(uriString)); }
    public IUri Create2(string uriString, UriKind uriKind) { return new Uri(new System.Uri(uriString, (System.UriKind) (int) uriKind)); }
    public IUri Create3(IUri baseUri, string relativeUri) { return new Uri(new System.Uri(((Uri) baseUri).Inner, relativeUri)); }
    public IUri Create4(IUri baseUri, IUri relativeUri) { return new Uri(new System.Uri(((Uri) baseUri).Inner, ((Uri) relativeUri).Inner)); }
}

[ComVisible(true)]
internal class Uri : IUri
{
    internal readonly System.Uri Inner;
    internal Uri(System.Uri inner) { Inner = inner; }
    public string GetComponents(UriComponents components, UriFormat format) => Inner.GetComponents((System.UriComponents) components, (System.UriFormat) format);
    public string GetLeftPart(UriPartial part) => Inner.GetLeftPart((System.UriPartial) part);
    public bool IsBaseOf(IUri uri) => Inner.IsBaseOf(((Uri) uri).Inner);
    public bool IsWellFormedOriginalString() => Inner.IsWellFormedOriginalString();
    public IUri MakeRelativeUri(IUri uri) => new Uri(Inner.MakeRelativeUri(((Uri) uri).Inner));
    public string AbsolutePath => Inner.AbsolutePath;
    public string AbsoluteUri => Inner.AbsoluteUri;
    public string Authority => Inner.Authority;
    public string DnsSafeHost => Inner.DnsSafeHost;
    public string Fragment => Inner.Fragment;
    public string Host => Inner.Host;
    public UriHostNameType HostNameType => (UriHostNameType) (int) Inner.HostNameType;
    public bool IsAbsoluteUri => Inner.IsAbsoluteUri;
    public bool IsDefaultPort => Inner.IsDefaultPort;
    public bool IsFile => Inner.IsFile;
    public bool IsLoopback => Inner.IsLoopback;
    public bool IsUnc => Inner.IsUnc;
    public string LocalPath => Inner.LocalPath;
    public string OriginalString => Inner.OriginalString;
    public string PathAndQuery => Inner.PathAndQuery;
    public int Port => Inner.Port;
    public string Query => Inner.Query;
    public string Scheme => Inner.Scheme;
    public string[] Segments => Inner.Segments;
    public bool UserEscaped => Inner.UserEscaped;
    public string UserInfo => Inner.UserInfo;
}