Using Custom WCF Body Deserialization without changing URI Template Deserialization

Well, this is maybe the most ridiculous thing I’ve had to do, but copying the source code for UriTemplateDispatchFormatter, you can simply return a UriTemplateDispatchFormatter with an “inner” IDispatchFormatter that corresponds to the IDispatchFormatter I provided here. Not sure why this class was made internal >_>

the following class definition:

class UriTemplateDispatchFormatter : IDispatchMessageFormatter
{
    internal Dictionary<int, string> pathMapping;
    internal Dictionary<int, KeyValuePair<string, Type>> queryMapping;
    Uri baseAddress;
    IDispatchMessageFormatter bodyFormatter;
    string operationName;
    QueryStringConverter qsc;
    int totalNumUTVars;
    UriTemplate uriTemplate;

    public UriTemplateDispatchFormatter(OperationDescription operationDescription, IDispatchMessageFormatter bodyFormatter, QueryStringConverter qsc, string contractName, Uri baseAddress)
    {
        this.bodyFormatter = bodyFormatter;
        this.qsc = qsc;
        this.baseAddress = baseAddress;
        this.operationName = operationDescription.Name;
        Populate(
            out this.pathMapping,
            out this.queryMapping,
            out this.totalNumUTVars,
            out this.uriTemplate,
            operationDescription,
            qsc,
            contractName);
    }

    public void DeserializeRequest(Message message, object[] parameters)
    {
        object[] bodyParameters = new object[parameters.Length - this.totalNumUTVars];

        if (bodyParameters.Length != 0)
        {
            this.bodyFormatter.DeserializeRequest(message, bodyParameters);
        }
        int j = 0;
        UriTemplateMatch utmr = null;
        string UTMRName = "UriTemplateMatchResults";
        if (message.Properties.ContainsKey(UTMRName))
        {
            utmr = message.Properties[UTMRName] as UriTemplateMatch;
        }
        else
        {
            if (message.Headers.To != null && message.Headers.To.IsAbsoluteUri)
            {
                utmr = this.uriTemplate.Match(this.baseAddress, message.Headers.To);
            }
        }
        NameValueCollection nvc = (utmr == null) ? new NameValueCollection() : utmr.BoundVariables;
        for (int i = 0; i < parameters.Length; ++i)
        {
            if (this.pathMapping.ContainsKey(i) && utmr != null)
            {
                parameters[i] = nvc[this.pathMapping[i]];
            }
            else if (this.queryMapping.ContainsKey(i) && utmr != null)
            {
                string queryVal = nvc[this.queryMapping[i].Key];
                parameters[i] = this.qsc.ConvertStringToValue(queryVal, this.queryMapping[i].Value);
            }
            else
            {
                parameters[i] = bodyParameters[j];
                ++j;
            }
        }
    }


    public Message SerializeReply(MessageVersion messageVersion, object[] parameters, object result)
    {
        throw new NotImplementedException();
    }

    private static void Populate(out Dictionary<int, string> pathMapping,
    out Dictionary<int, KeyValuePair<string, Type>> queryMapping,
    out int totalNumUTVars,
    out UriTemplate uriTemplate,
    OperationDescription operationDescription,
    QueryStringConverter qsc,
    string contractName)
    {
        pathMapping = new Dictionary<int, string>();
        queryMapping = new Dictionary<int, KeyValuePair<string, Type>>();
        string utString = GetUTStringOrDefault(operationDescription);
        uriTemplate = new UriTemplate(utString);
        List<string> neededPathVars = new List<string>(uriTemplate.PathSegmentVariableNames);
        List<string> neededQueryVars = new List<string>(uriTemplate.QueryValueVariableNames);
        Dictionary<string, byte> alreadyGotVars = new Dictionary<string, byte>(StringComparer.OrdinalIgnoreCase);
        totalNumUTVars = neededPathVars.Count + neededQueryVars.Count;
        for (int i = 0; i < operationDescription.Messages[0].Body.Parts.Count; ++i)
        {
            MessagePartDescription mpd = operationDescription.Messages[0].Body.Parts[i];
            string parameterName = XmlConvert.DecodeName(mpd.Name);
            if (alreadyGotVars.ContainsKey(parameterName))
            {
                throw new InvalidOperationException();
            }
            List<string> neededPathCopy = new List<string>(neededPathVars);
            foreach (string pathVar in neededPathCopy)
            {
                if (string.Compare(parameterName, pathVar, StringComparison.OrdinalIgnoreCase) == 0)
                {
                    if (mpd.Type != typeof(string))
                    {
                        throw new InvalidOperationException();
                    }
                    pathMapping.Add(i, parameterName);
                    alreadyGotVars.Add(parameterName, 0);
                    neededPathVars.Remove(pathVar);
                }
            }
            List<string> neededQueryCopy = new List<string>(neededQueryVars);
            foreach (string queryVar in neededQueryCopy)
            {
                if (string.Compare(parameterName, queryVar, StringComparison.OrdinalIgnoreCase) == 0)
                {
                    if (!qsc.CanConvert(mpd.Type))
                    {
                        throw new InvalidOperationException();
                    }
                    queryMapping.Add(i, new KeyValuePair<string, Type>(parameterName, mpd.Type));
                    alreadyGotVars.Add(parameterName, 0);
                    neededQueryVars.Remove(queryVar);
                }
            }
        }
        if (neededPathVars.Count != 0)
        {
            throw new InvalidOperationException();
        }
        if (neededQueryVars.Count != 0)
        {
            throw new InvalidOperationException();
        }
    }
    private static string GetUTStringOrDefault(OperationDescription operationDescription)
    {
        string utString = GetWebUriTemplate(operationDescription);
        if (utString == null && GetWebMethod(operationDescription) == "GET")
        {
            utString = MakeDefaultGetUTString(operationDescription);
        }
        if (utString == null)
        {
            utString = operationDescription.Name;
        }
        return utString;
    }
    private static string MakeDefaultGetUTString(OperationDescription od)
    {
        StringBuilder sb = new StringBuilder(XmlConvert.DecodeName(od.Name));
        //sb.Append("/*"); // note: not + "/*", see 8988 and 9653
        if (!IsUntypedMessage(od.Messages[0]))
        {
            sb.Append("?");
            foreach (MessagePartDescription mpd in od.Messages[0].Body.Parts)
            {
                string parameterName = XmlConvert.DecodeName(mpd.Name);
                sb.Append(parameterName);
                sb.Append("={");
                sb.Append(parameterName);
                sb.Append("}&");
            }
            sb.Remove(sb.Length - 1, 1);
        }
        return sb.ToString();
    }
    private static bool IsUntypedMessage(MessageDescription message)
    {

        if (message == null)
        {
            return false;
        }
        return (message.Body.ReturnValue != null && message.Body.Parts.Count == 0 && message.Body.ReturnValue.Type == typeof(Message)) ||
            (message.Body.ReturnValue == null && message.Body.Parts.Count == 1 && message.Body.Parts[0].Type == typeof(Message));
    }
    private static void EnsureOk(WebGetAttribute wga, WebInvokeAttribute wia, OperationDescription od)
    {
        if (wga != null && wia != null)
        {
            throw new InvalidOperationException();
        }
    }
    private static string GetWebUriTemplate(OperationDescription od)
    {
        // return exactly what is on the attribute
        WebGetAttribute wga = od.Behaviors.Find<WebGetAttribute>();
        WebInvokeAttribute wia = od.Behaviors.Find<WebInvokeAttribute>();
        EnsureOk(wga, wia, od);
        if (wga != null)
        {
            return wga.UriTemplate;
        }
        else if (wia != null)
        {
            return wia.UriTemplate;
        }
        else
        {
            return null;
        }
    }
    private static string GetWebMethod(OperationDescription od)
    {
        WebGetAttribute wga = od.Behaviors.Find<WebGetAttribute>();
        WebInvokeAttribute wia = od.Behaviors.Find<WebInvokeAttribute>();
        EnsureOk(wga, wia, od);
        if (wga != null)
        {
            return "GET";
        }
        else if (wia != null)
        {
            return wia.Method ?? "POST";
        }
        else
        {
            return "POST";
        }
    }

}

along with the following behavior:

class NewtonsoftJsonBehavior : WebHttpBehavior
{
    protected override IDispatchMessageFormatter GetRequestDispatchFormatter(OperationDescription operationDescription, ServiceEndpoint endpoint)
    {
        return new UriTemplateDispatchFormatter(
            operationDescription,
            new NewtonsoftJsonDispatchFormatter(operationDescription, endpoint, true),
            GetQueryStringConverter(operationDescription),
            endpoint.Contract.Name,
            endpoint.Address.Uri);
    }

    protected override IDispatchMessageFormatter GetReplyDispatchFormatter(OperationDescription od, ServiceEndpoint ep)
    {
        return new NewtonsoftJsonDispatchFormatter(od, ep, false);
    }

}

works