FormatSelectingMessageInspector.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / cdf / src / NetFx35 / System.ServiceModel.Web / System / ServiceModel / Dispatcher / FormatSelectingMessageInspector.cs / 1305376 / FormatSelectingMessageInspector.cs
                        
                        
                            //------------------------------------------------------------ 
// Copyright (c) Microsoft Corporation.  All rights reserved.
//-----------------------------------------------------------
#pragma warning disable 1634, 1691
namespace System.ServiceModel.Description 
{
    using System.Collections.Generic; 
    using System.Linq; 
    using System.Net.Mime;
    using System.Runtime; 
    using System.ServiceModel;
    using System.ServiceModel.Channels;
    using System.ServiceModel.Dispatcher;
    using System.ServiceModel.Web; 
    using System.Diagnostics;
    using System.ServiceModel.Diagnostics; 
 
    class FormatSelectingMessageInspector : IDispatchMessageInspector
    { 
        static readonly IEnumerable wildcardMediaTypes = new List() { "application", "text" };

        List mappings;
        Dictionary formatters; 
        Dictionary> caches;
        bool automaticFormatSelectionEnabled; 
 
        // There are technically an infinite number of valid accept headers for just xml and json,
        // but to prevent DOS attacks, we need to set an upper limit. It is assumed that there would 
        // never be more than two dozen valid accept headers actually used out in the wild.
        static readonly int maxCachedAcceptHeaders = 25;

        public FormatSelectingMessageInspector(WebHttpBehavior webHttpBehavior, List mappings) 
        {
            if (webHttpBehavior == null) 
            { 
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperArgumentNull("webHttpBehavior");
            } 
            if (mappings == null)
            {
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperArgumentNull("mappings");
            } 

            this.automaticFormatSelectionEnabled = webHttpBehavior.AutomaticFormatSelectionEnabled; 
 
            this.formatters = new Dictionary();
 
            this.caches = new Dictionary>();

            this.mappings = mappings;
        } 

        public void RegisterOperation(string operationName, MultiplexingDispatchMessageFormatter formatter) 
        { 
            if (formatter == null)
            { 
                throw DiagnosticUtility.ExceptionUtility.ThrowHelperArgumentNull("formatter");
            }
            Fx.Assert(!this.formatters.ContainsKey(operationName), "An operation should only be registered once.");
            this.formatters.Add(operationName, formatter); 
            this.caches.Add(operationName, new NameValueCache(maxCachedAcceptHeaders));
        } 
 
        public object AfterReceiveRequest(ref Message request, IClientChannel channel, InstanceContext instanceContext)
        { 
            if (this.automaticFormatSelectionEnabled)
            {
                MessageProperties messageProperties = OperationContext.Current.IncomingMessageProperties;
                if (messageProperties.ContainsKey(WebHttpDispatchOperationSelector.HttpOperationNamePropertyName)) 
                {
                    string operationName = messageProperties[WebHttpDispatchOperationSelector.HttpOperationNamePropertyName] as string; 
                    if (!string.IsNullOrEmpty(operationName) && this.formatters.ContainsKey(operationName)) 
                    {
 
                        string acceptHeader = WebOperationContext.Current.IncomingRequest.Accept;
                        if (!string.IsNullOrEmpty(acceptHeader))
                        {
                            if (TrySetFormatFromCache(operationName, acceptHeader) || 
                                TrySetFormatFromAcceptHeader(operationName, acceptHeader, true /* matchCharSet */) ||
                                TrySetFormatFromAcceptHeader(operationName, acceptHeader, false /* matchCharSet */)) 
                            { 
                                return null;
                            } 
                        }
                        if (TrySetFormatFromContentType(operationName))
                        {
                            return null; 
                        }
                        SetFormatFromDefault(operationName); 
                    } 
                }
            } 
            return null;
        }

        public void BeforeSendReply(ref Message reply, object correlationState) 
        {
            // do nothing 
        } 

        bool TrySetFormatFromCache(string operationName, string acceptHeader) 
        {
            Fx.Assert(this.caches.ContainsKey(operationName), "The calling method is responsible for ensuring that the 'operationName' key exists in the caches dictionary.");
            Fx.Assert(acceptHeader != null, "The calling method is responsible for ensuring that 'acceptHeader' is not null");
 
            FormatContentTypePair pair = caches[operationName].Lookup(acceptHeader.ToUpperInvariant());
            if (pair != null) 
            { 
                SetFormatAndContentType(pair.Format, pair.ContentType);
                return true; 
            }
            return false;
        }
 
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Globalization", "CA1308:NormalizeStringsToUppercase", Justification = "Given that media types are generally in lowercase, it is awkward to normalize to uppercase.")]
        bool TrySetFormatFromAcceptHeader(string operationName, string acceptHeader, bool matchCharSet) 
        { 
            Fx.Assert(this.formatters.ContainsKey(operationName), "The calling method is responsible for ensuring that the 'operationName' key exists in the formatters dictionary.");
 
            IList acceptHeaderElements = WebOperationContext.Current.IncomingRequest.GetAcceptHeaderElements();

            for (int i = 0; i < acceptHeaderElements.Count; i++)
            { 
                string[] typeAndSubType = acceptHeaderElements[i].MediaType.Split('/');
                string type = typeAndSubType[0].Trim().ToLowerInvariant(); 
                string subType = typeAndSubType[1].Trim(); 

                if ((subType[0] == '*' && subType.Length == 1) && 
                     ((type[0] == '*' && type.Length == 1) ||
                      wildcardMediaTypes.Contains(type)))
                {
                    SetFormatFromDefault(operationName, acceptHeader); 
                    return true;
                } 
 
                foreach (MultiplexingFormatMapping mapping in mappings)
                { 
                    ContentType contentType;
                    WebMessageFormat format = mapping.MessageFormat;
                    if (this.formatters[operationName].SupportsMessageFormat(format) &&
                        mapping.CanFormatResponse(acceptHeaderElements[i], matchCharSet, out contentType)) 
                    {
                        string contentTypeStr = contentType.ToString(); 
                        this.caches[operationName].AddOrUpdate(acceptHeader.ToUpperInvariant(), new FormatContentTypePair(format, contentTypeStr)); 
                        SetFormatAndContentType(format, contentTypeStr);
                        return true; 
                    }
                }
            }
            return false; 
        }
 
        bool TrySetFormatFromContentType(string operationName) 
        {
            Fx.Assert(this.formatters.ContainsKey(operationName), "The calling method is responsible for ensuring that the 'operationName' key exists in the formatters dictionary."); 

            string contentTypeStr = WebOperationContext.Current.IncomingRequest.ContentType;
            if (contentTypeStr != null)
            { 
                ContentType contentType = IncomingWebRequestContext.GetContentType(contentTypeStr);
                if (contentType != null) 
                { 
                    foreach (MultiplexingFormatMapping mapping in mappings)
                    { 
                        ContentType responseContentType;
                        if (this.formatters[operationName].SupportsMessageFormat(mapping.MessageFormat) &&
                            mapping.CanFormatResponse(contentType, false, out responseContentType))
                        { 
                            SetFormatAndContentType(mapping.MessageFormat, responseContentType.ToString());
                            return true; 
                        } 
                    }
                } 
            }

            return false;
        } 

        void SetFormatFromDefault(string operationName) 
        { 
            SetFormatFromDefault(operationName, null);
        } 

        void SetFormatFromDefault(string operationName, string acceptHeader)
        {
            Fx.Assert(this.formatters.ContainsKey(operationName), "The calling method is responsible for ensuring that the 'operationName' key exists in the formatters dictionary."); 
            WebMessageFormat format = this.formatters[operationName].DefaultFormat;
 
            if (!string.IsNullOrEmpty(acceptHeader)) 
            {
                this.caches[operationName].AddOrUpdate(acceptHeader.ToUpperInvariant(), new FormatContentTypePair(format, null)); 
            }

            WebOperationContext.Current.OutgoingResponse.Format = format;
 
            if (DiagnosticUtility.ShouldTraceInformation)
            { 
                TraceUtility.TraceEvent(TraceEventType.Information, TraceCode.AutomaticFormatSelectedOperationDefault, SR2.GetString(SR2.TraceCodeAutomaticFormatSelectedOperationDefault, format.ToString())); 
            }
        } 

        void SetFormatAndContentType(WebMessageFormat format, string contentType)
        {
            OutgoingWebResponseContext outgoingResponse = WebOperationContext.Current.OutgoingResponse; 
            outgoingResponse.Format = format;
            outgoingResponse.AutomatedFormatSelectionContentType = contentType; 
 
            if (DiagnosticUtility.ShouldTraceInformation)
            { 
                TraceUtility.TraceEvent(TraceEventType.Information, TraceCode.AutomaticFormatSelectedRequestBased, SR2.GetString(SR2.TraceCodeAutomaticFormatSelectedRequestBased, format.ToString(), contentType));
            }
        }
 
        class FormatContentTypePair
        { 
            WebMessageFormat format; 
            string contentType;
 
            public FormatContentTypePair(WebMessageFormat format, string contentType)
            {
                this.format = format;
                this.contentType = contentType; 
            }
 
            public WebMessageFormat Format 
            {
                get { return this.format; } 
            }

            public string ContentType
            { 
                get { return this.contentType; }
            } 
        } 
    }
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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FormatSelectingMessageInspector.cs source code in C# .NET

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