/// <summary>
/// Substitute the stream from the messageWriter before writing, then read out the substituted stream
/// and translate, then write to the original response stream.
/// </summary>
/// <param name="messageWriter">ODataMessageWriter</param>
/// <param name="edmType">Type of object to be serialized</param>
/// <param name="writeAction">Writer's action to write to stream</param>
public static void PreemptivelyTranslateResponseStream(this ODataMessageWriter messageWriter, IEdmTypeReference edmType, Action <ODataMessageWriter> writeAction)
{
Stream substituteStream = new MemoryStream();
Stream originalStream = messageWriter.SubstituteResponseStream(substituteStream);
writeAction(messageWriter);
// read fake stream, walk translate json object, add item
JToken responsePayload;
StreamReader reader = new StreamReader(substituteStream);
substituteStream.Seek(0, SeekOrigin.Begin);
string requestBody = reader.ReadToEnd();
if (!string.IsNullOrEmpty(requestBody))
{
responsePayload = JToken.Parse(requestBody);
WalkTranslateResponse(responsePayload, edmType);
// Write to actual stream
// We cannot dispose of the stream, the outside methods will close it
StreamWriter streamWriter = new StreamWriter(originalStream);
JsonTextWriter writer = new JsonTextWriter(streamWriter);
JsonSerializer serializer = new JsonSerializer();
serializer.Serialize(writer, responsePayload);
writer.Flush();
}
messageWriter.SubstituteResponseStream(originalStream);
}
/// <summary>
/// Read and serialize outgoing object to HTTP request stream.
/// </summary>
internal static void WriteToStream(
Type type,
object value,
IEdmModel model,
Uri baseAddress,
MediaTypeHeaderValue contentType,
IUrlHelper internalUrlHelper,
HttpRequest internalRequest,
IHeaderDictionary internalRequestHeaders,
Func <IServiceProvider, ODataMigrationMessageWrapper> getODataMessageWrapper,
Func <IEdmTypeReference, ODataSerializer> getEdmTypeSerializer,
Func <Type, ODataSerializer> getODataPayloadSerializer,
Func <ODataSerializerContext> getODataSerializerContext)
{
if (model == null)
{
throw new InvalidOperationException("Request must have model");
}
ODataSerializer serializer = GetSerializer(type, value, internalRequest, getEdmTypeSerializer, getODataPayloadSerializer);
// special case: if the top level serializer is an ODataPrimitiveSerializer then swap it out for an ODataMigrationPrimitiveSerializer
// This only applies to the top level because inline primitives are translated but top level primitives are not, unless we use a customized serializer.
if (serializer is ODataPrimitiveSerializer)
{
serializer = new ODataMigrationPrimitiveSerializer();
}
ODataPath path = internalRequest.ODataFeature().Path;
IEdmNavigationSource targetNavigationSource = path == null ? null : path.NavigationSource;
// serialize a response
string preferHeader = GetRequestPreferHeader(internalRequestHeaders);
string annotationFilter = null;
if (!String.IsNullOrEmpty(preferHeader))
{
ODataMigrationMessageWrapper messageWrapper = getODataMessageWrapper(null);
messageWrapper.SetHeader("Prefer", preferHeader);
annotationFilter = messageWrapper.PreferHeader().AnnotationFilter;
}
ODataMigrationMessageWrapper responseMessageWrapper = getODataMessageWrapper(internalRequest.GetRequestContainer());
IODataResponseMessage responseMessage = responseMessageWrapper;
if (annotationFilter != null)
{
responseMessage.PreferenceAppliedHeader().AnnotationFilter = annotationFilter;
}
ODataMessageWriterSettings writerSettings = internalRequest.GetWriterSettings();
writerSettings.BaseUri = baseAddress;
writerSettings.Version = ODataVersion.V4; // Todo how to specify v3? Maybe don't because reading as v4
writerSettings.Validations = writerSettings.Validations & ~ValidationKinds.ThrowOnUndeclaredPropertyForNonOpenType;
string metadataLink = internalUrlHelper.CreateODataLink(MetadataSegment.Instance);
if (metadataLink == null)
{
throw new SerializationException("Unable to determine metadata url");
}
writerSettings.ODataUri = new ODataUri
{
ServiceRoot = baseAddress,
SelectAndExpand = internalRequest.ODataFeature()?.SelectExpandClause,
Apply = internalRequest.ODataFeature().ApplyClause,
Path = (path == null || IsOperationPath(path)) ? null : path.Path,
};
ODataMetadataLevel metadataLevel = ODataMetadataLevel.MinimalMetadata;
if (contentType != null)
{
IEnumerable <KeyValuePair <string, string> > parameters =
contentType.Parameters.Select(val => new KeyValuePair <string, string>(val.Name.Value, val.Value.Value));
metadataLevel = ODataMediaTypes.GetMetadataLevel(contentType.MediaType.Value, parameters);
}
using (ODataMessageWriter messageWriter = new ODataMessageWriter(responseMessage, writerSettings, model))
{
ODataSerializerContext writeContext = getODataSerializerContext();
writeContext.NavigationSource = targetNavigationSource;
writeContext.Model = model;
writeContext.RootElementName = GetRootElementName(path) ?? "root";
writeContext.SkipExpensiveAvailabilityChecks = serializer.ODataPayloadKind == ODataPayloadKind.ResourceSet;
writeContext.Path = path;
writeContext.SelectExpandClause = internalRequest.ODataFeature()?.SelectExpandClause;
writeContext.MetadataLevel = metadataLevel;
// Substitute stream to swap @odata.context
Stream substituteStream = new MemoryStream();
Stream originalStream = messageWriter.SubstituteResponseStream(substituteStream);
serializer.WriteObject(value, type, messageWriter, writeContext);
StreamReader reader = new StreamReader(substituteStream);
substituteStream.Seek(0, SeekOrigin.Begin);
JToken responsePayload = JToken.Parse(reader.ReadToEnd());
// If odata context is present, replace with odata metadata
if (responsePayload["@odata.context"] != null)
{
responsePayload["odata.metadata"] = responsePayload["@odata.context"].ToString().Replace("$entity", "@Element");
((JObject)responsePayload).Property("@odata.context").Remove();
}
// Write to actual stream
// We cannot dispose of the stream because this method does not own the stream (subsequent methods will close the streamwriter)
StreamWriter streamWriter = new StreamWriter(originalStream);
JsonTextWriter writer = new JsonTextWriter(streamWriter);
JsonSerializer jsonSerializer = new JsonSerializer();
jsonSerializer.Serialize(writer, responsePayload);
writer.Flush();
messageWriter.SubstituteResponseStream(originalStream);
}
}