/// <summary>
/// Create a new instance of ODataMessageWriterSettings for batch requests.
/// </summary>
/// <param name="dataService">Data service instance.</param>
/// <returns>An instance of a message writer with the appropriate settings.</returns>
internal static MessageWriterBuilder ForBatch(IDataService dataService)
{
Uri serviceUri = dataService.OperationContext.RequestMessage.AbsoluteServiceUri;
Version responseVersion = VersionUtil.GetEffectiveMaxResponseVersion(dataService.OperationContext.RequestMessage.RequestMaxVersion, dataService.Configuration.DataServiceBehavior.MaxProtocolVersion.ToVersion());
MessageWriterBuilder messageWriterBuilder = new MessageWriterBuilder(serviceUri, responseVersion, dataService, dataService.OperationContext.ResponseMessage, null /*model*/);
// Astoria does not do content negotiation for the top level batch payload at all in V1/V2
// Hence passing */* as the accept header value by default.
string contentType = XmlConstants.MimeAny;
if (dataService.OperationContext.RequestMessage != null &&
string.CompareOrdinal(
XmlConstants.ODataVersion4Dot0,
dataService.OperationContext.RequestMessage.GetHeader(XmlConstants.HttpODataVersion)) == 0)
{
// For V4, batch request & response payload can be in Json format
string accept = dataService.OperationContext.RequestMessage.GetHeader(XmlConstants.HttpAccept);
if (accept != null && accept.StartsWith(XmlConstants.MimeApplicationJson))
{
contentType = accept;
}
}
messageWriterBuilder.WriterSettings.SetContentType(contentType, null /*acceptableCharSets*/);
return(messageWriterBuilder);
}
/// <summary>
/// Create a new instance of ODataMessageWriterSettings for errors.
/// </summary>
/// <param name="serviceUri">Service base uri.</param>
/// <param name="dataService">Data service instance.</param>
/// <param name="responseVersion">Version of the response payload.</param>
/// <param name="responseMessage">IODataResponseMessage implementation.</param>
/// <param name="acceptHeaderValue">Accept header value.</param>
/// <param name="acceptCharSetHeaderValue">Accept charset header value.</param>
/// <returns>An instance of a message writer with the appropriate settings.</returns>
internal static MessageWriterBuilder ForError(Uri serviceUri, IDataService dataService, Version responseVersion, IODataResponseMessage responseMessage, string acceptHeaderValue, string acceptCharSetHeaderValue)
{
MessageWriterBuilder messageWriterBuilder = new MessageWriterBuilder(serviceUri, responseVersion, dataService, responseMessage, null /*model*/);
messageWriterBuilder.WriterSettings.SetContentType(acceptHeaderValue, acceptCharSetHeaderValue);
return(messageWriterBuilder);
}
/// <summary>
/// Create a new instance of ODataMessageWriterSettings for batch requests.
/// </summary>
/// <param name="dataService">Data service instance.</param>
/// <returns>An instance of a message writer with the appropriate settings.</returns>
internal static MessageWriterBuilder ForBatch(IDataService dataService)
{
Uri serviceUri = dataService.OperationContext.RequestMessage.AbsoluteServiceUri;
Version responseVersion = VersionUtil.GetEffectiveMaxResponseVersion(dataService.OperationContext.RequestMessage.RequestMaxVersion, dataService.Configuration.DataServiceBehavior.MaxProtocolVersion.ToVersion());
MessageWriterBuilder messageWriterBuilder = new MessageWriterBuilder(serviceUri, responseVersion, dataService, dataService.OperationContext.ResponseMessage, null /*model*/);
// Astoria does not do content negotiation for the top level batch payload at all in V1/V2
// Hence passing */* as the accept header value.
messageWriterBuilder.WriterSettings.SetContentType(XmlConstants.MimeAny, null /*acceptableCharSets*/);
return(messageWriterBuilder);
}
/// <summary>Handles an exception when processing a batch response.</summary>
/// <param name='service'>Data service doing the processing.</param>
/// <param name="requestMessage">requestMessage holding information about the request that caused an error</param>
/// <param name="responseMessage">responseMessage to which we need to write the exception message</param>
/// <param name='exception'>Exception thrown.</param>
/// <param name='batchWriter'>Output writer for the batch.</param>
/// <param name="responseStream">Underlying response stream.</param>
/// <param name="defaultResponseVersion">The data service version to use for response, if it cannot be computed from the requestMessage.</param>
internal static void HandleBatchOperationError(IDataService service, AstoriaRequestMessage requestMessage, IODataResponseMessage responseMessage, Exception exception, ODataBatchWriter batchWriter, Stream responseStream, Version defaultResponseVersion)
{
Debug.Assert(service != null, "service != null");
Debug.Assert(exception != null, "exception != null");
Debug.Assert(batchWriter != null, "batchWriter != null");
Debug.Assert(service.Configuration != null, "service.Configuration != null");
Debug.Assert(CommonUtil.IsCatchableExceptionType(exception), "CommonUtil.IsCatchableExceptionType(exception)");
ErrorHandler handler = CreateHandler(service, requestMessage, exception, defaultResponseVersion);
service.InternalHandleException(handler.exceptionArgs);
if (requestMessage != null && responseMessage != null)
{
responseMessage.SetHeader(XmlConstants.HttpODataVersion, handler.responseVersion.ToString(2) + ";");
requestMessage.ProcessException(handler.exceptionArgs);
// if ProcessBenignException returns anything, we can safely not write to the stream.
if (ProcessBenignException(exception, service) != null)
{
return;
}
}
if (requestMessage != null)
{
responseMessage = requestMessage.BatchServiceHost.GetOperationResponseMessage();
WebUtil.SetResponseHeadersForBatchRequests(responseMessage, requestMessage.BatchServiceHost);
}
else
{
responseMessage = batchWriter.CreateOperationResponseMessage(null);
responseMessage.StatusCode = handler.exceptionArgs.ResponseStatusCode;
}
MessageWriterBuilder messageWriterBuilder = MessageWriterBuilder.ForError(
null,
service,
handler.responseVersion,
responseMessage,
handler.contentType,
null /*acceptCharsetHeaderValue*/);
using (ODataMessageWriter messageWriter = messageWriterBuilder.CreateWriter())
{
ODataError error = handler.exceptionArgs.CreateODataError();
WriteErrorWithFallbackForXml(messageWriter, handler.encoding, responseStream, handler.exceptionArgs, error, messageWriterBuilder);
}
}
/// <summary>
/// Create a new instance of ODataMessageWriterSettings for normal requests.
/// </summary>
/// <param name="dataService">Data service instance.</param>
/// <param name="requestDescription">The current request description.</param>
/// <param name="responseMessage">IODataResponseMessage implementation.</param>
/// <param name="model">The model to provide to the message writer.</param>
/// <returns>An instance of a message writer with the appropriate settings.</returns>
internal static MessageWriterBuilder ForNormalRequest(IDataService dataService, RequestDescription requestDescription, IODataResponseMessage responseMessage, IEdmModel model)
{
Debug.Assert(dataService != null, "dataService != null");
Debug.Assert(dataService.OperationContext != null, "dataService.OperationContext != null");
Debug.Assert(requestDescription != null, "requestDescription != null");
Debug.Assert(dataService.OperationContext.RequestMessage != null, "dataService.OperationContext.RequestMessage != null");
Debug.Assert(responseMessage != null, "responseMessage != null");
Uri serviceUri = dataService.OperationContext.AbsoluteServiceUri;
Version responseVersion = requestDescription.ActualResponseVersion;
MessageWriterBuilder messageWriterBuilder = new MessageWriterBuilder(serviceUri, responseVersion, dataService, responseMessage, model);
// ODataLib doesn't allow custom MIME types on raw values (must be text/plain for non-binary, and application/octet for binary values).
// To maintain existing V1/V2 behavior, work around this by setting the format as RawValue (we handle conneg ourself for this, so don't make ODL do its own),
// and then later manually override the content type header. Conneg is done by Astoria in DataService.CreateResponseBodyWriter.
if (requestDescription.ResponsePayloadKind == ODataPayloadKind.Value && !string.IsNullOrEmpty(requestDescription.MimeType))
{
messageWriterBuilder.WriterSettings.SetContentType(ODataFormat.RawValue);
}
else
{
string acceptHeaderValue = dataService.OperationContext.RequestMessage.GetAcceptableContentTypes();
// In V1/V2 we defaulted to charset=utf-8 for the response when there was no specific Accept-Charset.
// ODataMessageWriter uses a different default in some cases depending on the media type, so we need to override that here.
string requestAcceptCharSet = dataService.OperationContext.RequestMessage.GetRequestAcceptCharsetHeader();
if (string.IsNullOrEmpty(requestAcceptCharSet) || requestAcceptCharSet == "*")
{
requestAcceptCharSet = XmlConstants.Utf8Encoding;
}
messageWriterBuilder.WriterSettings.SetContentType(acceptHeaderValue, requestAcceptCharSet);
}
// always set the metadata document URI. ODataLib will decide whether or not to write it.
messageWriterBuilder.WriterSettings.ODataUri = new ODataUri()
{
ServiceRoot = serviceUri,
SelectAndExpand = requestDescription.ExpandAndSelect.Clause,
Path = requestDescription.Path
};
messageWriterBuilder.WriterSettings.JsonPCallback = requestDescription.JsonPaddingFunctionName;
return(messageWriterBuilder);
}
/// <summary>
/// Create a new instance of ODataMessageWriterSettings for normal requests.
/// </summary>
/// <param name="dataService">Data service instance.</param>
/// <param name="requestDescription">The current request description.</param>
/// <param name="responseMessage">IODataResponseMessage implementation.</param>
/// <param name="model">The model to provide to the message writer.</param>
/// <returns>An instance of a message writer with the appropriate settings.</returns>
internal static MessageWriterBuilder ForNormalRequest(IDataService dataService, RequestDescription requestDescription, IODataResponseMessage responseMessage, IEdmModel model)
{
Debug.Assert(dataService != null, "dataService != null");
Debug.Assert(dataService.OperationContext != null, "dataService.OperationContext != null");
Debug.Assert(requestDescription != null, "requestDescription != null");
Debug.Assert(dataService.OperationContext.RequestMessage != null, "dataService.OperationContext.RequestMessage != null");
Debug.Assert(responseMessage != null, "responseMessage != null");
Uri serviceUri = dataService.OperationContext.AbsoluteServiceUri;
Version responseVersion = requestDescription.ActualResponseVersion;
MessageWriterBuilder messageWriterBuilder = new MessageWriterBuilder(serviceUri, responseVersion, dataService, responseMessage, model);
// ODataLib doesn't allow custom MIME types on raw values (must be text/plain for non-binary, and application/octet for binary values).
// To maintain existing V1/V2 behavior, work around this by setting the format as RawValue (we handle conneg ourself for this, so don't make ODL do its own),
// and then later manually override the content type header. Conneg is done by Astoria in DataService.CreateResponseBodyWriter.
if (requestDescription.ResponsePayloadKind == ODataPayloadKind.Value && !string.IsNullOrEmpty(requestDescription.MimeType))
{
messageWriterBuilder.WriterSettings.SetContentType(ODataFormat.RawValue);
}
else
{
string acceptHeaderValue = dataService.OperationContext.RequestMessage.GetAcceptableContentTypes();
// In V1/V2 we defaulted to charset=utf-8 for the response when there was no specific Accept-Charset.
// ODataMessageWriter uses a different default in some cases depending on the media type, so we need to override that here.
string requestAcceptCharSet = dataService.OperationContext.RequestMessage.GetRequestAcceptCharsetHeader();
if (string.IsNullOrEmpty(requestAcceptCharSet) || requestAcceptCharSet == "*")
{
requestAcceptCharSet = XmlConstants.Utf8Encoding;
}
messageWriterBuilder.WriterSettings.SetContentType(acceptHeaderValue, requestAcceptCharSet);
}
// always set the metadata document URI. ODataLib will decide whether or not to write it.
messageWriterBuilder.WriterSettings.ODataUri = new ODataUri()
{
ServiceRoot = serviceUri,
SelectAndExpand = requestDescription.ExpandAndSelect.Clause,
Path = requestDescription.Path
};
messageWriterBuilder.WriterSettings.JsonPCallback = requestDescription.JsonPaddingFunctionName;
return messageWriterBuilder;
}
/// <summary>Handles an exception before the response has been written out.</summary>
/// <param name='exception'>Exception thrown.</param>
/// <param name='service'>Data service doing the processing.</param>
/// <returns>An action that can serialize the exception into a stream.</returns>
internal static Action <Stream> HandleBeforeWritingException(Exception exception, IDataService service)
{
Debug.Assert(CommonUtil.IsCatchableExceptionType(exception), "CommonUtil.IsCatchableExceptionType(exception)");
Debug.Assert(exception != null, "exception != null");
Debug.Assert(service != null, "service != null");
AstoriaRequestMessage requestMessage = service.OperationContext.RequestMessage;
Debug.Assert(requestMessage != null, "requestMessage != null");
ErrorHandler handler = CreateHandler(service, requestMessage, exception, VersionUtil.DataServiceDefaultResponseVersion);
service.InternalHandleException(handler.exceptionArgs);
service.OperationContext.ResponseMessage.SetHeader(XmlConstants.HttpODataVersion, handler.responseVersion.ToString(2) + ";");
requestMessage.ProcessException(handler.exceptionArgs);
Action <Stream> action = ProcessBenignException(exception, service);
if (action != null)
{
return(action);
}
MessageWriterBuilder messageWriterBuilder = MessageWriterBuilder.ForError(
service.OperationContext.RequestMessage.AbsoluteServiceUri,
service,
handler.responseVersion,
service.OperationContext.ResponseMessage,
handler.contentType,
service.OperationContext.RequestMessage.GetRequestAcceptCharsetHeader());
ODataMessageWriter messageWriter = messageWriterBuilder.CreateWriter();
ODataUtils.SetHeadersForPayload(messageWriter, ODataPayloadKind.Error);
return(stream =>
{
service.OperationContext.ResponseMessage.SetStream(stream);
ODataError error = handler.exceptionArgs.CreateODataError();
WriteErrorWithFallbackForXml(messageWriter, handler.encoding, stream, handler.exceptionArgs, error, messageWriterBuilder);
});
}
/// <summary>Initializes a new <see cref="ResponseBodyWriter"/> that can write the body of a response.</summary>
/// <param name="service">Service for the request being processed.</param>
/// <param name="queryResults">Enumerator for results.</param>
/// <param name="requestDescription">Description of request made to the system.</param>
/// <param name="actualResponseMessageWhoseHeadersMayBeOverridden">IODataResponseMessage instance for the response.</param>
internal ResponseBodyWriter(
IDataService service,
QueryResultInfo queryResults,
RequestDescription requestDescription,
IODataResponseMessage actualResponseMessageWhoseHeadersMayBeOverridden)
{
Debug.Assert(service != null, "service != null");
Debug.Assert(requestDescription != null, "requestDescription != null");
Debug.Assert(actualResponseMessageWhoseHeadersMayBeOverridden != null, "actualResponseMessageWhoseHeadersMayBeOverridden != null");
this.service = service;
this.queryResults = queryResults;
this.requestDescription = requestDescription;
this.actualResponseMessageWhoseHeadersMayBeOverridden = actualResponseMessageWhoseHeadersMayBeOverridden;
Debug.Assert(this.PayloadKind != ODataPayloadKind.Unsupported, "payloadKind != ODataPayloadKind.Unsupported");
this.encoding = ContentTypeUtil.EncodingFromAcceptCharset(this.service.OperationContext.RequestMessage.GetRequestAcceptCharsetHeader());
if (this.PayloadKind == ODataPayloadKind.Entry ||
this.PayloadKind == ODataPayloadKind.Feed ||
this.PayloadKind == ODataPayloadKind.Property ||
this.PayloadKind == ODataPayloadKind.Collection ||
this.PayloadKind == ODataPayloadKind.EntityReferenceLink ||
this.PayloadKind == ODataPayloadKind.EntityReferenceLinks ||
this.PayloadKind == ODataPayloadKind.Error ||
this.PayloadKind == ODataPayloadKind.ServiceDocument ||
this.PayloadKind == ODataPayloadKind.Parameter)
{
AstoriaRequestMessage requestMessage = service.OperationContext.RequestMessage;
IODataResponseMessage responseMessageOnOperationContext = service.OperationContext.ResponseMessage;
Version effectiveMaxResponseVersion = VersionUtil.GetEffectiveMaxResponseVersion(service.Configuration.DataServiceBehavior.MaxProtocolVersion.ToVersion(), requestMessage.RequestMaxVersion);
bool isEntityOrFeed = this.PayloadKind == ODataPayloadKind.Entry || this.PayloadKind == ODataPayloadKind.Feed;
if (ContentTypeUtil.IsResponseMediaTypeJsonLight(requestMessage.GetAcceptableContentTypes(), isEntityOrFeed, effectiveMaxResponseVersion))
{
// If JSON light 'wins', then bump the version to V3.
requestDescription.VerifyAndRaiseResponseVersion(VersionUtil.Version4Dot0, service);
responseMessageOnOperationContext.SetHeader(XmlConstants.HttpODataVersion, XmlConstants.ODataVersion4Dot0 + ";");
}
}
if (this.requestDescription.TargetKind == RequestTargetKind.MediaResource)
{
Debug.Assert(this.PayloadKind == ODataPayloadKind.BinaryValue, "payloadKind == ODataPayloadKind.BinaryValue");
// Note that GetReadStream will set the ResponseETag before it returns
this.mediaResourceStream = service.StreamProvider.GetReadStream(
this.queryResults.Current,
this.requestDescription.StreamProperty,
this.service.OperationContext);
}
else if (this.PayloadKind != ODataPayloadKind.BinaryValue)
{
IEdmModel model;
if (this.PayloadKind == ODataPayloadKind.MetadataDocument)
{
model = MetadataSerializer.PrepareModelForSerialization(this.service.Provider, this.service.Configuration);
}
else
{
model = this.GetModelFromService();
}
// Create the message writer using which the response needs to be written.
this.messageWriterBuilder = MessageWriterBuilder.ForNormalRequest(
this.service,
this.requestDescription,
this.actualResponseMessageWhoseHeadersMayBeOverridden,
model);
this.messageWriter = this.messageWriterBuilder.CreateWriter();
try
{
// Make sure all the headers are written before the method returns.
this.contentFormat = ODataUtils.SetHeadersForPayload(this.messageWriter, this.PayloadKind);
}
catch (ODataContentTypeException contentTypeException)
{
throw new DataServiceException(415, null, Strings.DataServiceException_UnsupportedMediaType, null, contentTypeException);
}
Debug.Assert(requestDescription.ResponseFormat != null, "Response format should already have been determined.");
Debug.Assert(ReferenceEquals(this.contentFormat, requestDescription.ResponseFormat.Format), "Response format in request description did not match format when writing.");
if (this.PayloadKind == ODataPayloadKind.Value && !String.IsNullOrEmpty(this.requestDescription.MimeType))
{
this.actualResponseMessageWhoseHeadersMayBeOverridden.SetHeader(XmlConstants.HttpContentType, this.requestDescription.MimeType);
}
// EPM is currently removed, but this doesn't seem to be used for EPM only. The old comment was saying:
// In astoria, there is a bug in V1/V2 that while computing response version, we did not take
// epm into account. Hence while creating the writer, we need to pass the RequestDescription.ActualResponseVersion
// so that ODataLib can do the correct payload validation. But we need to write the response version without
// the epm into the response headers because of backward-compat issue. Hence over-writing the response version
// header with the wrong version value.
string responseVersion = this.requestDescription.ResponseVersion.ToString() + ";";
this.actualResponseMessageWhoseHeadersMayBeOverridden.SetHeader(XmlConstants.HttpODataVersion, responseVersion);
}
}
/// <summary>Initializes a new <see cref="ResponseBodyWriter"/> that can write the body of a response.</summary>
/// <param name="service">Service for the request being processed.</param>
/// <param name="queryResults">Enumerator for results.</param>
/// <param name="requestDescription">Description of request made to the system.</param>
/// <param name="actualResponseMessageWhoseHeadersMayBeOverridden">IODataResponseMessage instance for the response.</param>
internal ResponseBodyWriter(
IDataService service,
QueryResultInfo queryResults,
RequestDescription requestDescription,
IODataResponseMessage actualResponseMessageWhoseHeadersMayBeOverridden)
{
Debug.Assert(service != null, "service != null");
Debug.Assert(requestDescription != null, "requestDescription != null");
Debug.Assert(actualResponseMessageWhoseHeadersMayBeOverridden != null, "actualResponseMessageWhoseHeadersMayBeOverridden != null");
this.service = service;
this.queryResults = queryResults;
this.requestDescription = requestDescription;
this.actualResponseMessageWhoseHeadersMayBeOverridden = actualResponseMessageWhoseHeadersMayBeOverridden;
Debug.Assert(this.PayloadKind != ODataPayloadKind.Unsupported, "payloadKind != ODataPayloadKind.Unsupported");
this.encoding = ContentTypeUtil.EncodingFromAcceptCharset(this.service.OperationContext.RequestMessage.GetRequestAcceptCharsetHeader());
if (this.PayloadKind == ODataPayloadKind.Entry ||
this.PayloadKind == ODataPayloadKind.Feed ||
this.PayloadKind == ODataPayloadKind.Property ||
this.PayloadKind == ODataPayloadKind.Collection ||
this.PayloadKind == ODataPayloadKind.EntityReferenceLink ||
this.PayloadKind == ODataPayloadKind.EntityReferenceLinks ||
this.PayloadKind == ODataPayloadKind.Error ||
this.PayloadKind == ODataPayloadKind.ServiceDocument ||
this.PayloadKind == ODataPayloadKind.Parameter)
{
AstoriaRequestMessage requestMessage = service.OperationContext.RequestMessage;
IODataResponseMessage responseMessageOnOperationContext = service.OperationContext.ResponseMessage;
Version effectiveMaxResponseVersion = VersionUtil.GetEffectiveMaxResponseVersion(service.Configuration.DataServiceBehavior.MaxProtocolVersion.ToVersion(), requestMessage.RequestMaxVersion);
bool isEntityOrFeed = this.PayloadKind == ODataPayloadKind.Entry || this.PayloadKind == ODataPayloadKind.Feed;
if (ContentTypeUtil.IsResponseMediaTypeJsonLight(requestMessage.GetAcceptableContentTypes(), isEntityOrFeed, effectiveMaxResponseVersion))
{
// If JSON light 'wins', then bump the version to V3.
requestDescription.VerifyAndRaiseResponseVersion(VersionUtil.Version4Dot0, service);
responseMessageOnOperationContext.SetHeader(XmlConstants.HttpODataVersion, XmlConstants.ODataVersion4Dot0 + ";");
}
}
if (this.requestDescription.TargetKind == RequestTargetKind.MediaResource)
{
Debug.Assert(this.PayloadKind == ODataPayloadKind.BinaryValue, "payloadKind == ODataPayloadKind.BinaryValue");
// Note that GetReadStream will set the ResponseETag before it returns
this.mediaResourceStream = service.StreamProvider.GetReadStream(
this.queryResults.Current,
this.requestDescription.StreamProperty,
this.service.OperationContext);
}
else if (this.PayloadKind != ODataPayloadKind.BinaryValue)
{
IEdmModel model;
if (this.PayloadKind == ODataPayloadKind.MetadataDocument)
{
model = MetadataSerializer.PrepareModelForSerialization(this.service.Provider, this.service.Configuration);
}
else
{
model = this.GetModelFromService();
}
// Create the message writer using which the response needs to be written.
this.messageWriterBuilder = MessageWriterBuilder.ForNormalRequest(
this.service,
this.requestDescription,
this.actualResponseMessageWhoseHeadersMayBeOverridden,
model);
this.messageWriter = this.messageWriterBuilder.CreateWriter();
try
{
// Make sure all the headers are written before the method returns.
this.contentFormat = ODataUtils.SetHeadersForPayload(this.messageWriter, this.PayloadKind);
}
catch (ODataContentTypeException contentTypeException)
{
throw new DataServiceException(415, null, Strings.DataServiceException_UnsupportedMediaType, null, contentTypeException);
}
Debug.Assert(requestDescription.ResponseFormat != null, "Response format should already have been determined.");
Debug.Assert(ReferenceEquals(this.contentFormat, requestDescription.ResponseFormat.Format), "Response format in request description did not match format when writing.");
if (this.PayloadKind == ODataPayloadKind.Value && !String.IsNullOrEmpty(this.requestDescription.MimeType))
{
this.actualResponseMessageWhoseHeadersMayBeOverridden.SetHeader(XmlConstants.HttpContentType, this.requestDescription.MimeType);
}
// EPM is currently removed, but this doesn't seem to be used for EPM only. The old comment was saying:
// In astoria, there is a bug in V1/V2 that while computing response version, we did not take
// epm into account. Hence while creating the writer, we need to pass the RequestDescription.ActualResponseVersion
// so that ODataLib can do the correct payload validation. But we need to write the response version without
// the epm into the response headers because of backward-compat issue. Hence over-writing the response version
// header with the wrong version value.
string responseVersion = this.requestDescription.ResponseVersion.ToString() + ";";
this.actualResponseMessageWhoseHeadersMayBeOverridden.SetHeader(XmlConstants.HttpODataVersion, responseVersion);
}
}
/// <summary>
/// Writes the error with fallback logic for XML cases where the writer is in an error state and a new writer must be created.
/// </summary>
/// <param name="messageWriter">The message writer.</param>
/// <param name="encoding">The encoding to use for the error if we have to fallback.</param>
/// <param name="responseStream">The response stream to write to in the fallback case.</param>
/// <param name="args">The args for the error.</param>
/// <param name="error">The error to write.</param>
/// <param name="messageWriterBuilder">MessageWriterBuilder to use if a new ODataMessageWriter needs to be constructed.</param>
private static void WriteErrorWithFallbackForXml(ODataMessageWriter messageWriter, Encoding encoding, Stream responseStream, HandleExceptionArgs args, ODataError error, MessageWriterBuilder messageWriterBuilder)
{
Debug.Assert(args != null, "args != null");
#if DEBUG
Debug.Assert(args.ProcessExceptionWasCalled, "ProcessException was not called by the time we tried to serialze this error message with ODataLib.");
#endif
if (messageWriter != null)
{
try
{
// If the XmlWriter inside the ODataMessageWriter had entered Error state, ODataMessageWriter.WriteError would throw an InvalidOperationException
// when we try to write to it. Note that XmlWriter doesn't always throw an XmlException when it enters Error state.
// The right thing to do is we don't write any more because at this point we don't know what's been written to the underlying
// stream. However we still should flush the writer to make sure that all the content that was written but is sitting in the buffers actually appears
// in the stream before writing the instream error. Otherwise the buffer will be flushed when disposing the writer later and we would end up with
// either content written after the instream error (this would also result in having the Xml declaration in the middle of the payload -
// [Astoria-ODataLib-Integration] In-stream errors due to XmlExceptions are written out backwards (error before partial valid payload)) or,
// hypothetically, the instream error in the middle of the other content that was already partially written. For example we can end up with a payload that
// looks like <element attr="val<m:error... The XmlReader would not be able to parse the error payload in this case. Disposing the writer will flush the buffer.
// It is fine to do it since the writer is not usable at this point anyways. Also note that the writer will be disposed more than once (e.g. in finally block
// in ResponseBodySerializer) but only the first call will have any effect.
// However since in the versions we shipped we always create a new XmlWriter to serialize the error payload when the existing
// one is in error state, we will continue to do the same to avoid introducing any breaking change here.
messageWriter.WriteError(error, args.UseVerboseErrors);
}
catch (ODataException e)
{
// Yikes, ODataLib threw while writing the error. This tends to happen if the service author did something invalid during custom
// error handling, such as add an custom instance annotation to the error payload. In this dire case, we treat it almost like
// an in-stream error, and abort the previous writing. We write out the new error. Note that this will produce an invalid payload like
// the situation noted above with XmlWriter errors.
WebUtil.Dispose(messageWriter);
messageWriterBuilder.SetMessageForErrorInError();
var newErrorWriter = messageWriterBuilder.CreateWriter();
ODataError errorWhileWritingOtherError = new ODataError()
{
ErrorCode = "500",
InnerError = new ODataInnerError(e),
Message = Strings.ErrorHandler_ErrorWhileWritingError
};
newErrorWriter.WriteError(errorWhileWritingOtherError, args.UseVerboseErrors);
}
catch (InvalidOperationException)
{
Debug.Assert(ContentTypeUtil.IsNotJson(args.ResponseContentType), "Should never get here for JSON responses");
WebUtil.Dispose(messageWriter);
// if either an InvalidOperationException was encountered (see comment above) or the message writer was null, write the error out manually.
Debug.Assert(responseStream != null, "responseStream != null");
using (XmlWriter xmlWriter = XmlWriter.Create(responseStream, XmlUtil.CreateXmlWriterSettings(encoding)))
{
ErrorUtils.WriteXmlError(xmlWriter, error, args.UseVerboseErrors, MaxInnerErrorDepth);
}
}
}
}
/// <summary>
/// Handles an exception that occurred while writing a response.
/// </summary>
/// <param name="service">Data service doing the processing.</param>
/// <param name="exception">The exception that was thrown.</param>
/// <param name="responseMessage">The response message.</param>
/// <param name="messageWriter">The message writer, if null this will fall back to writing a raw XML error to the stream.</param>
/// <param name="encoding">The encoding to while writing the error.</param>
/// <param name="responseStream">The response stream to write the error to.</param>
/// <param name="messageWriterBuilder">MessageWriterBuilder to use in case a new ODataMessageWriter needs to be constructed.</param>
internal static void HandleExceptionWhileWriting(IDataService service, Exception exception, IODataResponseMessage responseMessage, ODataMessageWriter messageWriter, Encoding encoding, Stream responseStream, MessageWriterBuilder messageWriterBuilder)
{
Debug.Assert(service != null, "service != null");
Debug.Assert(service.Configuration != null, "service.Configuration != null");
Debug.Assert(exception != null, "exception != null");
Debug.Assert(CommonUtil.IsCatchableExceptionType(exception), "CommonUtil.IsCatchableExceptionType(exception)");
Debug.Assert(responseMessage != null, "responseMessage != null");
string contentType = responseMessage.GetHeader(XmlConstants.HttpContentType);
HandleExceptionArgs args = new HandleExceptionArgs(exception, true, contentType, service.Configuration.UseVerboseErrors);
service.InternalHandleException(args);
service.OperationContext.RequestMessage.ProcessException(args);
ODataError error = args.CreateODataError();
WriteErrorWithFallbackForXml(messageWriter, encoding, responseStream, args, error, messageWriterBuilder);
}
/// <summary>
/// Writes the error with fallback logic for XML cases where the writer is in an error state and a new writer must be created.
/// </summary>
/// <param name="messageWriter">The message writer.</param>
/// <param name="encoding">The encoding to use for the error if we have to fallback.</param>
/// <param name="responseStream">The response stream to write to in the fallback case.</param>
/// <param name="args">The args for the error.</param>
/// <param name="error">The error to write.</param>
/// <param name="messageWriterBuilder">MessageWriterBuilder to use if a new ODataMessageWriter needs to be constructed.</param>
private static void WriteErrorWithFallbackForXml(ODataMessageWriter messageWriter, Encoding encoding, Stream responseStream, HandleExceptionArgs args, ODataError error, MessageWriterBuilder messageWriterBuilder)
{
Debug.Assert(args != null, "args != null");
#if DEBUG
Debug.Assert(args.ProcessExceptionWasCalled, "ProcessException was not called by the time we tried to serialze this error message with ODataLib.");
#endif
if (messageWriter != null)
{
try
{
// If the XmlWriter inside the ODataMessageWriter had entered Error state, ODataMessageWriter.WriteError would throw an InvalidOperationException
// when we try to write to it. Note that XmlWriter doesn't always throw an XmlException when it enters Error state.
// The right thing to do is we don't write any more because at this point we don't know what's been written to the underlying
// stream. However we still should flush the writer to make sure that all the content that was written but is sitting in the buffers actually appears
// in the stream before writing the instream error. Otherwise the buffer will be flushed when disposing the writer later and we would end up with
// either content written after the instream error (this would also result in having the Xml declaration in the middle of the payload -
// [Astoria-ODataLib-Integration] In-stream errors due to XmlExceptions are written out backwards (error before partial valid payload)) or,
// hypothetically, the instream error in the middle of the other content that was already partially written. For example we can end up with a payload that
// looks like <element attr="val<m:error... The XmlReader would not be able to parse the error payload in this case. Disposing the writer will flush the buffer.
// It is fine to do it since the writer is not usable at this point anyways. Also note that the writer will be disposed more than once (e.g. in finally block
// in ResponseBodySerializer) but only the first call will have any effect.
// However since in the versions we shipped we always create a new XmlWriter to serialize the error payload when the existing
// one is in error state, we will continue to do the same to avoid introducing any breaking change here.
messageWriter.WriteError(error, args.UseVerboseErrors);
}
catch (ODataException e)
{
// Yikes, ODataLib threw while writing the error. This tends to happen if the service author did something invalid during custom
// error handling, such as add an custom instance annotation to the error payload. In this dire case, we treat it almost like
// an in-stream error, and abort the previous writing. We write out the new error. Note that this will produce an invalid payload like
// the situation noted above with XmlWriter errors.
WebUtil.Dispose(messageWriter);
messageWriterBuilder.SetMessageForErrorInError();
var newErrorWriter = messageWriterBuilder.CreateWriter();
ODataError errorWhileWritingOtherError = new ODataError()
{
ErrorCode = "500",
InnerError = new ODataInnerError(e),
Message = Strings.ErrorHandler_ErrorWhileWritingError
};
newErrorWriter.WriteError(errorWhileWritingOtherError, args.UseVerboseErrors);
}
catch (InvalidOperationException)
{
Debug.Assert(ContentTypeUtil.IsNotJson(args.ResponseContentType), "Should never get here for JSON responses");
WebUtil.Dispose(messageWriter);
// if either an InvalidOperationException was encountered (see comment above) or the message writer was null, write the error out manually.
Debug.Assert(responseStream != null, "responseStream != null");
using (XmlWriter xmlWriter = XmlWriter.Create(responseStream, XmlUtil.CreateXmlWriterSettings(encoding)))
{
ErrorUtils.WriteXmlError(xmlWriter, error, args.UseVerboseErrors, MaxInnerErrorDepth);
}
}
}
}
/// <summary>
/// Handles an exception that occurred while writing a response.
/// </summary>
/// <param name="service">Data service doing the processing.</param>
/// <param name="exception">The exception that was thrown.</param>
/// <param name="responseMessage">The response message.</param>
/// <param name="messageWriter">The message writer, if null this will fall back to writing a raw XML error to the stream.</param>
/// <param name="encoding">The encoding to while writing the error.</param>
/// <param name="responseStream">The response stream to write the error to.</param>
/// <param name="messageWriterBuilder">MessageWriterBuilder to use in case a new ODataMessageWriter needs to be constructed.</param>
internal static void HandleExceptionWhileWriting(IDataService service, Exception exception, IODataResponseMessage responseMessage, ODataMessageWriter messageWriter, Encoding encoding, Stream responseStream, MessageWriterBuilder messageWriterBuilder)
{
Debug.Assert(service != null, "service != null");
Debug.Assert(service.Configuration != null, "service.Configuration != null");
Debug.Assert(exception != null, "exception != null");
Debug.Assert(CommonUtil.IsCatchableExceptionType(exception), "CommonUtil.IsCatchableExceptionType(exception)");
Debug.Assert(responseMessage != null, "responseMessage != null");
string contentType = responseMessage.GetHeader(XmlConstants.HttpContentType);
HandleExceptionArgs args = new HandleExceptionArgs(exception, true, contentType, service.Configuration.UseVerboseErrors);
service.InternalHandleException(args);
service.OperationContext.RequestMessage.ProcessException(args);
ODataError error = args.CreateODataError();
WriteErrorWithFallbackForXml(messageWriter, encoding, responseStream, args, error, messageWriterBuilder);
}
/// <summary>
/// Create a new instance of ODataMessageWriterSettings for errors.
/// </summary>
/// <param name="serviceUri">Service base uri.</param>
/// <param name="dataService">Data service instance.</param>
/// <param name="responseVersion">Version of the response payload.</param>
/// <param name="responseMessage">IODataResponseMessage implementation.</param>
/// <param name="acceptHeaderValue">Accept header value.</param>
/// <param name="acceptCharSetHeaderValue">Accept charset header value.</param>
/// <returns>An instance of a message writer with the appropriate settings.</returns>
internal static MessageWriterBuilder ForError(Uri serviceUri, IDataService dataService, Version responseVersion, IODataResponseMessage responseMessage, string acceptHeaderValue, string acceptCharSetHeaderValue)
{
MessageWriterBuilder messageWriterBuilder = new MessageWriterBuilder(serviceUri, responseVersion, dataService, responseMessage, null /*model*/);
messageWriterBuilder.WriterSettings.SetContentType(acceptHeaderValue, acceptCharSetHeaderValue);
return messageWriterBuilder;
}
/// <summary>
/// Create a new instance of ODataMessageWriterSettings for batch requests.
/// </summary>
/// <param name="dataService">Data service instance.</param>
/// <returns>An instance of a message writer with the appropriate settings.</returns>
internal static MessageWriterBuilder ForBatch(IDataService dataService)
{
Uri serviceUri = dataService.OperationContext.RequestMessage.AbsoluteServiceUri;
Version responseVersion = VersionUtil.GetEffectiveMaxResponseVersion(dataService.OperationContext.RequestMessage.RequestMaxVersion, dataService.Configuration.DataServiceBehavior.MaxProtocolVersion.ToVersion());
MessageWriterBuilder messageWriterBuilder = new MessageWriterBuilder(serviceUri, responseVersion, dataService, dataService.OperationContext.ResponseMessage, null /*model*/);
// Astoria does not do content negotiation for the top level batch payload at all in V1/V2
// Hence passing */* as the accept header value.
messageWriterBuilder.WriterSettings.SetContentType(XmlConstants.MimeAny, null /*acceptableCharSets*/);
return messageWriterBuilder;
}
