/// <summary>
/// Read the start of the top-level data wrapper in JSON responses.
/// </summary>
/// <param name="payloadKind">The kind of payload we are reading; this guides the parsing of the context URI.</param>
/// <param name="duplicatePropertyNamesChecker">The duplicate property names checker.</param>
/// <param name="isReadingNestedPayload">true if we are deserializing a nested payload, e.g. an entry, a feed or a collection within a parameters payload.</param>
/// <param name="allowEmptyPayload">true if we allow a comletely empty payload; otherwise false.</param>
/// <returns>The parsed context URI.</returns>
/// <remarks>
/// Pre-Condition: JsonNodeType.None: assumes that the JSON reader has not been used yet when not reading a nested payload.
/// Post-Condition: The reader is positioned on the first property of the payload after having read (or skipped) the context URI property.
/// Or the reader is positioned on an end-object node if there are no properties (other than the context URI which is required in responses and optional in requests).
/// </remarks>
internal Task ReadPayloadStartAsync(
ODataPayloadKind payloadKind,
DuplicatePropertyNamesChecker duplicatePropertyNamesChecker,
bool isReadingNestedPayload,
bool allowEmptyPayload)
{
this.JsonReader.AssertNotBuffering();
Debug.Assert(isReadingNestedPayload || this.JsonReader.NodeType == JsonNodeType.None, "Pre-Condition: JSON reader must not have been used yet when not reading a nested payload.");
return(TaskUtils.GetTaskForSynchronousOperation(() =>
{
string contextUriAnnotationValue = this.ReadPayloadStartImplementation(
payloadKind,
duplicatePropertyNamesChecker,
isReadingNestedPayload,
allowEmptyPayload);
// The context URI is only recognized in non-error response top-level payloads.
// If the payload is nested (for example when we read URL literals) we don't recognize the context URI.
// Top-level error payloads don't need and use the context URI.
if (!isReadingNestedPayload && payloadKind != ODataPayloadKind.Error)
{
this.contextUriParseResult = this.jsonLightInputContext.PayloadKindDetectionState == null
? null
: this.jsonLightInputContext.PayloadKindDetectionState.ContextUriParseResult;
if (this.contextUriParseResult == null && contextUriAnnotationValue != null)
{
this.contextUriParseResult = ODataJsonLightContextUriParser.Parse(
this.Model,
contextUriAnnotationValue,
payloadKind,
this.Version,
this.MessageReaderSettings.ReaderBehavior,
this.JsonLightInputContext.ReadingResponse);
}
}
#if DEBUG
this.contextUriParseResultReady = true;
#endif
}));
}
/// <summary>
/// Creates a context URI parser and parses the context URI read from the payload.
/// </summary>
/// <param name="model">The model to use when resolving the target of the URI.</param>
/// <param name="contextUriFromPayload">The string value of the odata.metadata annotation read from the payload.</param>
/// <param name="payloadKind">The payload kind we expect the context URI to conform to.</param>
/// <param name="readerBehavior">Reader behavior if the caller is a reader, null if no reader behavior is available.</param>
/// <param name="needParseFragment">Whether the fragment after $metadata should be parsed, if set to false, only MetadataDocumentUri is parsed.</param>
/// <returns>The result from parsing the context URI.</returns>
internal static ODataJsonLightContextUriParseResult Parse(
IEdmModel model,
string contextUriFromPayload,
ODataPayloadKind payloadKind,
ODataReaderBehavior readerBehavior,
bool needParseFragment)
{
if (contextUriFromPayload == null)
{
throw new ODataException(ODataErrorStrings.ODataJsonLightContextUriParser_NullMetadataDocumentUri);
}
// Create an absolute URI from the payload string
// TODO: Support relative context uri and resolving other relative uris
Uri contextUri;
if (!Uri.TryCreate(contextUriFromPayload, UriKind.Absolute, out contextUri))
{
throw new ODataException(ODataErrorStrings.ODataJsonLightContextUriParser_TopLevelContextUrlShouldBeAbsolute(contextUriFromPayload));
}
ODataJsonLightContextUriParser parser = new ODataJsonLightContextUriParser(model, contextUri);
parser.TokenizeContextUri();
if (needParseFragment)
{
parser.ParseContextUri(payloadKind, readerBehavior);
}
return parser.parseResult;
}