Microsoft.OData.Core<\/code><\/h2>\nChanged default JSON writer<\/h3>\n
OData .NET 8 default JSON writer is now based on\u00a0Utf8JsonWriter<\/code>. This JSON writer was already available as an option in OData .NET 7 but was not the default. This writer improves performance and reduces memory usage compared to the previous default, especially when performing serialization using the async API.<\/p>\nin OData .NET 8 the\u00a0JavaScriptEncoder.UnsafeRelaxedJsonEscaping<\/code>\u00a0option is used by default. This option provides better consistency with ASP.NET Core applications and can result in better performance since fewer characters need to be escaped.<\/p>\nThis writer has some notable changes in how some values are handled during serialization:<\/p>\n
String Escaping<\/h4>\n
The default writer in version 8 uses uppercase letters for unicode code points, the default in version 7 uses lowercase letters<\/p>\n
\n- OData.NET v7 default writer: “Cust1 \\ud800\\udc05 \\u00e4”<\/li>\n
- OData .NET v8 default writer: “Cust1 \\uD800\\uDC05 \\u00E4”<\/li>\n<\/ul>\n
Both versions are valid and equivalent, compliant clients should handle them the same way.<\/p>\n
Number handling<\/h4>\n
float.PositiveInfinity<\/code>\u00a0and\u00a0double.PositiveInfinity<\/code>\u00a0are written as “INF”.\u00a0float.NegativeInfinity<\/code>\u00a0and\u00a0double.NegativeInfinity<\/code>\u00a0are written as\u00a0\"-INF\"<\/code>. This is consistent with OData .NET 7, but is different from how the values are handled by\u00a0Utf8JsonWriter<\/code>\u00a0or\u00a0JsonSerializer<\/code>\u00a0by default.<\/p>\nOData .NET 8 serializes a decimal value like\u00a01.0M<\/code>\u00a0as\u00a01.0<\/code>, but OData .NET 7 serializes it as\u00a01<\/code>.<\/p>\nDateTimeOffset<\/h4>\n
DateTimeOffset<\/code>\u00a0values where the offset is 0 use\u00a0Z<\/code>\u00a0to indicate the timezone, e.g.\u00a02022-11-09T09:42:30Z<\/code>. This is consistent with OData .NET 7, but is different from the default behaviour of\u00a0Utf8JsonWriter<\/code>\u00a0which uses\u00a0+00:00<\/code>\u00a0like\u00a02022-11-09T09:42:30+00:00<\/code>.<\/p>\nSwitching to the old JSON writer<\/h4>\n
You can change the JSON writer used by\u00a0ODataMessageWriter<\/code>\u00a0and by injecting an implementation of\u00a0IJsonWriterFactory<\/code>\u00a0to the service provider attached to the\u00a0IODataRequestMessage<\/code>\u00a0or\u00a0IODataResponseMessage<\/code>. The implementation that corresponds to the old default writer is called\u00a0ODataJsonWriterFactory<\/code>:<\/p>\nservices.AddSingleton<IJsonWriterFactory>(new ODataJsonWriterFactory());\r\n<\/code><\/pre>\nChanging\u00a0JavaScriptEncoder<\/code><\/h4>\nIf you want to change which characters are escaped or encoded you can change the\u00a0JavaScriptEncoder<\/code>\u00a0used by the underlying\u00a0Utf8JsonWriter<\/code>. You can do so by injecting an instance of\u00a0ODataUtf8JsonWriter<\/code>\u00a0to the service provider and specifying the instance of\u00a0JavaScriptEncoder<\/code>\u00a0to be used:<\/p>\nservices.AddSingleton<IJsonWriterFactory>(new<\/span> ODataUtf8JsonWriterFactory(JavaScriptEncoder.Default));\r\n<\/code><\/pre>\nChanged\u00a0ODataResource.Properties<\/code>\u00a0property type<\/h3>\nIn OData .NET 7, the\u00a0ODataResource.Properties<\/code>\u00a0property is of type\u00a0IEnumerable<ODataProperty><\/code>.<\/p>\nIn OData .NET 8, the\u00a0ODataResource.Properties<\/code>‘s type has been changed to\u00a0IEnumerable<ODataPropertyInfo><\/code>.<\/p>\nODataPropertyInfo<\/code>\u00a0is the base class of\u00a0ODataProperty<\/code>. The main difference between the two is that\u00a0ODataProperty<\/code>\u00a0has a value. The purpose of this change was to make it easier to represent properties in the payloads that don’t have a value. Sometimes we need to write metadata about a property that is not included in the payload. For example, in the following payload, the\u00a0password<\/code>\u00a0property is missing but the payload includes metadata about the property in the form of\u00a0security.omitted<\/code>\u00a0annotation.<\/p>\n{<\/span>\r\n \"@context\"<\/span>:<\/span>\"users\/$entity\"<\/span>,<\/span>\r\n \"id\"<\/span>:<\/span> 1<\/span>,<\/span>\r\n \u2026\r\n \"password@security.omitted\"<\/span>:<\/span> \u201cpassword is read-only\u201d,<\/span>\r\n \u2026\r\n \"hobbies@count\"<\/span>:<\/span>10<\/span>,<\/span>\r\n}<\/span>\r\n<\/code><\/pre>\nThe liberty to add\u00a0ODataPropertyInfo<\/code>\u00a0instances in the\u00a0ODataResource.Properties<\/code>\u00a0collection makes it possible to read and write metadata of properties that should be exluded from the payload.<\/p>\nOne consequence of this change is that in cases where we want to write properties with values, we should filter out properties that don’t have value. We can do this by attempting a cast to\u00a0ODataProperty<\/code>\u00a0before writing the value:<\/p>\nvoid<\/span> WriteProperties<\/span>(ODataResource resource<\/span>)<\/span>\r\n{\r\n foreach<\/span> (ODataPropertyInfo propertyInfo in<\/span> resource.Properties)\r\n {\r\n if<\/span> (propertyInfo is<\/span> ODataProperty property)\r\n {\r\n WriteValue(property.Value)\r\n }\r\n }\r\n}<\/code><\/pre>\n<\/div>\n<\/div>\n
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Removed\u00a0ODataSimplifiedOptions<\/code>\u00a0class<\/h3>\nIn OData .NET 7, an instance of\u00a0ODataSimplifiedOptions<\/code>\u00a0could be injected in the service provider to configure certain behaviour when parsing URLs, and when reading and writing payloads. This led to confusion because we already have other settings classes like\u00a0ODataMessageReaderSettings<\/code>,\u00a0ODataMessageWriterSettings<\/code>\u00a0and\u00a0ODataUriParsing<\/code>. In OData .NET 8, the\u00a0ODataSimplifiedOptions<\/code> class has been removed and its settings properties and methods have been moved to the other classes:<\/p>\n\nEnableReadingKeyAsSegment<\/code>\u00a0and\u00a0EnableReadingODataAnnotationWithoutPrefix<\/code>\u00a0properties moved to\u00a0ODataMessageReaderSettings<\/code>\u00a0class.<\/li>\nEnableWritingKeyAsSegment<\/code>\u00a0property moved to\u00a0ODataMessageWriterSettings<\/code>\u00a0class.<\/li>\nSetOmitODataPrefix(bool)<\/code>,\u00a0SetOmitODataPrefix(bool, ODataVersion)<\/code>,\u00a0GetOmitODataPrefix()<\/code>, and\u00a0GetOmitODataPrefix(ODataVersion)<\/code>\u00a0methods moved to\u00a0ODataMessageWriterSettings<\/code>\u00a0class.<\/li>\nEnableParsingKeyAsSegment<\/code>\u00a0property moved to\u00a0ODataUriParserSettings<\/code>\u00a0class.<\/li>\n<\/ul>\n<\/div>\n\n
Removed\u00a0IContainerBuilder<\/code>\u00a0and replaced with\u00a0IServiceProvider<\/code><\/h3>\nOData .NET 7 used a custom interface called\u00a0IContainerBuilder<\/code>\u00a0for dependency injection. This meant that developers who would need to inject custom services would have to create a custom implementation. Most custom implementations, including the one used in ASP.NET Core OData were basic wrappers around\u00a0Microsoft.Extensions.DepencyInjection<\/code>‘s\u00a0IServiceProvider<\/code>\u00a0and\u00a0ServiceCollection<\/code>\u00a0APIs.<\/p>\nOData .NET 8 has removed the\u00a0IContainerBuilder<\/code>\u00a0interface and now uses\u00a0IServiceProvider<\/code>\u00a0for dependency injection:<\/p>\n\nAddDefaultODataServices(IServiceCollection, ODataVersion, Action<ODataMessageReaderSettings>, Action<ODataMessageWriterSettings>, Action<ODataUriParserSettings>)<\/code>\u00a0extension method introduced for the purpose of registering OData services.<\/li>\nIContainerProvider<\/code>\u00a0interface replaced by\u00a0IServiceCollectionProvider<\/code>\u00a0interface. It’s a provider for the\u00a0IServiceProvider<\/code>\u00a0IoC container.<\/li>\nODataBatchOperationRequestMessage<\/code>\u00a0now implements\u00a0IServiceCollectionProvider<\/code>\u00a0instead of\u00a0IContainerProvider<\/code>.<\/li>\nODataBatchOperationResponseMessage<\/code>\u00a0now implements\u00a0IServiceCollectionProvider<\/code>\u00a0instead of\u00a0IContainerProvider<\/code>.<\/li>\n<\/ul>\nFor example, if you want to add custom configurations to OData services, you’d follow these steps:<\/p>\n
Create implementation of\u00a0IODataRequestMessage<\/code>\u00a0or\u00a0IODataResponseMessage<\/code>\u00a0that also implements\u00a0IServiceCollectionProvider<\/code><\/p>\npublic<\/span> class<\/span> ODataMessage<\/span> : IODataRequestMessage<\/span>, IODataResponseMessage<\/span>, IServiceCollectionProvider<\/span>\r\n{\r\n\r\n public<\/span> ODataMessage<\/span>(..., IServiceProvider services<\/span>)<\/span>\r\n {\r\n ServiceProvider = services;\r\n }\r\n\r\n