1 Introduction

The OData protocol is comprised of a set of specifications for representing and interacting with structured content. The core specification for the protocol is in [OData-Protocol]; this document is an extension of the core protocol. This document defines representations for the OData requests and responses using the JavaScript Object Notation (JSON), see [RFC4627].

An OData JSON payload may represent:

a single primitive value
a collection of primitive values
a single complex type value
a collection of complex type values
a single entity or entity reference
a collection of entities or entity references
a collection of changes
a service document describing the top-level resources exposed by the service
an error.

1.1 Terminology

The key words “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “MAY”, and “OPTIONAL” in this document are to be interpreted as described in [RFC2119].

1.2 Normative References

[GeoJSON] Butler, H., Daly, M., Doyle, A., Gillies, S., Schaub, T.,
Schmidt, C., "The GeoJSON Format Specification", Revision 1.0, June 2008. http://geojson.org/geojson-spec.html.

[OData-ABNF] OData ABNF Construction Rules Version 4.0.
See link in “Related work” section on cover page.

[OData-CSDL] OData Version 4.0 Part 3: Common Schema Definition Language (CSDL).
See link in “Related work” section on cover page.

[OData-Protocol] OData Version 4.0 Part 1: Protocol.
See link in “Related work” section on cover page.

[OData-URL] OData Version 4.0 Part 2: URL Conventions.
See link in "Related work" section on cover page.

[OData-VocCap] OData Capabilities Vocabulary.
See link in "Related work" section on cover page.

[RFC2119] Bradner, S., “Key words for use in RFCs to Indicate Requirement Levels”, BCP 14, RFC 2119, March 1997. http://www.ietf.org/rfc/rfc2119.txt.

[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, “Uniform Resource Identifier (URI): Generic Syntax”, IETF RFC3986, January 2005. http://www.ietf.org/rfc/rfc3986.txt.

[RFC3987] Duerst, M. and, M. Suignard, “Internationalized Resource Identifiers (IRIs)”, RFC 3987, January 2005. http://www.ietf.org/rfc/rfc3987.txt.

[RFC4627] Crockford, D., “The application/json Media Type for JavaScript Object Notation (JSON)”, RFC 4627, July 2006. http://tools.ietf.org/html/rfc4627.

[RFC5646] Phillips, A., Ed., and M. Davis, Ed., “Tags for Identifying Languages”, BCP 47, RFC 5646, September 2009. http://tools.ietf.org/html/rfc5646.

[ECMAScript] ECMAScript Language Specification Edition 5,1. June 2011. Standard ECMA-262. http://www.ecma-international.org/publications/standards/Ecma-262.htm.

1.3 Typographical Conventions

Keywords defined by this specification use this monospaced font.

Normative source code uses this paragraph style.

Some sections of this specification are illustrated with non-normative examples.

Example 1: text describing an example uses this paragraph style

Non-normative examples use this paragraph style.

All examples in this document are non-normative and informative only.

All other text is normative unless otherwise labeled.

2 JSON Format Design

JSON, as described in [RFC4627], defines a text format for serializing structured data. Objects are serialized as an unordered collection of name-value pairs.

JSON does not define any semantics around the name/value pairs that make up an object, nor does it define an extensibility mechanism for adding control information to a payload.

OData’s JSON format extends JSON by defining general conventions for name-value pairs that annotate a JSON object, property or array. OData defines a set of canonical annotations for control information such as ids, types, and links, and custom annotations MAY be used to add domain-specific information to the payload.

A key feature of OData’s JSON format is to allow omitting predictable parts of the wire format from the actual payload. To reconstitute this data on the receiving end, expressions are used to compute missing links, type information, and other control data. These expressions (together with the data on the wire) can be used by the client to compute predictable payload pieces as if they had been included on the wire directly.

Annotations are used in JSON to capture control information that cannot be predicted (e.g., the next link of a collection of entities) as well as a mechanism to provide values where a computed value would be wrong (e.g., if the media read link of one particular entity does not follow the standard URL conventions). Computing values from metadata expressions is compute intensive and some clients might opt for a larger payload size to avoid computational complexity; to accommodate for this the Accept header allows the client to control the amount of control information added to the response.

To optimize streaming scenarios, there are a few restrictions that MAY be imposed on the sequence in which name/value pairs appear within JSON objects. For details on the ordering requirements see Payload Ordering Constraints.

3 Requesting the JSON Format

The OData JSON format can be requested using the $format query option in the request URL with the MIME type application/json, optionally followed by format parameters, or the case-insensitive abbreviation json which MUST NOT be followed by format parameters.

Alternatively, this format can be requested using the Accept header with the MIME type application/json, optionally followed by format parameters.

If specified, $format overrides any value specified in the Accept header.

Services SHOULD advertise the supported MIME types by annotating the entity container with the term Capabilities.SupportedFormats defined in [OData-VocCap], listing all available formats and combinations of supported format parameters.

3.1 Controlling the Amount of Control Information in Responses

The amount of control information needed (or desired) in the payload depends on the client application and device. The odata.metadata parameter can be applied to the Accept header of an OData request to influence how much control information will be included in the response.

Other Accept header parameters (e.g., odata.streaming) are orthogonal to the odata.metadata parameter and are therefore not mentioned in this section.

If a client prefers a very small wire size and is intelligent enough to compute data using metadata expressions, the Accept header should include odata.metadata=minimal. If compute is more expensive than wire size or the client is incapable of computing control information, odata.metadata=full directs the service to inline the control information that normally would be computed from metadata expressions in the payload. odata.metadata=none is an option for clients that have out-of-band knowledge or don't require control information.

3.1.1 odata.metadata=minimal

The odata.metadata=minimal format parameter indicates that the service SHOULD remove computable control information from the payload wherever possible. This is the default value for the odata.metadata parameter and will be assumed if no other value is specified in the Accept header or $format query option. The response payload MUST contain at least the following common annotations:

· odata.context: the context URL of the payload

· odata.etag: the ETag of the entity, as appropriate

· odata.count: the total count of a collection of entities or collection of entity references, if requested

· odata.nextLink: the next link of a collection of entities or collection of entity references for partial results

· odata.deltaLink: the delta link for obtaining changes to the result, if requested

In addition, odata annotations MUST appear in the payload for cases where actual values are not the same as the computed values and MAY appear otherwise. When odata annotations appear in the payload, they are treated as exceptions to the computed values.

Media entities and stream properties MAY in addition contain the following annotations:

· odata.mediaEtag: the ETag of the stream, as appropriate

· odata.mediaContentType: the content type of the stream

3.1.2 odata.metadata=full

The odata.metadata=full format parameter indicates that the service MUST include all control information explicitly in the payload.

The full list of annotations that may appear in an odata.metadata=full response is as follows:

· odata.context: the context URL for a collection, entity, primitive value, or service document.

· odata.count: the total count of a collection of entities or collection of entity references, if requested.

· odata.nextLink: the next link of a collection of entities or collection of entity references for partial results

· odata.deltaLink: the delta link for obtaining changes to the result, if requested

· odata.id: the ID of the entity

· odata.etag: the ETag of the entity

· odata.readLink: the link used to read the entity, if the edit link cannot be used to read the entity

· odata.editLink: the link used to edit/update the entity, if the entity is updatable and the odata.id does not represent a URL that can be used to edit the entity

· odata.navigationLink: the link used to retrieve the values of a navigation property

· odata.associationLink: the link used to describe the relationship between this entity and related entities

· odata.type: the type of the containing object or targeted property if the type of the object or targeted property cannot be heuristically determined

Media entities and stream properties may in addition contain the following annotations:

· odata.mediaReadLink: the link used to read the stream

· odata.mediaEditLink: the link used to edit/update the stream

· odata.mediaEtag: the ETag of the stream, as appropriate

· odata.mediaContentType: the content type of the stream

3.1.3 odata.metadata=none

The odata.metadata=none format parameter indicates that the service SHOULD omit control information other than odata.nextLink, odata.count and odata.deltaLink. These annotations MUST continue to be included, as applicable, even in the odata.metadata=none case.

3.2 Controlling the Representation of Numbers

The IEEE754Compatible format parameter indicates that the service MUST serialize Edm.Int64 and Edm.Decimal numbers as strings.

This enables support for JavaScript numbers that are defined to be 64-bit binary format IEEE 754 values [ECMAScript] (see section 4.3.1.9) resulting in integers losing precision past 15 digits, and decimals losing precision due to the conversion from base 10 to base 2.

OData JSON payloads that format Edm.Int64 and Edm.Decimal values as strings MUST specify this format parameter in the media type returned in the Content-Type header.

4 Common Characteristics

This section describes common characteristics of the representation for OData values in JSON. A request or response body consists of several parts. It contains OData values as part of a larger document. Requests and responses are structured almost identical; the few existing differences will be explicitly called out in the respective subsections.

4.1 Header Content-Type

Requests and responses in JSON MUST have a Content-Type header value of application/json.

Requests MAY add the charset parameter to the content type. Allowed values are UTF-8, UTF-16, and UTF-32. If no charset parameter is present, UTF-8 MUST be assumed.

Responses MUST include the odata.metadata parameter to specify the amount of metadata included in the response.

Responses MUST include the IEEE754Compatible parameter if Edm.Int64 and Edm.Decimal numbers are represented as strings.

Requests and responses MAY add the odata.streaming parameter with a value of true or false, see section Payload Ordering Constraints.

4.2 Message Body

Each message body is represented as a single JSON object. This object is either the representation of an entity, an entity reference or a complex type instance, or it contains a name/value pair whose name MUST be value and whose value is the correct representation for a primitive value, a collection of primitive values, a collection of complex values, a collection of entities, or a collection of objects that represent changes to a previous result.

Client libraries MUST retain the order of objects within an array in JSON responses.

4.3 Relative URLs

URLs present in a payload (whether request or response) MAY be represented as relative URLs.

If a context URL is present in the same JSON object as the relative URL or an enclosing object, the relative URL is relative to the next context URL. This rule also applies to context URLs; they can be relative to the context URL of an enclosing object.

If no context URL is present in a request, relative URLs are relative to the request URL.

If no context URL is present in a response, relative URLs are relative to the Content-Location header of the response.

In responses without a Content-Location header or context URL, relative URLs are relative to the request URL.

Processors expanding the URLs MUST use normal URL expansion rules as defined in [RFC3986]. This means that if the base URL is a context URL, the part starting with $metadata# is ignored when resolving the relative URL.

Example 2:

{

"odata.context": "http://host/service/$metadata#Customers/$entity",

...

"odata.editLink": "Customers('ALFKI')",

...

"Orders@odata.navigationLink": "Customers('ALFKI')/Orders",

...

}

The resulting absolute URLs are http://host/service/Customers('ALFKI') and http://host/service/Customers('ALFKI')/Orders.

4.4 Payload Ordering Constraints

Ordering constraints MAY be imposed on the JSON payload in order to support streaming scenarios. These ordering constraints MUST only be assumed if explicitly specified as some clients (and services) might not be able to control, or might not care about, the order of the JSON properties in the payload.

Clients can request that a JSON response conform to these ordering constraints by specifying a media type of application/json with the odata.streaming=true parameter in the Accept header or $format query option. Services MUST return 406 Not Acceptable if the client only requests streaming and the service does not support it.

Processors MUST only assume streaming support if it is explicitly indicated in the Content-Type header via the odata.streaming=true parameter.

Example 3: a payload with

Content-Type: application/json;odata.metadata=minimal;odata.streaming=true

can be assumed to support streaming, whereas a payload with

Content-Type: application/json;odata.metadata=minimal

cannot be assumed to support streaming.

JSON producers are encouraged to follow the payload ordering constraints whenever possible (and include the odata.streaming=true content type parameter) to support the maximum set of client scenarios.

To support streaming scenarios the following payload ordering constraints have to be met:

If present, the odata.context annotation MUST be the first property in the JSON object.
The odata.type annotation, if present, MUST appear next in the JSON object.
The odata.id and odata.etag annotations MUST appear before any property or property annotation.
All annotations for a structural or navigation property MUST appear as a group immediately before the property they annotate. The one exception is the odata.nextlink annotation of an expanded collection which MAY appear after the navigation property it annotates.
All other odata annotations can appear anywhere in the payload as long as they do not violate any of the above rules.
Annotations for navigation properties MUST appear after all structural properties.

4.5 Control Information

In addition to the “pure data” a message body MAY contain control information that is represented as annotations whose names start with odata followed by a dot.

Clients that encounter unknown annotations in any namespace, including the odata namespace, MUST NOT stop processing and MUST NOT signal an error.

4.5.1 Annotation odata.context

The odata.context annotation returns the context URL (see [OData-Protocol]) for the payload. The odata.context annotation MUST be the first property of any JSON response that does not specify odata.metadata=none.

The odata.context annotation MUST also be included for entities whose entity set cannot be determined from the context URL of the collection. This URL can be absolute or relative to the context URL of the collection.

The odata.context annotation MUST also be applied to navigation links for navigation properties not described in the metadata of the containing type. In this case the context URL MAY be relative to the context URL describing the parent entity and becomes the root context URL for the related entity or collection.

For more information on the format of the context URL, see [OData-Protocol].

Request payloads in JSON do not require context URLs. It MAY be included as a base URL for relative URLs in the request payload.

Response payloads SHOULD NOT contain the context URL if odata.metadata=none is requested.

Example 4:

{

"odata.context": "http://host/service/$metadata#Customers/$entity",

"odata.metadataEtag": "W/\"A1FF3E230954908F\"",

...

}

4.5.2 Annotation odata.metadataEtag

The odata.metadataEtag annotation MAY appear in a response in order to specify the entity tag (ETag) that can be used to determine the version of the metadata of the response.

For details on how ETags are used, see [OData-Protocol].

4.5.3 Annotation odata.type

The odata.type annotation specifies the type of a JSON object or name/value pair. Its value is a URI that identifies the type of the property or object. For built-in primitive types the value is the unqualified name of the primitive type. For all other types, the URI may be absolute or relative to the URI of the containing type. The root odata.type may be absolute or relative to the root context URL.

For non-built in primitive types, the URI contains the namespace-qualified or alias-qualified type, specified as a URI fragment. For properties that represent a collection of values, the fragment is the namespace-qualified or alias-qualified element type enclosed in parentheses and prefixed with Collection.

The odata.type annotation MUST appear if the type cannot be heuristically determined, as described below, and one of the following is true:

· The type is derived from the type specified for the (collection of) entities or (collection of) complex type instances, or

· The type is for a property whose type is not declared in $metadata.

The following heuristics are used to determine the primitive type of a dynamic property in the absence of the odata.type annotation:

· Boolean values have a first-class representation in JSON and do not need any additional annotations.

· Numeric values have a first-class representation in JSON and do not need any additional annotations. If the value of a property is represented as a number without a dot (.), e or E embedded, the type should be interpreted as an integer value, otherwise as a decimal, double, or single value.

· The floating-point values NaN, INF, and -INF are serialized as strings and MUST have an odata.type annotation to specify the numeric type.

· String values do have a first class representation in JSON, but there is an obvious collision: OData also encodes a number of other primitive types as strings, e.g. DateTimeOffset, Int64 in the presence of the IEEE754Compatible format parameter etc. If a property appears in JSON string format, it should be treated as a string value unless the property is known (from the metadata document) to have a different type.

For more information on namespace- and alias-qualified names, see [OData-CSDL].

Example 5: entity of type Model.VipCustomer defined in the metadata document of the same service

{

"odata.context": "http://host/service/$metadata#Customers/$entity",

"odata.type": "#Model.VipCustomer",

"ID": 2,

...

}

Example 6: entity of type Model.VipCustomer defined in the metadata document of a different service

{

"odata.context": "http://host/service/$metadata#Customers/$entity",

"odata.type": "http://host/alternate/$metadata#Model.VipCustomer",

"ID": 2,

...

}

4.5.4 Annotation odata.count

The odata.count annotation contains the count of a collection of entities or a collection of entity references, see [OData-Protocol] section 11.2.4.5 System Query Option $count. Its value is an Edm.Int64 value corresponding to the total count of members in the collection represented by the request.

4.5.5 Annotation odata.nextLink

The odata.nextLink annotation indicates that a response is only a subset of the requested collection of entities or collection of entity references. It contains a URL that allows retrieving the next subset of the requested collection.

This annotation can also be applied to expanded to-many navigation properties.

4.5.6 Annotation odata.deltaLink

The odata.deltaLink annotation contains a URL that can be used to retrieve changes to the current set of results. The odata.deltaLink annotation MUST only appear on the last page of results. A page of results MUST NOT have both an odata.deltaLink annotation and an odata.nextLink annotation.

4.5.7 Annotation odata.id

The odata.id annotation contains the entity-id; see [OData-Protocol]. By convention the entity-id is identical to the canonical URL of the entity, as defined in [OData-URL].

The odata.id annotation MUST appear if odata.metadata=full is requested or if the entity-id is not identical to the canonical URL of the entity after IRI-toURI conversion as defined in [RFC3987], resolution of relative URLs and percent-encoding normalization as defined in [RFC3986]. If the odata.id is represented, it MAY be a relative URL.

If the entity is transient (i.e. cannot be read or updated), the odata.id annotation MUST appear and have the null value.

The odata.id annotation MUST NOT appear for a collection. Its meaning in this context is reserved for future versions of this specification.

Entities with odata.id equal to null cannot be compared to other entities, reread, or updated. If odata.metadata=minimal is specified and the odata.id is not present in the entity then the canonical URL MUST be used as the entity-id.

4.5.8 Annotation odata.editLink and odata.readLink

The odata.editLink annotation contains the edit URL of the entity; see [OData-Protocol].

The odata.readLink annotation contains the read URL of the entity or collection; see [OData-Protocol].

The default value of both the edit URL and read URL is the entity's entity-id appended with a cast segment to the type of the entity if its type is derived from the declared type of the entity set. If neither the odata.editLink nor the odata.readLink annotation is present in an entity, the client uses this default value for the edit URL.

For updatable entities:

· The odata.editLink annotation is written if odata.metadata=full is requested or if the edit URL differs from the default value of the edit URL.

· The odata.readLink annotation is written if the read URL is different from the edit URL. If no odata.readLink annotation is present, the read URL is identical to the edit URL.

For read-only entities:

· The odata.readLink annotation is written if odata.metadata=full is requested or if its value differs from the default value of the read URL.

· The odata.readLink annotation may also be written if odata.metadata=minimal is specified in order to signal that an individual entity is read-only.

For collections:

· The odata.readLink annotation, if written, MUST be the request URL that produced the collection.

· The odata.editLink annotation MUST NOT be written as its meaning in this context is reserved for future versions of this specification.

4.5.9 Annotation odata.etag

The odata.etag annotation MAY be applied to an entity. The value of the annotation is an entity tag (ETag) which is an opaque string value that can be used in a subsequent request to determine if the value of the entity has changed.

For details on how ETags are used, see [OData-Protocol].

4.5.10 Annotation odata.navigationLink and odata.associationLink

The odata.navigationLink annotation contains a navigation URL that can be used to retrieve an entity or collection of entities related to the current entity via a navigation property.

The default computed value of a navigation URL is the value of the read URL appended with a segment containing the name of the navigation property. The service MAY omit the odata.navigationLink annotation if odata.metadata=minimal has been specified on the request and the navigation link matches this computed value.

The odata.associationLink annotation contains an association URL that can be used to retrieve a reference to an entity or a collection of references to entities related to the current entity via a navigation property.

The default computed value of an association URL is the value of the navigation URL appended with /$ref. The service may omit the odata.associationLink annotation if odata.metadata=minimal has been specified on the request and the association link matches this computed value.

4.5.11 Annotation odata.media*

For media entities and stream properties that don't follow standard URL conventions as defined in [OData-URL], at least one of the annotations odata.mediaEditLink and odata.mediaReadLink MUST be included.

The odata.mediaEditLink annotation contains a URL that can be used to update the binary stream associated with the media entity or stream property. It MUST be included for updatable media entities if it differs from the value of the odata.id, and for updatable stream properties if it differs from standard URL conventions.

The odata.mediaReadLink annotation contains a URL that can be used to read the binary stream associated with the media entity or stream property. It MUST be included if its value differs from the value of the associated odata.mediaEditLink, if present, or the value of the odata.id for media entities if the associated odata.mediaEditLink is not present.

The odata.mediaContentType annotation MAY be included; its value SHOULD match the content type of the binary stream represented by the odata.mediaReadLink URL. This is only a hint; the actual content type will be included in a header when the resource is requested.

The odata.mediaEtag annotation MAY be included; its value is the ETag of the binary stream represented by this media entity or stream property.

Example 7:

{

"odata.context": "http://host/service/$metadata#Employees/$entity",

"odata.mediaReadLink": "Employees(1)/$value",

"odata.mediaContentType": "image/jpeg",

"EmployeeID": 1,

...

}

5 Service Document

A service document in JSON is represented as a single JSON object with at least two properties; odata.context and odata.value.

The value of the odata.context property MUST be the URL of the metadata document, without any fragment part.

The value of the value property MUST be a JSON Array containing one element for each entity set and function import with an explicit or default value of true for the attribute IncludeInServiceDocument and each singleton exposed by the service, see [OData-CSDL].

Each element MUST be a JSON object with at least two name/value pairs, one with name name containing the name of the entity set, function import, or singleton, and one with name url containing the URL of the entity set, which may be absolute or relative to the context URL. It MAY contain a name/value pair with name title containing a human-readable, language-dependent title for the object.

JSON objects representing an entity set MAY contain an additional name/value pair with name kind and a value of EntitySet. If the kind name/value pair is not present, the object MUST represent an entity set.

JSON objects representing a function import MUST contain the kind name/value pair with a value of FunctionImport, respectively.

JSON objects representing a singleton MUST contain the kind name/value pair with a value of Singleton.

JSON objects representing a related service document MUST contain the kind name/value pair with a value of ServiceDocument.

Clients that encounter unknown values of the kind name/value pair not defined in this version of the specification MUST NOT stop processing and MUST NOT signal an error.

Example 8:

{

"odata.context": "http://host/service/$metadata",

"value": [

{

"name": "Orders",

"kind": "EntitySet",

"url": "Orders"

{

"name": "OrderItems",

"title": "Order Details",

"url": "OrderItems"

{

"name": "TopProducts",

"title": "Best-Selling Products",

"kind": "FunctionImport",

"url": "TopProducts"

{

"name": "Contoso",

"title": "Contoso Ltd.",

"kind": "Singleton",

"url": "Contoso"

{

"name": "Human Resources",

"kind": "ServiceDocument",

"url": "http://host/HR/"

}

]

}

6 Entity

An entity is serialized as a JSON object.

Each property to be transmitted is represented as a name/value pair within the object. The order properties appear within the object is considered insignificant.

An entity in a payload may be a complete entity, a projected entity (see System Query Option $select [OData-Protocol]), or a partial entity update (see Update an Entity in [OData-Protocol]).

An entity representation can be (modified and) round-tripped to the service directly. The context URL is used in requests only as a base for relative URLs.

Example 9: entity with odata.metadata=minimal

{

"odata.context": "http://host/service/$metadata#Customers/$entity",

"ID": "ALFKI",

"CompanyName": "Alfreds Futterkiste",

"ContactName": "Maria Anders",

"ContactTitle": "Sales Representative",

"Phone": "030-0074321",

"Fax": "030-0076545",

"Address": {

"Street": "Obere Str. 57",

"City": "Berlin",

"Region": null,

"PostalCode": "D-12209",

}

Example 10: entity with odata.metadata=full

{

"odata.context": "http://host/service/$metadata#Customers/$entity",

"odata.id": "Customers('ALFKI')",

"odata.etag": "W/\"MjAxMy0wNS0yN1QxMTo1OFo=\"",

"odata.editLink": "Customers('ALFKI')",

"Orders@odata.navigationLink": "Customers('ALFKI')/Orders",

"Orders@odata.associationLink": "Customers('ALFKI')/Orders/$ref",

"ID": "ALFKI",

"CompanyName": "Alfreds Futterkiste",

"ContactName": "Maria Anders",

"ContactTitle": "Sales Representative",

"Phone": "030-0074321",

"Fax": "030-0076545",

"Address": {

"Street": "Obere Str. 57",

"City": "Berlin",

"Region": null,

"PostalCode": "D-12209",

"Country@odata.navigationLink": "Customers('ALFKI')/Address/Country",

"Country@odata.associationLink":"Customers('ALFKI')/Address/Country/$ref",

}

7 Structural Property

A property within an entity or complex type instance is represented as a name/value pair. The name MUST be the name of the property; the value is represented depending on its type as a primitive value, a complex value, a collection of primitive values, or a collection of complex values.

7.1 Primitive Value

Primitive values are represented following the rules of [RFC4627].

Null values are represented as the JSON literal null.

Values of type Edm.Boolean are represented as the JSON literals true and false

Values of types Edm.Byte, Edm.SByte, Edm.Int16, Edm.Int32, Edm.Int64, Edm.Single, Edm.Double, and Edm.Decimal are represented as JSON numbers, except for NaN, INF, and –INF which are represented as strings.

Values of type Edm.String are represented as JSON strings, using the JSON string escaping rules.

Values of type Edm.Binary, Edm.Date, Edm.DateTimeOffset, Edm.Duration, Edm.Guid, and Edm.TimeOfDay as well as enumeration values are represented as JSON strings whose content satisfies the rules binaryValue, dateValue, dateTimeOffsetValue, durationValue, guidValue, timeOfDayValue, and enumValue, respectively, in [OData-ABNF].

Geography and geometry values are represented as defined in [GeoJSON], with the following modifications:

· Keys SHOULD be ordered with type first, then coordinates, then any other keys

· The coordinates member of a LineString can have zero or more positions

· If the optional CRS object is present, it MUST be of type name, where the value of the name member of the contained properties object is an EPSG SRID legacy identifier.

Example 11:

{

"NullValue": null,

"TrueValue": true,

"FalseValue": false,

"IntegerValue": -128,

"DoubleValue": 3.1415926535897931,

"SingleValue": "INF",

"DecimalValue": "34.95",

"StringValue": "Say \"Hello\",\nthen go",

"DateValue": "2012-12-03",

"DateTimeOffsetValue": "2012-12-03T07:16:23Z",

"DurationValue": "P12DT23H59M59.999999999999S",

"TimeOfDayValue": "07:59:59.999",

"GuidValue": "01234567-89ab-cdef-0123-456789abcdef",

"Int64Value": "0",

"ColorEnumValue": "Yellow",

"GeographyPoint": {"type": "point","coordinates":[142.1,64.1]}

}

7.2 Complex Value

A complex value is represented as a single JSON object containing one name/value pair for each property that makes up the complex type. Each property value is formatted as appropriate for the type of the property.

It MAY have name/value pairs for instance annotations, including odata annotations.

Example 12:

{

"odata.context": "http://host/service/$metadata#Customers/$entity",

...

"Address": {

"Street": "Obere Str. 57",

"City": "Berlin",

"Region": null,

"PostalCode": "D-12209",

}

7.3 Collection of Primitive Values

A collection of primitive values is represented as a JSON array; each element in the array is the representation of a primitive value. An empty collection is represented as an empty array.

Example 13:

{

"odata.context": "http://host/service/$metadata#Customers/$entity",

...

"EmailAddresses": [

"Julie@Swansworth.com",

"Julie.Swansworth@work.com"

]

}

7.4 Collection of Complex Values

A collection of complex values is represented as a JSON array; each element in the array is the representation of a complex value. An empty collection is represented as an empty array.

Example 14:

{

"PhoneNumbers": [

{

"Number": "425-555-1212",

"Type": "Home"

{

"odata.type": "#Model.CellPhoneNumber",

"Number": "425-555-0178",

"Type": "Cell",

"Carrier": "Sprint"

}

]

}

8 Navigation Property

A navigation property is a reference from a source entity to zero or more related entities.

8.1 Navigation Link

The navigation link for a navigation property is represented as a name/value pair. The name is the name of the property, followed by @odata.navigationLink. The value is a URL that allows retrieving the related entity or collection of entities. It MAY be relative to the odata.context URL.

The navigation link for a navigation property is only represented if the client requests odata.metadata=full or the navigation link cannot be computed, e.g. if it is within a collection of complex type instances. If it is represented it MUST immediately precede the expanded navigation property if the latter is represented.

Example 15:

{

"odata.context": "http://host/service/$metadata#Customers/$entity",

...

"Orders@odata.navigationLink“: “Customers('ALFKI')/Orders",

...

}

8.2 Association Link

The association link for a navigation property is represented as a name/value pair. The name is the name of the property, followed by @odata.associationLink. The value is a URL that can be used to retrieve the reference or collection of references to the related entity or entities. It MAY be relative to the odata.context URL.

The association link for a navigation property is only represented if the client requests odata.metadata=full or the association link cannot be computed by appending /$ref to the navigation link. If it is represented, it MUST immediately precede the navigation link if the latter is represented.

Example 16:

{

"odata.context": "http://host/service/$metadata#Customers/$entity",

...

"Orders@odata.associationLink“: “Customers('ALFKI')/Orders/$ref",

...

}

8.3 Expanded Navigation Property

An expanded navigation property is represented as a name/value pair where the name is the name of the navigation property, and the value is the representation of the related entity or collection of entities.

If at most one entity can be related, the value is the representation of the related entity, or null if no entity is currently related.

If a collection of entities can be related, it is represented as a JSON array. Each element is the representation of an entity or the representation of an entity reference. An empty collection of entities (one that contains no entities) is represented as an empty JSON array. The navigation property MAY be annotated with odata.context, odata.count or odata.nextlink.

Example 17:

{

"odata.context": "http://host/service/$metadata#Customers/$entity",

...

"Orders@odata.count": "42",

"Orders": [ ... ],

"Orders@odata.nextLink": "...",

...

}

8.4 Deep Insert

When inserting a new entity with a POST request, related new entities MAY be specified using the same representation as for an expanded navigation property.

Deep inserts are not allowed in update operations using PUT or PATCH requests.

Example 18: inserting a new order for a new customer with order items related to existing products:

{

"Customer": {

"ID": "ANEWONE",

...

"Items": [

{

"Product@odata.bind": "Products(28)",

...

{

"Product@odata.bind": "Products(39)",

...

}

"ID": 11643,

...

}

8.5 Bind Operation

When inserting or updating an entity, relationships of navigation properties MAY be inserted or updated via bind operations. A bind operation is encoded as a property annotation odata.bind on the navigation property it belongs to and has a single value for singleton navigation properties or an array of values for collection navigation properties.

The values are the ids of the related entities. They MAY be relative URLs.

For insert operations collection navigation property bind operations and deep insert operations can be combined. In this case, the bind operations MUST appear before the deep insert operations in the payload.

For update operations a bind operation on a collection navigation property adds additional relationships, it does not replace existing relationships, while bind operations on an entity navigation property update the relationship.

Example 19: assign an existing product to an existing category with a partial update request

PATCH http://host/service/Products(42) HTTP/1.1

{

"Category@odata.bind": "Categories(6)"

}

9 Stream Property

An entity can have one or more stream properties. The actual stream data is not contained in the entity. Instead stream property data is read and edited via URLs. The value for a stream property contains the URLs for reading and editing the stream data along with other metadata for the stream.

The value of a stream property is represented as a set of odata.media* annotations.

Example 20:

{

"odata.context": "http://host/service/$metadata#Products/$entity",

...

"Thumbnail@odata.mediaReadLink": “http://server/Thumbnail546.jpg",

"Thumbnail@odata.mediaEditLink": “http://server/uploads/Thumbnail546.jpg",

"Thumbnail@odata.mediaContentType": "image/jpeg",

"Thumbnail@odata.mediaEtag": "W/\"####\"",

...

}

10 Media Entity

Media entities are entities that describe a media resource, for example a photo. They are represented as entities that contain additional odata.media* annotations.

Example 21:

{

"odata.context": "http://host/service/$metadata#Employees/$entity",

"odata.mediaReadLink": "Employees(1)/$value",

"odata.mediaContentType": "image/jpeg",

"ID": 1,

...

}

11 Individual Property

An individual property is represented as a JSON object.

A single-valued property that has the null value does not have a representation; see [OData-Protocol].

A property that is of a primitive type is represented as an object with a single name/value pair, whose name is value and whose value is a primitive value.

A property that is of complex type is represented as a complex value.

A property that is of a collection type is represented as an object with a single name/value pair whose name is value. Its value is the JSON representation of a collection of complex type values or collection of primitive values.

Example 22: primitive value

{

"odata.context": "http://host/service/$metadata#Edm.String",

"value": "Pilar Ackerman"

}

Example 23: collection of primitive values

{

"odata.context": "http://host/service/$metadata#Collection(Edm.String)",

"value": ["small", "medium", "extra large"]

}

Example 24: empty collection of primitive values

{

"odata.context": "http://host/service/$metadata#Collection(Edm.String)",

"value": []

}

Example 25: complex value

{

"odata.context": "http://host/service/$metadata#Model.Address",

"Street": "12345 Grant Street",

"City": "Taft",

"Region": "Ohio",

"PostalCode": "OH 98052",

"Country@odata.navigationLink": "Countries('US')"

}

Example 26: empty collection of complex values

{
"odata.context":"http://host/service/$metadata#Collection(Model.Address)",
"value": []

}

Note: the context URL is optional in requests.

12 Collection of Entities

A collection of entities is represented as a JSON object containing a name/value pair named value. It MAY contain odata.context, odata.count, odata.nextLink, or odata.deltaLink annotations.

If present, the odata.context annotation MUST be the first name/value pair in the response.

The odata.count name/value pair represents the number of entities in the collection. If present, it MUST come before the value name/value pair.

The value of the value name/value pair is a JSON array where each element is representation of an entity or a representation of an entity reference. An empty collection is represented as an empty JSON array.

Functions or actions that are bound to this collection of entities are advertised in the “wrapper object” in the same way as functions or actions are advertised in the object representing a single entity.

The odata.nextLink annotation MUST be included in a response that represents a partial result.

Example 27:

{

"odata.context": "...",

"odata.count": 37,

"value": [

{ ... },

{ ... }

"odata.nextLink": "...?$skiptoken=342r89",

}

13 Entity Reference

An entity reference (see [OData-Protocol]) MAY take the place of an entity instance in a JSON payload, based on the client request. It is serialized as a JSON object that MUST contain the id of the referenced entity and MAY contain the odata.type.

A collection of entity references is represented as a collection of entities, with entity reference representations instead of entity representations as items in the array value of the value name/value pair.

The outermost JSON object MUST contain an odata.context annotation and MAY contain odata.count, odata.nextLink, or odata.deltaLink annotations.

Example 28: entity reference to order 10643

{

"odata.context": "http://host/service/$metadata#$ref/$entity",

"odata.id": "Orders(10643)"

}

Example 29: collection of entity references

{

"odata.context": "http://host/service/$metadata#$ref",

"value": [

{ "odata.id": "Orders(10643" },

{ "odata.id": "Orders(10759" }

]

}

14 Delta Response

The non-format specific aspects of the delta handling are described in the section “Requesting Changes” in [OData-Protocol].

Responses from a delta request are returned as a JSON object. The JSON object MUST contain an array-valued property named value containing all added, changed, or deleted entities, as well as added or deleted links between entities, and MAY contain additional, unchanged entities.

If the delta response contains a partial list of changes, it MUST include a next link for the client to retrieve the next set of changes.

The last page of a delta response SHOULD contain a delta link for retrieving subsequent changes once the current set of changes has been applied to the initial set.

If the response from the delta link contains an odata.count annotation, the returned number MUST include all added, changed, or deleted entities, as well as added or deleted links.

Example 30: delta response with five changes, in order of occurrence

1. ContactName for customer 'BOTTM' was changed to "Susan Halvenstern"

2. Order 10643 was removed from customer 'ALFKI'

3. Order 10645 was added to customer 'BOTTM'

4. The shipping information for order 10643 was updated

5. Customer 'ANTON' was deleted

{

"odata.context":"http://host/service/$metadata#Customers/$delta ",

"odata.count":5,

"value":

[

{

"odata.id":"Customers('BOTTM')'",

"ContactName":"Susan Halvenstern"

{

"odata.context":"$metadata#Customers/$deletedLink",

"source":"Customers('ALFKI')'",

"relationship":"Orders",

"target":"Orders(10643)"

{

"odata.context":"$metadata#Orders/$link",

"source":"Customers('BOTTM')",

"relationship":"Orders",

"target":"Orders(10645)"

{

"odata.context":"$metadata#Orders/$entity",

"odata.id":"Orders(10643)",

"ShippingAddress":{

"Street":"23 Tsawassen Blvd.",

"City":"Tsawassen"

"Region":"BC",

"PostalCode":"T2F 8M4"

{

"odata.context":"$metadata#Customers/$deletedEntity",

"id":"http://host/service/Customers('ANTON')",

"reason":"deleted"

}

"odata.deltaLink":

"http://host/service/Customers?$expand=Orders&$deltatoken=8015"

}

14.1 Added/Changed Entity

Added or changed entities within a delta response are represented as entities

Added entities MUST include all available selected properties and MAY include additional, unselected properties. Collection-valued properties are treated as atomic values; any collection-valued properties returned from a delta request MUST contain all current values for that collection.

Changed entities MUST include all available selected properties that have changed and MAY include additional properties.

Entities that are not part of the entity set specified by the context URL MUST include the odata.context annotation to specify the entity set of the entity.

Entities include annotations for selected navigation links based on odata.metadata but MUST NOT include expanded navigation properties inline.

14.2 Deleted Entity

Deleted entities in JSON are returned as deleted-entity objects. Delta responses MUST contain a deleted-entity object for each deleted entity.

The deleted-entity object has the following properties:

· odata.context – the context URL fragment MUST be #{entity-set}/$deletedEntity, where {entity-set} is the entity set of the deleted entity

· id – The id of the deleted entity (same as the odata.id returned or computed when calling GET on resource),

· reason – An optional string value; either deleted, if the entity was deleted (destroyed), or changed if the entity was removed from membership in the result (i.e., due to a data change).

14.3 Added Link

Links within a delta response are represented as link objects.

Delta responses MUST contain a link object for each added link that corresponds to a $expand path in the initial request.

The link object MUST include the following properties:

· odata.context – the context URL fragment MUST be #{entity-set}/$link, where {entity-set} is the entity set containing the source entity

· source – The id of the entity from which the relationship is defined, which may be absolute or relative to the context URL

· relationship – The name of the relationship property on the parent object

· target – The id of the related entity, which may be absolute or relative to the context URL

14.4 Deleted Link

Deleted links within a delta response are represented as deleted-link objects.

Delta responses MUST contain a deleted-link object for each deleted link that corresponds to a $expand path in the initial request, unless either of the following is true:

· The source or target entity has been deleted

· The maximum cardinality of the related entity is one and there is a subsequent link object that specifies the same source and relationship.

The deleted-link object MUST include the following properties:

· odata.context – the context URL fragment MUST be #{entity-set}/$deletedLink, where {entity-set} is the entity set containing the source entity

· source – The id of the entity from which the relationship is defined, which may be absolute or relative to the context URL

· relationship – The name of the relationship property on the parent object

· target – The id of the related entity, which may be absolute or relative to the context URL

15 Bound Function

A function that is bound to the current entity is advertised via a name/value pair where the name is a hash (#) character followed by the namespace- or alias-qualified name of the function.

Functions that are bound to a collection of entities are advertised in representations of that collection.

If function overloads exist that cannot be bound to the current entity type, the name SHOULD address a specific function overload by appending the parentheses-enclosed, comma-separated list of non-binding parameter names, see rule qualifiedFunctionName in [OData-ABNF].

If odata.metadata=full is requested, each value object MUST have at least the two name/value pairs title and target. It MAY contain annotations. The order of the name/value pairs MUST be considered insignificant.

The target name/value pair contains a bound function or action URL.

The title name/value pair contains the function or action title as a string.

If odata.metadata=minimal is requested, the target name/value pair MUST be included if its value differs from the canonical function or action URL.

Example 31: minimal representation of a function where all overloads are applicable

{

"odata.context": "http://host/service/$metadata#Employees/$entity",

"#Model.RemainingVacation": {},

...

}

Example 32: full representation of a specific overload

{

"odata.context": "http://host/service/$metadata#Employees/$entity",

"#Model.RemainingVacation(Year)": {

"title": "Remaining vacation from year...",

"target": "Employees(2)/RemainingVacation"

...

}

Example 33: full representation in a collection

{

"odata.context": "http://host/service/$metadata#Employees",

"#Model.RemainingVacation": {

"title": "Remaining Vacation",

"target": "Managers(22)/Employees/RemainingVacation"

"value": [ ... ]

}

16 Bound Action

An action that is bound to the current entity is advertised via a name/value pair where the name is a hash (#) character followed by the namespace- or alias-qualified name of the action.

Actions that are bound to a collection of entities are advertised in representations of that collection.

If odata.metadata=full is requested, each value object MUST have at least the two name/value pairs title and target. It MAY contain annotations. The order of these name/value pairs MUST be considered insignificant.

The target name/value pair contains a bound function or action URL.

The title name/value pair contains the function or action title as a string.

If odata.metadata=minimal is requested, the target name/value pair MUST be included if its value differs from the canonical function or action URL.

Example 34: minimal representation in an entity

{

"odata.context": "http://host/service/$metadata#LeaveRequests/$entity",

"#Model.Approval": {},

...

}

Example 35: full representation in an entity:

{

"odata.context": "http://host/service/$metadata#LeaveRequests/$entity",

"#Model.Approval": {

"title": "Approve Leave Request",

"target": "LeaveRequests(2)/Approval"

...

}

Example 36: full representation in a collection

{

"odata.context": "http://host/service/$metadata#LeaveRequests",

"#Model.Approval": {

"title": "Approve All Leave Requests",

"target": "Managers(22)/Inbox/Approval"

"value": [ ... ]

}

17 Action Invocation

Action parameter values are encoded in a single JSON object in the request body.

Each non-binding parameter value is encoded as a separate name/value pair in this JSON object. The name is the name of the parameter. The value is the parameter value in the JSON representation appropriate for its type.

Any parameter values not specified in the JSON object are assumed to have the null value.

Example 37:

{

"param1": 42,

"param2": {

"Street": "One Microsoft Way",

"Zip": 98052

"param3": [ 1, 42, 99 ],

"param4": null

}

18 Instance Annotations

Annotations are an extensibility mechanism that allows services and clients to include information other than the raw data in the request or response. Annotations are used to include control information in many payloads.

Annotations are name/value pairs that have a dot (.) as part of the name. All annotations that start with odata are reserved for future extensions of the protocol and format. Custom annotations are annotations that have a non-empty prefix that is different from odata.

Annotations can be applied to any name/value pair in a JSON payload that represents a value of any type from the entity data model (see [OData-CSDL]).

Example 38:

{

"odata.context": "http://host/service/$metadata#Customers",

"com.contoso.customer.setkind": "VIPs",

"value": [

{

"com.contoso.display.highlight": true,

"ID": "ALFKI",

"CompanyName@com.contoso.display.style": { "title": true, "order": 1 },

"CompanyName": "Alfreds Futterkiste",

"Orders@com.contoso.display.style": { "order": 2 }

}

]

}

Annotations are always expressed as name/value pairs. For entity data model constructs represented as JSON objects the annotation name/value pairs are placed within the object; for constructs represented as JSON arrays or primitives they are placed next to the annotated model construct.

18.1 Annotate a JSON Object

When annotating a name/value pair for which the value is represented as a JSON object, each annotation is placed within the object and represented as a single name/value pair.

The name is the namespace- or alias-qualified name of the annotation, i.e. the namespace or alias of the schema that defines the term, followed by a dot (.), followed by the name of the term. The namespace or alias MUST be defined in the metadata document, see [OData-CSDL].

The value MUST be an appropriate value for the annotation.

18.2 Annotate a JSON Array or Primitive

When annotating a name/value pair for which the value is represented as a JSON array or primitive value, each annotation that applies to this name/value pair MUST be placed next to the annotated name/value pair and represented as a single name/value pair.

The name is the same as the name of the name/value pair being annotated, followed by the “at” sign (@), followed by the namespace- or alias-qualified name of the annotation, followed by a dot (.), followed by the name of the term. The namespace or alias MUST be defined in the metadata document, see [OData-CSDL].

The value MUST be an appropriate value for the annotation.

19 Error Response

The error response MUST be a single JSON object. This object MUST have a single name/value pair named error. The value must be a JSON object.

This object MUST contain name/value pairs with the names code and message, and it MAY contain name/value pairs with the names target, details and innererror.

The value for the code name/value pair is a language-independent string. Its value is a service-defined error code. This code serves as a sub-status for the HTTP error code specified in the response.

The value for the message name/value pair MUST be a human-readable, language-dependent representation of the error. The Content-Language header MUST contain the language code from [RFC5646] corresponding to the language in which the value for message is written.

The value for the target name/value pair is the target of the particular error (for example, the name of the property in error).

The value for the details name/value pair MUST be an array of JSON objects that MUST contain name/value pairs for code and message, and MAY contain a name/value pair for target, as described above.

The value for the innererror name/value pair MUST be an object. The contents of this object are service-defined. Usually this object contains information that will help debug the service. The innererror name/value pair SHOULD only be used in development environments in order to guard against potential security concerns around information disclosure.

Error responses MAY contain annotations in any of its JSON objects.

Example 39:

{

"error": {

"code": "501",

"message": "Unsupported functionality",

"target": "query",

"details": [

{

"code": "301",

"target": "$search"

"message": "$search query option not supported",

}

]

"innererror": {

"trace": [...],

"context": {...}

}

20 Extensibility

Implementations can add custom annotations of the form namespace.termname or property@namespace.termname to any JSON object, where property MAY or MAY NOT match the name of a name/value pair within the JSON object. However, the namespace MUST NOT start with odata and SHOULD NOT be required to be understood by the receiving party in order to correctly interpret the rest of the payload as the receiving party MUST ignore unknown annotations not defined in this version of the OData JSON Specification.

21 Security Considerations

This specification raises no security issues.

This section is provided as a service to the application developers, information providers, and users of OData version 4.0 giving some references to starting points for securing OData services as specified. OData is a REST-full multi-format service that depends on other services and thus inherits both sides of the coin, security enhancements and concerns alike from the latter.

For JSON-relevant security implications please cf. at least the relevant subsections of [RFC4627] as starting point.

22 Conformance

Conforming clients MUST be prepared to consume a service that uses any or all of the constructs defined in this specification. The exception to this are the constructs defined in Delta Response, which are only required for clients that request changes.

In order to be a conforming consumer of the OData JSON format, a client or service:

1. MUST either:

a. understand odata.metadata=minimal (section 3.1.1) or

b. explicitly specify odata.metadata=none (section 3.1.3) or odata.metadata=full (section 3.1.2) in the request (client)

2. MUST be prepared to consume a response with full metadata

3. MUST be prepared to receive all data types (section 7.1)

a. defined in this specification (client)

b. exposed by the service (service)

4. MUST interpret all odata annotations defined according to the OData-Version header of the payload (section 4.5)

5. MUST be prepared to receive any annotations, including custom annotations and odata annotations not defined in the OData-Version header of the payload (section 20)

6. MUST NOT require odata.streaming=true in the Content-Type header (section 4.4)

In addition, in order to conform to the OData JSON format, a service:

7. MUST comply with one of the conformance levels defined in [OData-Protocol]

8. MUST support the application/json media type in the Accept header (section 3)

9. MUST return well-formed JSON payloads

10. MUST support odata.metadata=full (section 3.1.2)

11. MUST include the odata.nextLink annotation in partial results for entity collections (section 4.5.5)

12. MUST support entity instances with external metadata (section 4.5.1)

13. MUST support properties with externally defined data types (section 4.5.3)

14. MUST NOT violate any other aspects of this OData JSON specification

15. SHOULD support the $format system query option (section 3)

16. MAY support the odata.streaming=true parameter in the Accept header (section 4.4)

17. MAY return full metadata regardless of odata.metadata (section 3.1.2)

Appendix A. Acknowledgments

The contributions of the OASIS OData Technical Committee members, enumerated in [OData-Protocol], are gratefully acknowledged.

Appendix B. Revision History

Revision	Date	Editor	Changes Made
Working Draft 01	2012-08-22	Michael Pizzo	Translated Contribution to OASIS format/template
Working Draft 01.1	2013-1-31	Ralf Handl	Adopted new, more concise JSON format
Committee Specification Draft 01	2013-04-26	Ralf Handl Michael Pizzo	Expanded error information Added enumerations Fleshed out descriptions and examples and addressed numerous editorial and technical issues through processed through the TC Added Conformance section
Committee Specification Draft 02	2013-07-01	Ralf Handl Michael Pizzo	Improved rules for odata.id, odata.editLink, and odata.readLink Improved action/function advertisement Improved entity references Improved rules for relative URLs Simplified delta responses GeoJSON for Geo types Improved description of primitive value representation Improved examples, aligned with Atom format specification Aligned terms across specifications