Protocollo Open Data

In informatica, Il Protocollo Open Data (in inglese: Open Data Protocol) o OData è un protocollo aperto che permette la creazione e il consumo di API RESTful interoperabili e interrogabili in maniera semplice e standard. Microsoft creò gli OData nel 2007. Le versioni 1.0, 2.0 e 3.0 sono state rilasciate sotto la licenza Microsoft Open Specification Promise. La versione 4.0 fu standardizzata presso l'OASIS nel marzo 2014. Nell'aprile 2015 OASIS propone gli Odata versione 4 e il formato OData JSON versione 4 all'ISO/IEC JTC 1 per un'approvazione come standard internazionale. Il 23 febbraio 2017 ISO/IEC JTC 1 approva lo standard OData (ISO/IEC 20802-1:2016 e ISO/IEC 20802-2:2016 ) per lo scambio degli Open Data .

Rappresentazione delle risorse Esempio di payload OData JSON A collection of products: { "@odata.context": "http://services.odata.org/V4/OData/OData.svc/$metadata#Products", "value": [

"ID": 0, "Name": "Bread", "Description": "Whole grain bread", "ReleaseDate": "1992-01-01T00:00:00Z", "DiscontinuedDate": null, "Rating": 4, "Price": 2.5 },

"ID": 1, "Name": "Milk", "Description": "Low fat milk", "ReleaseDate": "1995-10-01T00:00:00Z", "DiscontinuedDate": null, "Rating": 3, "Price": 3.5 }, ... ] }

Un esempio di payload OData Atom A collection of products: <feed xml:base="http://services.odata.org/V4/OData/OData.svc/" m:context="http://services.odata.org/V4/OData/OData.svc/$metadata#Products" xmlns="http://www.w3.org/2005/Atom" xmlns:d="http://docs.oasis-open.org/odata/ns/data" xmlns:m="http://docs.oasis-open.org/odata/ns/metadata" xmlns:georss="http://www.georss.org/georss" xmlns:gml="http://www.opengis.net/gml"> <id>http://services.odata.org/v4/odata/odata.svc/Products</id> <title type="text">Products</title> <updated>2015-05-19T03:38:50Z</updated> <link rel="self" title="Products" href="Products"/> <entry> <id>http://services.odata.org/V4/OData/OData.svc/Products(0)</id> <category term="#ODataDemo.Product" scheme="http://docs.oasis-open.org/odata/ns/scheme"/> <link rel="edit" title="Product" href="Products(0)"/> <link rel="http://docs.oasis-open.org/odata/ns/relatedlinks/Categories" type="application/xml" title="Categories" href="Products(0)/Categories/$ref"/> <link rel="http://docs.oasis-open.org/odata/ns/related/Categories" type="application/atom+xml;type=feed" title="Categories" href="Products(0)/Categories"/> <link rel="http://docs.oasis-open.org/odata/ns/relatedlinks/Supplier" type="application/xml" title="Supplier" href="Products(0)/Supplier/$ref"/> <link rel="http://docs.oasis-open.org/odata/ns/related/Supplier" type="application/atom+xml;type=entry" title="Supplier" href="Products(0)/Supplier"/> <link rel="http://docs.oasis-open.org/odata/ns/relatedlinks/ProductDetail" type="application/xml" title="ProductDetail" href="Products(0)/ProductDetail/$ref"/> <link rel="http://docs.oasis-open.org/odata/ns/related/ProductDetail" type="application/atom+xml;type=entry" title="ProductDetail" href="Products(0)/ProductDetail"/> <title/> <updated>2015-05-19T03:38:50Z</updated> <author> <name/> </author> <content type="application/xml"> <m:properties> <d:ID m:type="Int32">0</d:ID> <d:Name>Bread</d:Name> <d:Description>Whole grain bread</d:Description> <d:ReleaseDate m:type="DateTimeOffset">1992-01-01T00:00:00Z</d:ReleaseDate> <d:DiscontinuedDate m:null="true"/> <d:Rating m:type="Int16">4</d:Rating> <d:Price m:type="Double">2.5</d:Price> </m:properties> </content> </entry> <entry> <id>http://services.odata.org/V4/OData/OData.svc/Products(1)</id> <category term="#ODataDemo.Product" scheme="http://docs.oasis-open.org/odata/ns/scheme"/> <link rel="edit" title="Product" href="Products(1)"/> <link rel="http://docs.oasis-open.org/odata/ns/relatedlinks/Categories" type="application/xml" title="Categories" href="Products(1)/Categories/$ref"/> <link rel="http://docs.oasis-open.org/odata/ns/related/Categories" type="application/atom+xml;type=feed" title="Categories" href="Products(1)/Categories"/> <link rel="http://docs.oasis-open.org/odata/ns/relatedlinks/Supplier" type="application/xml" title="Supplier" href="Products(1)/Supplier/$ref"/> <link rel="http://docs.oasis-open.org/odata/ns/related/Supplier" type="application/atom+xml;type=entry" title="Supplier" href="Products(1)/Supplier"/> <link rel="http://docs.oasis-open.org/odata/ns/relatedlinks/ProductDetail" type="application/xml" title="ProductDetail" href="Products(1)/ProductDetail/$ref"/> <link rel="http://docs.oasis-open.org/odata/ns/related/ProductDetail" type="application/atom+xml;type=entry" title="ProductDetail" href="Products(1)/ProductDetail"/> <title/> <updated>2015-05-19T03:38:50Z</updated> <author> <name/> </author> <content type="application/xml"> <m:properties> <d:ID m:type="Int32">1</d:ID> <d:Name>Milk</d:Name> <d:Description>Low fat milk</d:Description> <d:ReleaseDate m:type="DateTimeOffset">1995-10-01T00:00:00Z</d:ReleaseDate> <d:DiscontinuedDate m:null="true"/> <d:Rating m:type="Int16">3</d:Rating> <d:Price m:type="Double">3.5</d:Price> </m:properties> </content> </entry> ... </feed>

Un esempio di documento metadato OData <edmx:Edmx Version="4.0" xmlns:edmx="http://docs.oasis-open.org/odata/ns/edmx"> <edmx:DataServices> <Schema Namespace="ODataDemo" xmlns="http://docs.oasis-open.org/odata/ns/edm"> <EntityType Name="Product"> <Key> <PropertyRef Name="ID"/> </Key> <Property Name="ID" Type="Edm.Int32" Nullable="false"/> <Property Name="Name" Type="Edm.String"/> <Property Name="Description" Type="Edm.String"/> <Property Name="ReleaseDate" Type="Edm.DateTimeOffset" Nullable="false"/> <Property Name="DiscontinuedDate" Type="Edm.DateTimeOffset"/> <Property Name="Rating" Type="Edm.Int16" Nullable="false"/> <Property Name="Price" Type="Edm.Double" Nullable="false"/> </EntityType>

Note

Voci correlate GData Resource Description Framework

Collegamenti esterni

Standard OData OASIS

Categoria:XML

Protocollo Open Data

Źródło i licencja