Protocollo Open Data
Vai alla navigazione
Vai alla ricerca
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 [1] e ISO/IEC 20802-2:2016 [2]) per lo scambio degli Open Data [3].
Rappresentazione delle risorse[modifica | modifica wikitesto]
Esempio di payload OData JSON[modifica | modifica wikitesto]
A collection of products:
{
"@odata.context": "http://services.odata.org/V4/OData/OData.svc/$metadata#Products",
"value": [
{
"ID": 0,
"Name": "Bread",
"Description": "Whole grain bread",
"ReleaseDate": "1992-01-01T00:00:00Z",
"DiscontinuedDate": null,
"Rating": 4,
"Price": 2.5
},
{
"ID": 1,
"Name": "Milk",
"Description": "Low fat milk",
"ReleaseDate": "1995-10-01T00:00:00Z",
"DiscontinuedDate": null,
"Rating": 3,
"Price": 3.5
},
...
]
}
Un esempio di payload OData Atom[modifica | modifica wikitesto]
A collection of products:
<feed xml:base="http://services.odata.org/V4/OData/OData.svc/" m:context="http://services.odata.org/V4/OData/OData.svc/$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[modifica | modifica wikitesto]
<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>
<ComplexType Name="Address">
<Property Name="Street" Type="Edm.String"/>
<Property Name="City" Type="Edm.String"/>
<Property Name="State" Type="Edm.String"/>
<Property Name="ZipCode" Type="Edm.String"/>
<Property Name="Country" Type="Edm.String"/>
</ComplexType>
<EntityContainer Name="DemoService">
<EntitySet Name="Products" EntityType="ODataDemo.Product"></EntitySet>
</EntityContainer>
</Schema>
</edmx:DataServices>
</edmx:Edmx>
Note[modifica | modifica wikitesto]
- ^ ISO/IEC 20802-1:2016 - Open data protocol (OData) v4.0 - Part 1: Core, su iso.org. URL consultato il 23 luglio 2017.
- ^ ISO/IEC 20802-2:2016 - Open data protocol (OData) v4.0 -- Part 2: OData JSON Format, su iso.org. URL consultato il 23 luglio 2017.
- ^ OISO/IEC JTC 1 Approves OASIS OData Standard for Open Data Exchange, su oasis-open.org. URL consultato il 23 luglio 2017.
Voci correlate[modifica | modifica wikitesto]
Collegamenti esterni[modifica | modifica wikitesto]
- (EN) OData.org.
- (EN) Open Data Protocol by Example, su msdn.microsoft.com.
- (EN) OData Basics Presentation, su hanselman.com.
Standard OData OASIS[modifica | modifica wikitesto]
- OData Version 4.0 Part 1: Protocol, su docs.oasis-open.org.
- OData Version 4.0 Part 2: URL Conventions, su docs.oasis-open.org.
- OData Version 4.0 Part 3: Common Schema Definition Language (CSDL), su docs.oasis-open.org.
- ABNF components - OData ABNF Construction Rules Version 4.0 and OData ABNF Test Cases, su docs.oasis-open.org.
- Vocabulary components - OData Core Vocabulary and OData Measures Vocabulary, su docs.oasis-open.org.
- XML Schemas - OData EDMX XML Schema and OData EDM XML Schema, su docs.oasis-open.org.
- OData JSON Format Version 4.0, su docs.oasis-open.org.