OData and Impact on API Design

With

Brian Pagano

@brianpagano

Greg Brail

@gbrail

Anant Jhingran

@jhingran

groups.google.com/group/api-craft

youtube.com/apigee

slideshare.net/apigee

Introductions OData Primer API Design The OData Community Conclusions

@gbrail@brianpagano@jhingran

Interactions are shifting to edge of enterprise

Business

Networks

Social

Networks

Apps

Your

Company

Your

Web Site

Your Store

Your apps

Your Data

APIs

What the means is that

you’ve think about “data” –

what you expose, and what

you collect “differently”

- API-centric

Exposing data attracts business to the core even if data is not your core business

http://blog.apigee.com/detail/api_strategy_talk_web_2.0/

See Amundsen’s Dogs, Information Halos and APIs: The epic story of your API Strategy »

Exposing Data is more than the “R” of CRUD in REST

M(E/A)SS OF

INTERCONNECTED DATA

GOOD CLEAN API’S

How do you go from the m(e/a)ss to clean APIs?

Two schools of thought

Table1 Table2

1 N

REST APIS

“Schema-ed” Relational or

Relational-like view of “data”

REST APIS

“Linked Data” view – individual

objects, with properties and

interconnections

Today we’ll discuss the “Schema-ed” view of the world, and in particular, the OData approach

1 N

REST APIS

Let’s look at OData requests and responses.

SQL Query OData Request

select * from products where id = 1 /Products(1)

select * from productswhere name = ‘Milk’

/Products?$filter=name eq ‘Milk’

select name from products /Products?$select=name

select * from products order by name /Products?$orderby=name

select * from products offset 10 limit 10 /Products?$top=10&$skip=10

select * from prices r, products p where r.id = p.id

/Products(1)?$expand=Prices

OData by Example

(* sort of)

/Categories?$filter=Name eq ‘Dairy’

Filters

Logical Operators

eq ne gt ge lt le eq or and

Arithmetic Operators

add sub mul div mod

Parenthesis Operator

()

Canonical Functions

substrof endswith startswith

length indexof replace substring tolower

toupper trim concat year years month day

days hour hours minute minutes second

seconds round floor ceiling isof cast

atom json xml

(plus any other IANA-defined media types)

*If the $format query option is present in a request URI it takes precedence over the value(s) specified in the Accept request header.

Format

/Categories?$format=json *

Metadata

<edmx:Edmx Version="1.0" xmlns:edmx="http://schemas.microsoft.com/ado/2007/06/edmx">

<edmx:DataServices

xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata"

m:DataServiceVersion="1.0">

<Schema Namespace="NorthwindModel"

xmlns:d="http://schemas.microsoft.com/ado/2007/08/dataservices"

xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata"

xmlns="http://schemas.microsoft.com/ado/2008/09/edm">

<EntityType Name="Category">

<Key>

<PropertyRef Name="CategoryID" />

</Key>

<Property Name="CategoryID" Type="Edm.Int32" Nullable="false"

p8:StoreGeneratedPattern="Identity"

xmlns:p8="http://schemas.microsoft.com/ado/2009/02/edm/annotation" />

<Property Name="CategoryName" Type="Edm.String" Nullable="false"

MaxLength="15" Unicode="true" FixedLength="false" />

<Property Name="Description" Type="Edm.String" Nullable="true" MaxLength="Max"

Unicode="true" FixedLength="false" />

</EntityType>

</Schema>

</edmx:DataServices>

</edmx:Edmx>

Libraries

from http://www.odata.org/libraries

WTF is WCF?

Who is using OData?

Who created OData?

How does OData compare to other approaches?

Odata Request Web API Style

/Products(1) /Products/1

/Products?$filter=name eq ‘Milk’ /Products?name=Milk

/Products/1?$select=name /Products/1/name

/Products?$orderby=name /Products?orderby=name

/Products?$top=10&$skip=10 /Products?offset=10&limit=10

/Products(1)?$expand=Prices /Products/1?expand=Prices

OData or Not?

OData GData SOAP Observed API Patterns on the Web

How active is community support for OData?

Is it time to rally around a standard like OData?

Or is too early?

Should one implement OData?

Questions

THANK YOU

Greg Brail

@gbrail

Anant Jhingran

@jhingran

Brian Pagano

@brianpagano

Questions and ideas to:

groups.google.com/group/api-craft