1.
1
Presenter: Dukhabandhu Sahoo, Mindfire Solutions
Date: 18-May-2015
Introduction to OData

2.
About Me
Presenter: Dukhabandhu Sahoo, Mindfire Solutions
Connect With Me:
Twitter: https://twitter.com/dbsahoo99
FaceBook: http://www.facebook.com/dukhabandhusahoo
LinkedIn: http://www.linkedin.com/in/dukhabandhusahoo
Google+: https://plus.google.com/+DukhabandhuSahoo
Blog: http://dukhabandhu.wordpress.com/
Contact Me:
Email: dukhabandhus@mindfiresolutions.com
Skype: mfsi_dukhabandhus
MCTS Certifications:
1. Developing ASP.NET MVC Web Applications(70-486)
2. Web Applications Development with Microsoft .NET Framework 4(70-515)
3. Programming in HTML5 with JavaScript and CSS3(70-480)

3.
Agenda
Presenter: Dukhabandhu Sahoo, Mindfire Solutions
- What is OData?
- How it is different from SOAP, POX?
- OData Server Platforms
- OData implementation using WCF Data Service
- OData implementation using ASP.NET Web API
- OData query operators and methods

4.
- It stands for Open Data access protocol.
- An open protocol to allow the creation and consumption
of queryable and interoperable RESTful APIs in a simple
and standard way. (Odata.org)
- It is a RESTful architecture and supports most of the
HTTP verbs(GET, POST, PUT, DELETE, PATCH,
MERGE)
- It supports three types of data formatting:
ATOMPub(XML), JSON, and JSON light.
What is OData?
Presenter: Dukhabandhu Sahoo, Mindfire Solutions

5.
- It stands for Simple Object Access Protocol.
- It is mainly operation(Verb) focused and supports HTTP
POST only.
- It is based on XML and contains lots of meta-data. So it is
little slower.
Example:
<s:Envelope xmlns:s="">
<s:Headers>
</s:Headers>
<s:Body>
</s:Body>
</s:Envelope>
SOAP
Presenter: Dukhabandhu Sahoo, Mindfire Solutions

6.
- It stands for Plain Old XML.
- Since it is XML based so it is platform independent.
- POX is more interoperable than SOAP because clients no
longer need a SOAP client to consume the web service.
They can access it by using a standard Web Client and an
XML parser.
- But again it supports only XML format which forces the
clients to use XML parser. You cannot use JSON which is
lighter than XML.
POX
Presenter: Dukhabandhu Sahoo, Mindfire Solutions

7.
- It stands for REpresentational State Transfer.
- Representation of resources(e.g List of Products, Remote
Desktop, etc.)
- REST is an architectural style not an protocol unlike
SOAP and HTTP.
- It fully supports HTTP and it is less coupled to the server.
REST
Presenter: Dukhabandhu Sahoo, Mindfire Solutions

8.
OData features
Presenter: Dukhabandhu Sahoo, Mindfire Solutions

9.
- WCF Data Services
- Share Point, MS SQL Server Reporting Services, Windows
Azure, ASP.NET Web API
- Node.js, PHP, Java, IBM WebSphere/DB2/Informix
- OData producers are services that expose their data using
the OData protocol.
- http://www.odata.org/ecosystem/
OData Server Platforms
Presenter: Dukhabandhu Sahoo, Mindfire Solutions

10.
- No WCF knowledge needed.
- Complete implementation of the latest OData
specification.
- Complicated if you want to use non-LINQ data provider.
- Simple and Fast
OData Using WCF Data Service
Presenter: Dukhabandhu Sahoo, Mindfire Solutions

11.
- Add WCF Data Service File and install Nuget package
Microsoft.Data.Services.Client.
- If Entity Framework 6 is used for data provide then we
need to install
Microsoft.OData.EntityFrameworkProvider(-Pre)
package.
- Instead of DataService<T> we have to use
EntityFrameworkDataService<T>(
http://tinyurl.com/wcfdataservice-ef6)
- We can use custom data provider which returns
IQueryable<T> type
WCF Data Service - Demo
Presenter: Dukhabandhu Sahoo, Mindfire Solutions

12.
- Create new service operation.
- Add the appropriate service operation verb attribute(e.g
[WebGet])
- Allow access by registering the method in the service
constructor.
- For custom data providers use
[DataServiceKey("Name")] attribute for providing the key
column of the entity.
WCF Data Service(Contd...)
Presenter: Dukhabandhu Sahoo, Mindfire Solutions

13.
- There are two types of interceptor:
QueryInterceptor and ChangeInterceptor
- The QueryInterceptor is used for GET request and it takes
the entity set name as parameter and its return type is
Expression<Func<TEntitySet, bool>>
- The ChangeInterceptor is used for non-GET requests and
has void as return type.
- ChangeInterceptor method implementation takes first
parameter as entity type and second parameter as
UpdateOperations type.
Interceptors in WCF
Data Service
Presenter: Dukhabandhu Sahoo, Mindfire Solutions

14.
WCF Data Service Diagram
Presenter: Dukhabandhu Sahoo, Mindfire Solutions

15.
- Check that the entity has full permission enabled
(EntitySetRights.All).
- Create: POST( http://localhost:2194/DataServiceTest.svc/Products)
- Read: GET(http://localhost:2194/DataServiceTest.svc/Products(78))
- Update: PUT(http://localhost:2194/DataServiceTest.svc/Products(78))
- Delete: DELETE(http://localhost:2194/DataServiceTest.svc/Products(78))
CRUD in WCF Data Service
Presenter: Dukhabandhu Sahoo, Mindfire Solutions

16.
- The controller class inherits from ODataController class.
- To expose data in GET request, create method of return
type IQueryable<TEntity>.
- Add [EnableQuery]/[Queryable] attribute at the top of
the method.
- All the entities exposed via OData using Entity
Framework must have a key column.
OData using Web API
Presenter: Dukhabandhu Sahoo, Mindfire Solutions

17.
- To get the metadata go to URL
http://localhost:2674/odata/$metadata
- http://localhost:2674/odata/Products?
$top=3&$skip=3&$select=ProductName
- http://localhost:2674/odata/Products?$filter=ProductID
gt 5 and ProductID lt 8
- http: //services.odata.org/Northwind/Northwind.svc/
Customers?$filter=startswith(CompanyName, 'Alfr')
- The OData URL is case-sensitive.
Querying in Web API
Presenter: Dukhabandhu Sahoo, Mindfire Solutions

18.
-
-
Querying in OData
Presenter: Dukhabandhu Sahoo, Mindfire Solutions

19.
http://services.odata.org/OData/OData.svc/
/Products?$filter=ID eq 1
/Products?$orderby=Name desc
/Products?$top=2
/Products?$skip=10
/Products?$select=Rating,ReleaseDate
/Products?$inlinecount=allpages (<m:count>11</m:count>)
/Categories?$expand=Products&$select=Name,Products/Name&$top=1
/Products(1)/Name
/Products(1)/Name/$value
OData Query Examples
Presenter: Dukhabandhu Sahoo, Mindfire Solutions

20.
OData Logical Operators
Presenter: Dukhabandhu Sahoo, Mindfire Solutions
/Products?$filter=ID le 105 and ID gt 100
/Products?$filter=ID ge 10
/Products?$filter=Name ne 'Chai'

21.
OData Arithmetic Operators
Presenter: Dukhabandhu Sahoo, Mindfire Solutions
/Products?$filter=ID add 5 gt 10
/Products?$filter=ID sub 5 gt 10
/Products?$filter=ID mul 2 gt 100
/Products?$filter=ID div 5 gt 10
/Products?$filter=ID mod 2 eq 0

22.
String Functions in OData
Presenter: Dukhabandhu Sahoo, Mindfire Solutions
/Products?$filter=substring(Name, 1) eq 'hai'
/Products?$filter=substring(Name, 1, 2) eq 'ha'
/Products?$filter=substringof('lk', Name) eq true
/Products?$filter=indexof(Name, 'hai') eq 1
/Products?$filter=startswith(Name, 'a')
/Products?$filter=replace(Name, '-', '') eq 'Test'
/Products?$filter=tolower(Name) eq 'chai'
/Products?$filter=trim(Name) eq 'milk'

23.
Date Functions in OData
Presenter: Dukhabandhu Sahoo, Mindfire Solutions
/Employees?$filter=year(BirthDate) eq 1989
/Employees?$filter=minute(BirthDate) eq 20
/Employees?$filter=second(BirthDate) eq 40

24.
Math Functions in OData
Presenter: Dukhabandhu Sahoo, Mindfire Solutions
/Orders?$filter=round(Freight) eq 32
/Orders?$filter=floor(Freight) eq 30
/Orders?$filter=ceiling(Freight) eq 300
Currently no aggregate functions are supported in OData. You can
add service operation/custom method to expose the aggregate
functions.

25.
OData Response Formats
Presenter: Dukhabandhu Sahoo, Mindfire Solutions
ATOMPub
User-Agent: Fiddler
Accept: application/atom+xml
GET: http://services.odata.org/northwind/northwind.svc/Products
JSON Verbose
User-Agent: Fiddler
Accept: application/json;odata=verbose
JSON Light
User-Agent: Fiddler
Accept: application/json
The response size order is: ATOMPub > JSON Verbose > JSON
Light

26.
Recap
Presenter: Dukhabandhu Sahoo, Mindfire Solutions
- How OData is different from SOAP, POX?
- OData server platforms and consumers.
- OData implementation using WCF Data Service
- QueryInterceptor and ChangeInterceptor
- OData implementation using Web API
- Querying in OData(using $filter, $select, $top, etc.)
- Logical and arithmetic operators in OData
- String and date functions in OData

27.
References
Presenter: Dukhabandhu Sahoo, Mindfire Solutions
http://www.odata.org
https://msdn.microsoft.com/en-us/library/dd541437.aspx
http://en.wikipedia.org/wiki/Open_Data_Protocol
http://www.asp.net/web-api/overview/odata-support-
in-aspnet-web-api

28.
Questions?
Presenter: Dukhabandhu Sahoo, Mindfire Solutions

29.
Thank You
Presenter: Dukhabandhu Sahoo, Mindfire Solutions