Connecting and Consuming CRM webservices using WCF component

Being new to MS CRM environment and with my naive C# skills, i struggled my bit to create WCF component to connect/consume CRM web services.

In this blog, I will go through all the required steps from start to end. Also many resources are available for reference in bits and pieces, I thought of putting everything at one place.

Motive behind developing WCF component : 

We have users with out much knowledge of CRM and its terminology. we wanted a simplified, lite web application that our users can use with ease. Also we have multiple web components that are connecting to CRM. Hence we zeroed on developing WCF component which consumes CRM services. By hosting this WCF service, any one with corresponding link and credentials could connect/consume CRM services with out bothering much technical details. Also different user groups should be made to access only specific services. Also instead of using CRM DB context with LINQ queries, CRM Services will make developer life easier. As developer need not learn LINQ programming separately.

Step 1: Getting the services URI's

URI's for MS CRM RESTend & SOAP will be specified under

• Settings --> Customization --> Developer Resources

RESTend URI will be of form https://{your server name}/XRM/XRMServices/2011/Organizationdata.svc/

This section will provide WSDL URI's for SOAP and REST protocols.

SOAP Vs REST

using RESTend points is easy and straight forward( no need of C#/controller methods). It can be bind to frond end controls using Java Script/J Query. However handling security in web context is not that efficient. Also developing complex business logic can't be done. 

                                  RESTend points were introduced to avoid usage of fetchXML to perform small operations, which has many limitations. REST services can be used by creating JAVA Script(in CRM context we refer it as JScript) file in Settings --> customization --> Resources Section. This script can be used in any CRM web form to retrieve/insert/update data.   

 REST services follow ODATA protocol for data representation. RESTend points URI should be appended with corresponding table name and required operations.

$top	The maximum number of items returned in the result set for each page.
$skip	The number of rows to skip in the result set before beginning to return results.
$filter	Comparisons Eq – Equal to Gt – Greater than Lt – Less than Ne – Not equal to Concatinations And Or Field Names - Types: all OData supported types.
$orderby	Specifies the sort order of the result set. NOTE: Requires DataServiceVersion 2.0 or higher. To determine DataServiceVersion see Determine DataServiceVersion later in this topic.
$select	Specifies the fields returned in the result set.
$skiptoken	An opaque value that must be passed back to the server in order to continue getting results for the query. For more information seeSkip Token System Query Option ($skiptoken) at OData.org.
$count	Returns the count of a collection of entities. NOTE: Requires DataServiceVersion 2.0 or higher. To determine DataServiceVersion see Determine DataServiceVersion in this topic.
$inlinecount	$inlinecount is only supported for flexible query services. It is not supported for fixed query services. NOTE: Requires DataServiceVersion 2.0 or higher. To determine DataServiceVersion see Determine DataServiceVersion later in this topic.
$metadata	Retrieves a list of fields, their data types, mode, and other related information in a dataset.
ID operators	E.g. "/Companies('Microsoft')"
Comparison operators	eq – Equal to ne – Not equal to lt – Less than le – Less than or equal to gt – Greater than ge – Greater than or equal to
Logical operators	and – True only if both operands are true or – True if either or both operands are true not – opposite of operand
Arithimetic operators	add – Addition operator sub – Subtraction operator mult – Multiplication operator div – Division operator mod – Modulo (remainder after integer division) operator
Grouping operators	( and )
DateTime Functions	year month day hour minute second
Math functions	round ceiling floor

 SOAP services provides better security options while connecting to CRM.

            1. Active Director authentication

            2. IFD authentication

            3. Live/on-line authentication

If your Organizations CRM authentication method is set to AD, we have to use Discovery URL with AD options. When connecting to CRM with authentication from web-form/WCF component, we have to use IFD method. When customers log in using Microsoft Live Id, we will go for Live authentication. These methods are explained in detail in later part.
The corresponding URI's will be