Webservices In Salesforce (Part 1)

Presenter: Surya Kanta Mekap, Mindfire Solutions

Email: suryam@mindfiresolutions.com SkypeId: mfsi_suryam

Date: 4 Oct 2013

Overview

1. Introduction

2. What is SOAP?

3. What is REST?

4. SOAP vs REST

5. What to Choose?

6. SOAP Webservice

7. Public SOAP Webservice

8. SOAP Callout

9. Testing Webservice Callout

10. Summary

Webservice?

Webservice is a sofware function or method of an application exposed to the outside world allowing other application to invoke it from the web.

What is SOAP?

The Simple Object Access Protocol(SOAP) web service is a architecture pattern, which specifies the basic rules to be considered while designing web service platforms. The SOAP message itself consists of an envelope, inside of which are the SOAP headers and body, the actual information we want to send. It is based on the standard XML format, designed especially to transport and store structured data. SOAP may also refer to the format of the XML that the envelope uses. Best for activity oriented services. An activity is more than just insert or update or delete a record.

What is REST?

Representational State Transfer(REST) is another architectural pattern. Unlike SOAP, RESTful applications use the GET, POST, PUT and DELETE to perform CRUD operations. REST is resource-oriented and uses URI (or RESTful URLs). Roy Fielding is the Man who introduced the word REST and the concept in his doctoral thesis in 2000. It’s an excellent choice of technology for use with mobile applications and browser-based clients.

SOAP vs REST● SOAP is a XML based messaging protocol and REST is not a protocol but an

architectural style. ● SOAP has a standard specification but there is none for REST. ● Even SOAP based web services can be implemented in RESTful style. REST is a concept

that does not tie with any protocols. ● REST does not enforces message format as XML or JSON or etc. But SOAP is XML

based message protocol. ● REST follows stateless model. SOAP has specifications for stateful implementation as

well. ● SOAP is strongly typed, has strict specification for every part of implementation. But

REST gives the concept and less restrictive about the implementation. ● SOAP uses interfaces(WSDL) and named operations to expose business logic. REST uses

(generally) URI and methods like (GET, PUT, POST, DELETE) to expose resources.● REST only works over HTTP and HTTPS. SOAP works over HTTP, HTTPS, SMTP,

XMPP, etc.

What to Choose?

If you want a web service that is activity oriented or requires additional level of security or secure messaging then SOAP service is the best option to choose. Activity is much more than just CRUD operations. If you want a web service that is more of resource-oriented, need to do some CRUD operation on a resource then REST service is the best option to choose. Due to its light weight it is mostly preferred for browser based and mobile based applications. In general, when you're publishing an API to the outside world that is either complex or likely to change, SOAP will be more useful. Other than that, REST is usually the better option.

SOAP Webservice

1. First, create and define an Apex class as global. Then create and define an Apex method using both the static and webservice modifiers as shown below.

global class HelloWorld {

webService static string sayHello(){

return 'Hello';

}

}

The global access modifier declares that the class is visible to all Apex scripts everywhere.

This means the class can be used by any Apex code, not just the Apex in the same application.

SOAP Webservice(Continued...)2. To access the webservice WSDL, go to Setup | App Setup | Develop | Apex Classes, find the specific class where the web service is defined and click on the WSDL hyperlink and download it.

3. Collect the Enterprise WSDL from Setup | App Setup | Develop | API by clicking Generate Enterprise WSDL link.

The Partner and Enterprise WSDL have a login() method for which we need it along with our custom webservice wsdl so that we can give the username and password, get the session id, and then switch over to our custom web service to make it work. Session ids are tied to a given user in the organization, so we need to control what they can access by giving them their own profile and locking down access to only what they need to get to.

Those are the WSDL files which are to be imported into the external application(s) that will be invoking the web service.

SOAP Webservice(Continued...)● The webservice modifier can't be used on a class itself, or an interface or

interface methods or variables. ● The @future annotation needs to be used to make the Apex method

execute asynchronously.● Asynchronous callouts can be made with triggers but synchronous callout

with trigger is not supported(use actionpoller to check and show if a response has been received while other transactions were ongoing).

● All classes or inner classes that contain methods or variables defined with the webservice keyword must be declared as global.

● You must define any method that uses the webservice keyword as static. ● Methods defined with the webservice keyword cannot take the following

elements as parameters. While these elements can be used within the method, they cannot be used as return values.

Maps, Sets, Pattern objects, Matcher objects, Exception objects. ● You must use the webservice keyword with any member variables that

you want to expose as part of a web service.

Public SOAP Webservice1) Create a SOAP webservice.2) Go to Site > Setup > App Setup > Develop > Sites > Select your Site >

Give access of class "MerchandiseManager" to site profile 3) Extract WSDL of your class, go to your class and then click "Generate

WSDL". Now all we need to change the SOAP address location in the generated WSDL soap:address tag location value.

Lets say this is the location:https://ap1.salesforce.com/services/Soap/class/HelloWorld

And our site URL ishttps://mindfire-surya-developer-edition.ap1.force.com/

So our final location will be:https://mindfire-surya-developer-edition.ap1.force.com/services/Soap/class/HelloWorld

SOAP Callout Apex Callouts enable Apex to invoke external SOAP web services using WSDL so that you connect to third party services.

Before any Apex callout can call an external site, that site must be registered in the Remote Site Settings page, or the callout fails.

Skipping this will result in "System.CalloutException: IO Exception: Unauthorized endpoint, please check Setup->Security->Remote site settings. endpoint ="...

SOAP Callout(wsdl2apex)1. Collect the WSDL for the application that the salesforce is going to consume.

2. Import the WSDL into SalesforceDevelop > Apex Classes > Generate from WSDL.

3. The successfully generated Apex class includes methods for calling the third-party Web service represented by the WSDL document. Now create an instance of the stub in your Apex code and call the methods on generated Apex class.

Some free SOAP webservices with WSDL can be found :

http://www.actionscript.org/forums/showthread.php3?t=70742

WSDL Parsing ErrorsThere is a list of Supported WSDL Features listed: http://wiki.developerforce.com/page/Apex_Web_Services_and_Callouts#Supported_WSDL_Features

Beyond those you can modify the source WSDL to get a reasonable level of support. For example:1. WSDL with multiple portType, binding, port are not supported in Apex so do keep only respective PortType, binding and port before generating class from WSDL. 2. Datatype “anyType” is not supported in WSDLs used to generate Apex code that is saved using API version 15.0 and later, change the same to “string”.3. …......

SOAP Callout(Continued...)The WSDL2Apex generated code supports HTTP Headers. For example, you can use this feature to set the value of a cookie in an authorization header. To set HTTP headers, add inputHttpHeaders_x and outputHttpHeaders_x to the stub.

Here's an example that sets input HTTP Headers:docSample.DocSamplePort stub = new docSample.DocSamplePort();stub.inputHttpHeaders_x = new Map<String, String>();

//Setting a basic authentication headerstub.inputHttpHeaders_x.put('Authorization', 'Basic

QWxhZGRpbjpvcGVuIHNlc2FtZQ=='); //Setting a cookie headerstub.inputHttpHeaders_x.put('Cookie', 'name=value'); //Setting a custom HTTP headerstub.inputHttpHeaders_x.put('myHeader', 'myValue');....

SOAP Callout(Continued...)Here's one that accesses output HTTP Headers information:

docSample.DocSamplePort stub = new docSample.DocSamplePort();stub.outputHttpHeaders_x = new Map<String, String>();String input = 'This is the input string';String output = stub.EchoString(input); //Getting cookie headerString cookie = stub.outputHttpHeaders_x.get('Set-Cookie'); //Getting custom headerString myHeader = stub.outputHttpHeaders_x.get('My-Header');

Testing SOAP CalloutApex provides the built-in WebServiceMock interface and the Test.setMock method that we can use to receive fake responses in a test method for a SOAP callout.

SecurityAuthentication(Certificate 2way SSL)Authorization(SessionID or OAuth 2.0)Crypto classEncodingUtil Class

CertificateServer CertificateClient Certificate - Legacy Processstub.clientCert_x = 'xyz....';stub.clientCertPasswd_x = 'passwd'; // <<< Password for the keystore

-Salesforce Orgstub.clientCertName_x = 'Certificate Name'; // <<< Salesforce’s certificate name

When SFDC makes a call to a secured server, it first tries to see if the server has a Server Certificate. If it does, then it sends the Client Certificate. If this Client Certificate is accepted by the web server, then the communication is valid and the data is sent to and fro between SFDC and the web server

Oauth 2.0OAuth endpoints are the URLs you use to make OAuth authentication requests to Salesforce.You need to use the correct Salesforce OAuth endpoint when issuing authentication requests in your application. The primary OAuth endpoints are:

For authorization: https://login.salesforce.com/services/oauth2/authorize For token requests: https://login.salesforce.com/services/oauth2/token For revoking OAuth tokens: https://login.salesforce.com/services/oauth2/revoke

All endpoints require secure HTTP (HTTPS). Each OAuth flow defines which endpoints you need to use and what request data you need to provide.

-Web Server Agent Oauth-User Agent Oauth-Username Password Agent OAuth

Referenceshttp://wiki.developerforce.com/page/Apex_Web_Services_and_Callouts

http://forceguru.blogspot.in/2012/09/creating-public-web-service-in.html

http://blog.deadlypenguin.com/blog/2012/02/03/salesforce-and-soapui/

http://kperisetla.blogspot.in/2012/05/restful-services-on-forcecom-through.html

http://www.fishofprey.com/2011/03/consuming-aspnet-web-service-from.html

http://www.salesforce.com/us/developer/docs/apexcode/index.htm

http://stackoverflow.com/questions/209905/representational-state-transfer-rest-and-simple-object-access-protocol-soap

http://www.salesforce.com/us/developer/docs/api_rest/index_Left.html

http://blog.deadlypenguin.com/blog/2012/04/13/salesforce-and-soapui-using-the-default-query-method/

http://medbiq.org/std_specs/techguidelines/knowingwhentorest.pdf

http://www.developingthefuture.net/web-services-overview/

http://www.tgerm.com/2010/12/invoking-apex-wsdl-web-services-from.html

http://blogs.developerforce.com/tech-pubs/2011/10/salesforce-apis-what-they-are-when-to-use-them.html

Question and Answers

Thank You