Using SalesForce RestAPI VB.Net/C#

SalesForce API calls to fetch data

My exploration on SalesForce APIs had revealed a couple of approaches to fetch data from SalesForce. The main ones are listed below

SOAP Api
Rest calls
Bulk API
Data Loader

Before we begin, there are a set of prerequisites that you need to get done in order to run the sample or interact using the SalesForce API's.

Prerequisites:
User Name  
Password
Security Token (needed for the Api calls as the password is considered as password+security token)
Client Secret (Required for REST Call)
Client Id (Required for REST Call)
Call Back (This is required if we are authenticating from the web, else if we have a console application this could be some dummy value)


You can register for a developer license in case you don't have a user name and password at https://login.salesforce.com/.

Now let's take a look at each of the options available.

SOAP API
This is really an easy and fast way to query data from SalesForce. But is has got some serious drawbacks. Main ones being the limitations in the number of records that are fetched. The current limit is 2000 records per call. You will also need to consider the number of calls that are being made to SalesForce as there is a usage limit for each instance or Org based on the number of requests made. You need to tread with care when you have a large set of data to be retrieved.

The example shown is mainly a console application used to retrieve data from Sales Force

Steps:

1. Create a console application

2. Add reference to SalesForce Service

            You can add reference to the SalesForce service in two ways. Either directly browsing to the wsdl url or download the wsdl and adding it.

Follow the steps shown below to add the reference directly

Click on “Add Service Reference”

Click Advanced

Click “Add Web Reference”

Type the corresponding PARTNER wsdl(my example it was https://na15.salesforce.com/soap/wsdl.jsp) url in the URL and give an appropriate name to your service. Then click “Add Referece”

One important thing to note here is that you need to add a “web reference” itself. If you add a “Service Reference” the proxy class generated from the WSDL is entirely different. 

Where can I get the WSDL?

Once you login to your sales force service (http://login.salesforce.com), navigate to “Set Up” from the user name drop down menu

Click on Develop > API in the left hand navigation

You can see the different options for generating WSDL.

You have either the choice of choosing “Enterprise WSDL” or “Partner WSDL” or “APEX  WSDL”

Enterprise WSDL is useful when you want to have a proxy class that is tightly coupled to the schema you have built in sales force. You need to re-add the WSDL if you have changed the schema in sales force.

e.g. Dim account As Account = CType (qr.records(i), Account)

You can work directly with the Account entity and its fields if you have a reference to Enterprise WSDL.

The more generic one is the Partner WSDL,which is a loosely typed association. Here you will need to work on the generic object sObject to go through the data.

e.g Dim record As sForceService.sObject = qr.records(i)

3. Login to salesForce service:

You will need username and password. Password comprises of password + the security token. So if your password is “abcd” and token is “EFGH” then the password to be passed to the service is “abcdEFGH”.

' Create the binding to the sforce servics

 bindingService = New sForceService.SforceService

 ' Set the time out valie

 bindingService.Timeout = 60000

Dim loginRes As sForceService.LoginResult = bindingService.login(userName, password)

4. Assign the session Id to the SOAP header for subsequent calls:

This is required if you need to make further calls to the API service.

'Create a new session header object and set the session id to that returned by the login

 bindingService.SessionHeaderValue = New sForceService.SessionHeader

bindingService.SessionHeaderValue.sessionId = loginRes.sessionId

5. Get the new url for you org:

Once the login succeeds you need to change the endpoint url of you service to the new value returned after successful login.

'Change the binding to the new endpoint

bindingService.Url = loginRes.serverUrl

Initialize the forceService object. Execute the query method of the SforceService object.

'Set the query option, batch size (maximum value allowed is 2000, beyond this value it

'gives and INVALID_BATCH_SIZE error;

Dim results As sForceService.QueryResult = Nothing

bindingService.QueryOptionsValue = New sForceService.QueryOptions

bindingService.QueryOptionsValue.batchSize = 2000

bindingService.QueryOptionsValue.batchSizeSpecified = True

'Run the qquery

 results = bindingService.query("select FirstName, LastName from Contact")

Once you get the results you get loop through the results and get the column values.

For i As Integer = 0 To results.records.GetUpperBound(0)

    Dim record As sForceService.sObject = results.records(i)

Next

You will need to check if there are more results to be fetched. In that case you need to call the queryMore option with the current location of the returned results. The queryMore picks up the last record id and does a new fetch from that position.

If results.done Then

              bContinue = False

       Else

              results = bindingService.queryMore(qr.queryLocator)

End If

6. Done

Below is the required functions needed to call using the SOAP API

'      /*

    '* login sample

    '* Prompts for username and password, set class variable binding

    '* resets the url for the binding and adds the session header to

    '* the binding class variable

    '*/

    Private Function login() As Boolean

        Console.Write("Enter user name: ")

        Dim userName As String = Console.ReadLine()

        If userName.Length = 0 Then

            Return False

        End If

        Console.Write("Enter password: ")

        Dim password As String = Console.ReadLine()

        If password.Length = 0 Then

            Return False

        End If

        '//Provide feed back while we create the web service binding

        Console.WriteLine("Creating the binding to the web service...")

        ' Create the binding to the sforce servics

        bindingService = New sForceService.SforceService

        ' Set the time out valie

        bindingService.Timeout = 60000

        '//Attempt the login giving the user feedback

        Console.WriteLine("LOGGING IN NOW....")

        Try

            Dim loginRes As sForceService.LoginResult = bindingService.login(userName, password)

        Catch e As System.Web.Services.Protocols.SoapException

            '// This is likley to be caused by bad username or password

            Console.Write(e.Message & ", please try again." & vbCrLf & vbCrLf & "Hit return to continue...")

            Console.ReadLine()

            Return False

        Catch ex As Exception

            '// This is something else, probably comminication

            Console.Write(ex.Message & ", please try again." & vbCrLf & vbCrLf & "Hit return to continue...")

            Console.ReadLine()

            Return False

        End Try

        Console.WriteLine(vbCrLf & "The session id is: " & loginRes.sessionId)

        Console.WriteLine(vbCrLf & "The new server url is: " & loginRes.serverUrl)

        'Change the binding to the new endpoint

        bindingService.Url = loginRes.serverUrl

        'Create a new session header object and set the session id to that returned by the login

        bindingService.SessionHeaderValue = New sForceService.SessionHeader

        bindingService.SessionHeaderValue.sessionId = loginRes.sessionId

        Debug.WriteLine(loginRes.sessionId)

        loggedIn = True

        Return True

    End Function

Private Sub querySample()

        'Verify that we are already authenticated, if not

        'call the login function to do so

        If Not loggedIn Then

            If Not login() Then

                Return

            End If

        End If

        'Set the query option, batch size (maximum value allowed is 2000, beyond this value it

        'gives and INVALID_BATCH_SIZE error;

        Dim results As sForceService.QueryResult = Nothing

        bindingService.QueryOptionsValue = New sForceService.QueryOptions

        bindingService.QueryOptionsValue.batchSize = 2000

        bindingService.QueryOptionsValue.batchSizeSpecified = True

        Try

            'Run the qquery

            results = bindingService.query("select FirstName, LastName from Contact")

           

            'create a looop control variable for the loop & 1 behavior

            Dim bContinue As Boolean = True

            Dim loopCounter As Integer = 0

            While bContinue

                'process the query results

                loopCounter += 1

                Console.WriteLine(vbCrLf & "Results Set " &Convert.ToString(loopCounter) & " - ")

                For i As Integer = 0 To results.records.GetUpperBound(0)

                    Dim record As sForceService.sObject = results.records(i)

                    Dim fName As String = getFieldValue("FirstName", record.Any)

                    Dim lName As String = getFieldValue("LastName", record.Any)

                    If fName Is Nothing Then

                        Console.WriteLine("Contact " & (i + 1) & ": " & lName)

                    Else

                        Console.WriteLine("Contact " & (i + 1) & ": " & fName & " " & lName)

                    End If

                Next

                'handle the loop + 1 problem by checking to see if the most recent queryResult

                'set is

                If results.done Then

                    bContinue = False

                Else

                    results = bindingService.queryMore(results.queryLocator)

                End If

            End While

            Console.WriteLine(vbCrLf & "Query succesfully executed.")

            Console.Write(vbCrLf & "Hit return to continue...")

            Console.ReadLine()

        Catch ex As Exception

            Console.WriteLine(vbCrLf & "Failed to execute query succesfully, error message was: " & vbCrLf & ex.Message)

            Console.Write(vbCrLf & "Hit return to continue...")

            Console.ReadLine()

        End Try

Private Function getFieldValue(ByVal fieldName As String, ByVal fields() AsSystem.Xml.XmlElement) As String

        Dim returnValue As String = ""

        If Not fields Is Nothing Then

            For i As Integer = 0 To fields.GetUpperBound(0)

                If fields(i).LocalName.ToLower().Equals(fieldName.ToLower()) Then

                    returnValue = fields(i).InnerText

                End If

            Next

        End If

        Return returnValue

    End Function

Thats all for the call using SOAP API. Watch this space for updates on REST and the BULK API.

Hope this helps !!!