public String envelopeId {get;set;}
private String accountId = '7afed6db-0e61-4855-9573-4a75173ccd13';
private String userId = 'c20a0a11-d623-4d1f-89dc-fc8e10fd5a28';
private String password = 'madanamoni14';
private String integratorsKey = '1630d186-efe9-497f-8ad2-dce2fb35b1bc';
private String webServiceUrl = 'https://demo.docusign.net/api/3.0/dsapi.asmx';

public SendToDocuSignController (ApexPages.StandardController controller)
{
    this.contract = [select Id,CustomerSignedId,AccountId,ContractNumber  from Contract where id = :controller.getRecord().Id];
    envelopeId = 'Not sent yet';

    SendNow();
}

public void SendNow()
{
    DocuSignAPI.APIServiceSoap dsApiSend = new DocuSignAPI.APIServiceSoap();
    dsApiSend.endpoint_x = webServiceUrl;

    //Set Authentication
    String auth = '<DocuSignCredentials><Username>'+ userId
        +'</Username><Password>' + password
        + '</Password><IntegratorKey>' + integratorsKey
        + '</IntegratorKey></DocuSignCredentials>';
    System.debug('Setting authentication to: ' + auth);

    dsApiSend.inputHttpHeaders_x = new Map<String, String>();
    dsApiSend.inputHttpHeaders_x.put('X-DocuSign-Authentication',
        auth);

    DocuSignAPI.Envelope envelope = new DocuSignAPI.Envelope();
    envelope.Subject    = 'Please Sign this Contract: ' + contract.ContractNumber;
    envelope.EmailBlurb = 'This is my new eSignature service, it allows me to get your signoff without having to fax, scan, retype, refile and wait forever';
    envelope.AccountId  = accountId;


    // Render the contract
    System.debug('Rendering the contract');
    PageReference pageRef = new PageReference('/apex/RenderContract');
    pageRef.getParameters().put('id',contract.Id);
    Blob pdfBlob = pageRef.getContent();

    // Document
    DocuSignAPI.Document document = new DocuSignAPI.Document();
    document.ID = 1;
    document.pdfBytes = EncodingUtil.base64Encode(pdfBlob);
    document.Name = 'Contract';
    document.FileExtension = 'pdf';
    envelope.Documents = new DocuSignAPI.ArrayOfDocument();
    envelope.Documents.Document = new DocuSignAPI.Document[1];
    envelope.Documents.Document[0] = document;

    // Recipient
    System.debug('getting the contact');
    Contact contact = [SELECT email, FirstName, LastName from Contact where id = :contract.CustomerSignedId];
    System.debug('got ' + contact.email + ' ' + contact.FirstName + ' ' + contact.LastName);

    System.debug('Building up the recipient');
    DocuSignAPI.Recipient recipient = new DocuSignAPI.Recipient();
    recipient.ID = 1;
    recipient.Type_x = 'Signer';
    recipient.RoutingOrder = 1;
    recipient.Email = contact.Email;
    recipient.UserName = contact.FirstName + ' ' + contact.LastName;

    // This setting seems required or you see the error:
    // "The string '' is not a valid Boolean value. at System.Xml.XmlConvert.ToBoolean(String s)"
    recipient.RequireIDLookup = false;

    envelope.Recipients = new DocuSignAPI.ArrayOfRecipient();
    envelope.Recipients.Recipient = new DocuSignAPI.Recipient[1];
    envelope.Recipients.Recipient[0] = recipient;

    // Tab
    DocuSignAPI.Tab tab1 = new DocuSignAPI.Tab();
    tab1.Type_x = 'SignHere';
    tab1.RecipientID = 1;
    tab1.DocumentID = 1;
    tab1.AnchorTabItem = new DocuSignAPI.AnchorTab();
    tab1.AnchorTabItem.AnchorTabString = 'By:';
    tab1.AnchorTabItem.XOffset = 100;


    DocuSignAPI.Tab tab2 = new DocuSignAPI.Tab();
    tab2.Type_x = 'DateSigned';
    tab2.RecipientID = 1;
    tab2.DocumentID = 1;
    tab2.AnchorTabItem = new DocuSignAPI.AnchorTab();
    tab2.AnchorTabItem.AnchorTabString = 'Date Signed:';

    envelope.Tabs = new DocuSignAPI.ArrayOfTab();
    envelope.Tabs.Tab = new DocuSignAPI.Tab[2];
    envelope.Tabs.Tab[0] = tab1;
    envelope.Tabs.Tab[1] = tab2;

    System.debug('Calling the API');
    try {
        DocuSignAPI.EnvelopeStatus es = dsApiSend.CreateAndSendEnvelope(envelope);
        envelopeId = es.EnvelopeID;
        System.debug('Returned successfully, envelope id = ' + envelopeId );
    } catch ( CalloutException e) {
        System.debug('Exception - ' + e );
        envelopeId = 'Exception - ' + e;
    }

}
}