SIPSorcery.SIP.App.SIPClientUserAgent.GetInviteRequest C# (CSharp) Method

        private SIPRequest GetInviteRequest(SIPCallDescriptor sipCallDescriptor, string branchId, string callId, SIPEndPoint localSIPEndPoint, SIPRouteSet routeSet, string content, string contentType)
        {
            SIPRequest inviteRequest = new SIPRequest(SIPMethodsEnum.INVITE, sipCallDescriptor.Uri);
            inviteRequest.LocalSIPEndPoint = localSIPEndPoint;

            SIPHeader inviteHeader = new SIPHeader(sipCallDescriptor.GetFromHeader(), SIPToHeader.ParseToHeader(sipCallDescriptor.To), 1, callId);

            inviteHeader.From.FromTag = CallProperties.CreateNewTag();

            // For incoming calls forwarded via the dial plan the username needs to go into the Contact header.
            inviteHeader.Contact = new List<SIPContactHeader>() { new SIPContactHeader(null, new SIPURI(inviteRequest.URI.Scheme, localSIPEndPoint)) };
            inviteHeader.Contact[0].ContactURI.User = sipCallDescriptor.Username;
            inviteHeader.CSeqMethod = SIPMethodsEnum.INVITE;
            inviteHeader.UserAgent = m_userAgent;
            inviteHeader.Routes = routeSet;
            inviteRequest.Header = inviteHeader;

            if (!sipCallDescriptor.ProxySendFrom.IsNullOrBlank())
            {
                inviteHeader.ProxySendFrom = sipCallDescriptor.ProxySendFrom;
            }

            SIPViaHeader viaHeader = new SIPViaHeader(localSIPEndPoint, branchId);
            inviteRequest.Header.Vias.PushViaHeader(viaHeader);

            inviteRequest.Body = content;
            inviteRequest.Header.ContentLength = (inviteRequest.Body != null) ? inviteRequest.Body.Length : 0;
            inviteRequest.Header.ContentType = contentType;

            // Add custom switchboard headers.
            if (CallDescriptor.SwitchboardHeaders != null)
            {
                inviteHeader.SwitchboardOriginalCallID = CallDescriptor.SwitchboardHeaders.SwitchboardOriginalCallID;
                //inviteHeader.SwitchboardCallerDescription = CallDescriptor.SwitchboardHeaders.SwitchboardCallerDescription;
                inviteHeader.SwitchboardLineName = CallDescriptor.SwitchboardHeaders.SwitchboardLineName;
                //inviteHeader.SwitchboardOwner = CallDescriptor.SwitchboardHeaders.SwitchboardOwner;
                //inviteHeader.SwitchboardOriginalFrom = CallDescriptor.SwitchboardHeaders.SwitchboardOriginalFrom;
            }

            // Add custom CRM headers.
            if (CallDescriptor.CRMHeaders != null)
            {
                inviteHeader.CRMPersonName = CallDescriptor.CRMHeaders.PersonName;
                inviteHeader.CRMCompanyName = CallDescriptor.CRMHeaders.CompanyName;
                inviteHeader.CRMPictureURL = CallDescriptor.CRMHeaders.AvatarURL;
            }

            try
            {
                if (sipCallDescriptor.CustomHeaders != null && sipCallDescriptor.CustomHeaders.Count > 0)
                {
                    foreach (string customHeader in sipCallDescriptor.CustomHeaders)
                    {
                        if (customHeader.IsNullOrBlank())
                        {
                            continue;
                        }
                        else if (customHeader.Trim().StartsWith(SIPHeaders.SIP_HEADER_USERAGENT))
                        {
                            inviteRequest.Header.UserAgent = customHeader.Substring(customHeader.IndexOf(":") + 1).Trim();
                        }
                        else
                        {
                            inviteRequest.Header.UnknownHeaders.Add(customHeader);
                        }
                    }
                }
            }
            catch (Exception excp)
            {
                logger.Error("Exception Parsing CustomHeader for GetInviteRequest. " + excp.Message + sipCallDescriptor.CustomHeaders);
            }

            return inviteRequest;
        }