Using Reporting Services (SSRS) as a reference in an ASP.NET Core site

Reference to Nick's solution above, I fixed the running exception of "session identifier is missing".

Here I show the whole solution of calling Asp.net core 2.0 web api to access SSRS and return pdf report in browser.

    [HttpGet("getpdfreport")]
    public async Task<IActionResult> GetPDFReport()
    {
        string reportName = "YourReport";
        IDictionary<string, object> parameters = new Dictionary<string, object>();
        parameters.Add("companyId", "2");
        parameters.Add("customerId", "123");
        string languageCode = "en-us";

        byte[] reportContent = await this.RenderReport(reportName, parameters, languageCode, "PDF");

        Stream stream = new MemoryStream(reportContent);

        return new FileStreamResult(stream, "application/pdf");

    }

    /// <summary>
    /// </summary>
    /// <param name="reportName">
    ///  report name.
    /// </param>
    /// <param name="parameters">report's required parameters</param>
    /// <param name="exportFormat">value = "PDF" or "EXCEL". By default it is pdf.</param>
    /// <param name="languageCode">
    ///   value = 'en-us', 'fr-ca', 'es-us', 'zh-chs'. 
    /// </param>
    /// <returns></returns>
    private async Task<byte[]> RenderReport(string reportName, IDictionary<string, object> parameters,  string languageCode, string exportFormat)
    {
        //
        // SSRS report path. Note: Need to include parent folder directory and report name.
        // Such as value = "/[report folder]/[report name]".
        //
        string reportPath = string.Format("{0}{1}", ConfigSettings.ReportingServiceReportFolder, reportName);

        //
        // Binding setup, since ASP.NET Core apps don't use a web.config file
        //
        var binding = new BasicHttpBinding(BasicHttpSecurityMode.TransportCredentialOnly);
        binding.Security.Transport.ClientCredentialType = HttpClientCredentialType.Ntlm;
        binding.MaxReceivedMessageSize = this.ConfigSettings.ReportingServiceReportMaxSize; //It is 10MB size limit on response to allow for larger PDFs

        //Create the execution service SOAP Client
        ReportExecutionServiceSoapClient reportClient = new ReportExecutionServiceSoapClient(binding, new EndpointAddress(this.ConfigSettings.ReportingServiceUrl));

        //Setup access credentials. Here use windows credentials.
        var clientCredentials = new NetworkCredential(this.ConfigSettings.ReportingServiceUserAccount, this.ConfigSettings.ReportingServiceUserAccountPassword, this.ConfigSettings.ReportingServiceUserAccountDomain);
        reportClient.ClientCredentials.Windows.AllowedImpersonationLevel = System.Security.Principal.TokenImpersonationLevel.Impersonation;
        reportClient.ClientCredentials.Windows.ClientCredential = clientCredentials;

        //This handles the problem of "Missing session identifier"
        reportClient.Endpoint.EndpointBehaviors.Add(new ReportingServiceEndPointBehavior());

        string historyID = null ;
        TrustedUserHeader trustedUserHeader = new TrustedUserHeader();
        ExecutionHeader execHeader = new ExecutionHeader();

        trustedUserHeader.UserName = clientCredentials.UserName;

        //
        // Load the report
        //
        var taskLoadReport = await reportClient.LoadReportAsync(trustedUserHeader, reportPath, historyID);
        // Fixed the exception of "session identifier is missing".
        execHeader.ExecutionID = taskLoadReport.executionInfo.ExecutionID;

         //
         //Set the parameteres asked for by the report
         //
         ParameterValue[] reportParameters = null;
        if (parameters != null && parameters.Count > 0)
        {
            reportParameters = taskLoadReport.executionInfo.Parameters.Where(x => parameters.ContainsKey(x.Name)).Select(x => new ParameterValue() { Name = x.Name, Value = parameters[x.Name].ToString() }).ToArray();
        }

        await reportClient.SetExecutionParametersAsync(execHeader, trustedUserHeader, reportParameters, languageCode);
        // run the report
        const string deviceInfo = @"<DeviceInfo><Toolbar>False</Toolbar></DeviceInfo>";

        var response = await reportClient.RenderAsync(new RenderRequest(execHeader, trustedUserHeader, exportFormat ?? "PDF", deviceInfo));

        //spit out the result
        return response.Result;
    }



/// <summary>
///  Work for reporting service.
/// </summary>
public class ReportingServiceEndPointBehavior : IEndpointBehavior
{
    public void AddBindingParameters(ServiceEndpoint endpoint, BindingParameterCollection bindingParameters) { }

    public void ApplyClientBehavior(ServiceEndpoint endpoint, ClientRuntime clientRuntime)
    {
        clientRuntime.ClientMessageInspectors.Add(new ReportingServiceExecutionInspector());
    }

    public void ApplyDispatchBehavior(ServiceEndpoint endpoint, EndpointDispatcher endpointDispatcher) { }

    public void Validate(ServiceEndpoint endpoint) { }
}

public class ReportingServiceExecutionInspector : IClientMessageInspector
{
    private MessageHeaders headers;

    public void AfterReceiveReply(ref Message reply, object correlationState)
    {
        var index = reply.Headers.FindHeader("ExecutionHeader", "http://schemas.microsoft.com/sqlserver/2005/06/30/reporting/reportingservices");
        if (index >= 0 && headers == null)
        {
            headers = new MessageHeaders(MessageVersion.Soap11);
            headers.CopyHeaderFrom(reply, reply.Headers.FindHeader("ExecutionHeader", "http://schemas.microsoft.com/sqlserver/2005/06/30/reporting/reportingservices"));
        }
    }

    public object BeforeSendRequest(ref Message request, IClientChannel channel)
    {
        if (headers != null)
            request.Headers.CopyHeadersFrom(headers);

        return Guid.NewGuid(); //https://msdn.microsoft.com/en-us/library/system.servicemodel.dispatcher.iclientmessageinspector.beforesendrequest(v=vs.110).aspx#Anchor_0
    }
}