How to export a report from Telerik Report Server via .NET Client

Environment

Product

Progress® Telerik® Report Server

Description

Telerik Report Server provides a REST API which can be used to consume resources from an external application. How to communicate with the REST API using a JavaScript client is demonstrated in:

• Login

• Resources

• Export

The purpose of this article is to provide a demonstration of the same functionality but using a .NET client.

Solution

The same JavaScript client can be written as a .NET client that executes requests and handles their responses. The following example illustrates how to send requests to the Report Server API and ultimately export a report to a report document.

C#

using Newtonsoft.Json.Linq;
using System;
using System.Collections.Generic;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Threading.Tasks;

namespace GetAndExportReportFromRSWebApi
{
    class Program
    {
        static readonly string reportServerUrl = "http://localhost:83/";
        static readonly string reportServerApiUrl = reportServerUrl + "api/reportserver/";
        static readonly string username = "yourUsername";
        static readonly string password = "yourPassword";

        static void Main(string[] args)
        {
            var reportName = "Dashboard";
            var parameters = new { ReportYear = 2004 };
            var format = "PDF";

            CreateAndDownloadReportDocument(reportName, parameters, format).Wait();
        }

        static async Task CreateAndDownloadReportDocument(string reportName, object parameters, string format)
        {
            using (var client = new HttpClient())
            {
                client.BaseAddress = new Uri(reportServerApiUrl);
                client.DefaultRequestHeaders.Accept.Clear();
                client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

                // Authenticate via OAuth 2.0 Password Grant.
                var authToken = GetAuthenticationToken(client, username, password);
                client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", authToken);

                // List all reports.
                var reports = await GetAllReports(client, reportServerApiUrl);

                // Render the desired report.
                var report = reports.Find(r => r["Name"].Equals(reportName))["Id"];
                var documentUrl = await CreateDocument(client, reportServerApiUrl, format, report, parameters);

                // Download the created document.
                var downloadPath = DownloadDocument(documentUrl, reportName, false);

                // Open the document.
                System.Diagnostics.Process.Start(downloadPath);
            }
        }

        static string GetAuthenticationToken(HttpClient client, string usernameInput, string passwordInput)
        {
            var data = new FormUrlEncodedContent(new[]
            {
                new KeyValuePair<string, string>("grant_type", "password"),
                new KeyValuePair<string, string>("username", usernameInput),
                new KeyValuePair<string, string>("password", passwordInput)
            });

            // POST Token
                var response = client.PostAsync(reportServerUrl + "Token", data).Result;
                response.EnsureSuccessStatusCode();

                var result = response.Content.ReadAsStringAsync().Result;
                var token = JObject.Parse(result).SelectToken("access_token").ToString();

                return token;
            }

            static async Task<List<Dictionary<string, string>>> GetAllReports(HttpClient client, string apiUrl)
            {
                // GET api/reportserver/reports
                var response = await client.GetAsync(apiUrl + "reports");

                if (response.IsSuccessStatusCode)
                {
                    return await response.Content.ReadAsAsync<List<Dictionary<string, string>>>();
                }

                return null;
            }

            static async Task<string> CreateDocument(HttpClient client, string apiUrl, string format, string reportId, object parameterValues)
            {
                var data = new { ReportId = reportId, Format = format, ParameterValues = parameterValues };
                // POST api/reportserver/documents
                var response = await client.PostAsJsonAsync(apiUrl + "documents", data);
                response.EnsureSuccessStatusCode();

                var documentUrl = response.Headers.Location;

                return documentUrl.ToString();
            }

            static string DownloadDocument(string url, string reportName, bool asAttachment)
            {
                var queryString = asAttachment ? "?content-disposition=attachment" : "";
                var fileName = reportName + ".pdf";
                var folderName = System.IO.Path.GetTempPath();
                var filePath = System.IO.Path.Combine(folderName, fileName);

                using (var webClient = new System.Net.WebClient())
                {
                    webClient.DownloadFile(url + queryString, filePath);
                }

                return filePath;
            }
        }
    }