Download file from sharepoint rest service

To be able to download file from SharePoint Online/Office 365 using CSOM or REST the authentication has to be performed.

About SharePoint Online authentication

Since SharePoint Online (SPO) uses claims based authentication, you could consider the following options:

• SharePointOnlineCredentials class as part of SharePoint Online Client Components SDK provides credentials to access SharePoint Online resources.

• utilize a custom implementation, for example as explained in this great article. The article contains code sample with class MsOnlineClaimsHelper class that implements claim-based authentication for SharePoint Online.

Consume SharePoint REST service using .NET

In order to consume SharePoint REST service using .NET you could consider the following approaches:

• HttpClient - Provides a base class for sending HTTP requests and receiving HTTP responses from a resource identified by a URI. (.NET Framework 4.5)
• WebClient - provides common methods for sending data to and receiving data from a resource identified by a URI. (.NET Framework 1.1)
• HttpWebRequest - provides an HTTP-specific implementation of the WebRequest class, more low-level then the previous ones (.NET Framework 1.1)

All of them allows to download a file from SharePoint Online.

Examples

Example 1. How to specify SPO credentials using SharePointOnlineCredentials class

var request = (HttpWebRequest)WebRequest.Create(endpointUri); request.Credentials = new SharePointOnlineCredentials(username, securedPassword); //... 

Example 2. How to specify SPO authentication cookies using MsOnlineClaimsHelper class:

var claimshelper = new MsOnlineClaimsHelper(webUri, userName, password); var endpointUri = new Uri(webUri,string.Format("/_api/web/getfilebyserverrelativeurl('{0}')/$value", fileUrl)); var request = (HttpWebRequest)WebRequest.Create(endpointUri); request.Headers.Add("X-FORMS_BASED_AUTH_ACCEPTED", "f"); request.Method = "GET"; request.CookieContainer = claimshelper.CookieContainer; //... 

Key points:

• SharePoint Auth cookies are passed via CookieContainer property
• According to Files and folders REST API reference the following endpoint is used to retrieve file content: <app web url>/_api//web/getfilebyserverrelativeurl('<file url>')/$value

try this one :

using System.Net; using (WebClient webClient = new WebClient ()) { webClient.DownloadFile(fileurl , filename); } 

try this one. let me know it will work or not?

HttpResponseMessage response = Request.CreateResponse(HttpStatusCode.OK); response.Content = new StreamContent(new FileStream(HttpContext.Current.Server.MapPath("~/Documents/" + documentFileName.Name), FileMode.Open, FileAccess.Read)); response.Content.Headers.ContentDisposition = new System.Net.Http.Headers.ContentDispositionHeaderValue("attachment"); response.Content.Headers.ContentDisposition.FileName = documentFileName.Name; response;