Provider Hosted App – Upload Large Files using CSOM

Now the method to upload larger files is exactly the same. We only have to use FileCreationInformation.ContentStream property instead of FileCreationInformation.Contentproperty. The whole code is present below:

var spContext = SharePointContextProvider.Current.GetSharePointContext(HttpContext, SPHostUrl);

            using (var clientContext = spContext.CreateUserClientContextForSPAppWeb())

            {

                if (clientContext != null)

                {

                    //file is uploaded file. Could be read from Request.Files

                    using (FileStream fs = new FileStream(file.FileName, FileMode.Open))

                    {

                        //code for file size > 2MB. tested upto 50MB

                        FileCreationInformation newFile = new FileCreationInformation();

                        newFile.ContentStream = fs;

                        newFile.Url = Path.GetFileName(file.FileName);

                        newFile.Overwrite = true;

                        List docs = clientContext.Web.Lists.GetByTitle("Your List Name");

                        Microsoft.SharePoint.Client.File uploadFile = docs.RootFolder.Files.Add(newFile);

                        clientContext.Load(uploadFile);

                        clientContext.ExecuteQuery();

                    }

                }

            }

In some cases, you might get a FileNotFoundException while using above code. Below is another way to use the code

  var spContext = SharePointContextProvider.Current.GetSharePointContext(HttpContext, SPHostUrl);

            using (var clientContext = spContext.CreateUserClientContextForSPAppWeb())

            {

                if (clientContext != null)

                {

                    FileCreationInformation newFile = new FileCreationInformation();

                    //here file is the selected file. In this case of type HttpPostedFileBase

                    newFile.ContentStream = file.InputStream;

                    newFile.Url = Path.GetFileName(file.FileName);

                    newFile.Overwrite = true;

                    List docs = clientContext.Web.Lists.GetByTitle("List_Name");

                    Microsoft.SharePoint.Client.File uploadFile = docs.RootFolder.Files.Add(newFile);

                    clientContext.Load(uploadFile);

                    clientContext.ExecuteQuery();

                }

            }  

Note that I replaced FileStream with the input stream present in the uploaded file itself.

Note that I have tested the above code for files upto 20 MB. Once for 20MB file size it gave me time out error (which could be fixed by setting RequestTimeout property of client context)

Hope this helps. 

reference:

https://mysharepointlearnings.wordpress.com/2014/06/30/provider-hosted-app-upload-large-files-using-csom/