Google Drive API: Uploading & Downloading Files

Cloud Storage Access through API - ASP.NET MVC 5 - C# (Part-2) 

Google Drive API v3 -  a) File Uploading, 
                                       b) Viewing  
                                       c) Downloading &
                                       d) Deleting                        

Suggested Video:  1) Google Drive API - Enable for Application. 

                                2) Google Drive API - File Upload, View, Download & Delete 
                                   3) Google Drive API - Create folder, Upload file to folder, Show folder Contain. 
                                   4) Google Drive API - Move & Copy files between folders.
                                   5) Google Drive API - Manage Share & Set User Role Permissions.
                                   6) Google Drive API - View Share Users Permission Details.

This Video:  Click here 
Source Code:  Click to download [10.4 MB]

In Part-1 of this video series we have seen "How to Enable Google Drive API v3 for your application". After enabling API, a JSON(JavaScript Object Notation) file (client_secret.json) provided by Google. The contains of this files are clients information. 

These are some keys & its value  a) client id, 
                                                     b) client secret id, 
                                                     c) project_id
                                                     d) auth_uri,
                                                     e) token_uri
                                                     f) redirect_uris

The key & value information are extremely useful for every time your application communication with Google Drive APIs. 

A) Attach client secret Json file:
Please copy this downloaded client_secret.json file & paste into any path of your hard disk: 
In my case: D:\  

Now, Go to the Visual Studio 2013 or Higher version:

Step 1: First Create an Empty MVC Project. Name of the project: GoogleDriveRestAPI_v3
Step 2: Opening the NuGet Package Manager Console, Select the package source and run this following command. 

Step 3 (Model): 
Create a model class (Name: GoogleDriveFiles.cs) under the Model folder of project solution. Copy & Paste this code into this class.

namespace GoogleDriveRestAPI_v3.Models
{
    public class GoogleDriveFiles
    {
        public string Id { get; set; }
        public string Name { get; set; }
        public long? Size { get; set; }
        public long? Version { get; set; }
        public DateTime? CreatedTime { get; set; }
    }
}

B) Drive Access Permission Scope of Application:
Here, we need to get permission to our application.

DriveService.Scope.Drive: View and manage the files in your Google Drive.
DriveService.Scope.DriveAppdata: View and manage its own configuration data in your Google Drive.
DriveService.Scope.DriveFile: View and manage google drive files and folders that your are open and created with this app.

DriveService.Scope.DriveMetadata: View and manage metadata of files in your Google Drive
DriveService.Scope.Drive.MetadataReadonly: View metadata of files in your Google Drive.
DriveService.Scope.Drive.PhotosReadonly: views the photos, videos, albums in your Google Photos. 
DriveService.Scope.Drive.ReadOnly: View the files in your Google Drive.
DriveService.Scope.DriveScripts: Modify your Google apps Scripts script behavior.


Step 4 (Repository): 
After that, create an another class (Name: GoogleDriveFilesRepository.cs)  under this same Model folder. Copy & Paste this below code.

using Google.Apis.Auth.OAuth2;
using Google.Apis.Download;
using Google.Apis.Drive.v3;
using Google.Apis.Services;
using Google.Apis.Util.Store;
using System;
using System.Collections.Generic;
using System.IO;
using System.Threading;
using System.Web;

namespace GoogleDriveRestAPI_v3.Models
{
    public class GoogleDriveFilesRepository 
    {
       //defined scope.
        public static string[] Scopes = { DriveService.Scope.Drive };

         //create Drive API service.
        public static DriveService GetService()
        {
             //get Credentials from client_secret.json file 
            UserCredential credential;
            using (var stream = new FileStream( @"D:\client_secret.json", FileMode.Open, FileAccess.Read))
            {
                String FolderPath = @"D:\";
                String FilePath = Path.Combine(FolderPath, "DriveServiceCredentials.json");

                credential = GoogleWebAuthorizationBroker.AuthorizeAsync(
                    GoogleClientSecrets.Load(stream).Secrets,
                    Scopes,
                    "user",
                    CancellationToken.None,
                    new FileDataStore(FilePath, true)).Result;
            }

            //create Drive API service.
            DriveService service = new DriveService(new BaseClientService.Initializer()
            {
                HttpClientInitializer = credential,
                ApplicationName = "GoogleDriveRestAPI-v3",
            });
            return service;
        }

         //get all files from Google Drive.
        public static List<GoogleDriveFiles> GetDriveFiles()
        {
            DriveService service = GetService();
            
            // define parameters of request.
            FilesResource.ListRequest FileListRequest = service.Files.List();

            //listRequest.PageSize = 10;
            //listRequest.PageToken = 10;
            FileListRequest.Fields = "nextPageToken, files(id, name, size, version, createdTime)";

            //get file list.
            IList<Google.Apis.Drive.v3.Data.File> files = FileListRequest.Execute().Files;
            List<GoogleDriveFiles> FileList = new List<GoogleDriveFiles>();

            if (files != null && files.Count > 0)
            {
                foreach (var file in files)
                {
                    GoogleDriveFiles File = new GoogleDriveFiles {
                        Id = file.Id,
                        Name = file.Name,
                        Size = file.Size,
                        Version = file.Version,
                        CreatedTime = file.CreatedTime
                    };
                    FileList.Add(File);
                }
            }
            return FileList;
        }

       //file Upload to the Google Drive.
        public static void FileUpload(HttpPostedFileBase file)
        {
            if (file != null && file.ContentLength > 0)
            {
                DriveService service = GetService();

                string path = Path.Combine(HttpContext.Current.Server.MapPath("~/GoogleDriveFiles"),
                Path.GetFileName(file.FileName));
                file.SaveAs(path);

                var FileMetaData = new Google.Apis.Drive.v3.Data.File();
                FileMetaData.Name = Path.GetFileName(file.FileName);
                FileMetaData.MimeType = MimeMapping.GetMimeMapping(path);

                FilesResource.CreateMediaUpload request;

                using (var stream = new System.IO.FileStream(path, System.IO.FileMode.Open))
                {
                    request = service.Files.Create(FileMetaData, stream, FileMetaData.MimeType);
                    request.Fields = "id";
                    request.Upload();
                }
            }
        }

        //Download file from Google Drive by fileId.
        public static string DownloadGoogleFile(string fileId)
        {
            DriveService service = GetService();

            string FolderPath = System.Web.HttpContext.Current.Server.MapPath("/GoogleDriveFiles/");
            FilesResource.GetRequest request = service.Files.Get(fileId);

            string FileName = request.Execute().Name;
            string FilePath = System.IO.Path.Combine(FolderPath, FileName);

            MemoryStream stream1 = new MemoryStream();

            // Add a handler which will be notified on progress changes.
            // It will notify on each chunk download and when the
            // download is completed or failed.
            request.MediaDownloader.ProgressChanged += (Google.Apis.Download.IDownloadProgress progress) =>
            {
                switch (progress.Status)
                {
                    case DownloadStatus.Downloading:
                        {
                            Console.WriteLine(progress.BytesDownloaded);
                            break;
                        }
                    case DownloadStatus.Completed:
                        {
                            Console.WriteLine("Download complete.");
                            SaveStream(stream1, FilePath);
                            break;
                        }
                    case DownloadStatus.Failed:
                        {
                            Console.WriteLine("Download failed.");
                            break;
                        }
                }
            };
            request.Download(stream1);
            return FilePath;
        }

        // file save to server path
        private static void SaveStream(MemoryStream stream, string FilePath)
        {
            using (System.IO.FileStream file = new FileStream(FilePath, FileMode.Create, FileAccess.ReadWrite))
            {
                stream.WriteTo(file);
            }
        }

       //Delete file from the Google drive
        public static void DeleteFile(GoogleDriveFiles files)
        {
            DriveService service = GetService();
            try
            {
                // Initial validation.
                if (service == null)
                    throw new ArgumentNullException("service");

                if (files == null)
                    throw new ArgumentNullException(files.Id);

                // Make the request.
                service.Files.Delete(files.Id).Execute();
            }
            catch (Exception ex)
            {
                throw new Exception("Request Files.Delete failed.", ex);
            }
        }
    }
}

Step 5 (Controller): Add a controller class (HomeController.cs) under this controller folder.

                        

Copy & Paste this code this code within this controller:

using GoogleDriveRestAPI_v3.Models;
using System.IO;
using System.Web;
using System.Web.Mvc;

namespace GoogleDriveRestAPI_v3.Controllers
{
    public class HomeController : Controller
    {
        [HttpGet]
        public ActionResult GetGoogleDriveFiles()
        {
            return View(GoogleDriveFilesRepository.GetDriveFiles());
        }

        [HttpPost]
        public ActionResult DeleteFile(GoogleDriveFiles file)
        {
            GoogleDriveFilesRepository.DeleteFile(file);
            return RedirectToAction("GetGoogleDriveFiles");
        }
         
        [HttpPost]
        public ActionResult UploadFile(HttpPostedFileBase file)
        {
            GoogleDriveFilesRepository.FileUpload(file);
            return RedirectToAction("GetGoogleDriveFiles");
        }

        public void DownloadFile(string id)
        {
            string FilePath = GoogleDriveFilesRepository.DownloadGoogleFile(id);
            

            Response.ContentType = "application/zip";
            Response.AddHeader("Content-Disposition", "attachment; filename=" + Path.GetFileName(FilePath));
            Response.WriteFile(System.Web.HttpContext.Current.Server.MapPath("~/GoogleDriveFiles/" + Path.GetFileName(FilePath)));
            Response.End();
            Response.Flush();
        }
    }
}

Step 6 (View): Add a View (View Name: GetGoogleDriveFiles.cshtml) of 
GetGoogleDriveFiles action method.

@model IEnumerable<GoogleDriveRestAPI_v3.Models.GoogleDriveFiles>
@{
    ViewBag.Title = "Google Drive API v3 - ASP.NET MVC 5 [Everyday Be Coding]";
}

<h2>Google Drive API v3 - ASP.NET MVC 5 [Everyday Be Coding]</h2>
<script src="https://code.jquery.com/jquery-3.2.1.min.js"></script>

<style type="text/css">
    #header {
        width: 100%;
        background-color: #CCCCCC;
        text-align: center;
    }

    #layouttable {
        border: 0px;
        width: 100%;
        font-family: 'Segoe UI';
    }

        #layouttable td.col1 {
            width: 20%;
            vertical-align: top;
        }

        #layouttable td.col2 {
            width: 60%;
            vertical-align: top;
            background-color: #E8E8E8;
        }

        #layouttable td.col3 {
            width: 20%;
            vertical-align: top;
        }
</style>

<center>
    <div style="width:80%; text-align:left;">
        @using (Html.BeginForm("UploadFile", "Home", FormMethod.Post, new { enctype = "multipart/form-data" }))
        {
            <p>
                <label for="file">Upload file:</label>
                    <input type="file" name="file" id="file" />
                    <input type="submit" value="Upload"/>
            </p>
        }
    </div>

    <table class="table" border="1">
        <tr id="header">
            <th>
                @Html.DisplayNameFor(model => model.Name)
            </th>
            <th>
                @Html.DisplayNameFor(model => model.Size)
            </th>
            <th>
                @Html.DisplayNameFor(model => model.Version)
            </th>
            <th>
                @Html.DisplayNameFor(model => model.CreatedTime)
            </th>
            <th>
                Download
            </th>
            <th>
                Delete
            </th>
        </tr>

        @if (Model.Count() > 0)
        { 
         foreach (var item in Model)
         {
            <tr id="layouttable">
                <td>
                    @Html.DisplayFor(modelItem => item.Name)
                </td>
                <td>
                    @{ 
                        long? KiloByte = @item.Size/1024;
                        string NewSize = KiloByte + " KB";      
                     }
                   @NewSize
                </td>
                <td>
                    @Html.DisplayFor(modelItem => item.Version)
                </td>
                <td>
                    @string.Format("{0: MM/dd/yyyy}", Convert.ToDateTime(Html.DisplayFor(modelItem => item.CreatedTime).ToString()))
                </td>
                <td>
                    <input type="button" class="DownloadFile" value="Download" data-key=@item.Id style="align-content:center" />
                </td>
                <td>
                    @using (Html.BeginForm("DeleteFile", "Home", FormMethod.Post, new { enctype = "multipart/form-data" }))
                    {
                        <input type="hidden" name=Id value="@item.Id">
                        <input type="submit" class="DeleteFile" value="Delete" style="align-content:center" />
                    }

                </td>
            </tr>
        }
        }
        else
        {
            <td colspan="6">No files found</td>
        }
        
    </table>

</center>

<script>
    $(document).on('click', '.DownloadFile', function () {
        debugger;
        var fileId = $(this).attr("data-key");
        window.location.href = '/Home/DownloadFile/' + fileId;
    });
</script>

Step 7 (View): Change the default action method name 'Index' to  'GetGoogleDriveFiles'.

using System.Web.Mvc;
using System.Web.Routing;

namespace GoogleDriveRestAPI_v3
{
    public class RouteConfig
    {
        public static void RegisterRoutes(RouteCollection routes)
        {
            routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

            routes.MapRoute(
                name: "Default",
                url: "{controller}/{action}/{id}",
                defaults: new { controller = "Home", action = "GetGoogleDriveFiles", id = UrlParameter.Optional }
            );
        }
    }
}

Output :

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