System.web name space does not exist error

Question

I am trying to use Gmail API for windows phone 8.1 app.This is the code which I got from https://developers.google.com/gmail/api/quickstart/quickstart-cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Web;
using System.Web.Compilation;
using System.Text;
using System.Text.RegularExpressions;
using System.Web.Routing;
using System.Web.SessionState;

using Newtonsoft.Json;

// TODO(class) Reorder, this gets messy with alt+shift+F10
using Google.Apis.Auth.OAuth2;
using Google.Apis.Services;
using Google.Apis.Util;
using Google.Apis.Gmail;
using Google.Apis.Gmail.v1;
using Google.Apis.Gmail.v1.Data;
using Google.Apis.Oauth2;
using Google.Apis.Oauth2.v2;
using Google.Apis.Oauth2.v2.Data;
using Google.Apis.Plus.v1;
using Google.Apis.Auth.OAuth2.Responses;
using Google.Apis.Auth.OAuth2.Flows;
using System.Threading;

namespace GmailQuickstart
{
    /// <summary>
    ///  This is a minimal implementation of GMail demonstrating:
    ///  - Using the Google+ Sign-In button to get an OAuth 2.0 refresh token.
    ///  - Exchanging the refresh token for an access token.
    ///  - Making GMail API requests with the access token, including
    ///    getting a list GMail threads.
    ///  - Disconnecting the app from the user's Google account and revoking
    ///    tokens.
    /// </summary>
    /// @author class@google.com (Gus Class)
    public class Signin : IHttpHandler, IRequiresSessionState, IRouteHandler
    {
        // These come from the APIs console:
        //   https://code.google.com/apis/console
        public static ClientSecrets secrets = new ClientSecrets()
        {
            ClientId = "YOUR_CLIENT_ID",
            ClientSecret = "YOUR_CLIENT_SECRET"
        };

        // Configuration that you probably don't need to change.
        static public string APP_NAME = "GMail .NET Quickstart";

        // Stores token response info such as the access token and refresh token.
        private TokenResponse token; 

        // Used to peform API calls against Google APIs.
        private PlusService ps = null;
        private GmailService gs = null;

        /// <summary>Processes the request based on the path.</summary>
        /// <param name="context">Contains the request and response.</param>
        public void ProcessRequest(HttpContext context)
        {
            // Redirect base path to signin.
            if (context.Request.Path.EndsWith("/"))
            {
                context.Response.RedirectPermanent("signin.ashx");
            }


            // This is reached when the root document is passed. Return HTML
            // using index.html as a template.
            if (context.Request.Path.EndsWith("/signin.ashx"))
            {
                String state = (String)context.Session["state"];

                // Store a random string in the session for verifying
                // the responses in our OAuth2 flow.
                if (state == null)
                {
                    Random random = new Random((int)DateTime.Now.Ticks);
                    StringBuilder builder = new StringBuilder();
                    for (int i = 0; i < 13; i++)
                    {
                        builder.Append(Convert.ToChar(
                                Convert.ToInt32(Math.Floor(
                                        26 * random.NextDouble() + 65))));
                    }
                    state = builder.ToString();
                    context.Session["state"] = state;
                }

                // Render the templated HTML.
                String templatedHTML = File.ReadAllText(
                     context.Server.MapPath("index.html"));
                templatedHTML = Regex.Replace(templatedHTML,
                    "[{]{2}\\s*APPLICATION_NAME\\s*[}]{2}", APP_NAME);
                templatedHTML = Regex.Replace(templatedHTML,
                    "[{]{2}\\s*CLIENT_ID\\s*[}]{2}", secrets.ClientId);
                templatedHTML = Regex.Replace(templatedHTML,
                    "[{]{2}\\s*STATE\\s*[}]{2}", state);

                context.Response.ContentType = "text/html";
                context.Response.Write(templatedHTML);
                return;
            }

            if (context.Session["authState"] == null)
            {
                // The connect action exchanges a code from the sign-in button,
                // verifies it, and creates OAuth2 credentials.
                if (context.Request.Path.Contains("/connect"))
                {
                    // Get the code from the request POST body.
                    StreamReader sr = new StreamReader(
                        context.Request.InputStream);
                    string code = sr.ReadToEnd();

                    string state = context.Request["state"];

                    // Test that the request state matches the session state.
                    if (!state.Equals(context.Session["state"]))
                    {
                        context.Response.StatusCode = 401;
                        return;
                    }

                    // Use the code exchange flow to get an access and refresh token.
                    IAuthorizationCodeFlow flow =
                        new GoogleAuthorizationCodeFlow(new GoogleAuthorizationCodeFlow.Initializer
                        {
                            ClientSecrets = secrets,
                            Scopes = new string[] { PlusService.Scope.PlusLogin, GmailService.Scope.GmailReadonly}
                        });

                    token = flow.ExchangeCodeForTokenAsync("", code, "postmessage",
                            CancellationToken.None).Result;

                    // Create an authorization state from the returned token.
                    context.Session["authState"] = token;

                    // Get tokeninfo for the access token if you want to verify.
                    Oauth2Service service = new Oauth2Service(
                        new Google.Apis.Services.BaseClientService.Initializer());
                    Oauth2Service.TokeninfoRequest request = service.Tokeninfo();
                    request.AccessToken = token.AccessToken;

                    Tokeninfo info = request.Execute();

                    string gplus_id = info.UserId;
                }
                else
                {
                    // No cached state and we are not connecting.
                    context.Response.StatusCode = 400;
                    return;
                }
            }
            else if (context.Request.Path.Contains("/connect"))
            {
                // The user is already connected and credentials are cached.
                context.Response.ContentType = "application/json";
                context.Response.StatusCode = 200;
                context.Response.Write(JsonConvert.SerializeObject("Current user is already connected."));
                return;
            }
            else
            {
                // Register the authenticator and construct the Plus service
                // for performing API calls on behalf of the user.
                token = (TokenResponse)context.Session["authState"];
                IAuthorizationCodeFlow flow =
                    new GoogleAuthorizationCodeFlow(new GoogleAuthorizationCodeFlow.Initializer
                    {
                        ClientSecrets = secrets,
                        Scopes = new string[] { PlusService.Scope.PlusLogin, GmailService.Scope.GmailReadonly }
                    });

                UserCredential credential = new UserCredential(flow, "me", token);
                bool success = credential.RefreshTokenAsync(CancellationToken.None).Result;

                token = credential.Token;
                ps = new PlusService(
                    new Google.Apis.Services.BaseClientService.Initializer()
                    {
                        ApplicationName = ".NET Quickstart",
                        HttpClientInitializer = credential
                    });

                gs = new GmailService(
                    new Google.Apis.Services.BaseClientService.Initializer()
                    {
                        ApplicationName = ".NET Quickstart",
                        HttpClientInitializer = credential
                    });
            }

            // Perform an authenticated API request to retrieve the list of
            // people that the user has made visible to the app.
            if (context.Request.Path.Contains("/mail"))
            {
                // List the GMail threads for the current user.
                IList<Google.Apis.Gmail.v1.Data.Thread> threadFeed = 
                    gs.Users.Threads.List("me").Execute().Threads;

                string jsonContent =
                    Newtonsoft.Json.JsonConvert.SerializeObject(threadFeed);
                context.Response.ContentType = "application/json";
                context.Response.Write(jsonContent);
                return;
            }

            // Disconnect the user from the application by revoking the tokens
            // and removing all locally stored data associated with the user.
            if (context.Request.Path.Contains("/disconnect"))
            {
                // Perform a get request to the token endpoint to revoke the
                // refresh token.
                token = (TokenResponse)context.Session["authState"];
                string tokenToRevoke = (token.RefreshToken  != null) ?
                    token.RefreshToken : token.AccessToken;

                WebRequest request = WebRequest.Create(
                    "https://accounts.google.com/o/oauth2/revoke?token=" +
                    token);

                WebResponse response = request.GetResponse();

                // Remove the cached credentials.
                context.Session["authState"] = null;

                // You could reset the state in the session but you must also
                // reset the state on the client.
                // context.Session["state"] = null;
                context.Response.Write(
                    response.GetResponseStream().ToString().ToCharArray());
                return;
            }
        }

        /// <summary>
        /// Implements IRouteHandler interface for mapping routes to this
        /// IHttpHandler.
        /// </summary>
        /// <param name="requestContext">Information about the request.
        /// </param>
        /// <returns></returns>
        public IHttpHandler GetHttpHandler(RequestContext
            requestContext)
        {
            var page = BuildManager.CreateInstanceFromVirtualPath
                 ("~/signin.ashx", typeof(IHttpHandler)) as IHttpHandler;
            return page;
        }

        public bool IsReusable { get { return false; } }
    }
}

So I keep getting this error System.web,System.Web.Compilation namespaces are not available.So What can I do to fix this?

Answer 1

The error is correct. System.Web is not available to Windows Phone apps (either Silverlight or Runtime). If the Gmail API depends on it then it is probably designed for the full .Net Framework and not for Windows Phone. Instead you'll need to connect directly to the Gmail web API. It looks like google has docs for it at https://developers.google.com/gmail/api/v1/reference/

See .NET API for Windows Phone for .Net classes available in WP8 Silverlight apps.