Introduction to the .NET client library

https://code.google.com/p/google-api-dotnet-client/

Eyal Peled peleyal@

AgendaRestHttp LayerClient ServiceService RequestMedia OAuth2PCL3rd parties

DiscoveryCode Generator

https://code.google.com/p/google-api-dotnet-client/

AgendaRestHttp LayerClient ServiceService RequestMedia OAuth2PCL3rd parties

DiscoveryCode Generator

https://code.google.com/p/google-api-dotnet-client/

Google APIs .NET REST● Representational State Transfer● Client and servers transfer resource representations

● The set of verbs in a REST APIis typically limited to “CRUD”

● See Google API Explorer for linksto all Google API Rest services

https://code.google.com/p/google-api-dotnet-client/

AgendaRest

Http LayerClient ServiceService RequestMedia OAuth2PCL3rd parties

DiscoveryCode Generator

https://code.google.com/p/google-api-dotnet-client/

Google APIs .NET Http LayerHttpClient●A simple programming interface to code against -

SendAsync, GetAsync, etc.●It uses the new Task based asynchronous methods, which

makes writing responsive and performant UI applications across all platforms a lot simpler.

●Targets Windows 7 and 8, WP, etc. See PCL●Part of .NET 4.5 (not PCL) and available for .NET 4.0

developers as a PCL (using NuGet)

https://code.google.com/p/google-api-dotnet-client/

https://code.google.com/p/google-api-dotnet-client/

Google APIs .NET Http LayerHttpClient●Message handlers as a key architectural component●Every request is passed through a chain of handlers

(derive from HttpMessageHandler)●HttpClientHandler uses

● System.Net.HttpWebRequest and

● System.Net.HttpWebResponse under the cover, and provides a great abstraction.

Google APIs .NET Http Layer

ConfigurableMessageHandler The main HTTP logic IHttpExecuteInterceptor Interceptor before request is made IHttpUnsuccessfulResponseHandler Handler for abnormal HTTP response IHttpExceptionHandler Handler for an exception during a request

https://code.google.com/p/google-api-dotnet-client/

Google APIs .NET Http Layer

ws

https://code.google.com/p/google-api-dotnet-client/

ConfigurableHttpClient

● Inherits from HttpClient● Contains the handler

Google APIs .NET Http Layer

https://code.google.com/p/google-api-dotnet-client/

HttpClientFactory

• Constructs a new HttpClient• Great for mocking using CreateHandler

(By default creates HttpClientHandler)

Google APIs .NET Http Layer

https://code.google.com/p/google-api-dotnet-client/

BackOffHandler

● Implements exception and unsuccessful response handlers

● Contains a BackOff logic

AgendaRestHttp Layer

Client ServiceService RequestMedia OAuth2PCL3rd parties

DiscoveryCode Generator

https://code.google.com/p/google-api-dotnet-client/

Google APIs .NET Client Service

https://code.google.com/p/google-api-dotnet-client/

IClientService

● Serialization● GZip support● Authenticator(Will be removed after a new Auth library will be created)

Google APIs .NET Client Service

https://code.google.com/p/google-api-dotnet-client/

BaseClientService

● Thread-safe uses Initializer● Expoenential back-off policy● Api Key● GZip Enabled● Client Factory

Google APIs .NET Client Service

Generated services inherit from BaseClientSerivce● They implement resource related properties • They contain resources and methods based on Discovery

Follow DriveService implementation in the next slide...

https://code.google.com/p/google-api-dotnet-client/

Google APIs .NET Client Service public class DriveService : Google.Apis.Services.BaseClientService { public DriveService(Google.Apis.Services.BaseClientService.Initializer initializer) : base(initializer) { about = new AboutResource(this); files = new FilesResource(this); ... }

public override string Name { get { return "drive"; } } public override string BaseUri { get { return "https://www.googleapis.com/drive/v2/"; } } public override string BasePath { get { return "drive/v2/"; } } public enum Scopes { /// <summary>View and manage the files and documents in your Google Drive</summary> [Google.Apis.Util.StringValueAttribute("https://www.googleapis.com/auth/drive")] Drive, /// <summary>View and manage its own configuration data in your Google Drive</summary> [Google.Apis.Util.StringValueAttribute("https://www.googleapis.com/auth/drive.appdata")] DriveAppdata,/// <summary>View your Google Drive apps</summary> … }

https://code.google.com/p/google-api-dotnet-client/

AgendaRestHttp LayerClient Service

Service RequestMedia OAuth2PCL3rd parties

DiscoveryCode Generator

https://code.google.com/p/google-api-dotnet-client/

Google APIs .NET Service Request

https://code.google.com/p/google-api-dotnet-client/

ClientServiceRequest

● ETag support● based TPLExecute \ ExecuteAsyncExecuteAsStream \ ExecuteAsStreamAsync

Google APIs .NET Service Request

Generated requests inherit from ClientServiceRequest● They Implement the concrete HttpMethod, RestPath, etc.● They are executed by calling to Execute (or ExecuteAsync)

Follow GetRequest (File) implementation in the next slide...

https://code.google.com/p/google-api-dotnet-client/

Google APIs .NET Service Request public class GetRequest : DriveBaseServiceRequest<Google.Apis.Drive.v2.Data.File> { public GetRequest(Google.Apis.Services.IClientService service, string fileId) : base(service) { FileId = fileId; InitParameters(); } [Google.Apis.Util.RequestParameterAttribute("fileId", Google.Apis.Util.RequestParameterType.Path)] public virtual string FileId { get; private set; }

[Google.Apis.Util.RequestParameterAttribute("projection", Google.Apis.Util.RequestParameterType.Query)] public virtual System.Nullable<ProjectionEnum> Projection { get; set; }

public override string MethodName { get { return "get"; } } public override string HttpMethod { get { return "GET"; } } public override string RestPath { get { return "files/{fileId}"; } }

… }

https://code.google.com/p/google-api-dotnet-client/

AgendaRestHttp LayerClient ServiceService Request

Media OAuth2PCL3rd parties

DiscoveryCode Generator

https://code.google.com/p/google-api-dotnet-client/

Google APIs .NET MediaResumable Media Upload

https://code.google.com/p/google-api-dotnet-client/

The protocol

● Recovery server errors● Chunk size● Progress changed event● Upload● UploadAsync

Google APIs .NET MediaMedia Downloader

https://code.google.com/p/google-api-dotnet-client/

● Chunk size● ProgressChanged event● Download● DownloadAsync

AgendaRestHttp LayerClient ServiceService RequestMedia

OAuth2PCL3rd parties

DiscoveryCode Generator

https://code.google.com/p/google-api-dotnet-client/

Google APIs .NET OAuth2

https://code.google.com/p/google-api-dotnet-client/

Google APIs .NET OAuth2

https://code.google.com/p/google-api-dotnet-client/

Google OAuth2 documentationGoogle API ConsoleSupport installed and web applicationsSupport service account

Current implementation ●IAuthenticator to apply authorization header to a request●Usage of DotNetOpenAuth●Implementation is in Google.Apis.Authentication.OAuth2

Google APIs .NET OAuth2

https://code.google.com/p/google-api-dotnet-client/

Roadmap● Remove DotNetOpenAuth● Create a Google.Apis.Auth PCL● Create concrete implementation for

Google.Apis.Auth.DotNet4 (installed applications) Google.Apis.Auth.Mvc4 (web applications) Google.Apis.Auth.WP (Windows Phone) Google.Apis.Auth.WinRT (Windows 8 applications)

The main reason for creating a specific assembly for a platform is based on the way we read the authorization code.

AgendaRestHttp LayerClient ServiceService RequestMedia OAuth2

PCL3rd parties

DiscoveryCode Generator

https://code.google.com/p/google-api-dotnet-client/

Google APIs .NET PCLPortable Class Library

Current status● Google.Apis is PCL ● The generated APIs are PCLs as well

Roadmap● Create a Google.Apis.Auth PCL library (see OAuth slides)

https://code.google.com/p/google-api-dotnet-client/

AgendaRestHttp LayerClient ServiceService RequestMedia OAuth2PCL

3rd parties

DiscoveryCode Generator

https://code.google.com/p/google-api-dotnet-client/

Google APIs .NET 3rd partiesNuGet packages:• Newtonsoft.Json 5.0.5Json is the client's default data format• Microsoft.Net.Http 2.1.10We use HttpClient as our transport layer.• Microsoft.Bcl.Async 1.10.16Although we target .NET 4.0 we use async-await• Zlib.Portable 1.9.2While GZip is enabled, we use this library to encode messages

• log4netThe library's logging framework

https://code.google.com/p/google-api-dotnet-client/

AgendaRestHttp LayerClient ServiceService RequestMedia OAuth2PCL3rd parties

DiscoveryCode Generator

https://code.google.com/p/google-api-dotnet-client/

Google APIs .NET Discovery

● Each Google API service exposes a discovery doc using the json format (e.g. https://www.googleapis.com/discovery/v1/apis/drive/v2/rest)

● The service generator generates a service, resources, models and requests by this doc

● Similar to wsdl● Read more about Discovery API here

https://code.google.com/p/google-api-dotnet-client/

AgendaRestHttp LayerClient ServiceService RequestMedia OAuth2PCL3rd parties

Discovery

Code Generator

https://code.google.com/p/google-api-dotnet-client/

Google APIs .NET Code Generator

https://code.google.com/p/google-api-dotnet-client/

● From 1.5.0-beta we use Google APIs client generator (which is available here)

● The .NET specific templates for 1.5.0-beta are available here.

● The decision to move to Google APIs client generator was based on the following: Share logic with other Google APIs client libraries It is easier to use Django templates It reduces library code significantly One step forward supporting End Points

Resources• code.google.com - WIKI• Google API .NET Announcements blog• StackOverflow google-api-dotnet-client tag• Google Group

• Google API Explorer• Google API Console

https://code.google.com/p/google-api-dotnet-client/

Questions?

https://code.google.com/p/google-api-dotnet-client/