Five great reasons to use the new HttpClient API

Peter SmithProgram Manager4-092

5 top reasons to use the new HttpClient API

Reason C++ C# JavaScript

1. Shared cache, cookies, credentials ✔2. Strongly typed headers=fewer bugs in less time

3. Access to cookies and shared cookies

4. Control over caching and shared cache

5. Inject your code modules into the processing pipeline=cleaner, more modular code

✔new!

✔ new! new!

new! ✔ new!

new! ✔ new!

new! new! new!

REST/Web Service

HttpClient(has common

send methods)

Meet the family!Your App

HttpRequestMessage

HttpResponseMessage

Http Base Protocol

Filter(has in-depth

settings)

HttpContentString • Stream • Buffer

• Multipart • FormUrlEncoded

⛭

Simple exampletry{ var uri = new Uri("http://example.com/datalist.aspx"); var httpClient = new HttpClient(); var result = await httpClient.GetStringAsync(uri);}catch (Exception e){}

Let’s see it in action!

Reason #1:

HTTP Integration: cache, cookies, credentials…

Cache, cookies, credentials are already shared between <WebView>, <Image>, <Media>, …

These shared with Windows.Web.Http, too

(but not shared across apps)

Reason #2:

Strongly typed headers: fewer bugs in less time

Pramga:no-cacheLastModified:Fri, 08 Mar 2013 19:26:00 GMTCneonction:closentCoent-Length:190946

Headers are easy to mistype

The errors are hard to spot

Even big sites make mistakes

Strongly typed headers

Host// HostName is part of the Windows.Networking namespace.var request = new HttpRequestMessage();request.Headers.Host = new HostName("contoso.com");

Content-Lengthulong len = response.Content.Headers.ContentLength.Value;byte[] buffer = new byte[len];

Last-Modified

DateTimeOffset d = response.Content.Headers.LastModified.Value;

Setting a custom header

// Add a custom header to the request.request.Headers.TryAppendWithoutValidation

("X-Requested-With", "XMLHttpRequest");

List all headers // List all the headers in the response and response.Content. foreach (var header in httpResponse.Headers) { Log (header.Key + "=" + header.Value); } foreach (var header in httpResponse.Content.Headers) { Log (header.Key + "=" + header.Value); }

Reason #3:

list, set and delete cookies

How to set a cookie var bpf = new HttpBaseProtocolFilter(); var cookieManager = bpf.CookieManager; var cookie = new HttpCookie("myCookieName", ".example.com", "/"); cookie.Value = "myValue"; cookieManager.SetCookie(cookie);

// Use this base protocol file with an HttpClient var httpClient = new HttpClient(bpf);

Let’s see it in action!

Reason #4:

Influence over the system network cache

Where did my data come from?

var httpResponse = await httpClient.GetAsync(uri); switch (httpResponse.Source) { case HttpResponseMessageSource.Cache: break; case HttpResponseMessageSource.Network: break; case HttpResponseMessageSource.None: break; }

Cache write behaviorvar bpf = new HttpBaseProtocolFilter();

// Set the WriteBehavior.bpf.CacheControl.WriteBehavior = HttpCacheWriteBehavior.Default;bpf.CacheControl.WriteBehavior = HttpCacheWriteBehavior.NoCache;

// Use the base protocol filter in an HttpClientvar hc = new HttpClient(bpf);

Cache read behaviorvar bpf = new HttpBaseProtocolFilter();

// Set the ReadBehavior.bpf.CacheControl.ReadBehavior = HttpCacheReadBehavior.Default;bpf.CacheControl.ReadBehavior = HttpCacheReadBehavior.MostRecent;bpf.CacheControl.ReadBehavior = HttpCacheReadBehavior.OnlyFromCache;

// Use the base protocol filter in an HttpClientvar hc = new HttpClient(bpf);

Reason #5:

The HTTP Processing pipeline includes your filter code

REST/Web Service

HttpClient(has common

send methods)

Remember this diagram?

Your App

HttpRequestMessage

HttpResponseMessage

Http Base Protocol

Filter(has in-depth

settings)

HttpContentString • Stream • Buffer

• Multipart • FormUrlEncoded

⛭

Auth Filter

503 Retry Filter

Metered Network Filter

REST/Web Service

HttpClient(has common

send methods)

The filter pipeline

Your App

HttpRequestMessageHttpResponseMess

age

Http Base Protocol

Filter(has in-depth

settings)

HttpContentString • Stream • Buffer

• Multipart • FormUrlEncoded

⛭

Let’s see it in action!

Filters are WinRT ComponentsThey implement Windows.Web.Http.Filters.IHttpFilterIt’s just one method: SendRequestAsync (+dispose)You put them into the filter pipelineMost pipelines end with a HttpBaseProtocolFilterEach filter sees all requests going outAnd all responses coming backAnd can modify them

Filters are for:AuthCustom cachesLoggingNetwork RestrictionsRetryTesting

IHttpFilters

REST/Web Service

Auth Filter

503 Retry Filter

Metered Network Filter

Recap

HttpClientDelete Get Post Put SendRequestAsync

DefaultRequestHeaders

Your App

HttpRequestMessage

Http Base

Protocol Filter

HttpContentString • Stream • Buffer

• Multipart • FormUrlEncoded

HttpResponseMessage

5 top reasons to use the new HttpClient API

Reason C++ C# JavaScript

1. Shared cache, cookies, credentials ✔2. Strongly typed headers=fewer bugs in less time

3. Access to cookies and shared cookies

4. Control over caching and shared cache

5. Inject your code modules into the processing pipeline=cleaner, more modular code

✔new!

✔ new! new!

new! ✔ new!

new! ✔ new!

new! new! new!

HttpProgressSSL/TLS errors/certificates (including stronger security)Streaming uploads & Streaming downloadsAdditional settings on HttpBaseProtocolFilterMake your own IHttpContent & IHttpFilter classesConfiguring the OAuth 2.0 filterServer/Proxy credentialsClient certificate

Reasons 6 and up…

HttpClient sample has lots of code and the metered network filter and the 503 retry filter

Web Authorization Broker sample has an OAuth 2.0 filter

MSDN documentation (look under Windows.Web.Http)

MSDN Windows Store apps forums

How to get started

Resources3-090: Building great service connected apps3-113: Building a great authentication experience into your app

//build/ 2011PLAT-785T: Creating connected apps that work on today’s networks

Windows app developer blogApril 10, 2013: Creating connected Windows Store apps

What to do next?Find and use filtersMake and share filtersUpdate your code to use the new classes

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