28 October 2013 HttpClient, OAuth, Twitter Robert Muehsig

Die Twitter Timeline eines Nutzers über die API auszulesen ist nicht ganz so trivial wie ein RSS Feed parsen. Größte Hürde ist, dass fast alle API Aufrufe bei Twitter eine Authentifizierung erfordern. Dabei kommt OAuth zum Einsatz, welches selbst nicht ganz so einfach zu verstehen ist. Aber der Reihe nach…

Zusätzlich nutzen wir den “neuen” HttpClient der mit .NET 4.5 integriert wurde.

Twitter API – App mit Secret und Consumer Key wird benötigt

imageDie REST API von Twitter ist mehr oder minder gut dokumentiert und bei fast allen API Aufrufen findet man den Hinweis dass eine Authentifizierung benötigt wird.

Für die Authentifizierung benötigt man eine App im Twitter API Universum.

 

 

 

<p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <h3><strong>Twitter API – App erstellen</strong></h3> <p>Über die API Seite kann man eine neue App erstellen und nachdem man die benötigten Daten eingegeben hat, bekommt man auch die beiden interessanten Sachen zu sehen:</p> <p>&nbsp;</p> <p><a href="https://blog.codeinside.eu/assets/wp-images-de/image1932.png"><img title="image" style="border-top: 0px; border-right: 0px; background-image: none; border-bottom: 0px; padding-top: 0px; padding-left: 0px; border-left: 0px; display: inline; padding-right: 0px" border="0" alt="image" src="https://blog.codeinside.eu/assets/wp-images-de/image_thumb1069.png" width="551" height="469"></a></p> <p>&nbsp;</p> <p>Der Consumer Key und das Secret sollte “geheim” bleiben – da ich die App direkt im Anschluss wieder lösche ist dies aber kein Problem.</p> <h3><strong>Ab zum Code…</strong></h3> <p>Es gibt eine ganze Reihe von .NET Bibliotheken zum <a href="http://www.nuget.org/packages?q=twitter">Thema Twitter auf NuGet</a>, aber wir nutzen die “pure” Variante über den HttpClient.</p> <p>In dem Beispiel wollen wir die Tweets von <a href="https://twitter.com/robert0muehsig">meinem Twitter Profil</a> abrufen. Dafür müssen wir erst bei Twitter anmelden und dann <a href="https://dev.twitter.com/docs/api/1.1/get/statuses/user_timeline">gegen diesen REST Service eine Anfrage stellen</a>.</p> <div id="codeSnippetWrapper" style="overflow: auto; cursor: text; font-size: 8pt; border-top: silver 1px solid; font-family: 'Courier New', courier, monospace; border-right: silver 1px solid; width: 97.5%; border-bottom: silver 1px solid; padding-bottom: 4px; direction: ltr; text-align: left; padding-top: 4px; padding-left: 4px; margin: 20px 0px 10px; border-left: silver 1px solid; line-height: 12pt; padding-right: 4px; max-height: 200px; background-color: #f4f4f4"> <div id="codeSnippet" style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum1" style="color: #606060">   1:</span> <span style="color: #0000ff">class</span> Program</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum2" style="color: #606060">   2:</span>     {</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum3" style="color: #606060">   3:</span>         <span style="color: #0000ff">public</span> <span style="color: #0000ff">static</span> <span style="color: #0000ff">string</span> oAuthConsumerKey = <span style="color: #006080">"9jD2zxpqPF3zHRLnMek7Q"</span>;</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum4" style="color: #606060">   4:</span>         <span style="color: #0000ff">public</span> <span style="color: #0000ff">static</span> <span style="color: #0000ff">string</span> oAuthConsumerSecret = <span style="color: #006080">"yYSC6bRm50n2vvZOuVlSWtbk9B8lNImzjazyl5eYM"</span>;</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum5" style="color: #606060">   5:</span>         <span style="color: #0000ff">public</span> <span style="color: #0000ff">static</span> <span style="color: #0000ff">string</span> oAuthUrl = <span style="color: #006080">"https://api.twitter.com/oauth2/token"</span>;</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum6" style="color: #606060">   6:</span>         <span style="color: #0000ff">public</span> <span style="color: #0000ff">static</span> <span style="color: #0000ff">string</span> screenname = <span style="color: #006080">"robert0muehsig"</span>;</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum7" style="color: #606060">   7:</span>&nbsp; </pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum8" style="color: #606060">   8:</span>         <span style="color: #0000ff">public</span> <span style="color: #0000ff">static</span> async Task&lt;<span style="color: #0000ff">string</span>&gt; GetTwitterAccessToken()</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum9" style="color: #606060">   9:</span>         {</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum10" style="color: #606060">  10:</span>             var client = <span style="color: #0000ff">new</span> HttpClient();</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum11" style="color: #606060">  11:</span>&nbsp; </pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum12" style="color: #606060">  12:</span>             var authHeaderParameter = Convert.ToBase64String(Encoding.UTF8.GetBytes(Uri.EscapeDataString(oAuthConsumerKey) + <span style="color: #006080">":"</span> +</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum13" style="color: #606060">  13:</span>                                                              Uri.EscapeDataString((oAuthConsumerSecret))));</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum14" style="color: #606060">  14:</span>&nbsp; </pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum15" style="color: #606060">  15:</span>             var postBody = <span style="color: #006080">"grant_type=client_credentials"</span>;</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum16" style="color: #606060">  16:</span>&nbsp; </pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum17" style="color: #606060">  17:</span>             client.DefaultRequestHeaders.Authorization = <span style="color: #0000ff">new</span> AuthenticationHeaderValue(<span style="color: #006080">"Basic"</span>, authHeaderParameter);</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum18" style="color: #606060">  18:</span>&nbsp; </pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum19" style="color: #606060">  19:</span>             var response = await client.PostAsync(oAuthUrl, <span style="color: #0000ff">new</span> StringContent(postBody, Encoding.UTF8, <span style="color: #006080">"application/x-www-form-urlencoded"</span>));</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum20" style="color: #606060">  20:</span>&nbsp; </pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum21" style="color: #606060">  21:</span>             response.EnsureSuccessStatusCode();</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum22" style="color: #606060">  22:</span>&nbsp; </pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum23" style="color: #606060">  23:</span>             <span style="color: #0000ff">string</span> oauthtoken = await response.Content.ReadAsStringAsync();</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum24" style="color: #606060">  24:</span>             var jToken = JToken.Parse(oauthtoken);</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum25" style="color: #606060">  25:</span>             var accessToken = jToken.SelectToken(<span style="color: #006080">"access_token"</span>);</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum26" style="color: #606060">  26:</span>&nbsp; </pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum27" style="color: #606060">  27:</span>             <span style="color: #0000ff">return</span> accessToken.Value&lt;<span style="color: #0000ff">string</span>&gt;();</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum28" style="color: #606060">  28:</span>         }</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum29" style="color: #606060">  29:</span>&nbsp; </pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum30" style="color: #606060">  30:</span>         <span style="color: #0000ff">public</span> <span style="color: #0000ff">static</span> async Task&lt;IEnumerable&lt;<span style="color: #0000ff">string</span>&gt;&gt; GetTwitterTimeline(<span style="color: #0000ff">string</span> oauthToken)</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum31" style="color: #606060">  31:</span>         {</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum32" style="color: #606060">  32:</span>             var client = <span style="color: #0000ff">new</span> HttpClient();</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum33" style="color: #606060">  33:</span>&nbsp; </pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum34" style="color: #606060">  34:</span>             var timelineFormat = <span style="color: #006080">"https://api.twitter.com/1.1/statuses/user_timeline.json?screen_name={0}&amp;include_rts=1&amp;exclude_replies=1&amp;count=5"</span>;</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum35" style="color: #606060">  35:</span>             var timelineUrl = <span style="color: #0000ff">string</span>.Format(timelineFormat, screenname);</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum36" style="color: #606060">  36:</span>&nbsp; </pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum37" style="color: #606060">  37:</span>             client.DefaultRequestHeaders.Authorization = <span style="color: #0000ff">new</span> AuthenticationHeaderValue(<span style="color: #006080">"Bearer"</span>, oauthToken);</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum38" style="color: #606060">  38:</span>             var response = await client.GetAsync(timelineUrl);</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum39" style="color: #606060">  39:</span>&nbsp; </pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum40" style="color: #606060">  40:</span>             response.EnsureSuccessStatusCode();</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum41" style="color: #606060">  41:</span>&nbsp; </pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum42" style="color: #606060">  42:</span>             <span style="color: #0000ff">string</span> timeline = await response.Content.ReadAsStringAsync();</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum43" style="color: #606060">  43:</span>&nbsp; </pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum44" style="color: #606060">  44:</span>             var jTimeline = JArray.Parse(timeline);</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum45" style="color: #606060">  45:</span>             var textNodes = jTimeline.Children()[<span style="color: #006080">"text"</span>];</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum46" style="color: #606060">  46:</span>&nbsp; </pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum47" style="color: #606060">  47:</span>             var textValues = textNodes.Values&lt;<span style="color: #0000ff">string</span>&gt;();</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum48" style="color: #606060">  48:</span>&nbsp; </pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum49" style="color: #606060">  49:</span>             <span style="color: #0000ff">return</span> textValues;</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum50" style="color: #606060">  50:</span>         }</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum51" style="color: #606060">  51:</span>&nbsp; </pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum52" style="color: #606060">  52:</span>         <span style="color: #0000ff">static</span> <span style="color: #0000ff">void</span> Main(<span style="color: #0000ff">string</span>[] args)</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum53" style="color: #606060">  53:</span>         {</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum54" style="color: #606060">  54:</span>             var twitterAccessToken = GetTwitterAccessToken().Result;</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum55" style="color: #606060">  55:</span>&nbsp; </pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum56" style="color: #606060">  56:</span>             var timeline = GetTwitterTimeline(twitterAccessToken).Result;</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum57" style="color: #606060">  57:</span>&nbsp; </pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum58" style="color: #606060">  58:</span>             Console.WriteLine(<span style="color: #006080">"Twitter Timeline from: "</span> + screenname);</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum59" style="color: #606060">  59:</span>             <span style="color: #0000ff">foreach</span> (var timelineItem <span style="color: #0000ff">in</span> timeline)</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum60" style="color: #606060">  60:</span>             {</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum61" style="color: #606060">  61:</span>                 Console.WriteLine(timelineItem);</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum62" style="color: #606060">  62:</span>             }</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum63" style="color: #606060">  63:</span>&nbsp; </pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: #f4f4f4"><span id="lnum64" style="color: #606060">  64:</span>             Console.ReadLine();</pre><!--CRLF--><pre style="border-top-style: none; overflow: visible; font-size: 8pt; font-family: 'Courier New', courier, monospace; width: 100%; border-bottom-style: none; color: black; padding-bottom: 0px; direction: ltr; text-align: left; padding-top: 0px; border-right-style: none; padding-left: 0px; margin: 0em; border-left-style: none; line-height: 12pt; padding-right: 0px; background-color: white"><span id="lnum65" style="color: #606060">  65:</span>         }</pre><!--CRLF--></div></div>

Im ersten Schritt holen wir den AccessToken von Twitter. Dabei wird der Cosumer Key und das Secret im HTTP Authorization Header mit. Wir nutzen dazu noch JSON.NET, da als Antwort der Token als JSON daherkommt.

image

Danach nutzen wir den Access Token und schicken diesen als Header in den anderen Requests mit.

Anschliessend nur noch die Response parsen und fertig.

image

Ergebnis:

image

Nicht ganz einfach – aber wenn man den Dreh raus hat, ist es gar nicht so schwierig.

“Login with Twitter”?

Wer nach dem “Login with Twitter” Thema sucht, der könnte hier fündig werden.

Quellen

Der Blogpost geht auf den HttpClient näher ein. Die Antwort in diesem Stackoverflow Thread ist die Quelle des Source Codes – allerdings mit der “alten” WebClient Variante.

Happy Coding!

Den Code gibt es natürlich ebenfalls auf GitHub.


Written by Robert Muehsig

Software Developer - from Dresden, Germany, now living & working in Switzerland. Microsoft MVP & Web Geek.
Other Projects: KnowYourStack.com | ExpensiveMeeting | EinKofferVollerReisen.de

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