Case Study: 3
Scenario 3
Background
You are developing a video transcoding service. This service is used by customers to upload video files,
convert video to other formats, and view the converted files. This service is used by customers all over the
world.
Business Requirements
The user-facing portion of the application is an ASP.NET MVC application. It provides an interface for
administrators to upload video and schedule transcoding. It also enables administrators and users to download
the transcoded videos.
When videos are uploaded, they are populated with metadata used to identify the video. The video metadata is
gathered by only one system when the video upload is complete. Customers require support for Microsoft
Internet Explorer 7 and later. The application contains a header that is visible on every page. If thelogged-on
user is an administrator, then the header will contain links to administrative functions. This information is read
from a cookie that is set on the server. The administrative links must not be present if an error condition is
present.
Technical Requirements
User Experience:
The front-end web application enables a user to view a list of videos. The main view of the application is the
web page that displays the list of videos. HTML elements other than the list of videos are changed with every
request requiring the page to reload.
Compatibility:
Some customers use browsers that do not support the HTTP DELETE verb. These browsers send a POST
request with an HTTP header of X-Delete when the intended action is to delete.
Transcoding:
The video transcoding occurs on a set of Windows Azure worker roles. The transcoding is performed by a
third-party command line tool named transcode.exe. When the tool is installed, an Environment variable
named transcode contains the path to the utility.
A variable named license contains the license key. The license for the transcoding utility requires that it be
unregistered when it is not in use. The transcoding utility requires a significant amount of resources. A
maximum of 10 instances of the utility can be running at any one time. If an instance of the role cannot process
an additional video, it must not prevent any other roles from processing that video.
The utility logs errors to a Logs directory underthe utilities path. A local Azure directory resource named perf
is used to capture performance data.
Development:
Developers must use Microsoft Remote Desktop Protocol (RDP) to view errors generated by the transcode.
exe utility.
An x509 certificate has been created and distributed to the developers for this purpose.
Developers must be able to use only RDP and not any other administrative functions.
Application Structure



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You need to ensure that all customers can delete videos regardless of their browser capability. Which code
segment should you use as the body of the SendAsyncmethod in the DeleteHandler class?

A.
Option A

B.
Option B

C.
Option C

D.
Option D