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We'll start to build our request to send to the Text Analytics API.
Text Analytics API
The Text Analytics API demo that's shown in the video (https://text-analytics-demo.azurewebsites.net/) is no longer available. The home page for the Microsoft Cognitive Services Text Analytics API (including an interactive demo) can be found at https://azure.microsoft.com/en-us/services/cognitive-services/text-analytics/.
To get started with using the Text Analytics API (including how to get your API key), follow the instructions at https://docs.microsoft.com/en-us/azure/cognitive-services/text-analytics/quick-start.
We now know how to receive
data from a web resource.
0:00
Let's learn about how to
send data to a web resource.
0:03
We'll be using another Microsoft API
called text analytics.
0:07
I've got a demo up of it here.
0:12
This web service analyzes a piece of
text for sentiment, topics and language.
0:14
All we do is send it some text.
0:19
I love C#.
0:21
And it comes back with
analysis of the text we sent.
0:28
It says our sentence is 82% positive.
0:32
I'd agree with that.
0:35
Let's see what it says If I type in
something a little less positive.
0:36
I hate lima beans.
0:41
Analyze, it detected our text
was much less positive 10%.
0:46
We can use this service to analyze the
sentiment in each of our news headlines.
0:53
Let's click on getting started.
0:58
Let's see to follow along you
need to follow the steps and
1:02
task one here in order to get an API key.
1:07
It's a different key from the one
we used earlier for a new search.
1:10
Feel free to posit video and
get your API key ready.
1:14
Okay here's task two,
says we'll need to use these headers.
1:19
We'll get back to that in a bit.
1:25
Let's see,
we're going to need two new classes.
1:29
One for our request data and
one for response data.
1:32
Here, it's telling us how
to format our request.
1:35
Let's copy and paste this into
a new class in our application.
1:39
Add class, we'll call it,
SentimentRequest.
1:44
Then, edit, Paste Special,
Paste JSON As Classes.
1:54
No, it didn't like that.
2:01
This sample has some invalid JSON,
2:05
we can use a JSON validation service
to try and figure out what's wrong.
2:08
Head to google and JSON validation
2:13
service, we'll use this one JSONLint.
2:18
Let's paste our JSON here and
then click validate.
2:23
It's got line five highlighted, but
2:29
I think the problem is
these ellipses right here.
2:31
Let's delete that and try again.
2:35
Validate, all right, valid JSON.
2:37
Let's copy this and go back over and
try to paste it into our class again.
2:42
Edit, Paste Special,
Paste JSON as Classes.
2:45
All right, let's rename Rootobject
to SentimentRequest and
2:52
we'll change this array to a list,
List documents and
2:57
I'd like to change
the properties to capitals.
3:05
And we'll need our JsonProperty again.
3:15
JsonProperty all right,
3:20
PropertyName=document.
3:27
Copy that, that's an id,
3:33
and then our text field.
3:38
Okay, now we need a class for
our response data.
3:46
We can go back and get the response JSON.
3:50
Here it is, sentiment response.
3:55
Copy and paste that, it looks like
we've got our ellipses again.
3:59
Let's use JSONLint,
take out this ellipsis and validate.
4:03
Uh-oh, think we've got an extra
comma here, good thing we checked.
4:09
Validate and valid Json.
4:16
So we'll do the same
thing back in our code,
4:20
add another class, add class,
4:25
then this is going to be
called SentimentResponse.
4:28
And one more time Paste Special,
paste JSON as classes.
4:38
All right, great.
4:42
Rename the root object
to SentimentResponse
4:45
change our array to a list.
4:50
And, we've got a little red
squiggly line right here.
4:57
I think it's because we've got
two document classes defined, and
5:03
they're conflicting.
5:06
Well there are a lot of things
we could do to fix this,
5:08
but the simplest I can think of is
to rename one of these classes.
5:10
Well the response is giving us an ID and
a score.
5:15
That's not really a document is it?
5:19
Let's rename this to sentiment and
5:21
then we'll need to change the list
up here and the name to sentiments.
5:25
Then we'll need our JSON property.
5:30
JSON property, you'll be an expert
at the quick actions by now.
5:33
And property name equals documents,
5:38
and we'll capitalize our ID and
5:44
score down here.
5:50
ID capital I, and
5:53
one more time for score, Score.
5:56
Okay, that looks good.
6:02
Now we can get our method set up to
make the request to the web service.
6:08
Since the request can have more than one
piece to analyze, we can give the method
6:13
a list of news results and then have
it return the sentiment response.
6:17
All the way down here,
public static SentimentResponse,
6:22
and we'll call it GetSentimentResponse.
6:31
It'll take a list of NewsResults,
6:36
and we'll call those newsResults.
6:39
And we'll go ahead and
var SentimentResponse=
6:46
new SentimentResponse and return it,
6:54
so that visual studio is happy.
6:59
Okay, now we'll also
need a SentimentRequest,
7:04
SentimentRequest = new SentimentRequest.
7:10
Okay but we need to add data to
this SentimentRequest object.
7:19
We can use a foreach loop to iterate
through our news results and
7:24
add data to our SentimentRequest object.
7:27
foreach(var result in
7:29
newsResults), and
then inside the foreach loop,
7:34
we'll add a new document to the list that
contains the text from each news result.
7:39
sentimentRequest.Documents.Add,we can
7:44
use object initialization here to
create an instance of a document
7:51
as we add it to the list.
7:55
New document, in a curly brace.
7:57
I can use a space here to get it.
8:02
Okay, we've got ID equals,
we'll l use the headline as the ID,
8:04
result.Headline, and then Text equals,
8:10
it should be the summary, result.Summary.
8:17
There's one thing we need to do,
8:22
we need to instantiate this Documents
to a new list of documents.
8:24
So sentimentRequest.Documents
= new list of document.
8:29
If we didn't do this and
8:38
tried to add a document to the list,
we'd end up with a runtime error.
8:39
Now we can create our web client.
8:44
We can copy and
paste from our news requests to start
8:46
But this download data isn't
the method we're going to use.
9:01
We need to send data.
9:05
There's a different method on web
client called upload data .UploadData,
9:07
we can see that it wants a byte
array in addition to the url.
9:15
I think we can handle that.
9:18
We've already got our API key header but
we'll need to insert our new API key.
9:20
Make sure to use your own, and there
was some additional headers it wanted.
9:27
Let's go back to the documentation.
9:34
I think it was up here, there they are.
9:36
We need two more content type and accept.
9:42
We saw accept earlier on
those standard headers.
9:45
We'll copy this value since it's the same
for both, head back over the code.
9:49
Okay, webClient.Headers.Add.
9:56
And we'll use this enum here, Accept and
10:04
we'll pass in the value
which is application/JSON.
10:09
And web client.headers.Add,
10:14
one more content type there
it is at the bottom and
10:18
we'll pass application/JSON.
10:23
We'll go ahead and
change this search results to response.
10:26
We're almost ready to make this request.
10:33
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