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