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So let's go back to PowerShell. We'll first load XML data,

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then we'll look at how we load JSON data, and then we'll work

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on iterating XML and JSON data.

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So we looked previously at using variables,

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hash tables, arrays of information, but in reality,

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a lot of the data that we'll use will actually be from physical files.

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So I've just navigated to my data directory and you'll see I have a

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JSON file and some XML files that are available,

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So we're going to use this as a way of identifying data and retrieving it.

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So the first thing I want to do is obviously just

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specify my path Users\Trainer\Data,

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and that's going to be the path where the files are that we need to reside.

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Now if I want to retrieve and look at the XML data, I'm

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going to declare a variable here.

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I can say xml = and I can just use a standard Get‑Content where I pass

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a path like so and then I know my file is called module‑4.xml and I

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can just press Enter and then $xml, done,

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and I can see the information. So this gives me the countries

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with the names and the populations, etc. as we've been using

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previously, so fairly straightforward.

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Now what about if I needed to get the countries,

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for example, am I able to do this, for example. Nope.

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I have no way of accessing the various properties.

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I can retrieve the whole thing,

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but not individual values, and that's based on how we've selected the value.

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So what we can do instead is we have the path, what we can

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also do is declare what's called an xpath.

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So an xpath is effectively the structure that we wish

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to use from the XML definition.

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So, for example,

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if we, I tell you what if we just get rid of the xpath

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and just go back to XML for a second,

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you can see the xpath would be Countries Country, that

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would be the xpath that we want to go to,

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and then everything else underneath it would then come out of that.

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So if we go back here,

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we'll do $xpath = and then the way we use this is by doing

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slash, so I'm going to say Countries/Country like so. So I

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now have a path and an xpath.

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Now Microsoft provides a method called Select‑Xml.

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If I say Path,

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this is then going to be the path variable that we've got \module‑4.xml like

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so, and then we use the XPath option and I can pass my xpath to it, and then

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we can leave it as that and press Enter. Now,

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notice what happens.

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We get a really interesting thing come back. We get this node is country,

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then we get the path, and then we get a pattern, but we don't

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actually get the values back that we're expecting.

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So how do we change that? Well when we're using this type of data, we

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need to actually tell it what we'd like to get back.

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So Select‑Obj, and then we have a value called ExpandProperty and the

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one I wish to expand is the Node because remember,

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our XPath is countries and country and the nodes

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underneath it are the ones that we want.

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When we do that,

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it instantly returns the value back to us so now we have

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a list of values that come from XML.

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Now, of course,

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we can go a little bit further, there are ways of bringing other information in.

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So if we have other properties and values,

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then we can bring those values in and use them, so,

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for example,

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using attributes or other mechanisms. Now, XML has been around for a

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long time, it's not always the most up‑to‑date, one that people tend

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to use now, they like to use JSON instead.

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So let's update our path here to be the same, so Users\Trainer\Data like

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so, and what we'll do is create a JSON variable instead,

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and we'll do the same thing as before, so Get‑Content ‑Path $path\Module‑4.json,

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which is the file that we've got, and then we'll just press

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Enter and do $json, and of course we do.

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We get the JSON object listed, you can see it's got Countries, Country, Name,

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Population Validated, etc, the whole list is then provided.

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Now what PowerShell does for us is that we also have the option to

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take that same command and then say ConvertFrom Json.

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Now what difference did that make?

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Well,

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let's go back to json here and do a dot and you can see, if we go

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back, you just missed it there, Countries.Country.

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I can then start to iterate through the various

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properties that are available Now, some of them are closed,

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so I would have to use expanded properties, but when we

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use ConvertFrom‑Json, instead of it being just a static

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piece of text that comes back,

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it actually comes back as an actual JSON object so that

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we can then start to utilize that.

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Now, once we have the data stored like there,

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then we can do little things like we've done before,

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so I can say item in $json like so.

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So I'm going to say iterate through all of the JSON objects.

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I'm going to say item.Countries.Country, select Name and Population

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like so and then close that out and do Enter.

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Now, or you'll see I've got a extra one in there so let me go foreach loop,

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go back to there, it should have been a pipe command,

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not another bracket, and Enter.

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And so now because we have it as a JSON object,

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not a raw set of information that's come back, I can now

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start to use that as part of the queries.

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So that was a simple foreach statement where we're

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effectively saying for each object in the JSON,

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filter it out all the way down to country and then select the values.

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Now, of course, what you will see, let me just iterate through the fields again,

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is if I was to change this one, so let's do the for each, and if I

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got rid of country here and then did that, notice you'll get

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nothing back and that's because we haven't gone down to the lowest

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layer to be able to retrieve.

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That would need us to actually come into Select‑Object, Expand the property

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Country, then we would have to pipe that out to Select‑Object,

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and then we should be able to run.

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So depending on how far up the tree or how far you've gone up and down will

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determine whether you need to expand the various properties.

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Okay,

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so one other last thing that I'd like to talk about is really

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to do with Json, but in the real world, when you're accessing things like JSON,

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you're not necessarily calling it from a static file that someone has given you.

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So what I'm going to do here is there is a series of endpoints that

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are available for anybody to use for testing.

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So I'm going to use one of these and this is called, it's at

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swapi.dev and it's called api and people.

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Now, in order to populate the JSON from an external location,

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I'm going to use Invoke‑RestMethod and my Uri is

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going to be this uri that I created, which basically goes to API people.

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So I'm going to enter that there and then $json. If I look at it,

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you can see it's come back with some results.

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You can also,

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you can see Skywalker already so you get an idea of

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what the data is that's coming back.

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So what I can then do is do a foreach and say $item or you could

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give it a different name so like people. Now,

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when you're calling JSON from an invoke method,

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you'll always get a results object, that's normally how they're

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written so you can just call into that value.

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I can then say item and then I can just select the values

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that I want to get back, so Name, Height,

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Gender, for example, and then close that out.

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And sure enough,

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you can see that I now get a list of Star Wars characters with

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their height and their gender from an external API endpoint that

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was available and returning JSON. So not too complicated, but

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it's a real case scenario.

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There were lots of times where I've written PowerShell scripts that

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rely on an endpoint to either return XML or JSON,

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and so it's important to understand how to get those values back.

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In the worst case,

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you would always use convert from JSON on the object, so for example,

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if I say item here and then do the name,

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you can see that because it comes back as a results object, I get all of

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the values that are available to me. So you'll see one of those was films

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and it comes back with links to films to other entry points that are

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available, but I could say birth year, etc.

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So when you bring in data back from static places,

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whether it's from a database or something else,

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then convert from JSON so it can become an object that's usable. If you're calling from an API, it will probably do that for you.