Fetch data from JSON with powershell - json

Question

I have without success tried to figure out how to most efficiently fetch data with powershell from the below JSON that is returned to me by a REST API:
{
"$schema": "api:standardResponse",
"links": [
{
"rel": "canonical",
"href": "http://localhost:8501/services/v2/replicats",
"mediaType": "application/json"
},
{
"rel": "self",
"href": "http://localhost:8501/services/v2/replicats",
"mediaType": "application/json"
},
{
"rel": "describedby",
"href": "http://localhost:8501/services/v2/metadata-catalog/replicats",
"mediaType": "application/schema+json"
}
],
"messages": [],
"response": {
"$schema": "ogg:collection",
"items": [
{
"links": [
{
"rel": "parent",
"href": "http://localhost:8501/services/v2/replicats",
"mediaType": "application/json"
},
{
"rel": "canonical",
"href": "http://localhost:8501/services/v2/replicats/RNIMDA00",
"mediaType": "application/json"
}
],
"$schema": "ogg:collectionItem",
"name": "RNIMDA00"
},
{
"links": [
{
"rel": "parent",
"href": "http://localhost:8501/services/v2/replicats",
"mediaType": "application/json"
},
{
"rel": "canonical",
"href": "http://localhost:8501/services/v2/replicats/RNIMDA01",
"mediaType": "application/json"
}
],
"$schema": "ogg:collectionItem",
"name": "RNIMDA01"
},
{
"links": [
{
"rel": "parent",
"href": "http://localhost:8501/services/v2/replicats",
"mediaType": "application/json"
},
{
"rel": "canonical",
"href": "http://localhost:8501/services/v2/replicats/RNIMDA02",
"mediaType": "application/json"
}
],
"$schema": "ogg:collectionItem",
"name": "RNIMDA02"
}
]
}
}
I only need the data from the "name": node, and the data from the "href": node.
I have done some searching and found som examples where the JSON is converted with ConvertFrom-Json and then iterated with a foreach like the pseudo code below:
$users = $response | ConvertFrom-Json
foreach ($user in $users)
{
write-host "$($user.name) has the email: $($user.email)"
}
But I wonder if there is a better way of fetching data with powershell from a object that contains JSON.
Thanks :)

Answer 1

It is not really clear what your desired output should be.
Let's assume you have the JSON data converted in a variable $json using $json = $response | ConvertFrom-Json
Then if you do:
$json.response.items | Select-Object name, #{Name = 'href'; Expression = {$_.links.href}}
You will get objects with a name and a href property, where the href will be an array.
PowerShell would output this on screen as
name href
---- ----
RNIMDA00 {http://localhost:8501/services/v2/replicats, http://localhost:8501/services/v2/replicats/RNIMDA00}
RNIMDA01 {http://localhost:8501/services/v2/replicats, http://localhost:8501/services/v2/replicats/RNIMDA01}
RNIMDA02 {http://localhost:8501/services/v2/replicats, http://localhost:8501/services/v2/replicats/RNIMDA02}
If however you would like to return an object for each of the href values inside the links nodes you can do:
$json.response.items | ForEach-Object {
$name = $_.name
foreach ($link in $_.links) {
[PsCustomObject]#{
name = $name
href = $link.href
}
}
}
which will output
name href
---- ----
RNIMDA00 http://localhost:8501/services/v2/replicats
RNIMDA00 http://localhost:8501/services/v2/replicats/RNIMDA00
RNIMDA01 http://localhost:8501/services/v2/replicats
RNIMDA01 http://localhost:8501/services/v2/replicats/RNIMDA01
RNIMDA02 http://localhost:8501/services/v2/replicats
RNIMDA02 http://localhost:8501/services/v2/replicats/RNIMDA02

Answer 2

jq is what you need.
Just install the windows version, add it to your PATH (depending on how you installed it) and use the following command:
curl -s "https://your-url" | jq -r '.response.items.links.href'