How to do a webrequest with JSON Body containing arrays or lists?

Question

The Situation

I need to interact with a REST API which requires JSON post data. So I started working with something like this:

Simple working example

$ReqURI = 'http://httpbin.org/post'
Invoke-WebRequest -Method Post -Uri $ReqURI -Body @{
    'api.token' = "api.token"
    'action' = 'create item'
} -Verbose| fl *

So I tested it with httpbin.org:

Issue

But If you need to use a list or array in the body part like this example:

$ReqURI = 'http://httpbin.org/post'
$Response = Invoke-RestMethod -Method Post -Uri $ReqURI -Body @{
    'api.token' = "api.token"
    'names' = @('rJENK', 'rFOOBAR')
} -Verbose| fl *
$Response

... you get something like a converting error:

So I thought I could convert the body myself into a JSON string and using the -Depth parameter from ConvertTo-JSON. In addition to that I tried how it looks like if I convert the hashtable into an object first.

But both tries return the same and even worse result:

So finally I switched to Invoke-WebRequest. But the results here are the same.

My reference is a working api call with the JSON string:

"api.token" : "fooobar",
"names": [
    "rJENK",
    "rFOOBAR"
  ]

Personal Solution

I figured out a workaround. It seems like the api I'm working with can't handle requests containing nested elements or array created by PowerShell.

Non working example:

$ReqURI = 'http://httpbin.org/post'
$Response = Invoke-RestMethod -Method Post -Uri $ReqURI -Body @{
    'api.token' = "api.token"
    'names' = @('rJENK', 'rFOOBAR')
} -Verbose| fl *
$Response

Instead I had to fake an array with indexes. That's the workaround:

$ReqURI = 'http://httpbin.org/post'
$Response = Invoke-RestMethod -Method Post -Uri $ReqURI -Body @{
    'api.token' = "api.token"
    'names[0]' = 'rJENK'
    'names[1]' = 'rFOOBAR'
} -Verbose| fl *
$Response

Answer 1

So now you have to use the content type as Application/Json like:

$ReqURI = 'http://httpbin.org/post'

$Jsonbody= @{
    'api.token' = "api.token"
    'names' = @('rJENK', 'rFOOBAR')
        } | ConvertTo-Json

$Response = Invoke-RestMethod -Method Post -ContentType 'application/json' -Uri $ReqURI -Body $body -Verbose| fl *

This should do your work. Hope it helps.