Azure Advisor API Possible Limitations and Filter Issues - api

Question

I manage many subscriptions so the current Azure Advisor while interesting requires you to go through too many screens and there is no way to download the CSV recommendations and compile them using PowerShell. This led to attempt to interface with the API. The issue I am having is that it appears that it limits you to 200 records so changing top does nothing. Many of the records are a generic security warning with a risk of none. I attempted to filter them out but my knowledge of API filters is poor and the documentation Microsoft provides could be better. Below is the PowerShell command I am using:
Call:
$Response = Invoke-RestMethod -Uri "https://management.azure.com/subscriptions/${SubscriptionId}/providers/Microsoft.Advisor/Recommendations?api-version=2017-04-19&`$top=999&`$filter=risk -ne None" -Method GET -Headers #{"Authorization" = "$AccessToken"} -Verbose
Response:
Without Filter Parameter
https://management.azure.com/subscriptions/<SubID>/providers/microsoft.Advisor/recommendations?api-version=2017-04-19&$top=200&$s
kiptoken=<Token>
With Filter Parameter
Invoke-RestMethod -Uri "https://management.azure.com/subscriptions/${SubscriptionId}/providers/Microsoft.Advisor/Recommendations?api-version=2017-04-19&`$top=999&`$filter=risk -eq 'None'" -Method GET -Headers #{"Authorization" = "$AccessToken"} -Verbose
VERBOSE: GET https://management.azure.com/subscriptions/<sub ID>/providers/Microsoft.Advisor/Recommendations?api-version=2017-04-1
9&$top=999&$filter=risk -eq 'None' with 0-byte payload
Invoke-RestMethod : {"message":"Invalid $filter param"}
At line:1 char:13
+ $Response = Invoke-RestMethod -Uri "https://management.azure.com/subs ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (System.Net.HttpWebRequest:HttpWebRequest) [Invoke-RestMethod], WebException
+ FullyQualifiedErrorId : WebCmdletWebResponseException,Microsoft.PowerShell.Commands.InvokeRestMethodCommand

Answer 1

I have been struggling with exactly the same today, hence I found your article.
I managed to resolve my issue by using a later version of the API, and slightly changing the filter
For example:
$filter="Category eq 'Cost'"
$url = "https://management.azure.com/subscriptions/$Subscriptionid/providers/microsoft.Advisor/recommendations?api-version=2017-04-19&`$top=999&`$filter=$filter"

Answer 2

There is a mistake in your API. The right API grammar is &$filter not $filter, you could see your API, you lose a &.
The following script works for me.
##get token
$TENANTID=""
$APPID=""
$PASSWORD=""
$result=Invoke-RestMethod -Uri https://login.microsoftonline.com/$TENANTID/oauth2/token?api-version=1.0 -Method Post -Body #{"grant_type" = "client_credentials"; "resource" = "https://management.core.windows.net/"; "client_id" = "$APPID"; "client_secret" = "$PASSWORD" }
$token=$result.access_token
##set subscriptionId
$subscriptionId=""
$Headers=#{
'authorization'="Bearer $token"
'host'="management.azure.com"
'contentype'='application/json'
}
$url="https://management.azure.com/subscriptions/$subscriptionID/providers/Microsoft.Advisor/Recommendations?api-version=2017-03-31&`$top=999`&$filter=risk -eq 'None'"
Invoke-RestMethod -Uri $url -Headers $Headers -Method GET