AllowViewPermission.ps1

$env:API_TOKEN = "<replace>" # from https://ci.appveyor.com/api-token
$env:APPVEYOR_ACCOUNT_NAME = "<replace>" # from AppVeyor project URL
$env:APPVEYOR_PROJECT_SLUG = "<replace>" # from AppVeyor project URL
$env:ROLE_NAME = "<replace>" # role to update permissions

$API_URL = "https://ci.appveyor.com/api/projects/$env:APPVEYOR_ACCOUNT_NAME/$env:APPVEYOR_PROJECT_SLUG/settings"

$headers = @{
  "Authorization" = "Bearer $env:API_TOKEN"
  "Content-type" = "application/json"
}

# get variables collection from server
$s = Invoke-RestMethod -Uri $API_URL -Headers $headers  -Method Get
$rights = (($s.settings.securityDescriptor.roleAces | ? {$_.name -eq $env:ROLE_NAME}).accessRights | ? {$_.name -eq "View"})
if ($rights.allowed -ne $null) {$rights.allowed = $true} else {$rights | Add-Member "allowed" $true}

Invoke-RestMethod -Uri 'https://ci.appveyor.com/api/projects' -Headers $headers  -Body ($s.settings | ConvertTo-Json -Depth 10) -Method Put