Merge pull request #536 from Icinga/feature/easier_include_exclude_filtering

Feature: Adds function for easier include/exclude filtering

Adds generic function for easier managing include/exclude filtering for plugins and for cleaning arrays with not wanted content.

doc/100-General/10-Changelog.md

@@ -21,6 +21,7 @@ Released closed milestones can be found on [GitHub](https://github.com/Icinga/ic
 * [#40](https://github.com/Icinga/icinga-powershell-framework/issues/40) Adds support to set service recovery for the Icinga Agent and Icinga for Windows service, to restart them in case of a crash or error
 * [#525](https://github.com/Icinga/icinga-powershell-framework/pull/525) Adds new developer mode for `icinga` command and improved cache handling, to ensure within `-DeveloperMode` and inside a VS Code environment, the framework cache file is never overwritten, while still all functions are loaded and imported.
 * [#531](https://github.com/Icinga/icinga-powershell-framework/pull/531) Adds `Test-IcingaStateFile` and `Repair-IcingaStateFile`, which is integrated into `Test-IcingaAgent`, to ensure the Icinga Agent state file is healthy and not corrupt, causing the Icinga Agent to fail on start
+* [#536](https://github.com/Icinga/icinga-powershell-framework/pull/536) Adds new function `Test-IcingaArrayFilter` for easier include and exclude filtering during plugin runtime and to allow filtering of array content for intended values only
 
 ## 1.9.2 (2022-06-03)
 

lib/core/tools/Test-IcingaArrayFilter.psm1

@@ -0,0 +1,112 @@
+<#
+.SYNOPSIS
+    Compares an InputObject of type [array] or [string] to a specified
+    include and exclude array filter, returning either if the filter applies
+    as true/false or an object of type [array] for filtered InputObject values
+.DESCRIPTION
+    Compares an InputObject of type [array] or [string] to a specified
+    include and exclude array filter, returning either if the filter applies
+    as true/false or an object of type [array] for filtered InputObject values.
+
+    The function is designed to work as a general filter approach for check plugins as
+    example, to ensure filtering certain values is easy. After comparing the include
+    and exclude filter, the function will return True if the input object can be included
+    and will return False in case it should not be included.
+
+    For [array] objects, the function will return a filtered [array] object on which all
+    values which should be included and excluded were evaluated and only the remaining ones
+    are returned.
+.PARAMETER InputObject
+    The object to compare the filter against. This can be of type [array] or [string].
+    Using an [array] object will return a filtered [array] result, while a [string] value
+    will return a [bool], if the filter can be applied or not
+.PARAMETER Include
+    An [array] of values to compare the InputObject against and include only certain input
+.PARAMETER Exclude
+    An [array] of values to compare the InputObject against and exclude only certain input
+.EXAMPLE
+    PS> Test-IcingaArrayFilter -InputObject @('icinga2', 'icingapowershell', 'winrm') -Exclude @('icinga2');
+
+    icingapowershell
+    winrm
+.EXAMPLE
+    PS> Test-IcingaArrayFilter -InputObject @('icinga2', 'icingapowershell', 'winrm') -Exclude @('*icinga*');
+
+    winrm
+.EXAMPLE
+    PS> Test-IcingaArrayFilter -InputObject 'icinga2' -Include @('*icinga*', 'winrm');
+
+    True
+.EXAMPLE
+    PS> Test-IcingaArrayFilter -InputObject 'icinga2' -Include @('*icinga*', 'winrm') -Exclude @('*icinga*');
+
+    False
+#>
+
+function Test-IcingaArrayFilter()
+{
+    param (
+        $InputObject    = $null,
+        [array]$Include = @(),
+        [array]$Exclude = @()
+    );
+
+    [bool]$ReturnArray = $FALSE;
+
+    if ($InputObject -Is [array]) {
+        $ReturnArray = $TRUE;
+    }
+
+    [array]$FilteredArray = @();
+
+    if ($null -eq $InputObject) {
+        if ($ReturnArray) {
+            return $InputObject;
+        }
+
+        return $FALSE;
+    }
+
+    if ($Include.Count -eq 0 -And $Exclude.Count -eq 0) {
+        if ($ReturnArray) {
+            return $InputObject;
+        }
+
+        return $TRUE;
+    }
+
+    [bool]$IncludeFound = $FALSE;
+
+    if ($ReturnArray) {
+        # Handles if our input object is an array
+        # Will return an array object instead of boolean
+        foreach ($input in $InputObject) {
+            if ((Test-IcingaArrayFilter -InputObject $input -Include $Include -Exclude $Exclude)) {
+                $FilteredArray += $input;
+            }
+        }
+
+        return $FilteredArray;
+    } else {
+        foreach ($entry in $Exclude) {
+            if (([string]$InputObject).ToLower() -Like ([string]$entry).ToLower()) {
+                return $FALSE;
+            }
+        }
+
+        if ($Include.Count -eq 0) {
+            return $TRUE;
+        }
+
+        foreach ($entry in $Include) {
+            if (([string]$InputObject).ToLower() -Like ([string]$entry).ToLower()) {
+                $IncludeFound = $TRUE;
+                break;
+            }
+        }
+
+        return $IncludeFound;
+    }
+
+    return $IncludeFound;
+}