🩹 [Patch]: Strong type GitHubContext properties (#204)

## Description

- Changed the types of
  - `ApiBaseUri` from `string` to `uri`
  - `TokenExpirationDate` from `string` to `datetime`
- Added `Assert-GitHubContext` call to validate the authentication type
is `App`.

## Type of change

<!-- Use the check-boxes [x] on the options that are relevant. -->

- [ ] 📖 [Docs]
- [ ] 🪲 [Fix]
- [x] 🩹 [Patch]
- [ ] ⚠️ [Security fix]
- [ ] 🚀 [Feature]
- [ ] 🌟 [Breaking change]

## Checklist

<!-- Use the check-boxes [x] on the options that are relevant. -->

- [x] I have performed a self-review of my own code
- [x] I have commented my code, particularly in hard-to-understand areas

---------

Co-authored-by: Marius Storhaug <Marius.Storhaug@dnb.no>

Author: MariusStorhaug

src/classes/public/Context/GitHubContext.ps1

@@ -1,4 +1,4 @@
-class GitHubContext : Context {
+class GitHubContext : Context {
     # The GitHub Context Name.
     # HostName/Username or HostName/AppSlug
     # github.com/Octocat
@@ -18,7 +18,7 @@
 
     # The API base URI.
     # https://api.github.com
-    [string] $ApiBaseUri
+    [uri] $ApiBaseUri
 
     # The GitHub API version.
     # 2022-11-28

src/functions/public/API/Invoke-GitHubAPI.ps1

@@ -131,7 +131,7 @@
         $headers | Remove-HashtableEntry -NullOrEmptyValues
 
         if (-not $URI) {
-            $URI = ("$ApiBaseUri/" -replace '/$', '') + ("/$ApiEndpoint" -replace '^/', '')
+            $URI = ("$ApiBaseUri" -replace '/$'), ("$ApiEndpoint" -replace '^/') -join '/'
         }
 
         $APICall = @{

src/functions/public/Apps/GitHub Apps/Get-GitHubApp.ps1

@@ -40,6 +40,7 @@
     )
 
     $Context = Resolve-GitHubContext -Context $Context
+    Assert-GitHubContext -Context $Context -AuthType App
 
     switch ($PSCmdlet.ParameterSetName) {
         'BySlug' {

src/functions/public/Apps/GitHub Apps/Get-GitHubAppInstallation.ps1

@@ -26,6 +26,7 @@
     )
 
     $Context = Resolve-GitHubContext -Context $Context
+    Assert-GitHubContext -Context $Context -AuthType App
 
     $inputObject = @{
         Context     = $Context

src/functions/public/Apps/GitHub Apps/New-GitHubAppInstallationAccessToken.ps1

@@ -66,6 +66,7 @@
     )
 
     $Context = Resolve-GitHubContext -Context $Context
+    Assert-GitHubContext -Context $Context -AuthType App
 
     $inputObject = @{
         Context     = $Context

src/functions/public/Apps/Webhooks/Get-GitHubAppWebhookConfiguration.ps1

@@ -27,6 +27,7 @@
     )
 
     $Context = Resolve-GitHubContext -Context $Context
+    Assert-GitHubContext -Context $Context -AuthType App
 
     $inputObject = @{
         Context     = $Context

src/functions/public/Apps/Webhooks/Get-GitHubAppWebhookDelivery.ps1

@@ -26,6 +26,7 @@
     )
 
     $Context = Resolve-GitHubContext -Context $Context
+    Assert-GitHubContext -Context $Context -AuthType App
 
     $inputObject = @{
         Context     = $Context

src/functions/public/Auth/Assert-GitHubContext.ps1

@@ -18,16 +18,27 @@
             Mandatory,
             ValueFromPipeline
         )]
-        [GitHubContext] $Context,
+        [object] $Context,
 
         # The required authtypes for the command.
         [Parameter(Mandatory)]
         [string[]] $AuthType
     )
 
-    $command = (Get-PSCallStack)[1].Command
+    begin {
+        $commandName = $MyInvocation.MyCommand.Name
+        Write-Verbose "[$commandName] - Start"
+    }
+
+    process {
+        $command = (Get-PSCallStack)[1].Command
+
+        if ($Context.AuthType -notin $AuthType) {
+            throw "The context '$($Context.Name)' does not match the required AuthTypes [$AuthType] for [$command]."
+        }
+    }
 
-    if ($Context.AuthType -notin $AuthType) {
-        throw "The context '$($Context.Name)' does not match the required AuthTypes [$AuthType] for [$command]."
+    end {
+        Write-Verbose "[$commandName] - End"
     }
 }

src/functions/public/Auth/Connect-GitHubApp.ps1

@@ -1,4 +1,4 @@
-function Connect-GitHubApp {
+function Connect-GitHubApp {
     <#
         .SYNOPSIS
         Connects to GitHub as a installation using a GitHub App.
@@ -104,7 +104,7 @@
                     AuthType            = [string]'IAT'
                     TokenType           = [string]'ghs'
                     DisplayName         = [string]$Context.DisplayName
-                    ApiBaseUri          = [string]$Context.ApiBaseUri
+                    ApiBaseUri          = [uri]$Context.ApiBaseUri
                     ApiVersion          = [string]$Context.ApiVersion
                     HostName            = [string]$Context.HostName
                     ClientID            = [string]$Context.ClientID
@@ -113,18 +113,18 @@
                     Events              = [string[]]$installation.events
                     TargetType          = [string]$installation.target_type
                     Token               = [securestring]$token.Token
-                    TokenExpirationDate = [string]$token.ExpiresAt
+                    TokenExpirationDate = [datetime]$token.ExpiresAt
                 }
 
                 switch ($installation.target_type) {
                     'User' {
-                        $contextParams['TargetName'] = $installation.account.login
+                        $contextParams['TargetName'] = [string]$installation.account.login
                     }
                     'Organization' {
-                        $contextParams['TargetName'] = $installation.account.login
+                        $contextParams['TargetName'] = [string]$installation.account.login
                     }
                     'Enterprise' {
-                        $contextParams['TargetName'] = $installation.account.slug
+                        $contextParams['TargetName'] = [string]$installation.account.slug
                     }
                 }
                 Write-Verbose 'Logging in using a managed installation access token...'