(maint) Adds Get-GitHubRepositoryFileContent script

This can be used to improve performance of any update that requires you to grab the content of a file from a repository, e.g. a changelog.

scripts/Get-GitHubRelease.ps1

@@ -16,7 +16,7 @@
     [Parameter(Mandatory, Position = 1)]
     [string]$Name,
 
-    # The Name of the tag to get the relase for. Will default to the latest release.
+    # The Name of the tag to get the release for. Will default to the latest release.
     [string]$TagName,
 
     # GitHub token, used to reduce rate-limiting or access private repositories (needs repo scope)

scripts/Get-GitHubRepositoryFileContent.ps1

@@ -0,0 +1,65 @@
+function Get-GitHubRepositoryFileContent {
+  <#
+    .Synopsis
+      Returns the content of a given file in a repository via the REST API
+
+    .Link
+      https://docs.github.com/en/rest/repos/contents?apiVersion=2022-11-28
+
+    .Example
+      Get-GitHubRepositoryFileContent Kubernetes Kubernetes CHANGELOG/README.md
+
+    .Notes
+      Seems to be a lot faster than IWRing raw files.
+  #>
+  [CmdletBinding()]
+  param(
+    # The owner of the repository
+    [Parameter(Mandatory)]
+    [string]$Owner,
+
+    # The repository containing the file
+    [Parameter(Mandatory)]
+    [string]$Repository,
+
+    # The path to the file within the repository
+    [Parameter(ValueFromPipeline)]
+    [string]$Path,
+
+    # The branch, tag, or reference to get the content from. Defaults to the repository's default branch.
+    [Alias('ref', 'Tag')]
+    [string]$Branch,
+
+    # Returns the raw response
+    [switch]$Raw
+  )
+  process {
+    $restArgs = @{
+      Uri     = "https://api.github.com/repos/$($Owner)/$($Repository)/contents/$($Path.TrimStart('/'))"
+      Headers = @{
+        'Accept'               = 'application/vnd.github+json'
+        'X-GitHub-Api-Version' = '2022-11-28'
+      }
+    }
+    if ($Branch) {
+      $restArgs.Body = @{ref = $Branch}
+    }
+    if ($env:github_api_key) {
+      $restArgs.Headers.Authorization = "Bearer $($env:github_api_key)"
+    }
+
+    $Result = Invoke-RestMethod @restArgs -UseBasicParsing
+
+    if ($Raw) {
+      $Result
+    } elseif ($Result.encoding -eq 'base64') {
+      # Assumption made about the file being UTF8, here
+      [System.Text.Encoding]::UTF8.GetString(
+        [System.Convert]::FromBase64String($Result.content)
+      )
+    } else {
+      Write-Warning "$($Path) encoded as '$($Result.encoding)'"
+      $Result.content
+    }
+  }
+}

scripts/au_extensions.psm1

@@ -9,6 +9,7 @@ $funcs = @(
   'Clear-DependenciesList'
   'Get-AllGitHubReleases'
   'Get-GitHubRelease'
+  'Get-GitHubRepositoryFileContent'
   'Set-DescriptionFromReadme'
   'Update-ChangelogVersion'
   'Update-OnETagChanged'