Powershell function to retrieve a file from a Github repository

Invoke-GithubFileRequest.ps1

Set-StrictMode -Vesion Latest

function Invoke-GithubFileRequest {
    <# .SYNOPSIS
    Retrieves a file from a Github repository. #>
    [Alias('gh_curl')]
    Param(
        # URL of file to download
        [Parameter(Mandatory)]
        [Uri]$URL,
        # Output file path
        [IO.FileInfo]$FilePath = $URL.Segments[-1]
    )

    function _validate {
        Param([Uri]$link)
        switch ($link.Host) {
            'github.com' {
                if ($link.Segments.Count -lt 6 -or $link.Segments[3] -ne 'blob/') { break }
                return [Uri]('https://api.github.com/repos/{1}/{2}/contents/{5}?ref={4}' -f
                    $link.LocalPath.Split('/', 6))
            }
            'raw.githubusercontent.com' {
                if ($link.Segments.Count -lt 5) { break }
                return [Uri]('https://api.github.com/repos/{1}/{2}/contents/{4}?ref={3}' -f
                    $link.LocalPath.Split('/', 5))
            }
            'api.github.com' {
                if ($link.LocalPath -notmatch 'git/blobs|contents') { break }
                return $link
            }
        }
        Write-Output 'The provided URL is not a valid Github file URL:' $link.OriginalString
        break 2
    }

    [IO.File]::WriteAllBytes($FilePath, [Convert]::FromBase64String(
        (Invoke-RestMethod -Uri (_validate $URL)).Content))
}

Updated version available in my HelperFunctions module.