caddy-log-converter/source/CaddyLog-To-AccessLog.ps1

param (
    [Parameter(Mandatory = $false)][string] $inFile,
    [Parameter(Mandatory = $false)][string] $outFile,
    [Parameter(Mandatory = $false)][int] $lines = 0
)

if ([string]::IsNullOrWhiteSpace($inFile)) {
    $inFile = [System.Environment]::GetEnvironmentVariable("INFILE")
}

if ([string]::IsNullOrWhiteSpace($outFile)) {
    $outFile = [System.Environment]::GetEnvironmentVariable("OUTFILE")
}

$baseDate = (New-Object System.DateTime -ArgumentList @(1970, 1, 1, 0, 0, 0, [DateTimeKind]::Utc)).ToLocalTime()
$builder = New-Object System.Text.StringBuilder

$outputStream = [IO.File]::Open($outFile, [IO.FileMode]::Append, [IO.FileAccess]::Write, [IO.FileShare]::Read)
$outputWriter = New-Object -TypeName System.IO.StreamWriter -ArgumentList @($outputStream, [Text.Encoding]::UTF8)

Get-Content -Tail $lines -Wait -Path $inFile | ForEach-Object {
    $l = ConvertFrom-Json -InputObject $_
    $r = $l.request;

    $userAgent = $r.headers.'User-Agent' | Select-Object -First 1
    $referer = $r.headers.Referer | Select-Object -First 1

    $null = $builder.Clear()
    $null = $builder.Append($r.remote_ip)
    $null = $builder.Append(" - [")
    $null = $builder.Append($baseDate.AddSeconds($l.ts).ToString("yyyy-MM-dd HH:mm:ss.fff"))
    $null = $builder.Append("] """)
    $null = $builder.Append($r.host)
    $null = $builder.Append(""" ")
    $null = $builder.Append($r.method)
    $null = $builder.Append(" ")
    $null = $builder.Append($r.uri)
    $null = $builder.Append(" ")
    $null = $builder.Append($r.proto)
    $null = $builder.Append(" ")
    $null = $builder.Append($l.status)
    $null = $builder.Append(" ")
    $null = $builder.Append($l.size)
    $null = $builder.Append(" """)
    $null = $builder.Append($referer)
    $null = $builder.Append(""" """)
    $null = $builder.Append($userAgent)
    $null = $builder.Append("""")

    $commonLog = $builder.ToString()

    Write-Output $commonLog
    $outputWriter.WriteLine($commonLog)
    $outputWriter.Flush()

    #[system.string]::Join(
    #  " ",
    #  @(
    #    "$($r.remote_ip) - [$($baseDate.AddSeconds($l.ts).ToString("yyyy-MM-dd HH:mm:ss.fff"))]",
    #    """$($r.host)""",
    #    $r.method,
    #    $r.uri,
    #    $r.proto,
    #    $l.status,
    #    $l.size,
    #    """$($r.headers.Referer)""",
    #    """$ua"""
    #  ))
}