rest.ocr.ps1

using namespace Windows.Storage
using namespace Windows.Graphics.Imaging
using namespace System.IO.WindowsRuntimeStreamExtensions
using namespace System.IO.WindowsRuntimeStreamExtensions
using namespace System.Text
using namespace System.Text.Json

# Add the WinRT assembly, and load the appropriate WinRT types
Add-Type -AssemblyName System.Runtime.WindowsRuntime
Add-Type -AssemblyName System.Runtime.Serialization

$null = [Windows.Storage.StorageFile,                Windows.Storage,         ContentType = WindowsRuntime]
$null = [Windows.Media.Ocr.OcrEngine,                Windows.Foundation,      ContentType = WindowsRuntime]
$null = [Windows.Foundation.IAsyncOperation`1,       Windows.Foundation,      ContentType = WindowsRuntime]
$null = [Windows.Graphics.Imaging.SoftwareBitmap,    Windows.Foundation,      ContentType = WindowsRuntime]
$null = [Windows.Storage.Streams.RandomAccessStream, Windows.Storage.Streams, ContentType = WindowsRuntime]


# [Windows.Media.Ocr.OcrEngine]::AvailableRecognizerLanguages
$ocrEngine = [Windows.Media.Ocr.OcrEngine]::TryCreateFromLanguage("en")


# PowerShell doesn't have built-in support for Async operations, 
# but all the WinRT methods are Async.
# This function wraps a way to call those methods, and wait for their results.
$getAwaiterBaseMethod = [WindowsRuntimeSystemExtensions].GetMember('GetAwaiter').
                            Where({
                                    $PSItem.GetParameters()[0].ParameterType.Name -eq 'IAsyncOperation`1'
                                }, 'First')[0]

Function Await {
    param($AsyncTask, $ResultType)

    $getAwaiterBaseMethod.
        MakeGenericMethod($ResultType).
        Invoke($null, @($AsyncTask)).
        GetResult()
}


$http = [System.Net.HttpListener]::new()
# Hostname and port to listen on
$http.Prefixes.Add("http://+:80/")
# Start the Http Server
$http.Start()

Add-Type -AssemblyName System.Web
# Log ready message to terminal
if ($http.IsListening) {
    write-host "HTTP Server Ready!  " -f 'black' -b 'gre'
    write-host "$($http.Prefixes)" -f 'y'
}


while ($http.IsListening) {
    # Get Request Url
    # When a request is made in a web browser the GetContext() method will return a request object
    # Our route examples below will use the request object properties to decide how to respond
    $context = $http.GetContext()
    if ($context.Request.HttpMethod -eq 'GET') {
        $Context.Response.ContentType = "text/html"
        $buffer = [System.Text.Encoding]::UTF8.GetBytes("<input type=file onchange=""fetch('', {method: 'POST', body: this.files[0]}).then(r=>r.json()).then(console.log)"">")
        $context.Response.OutputStream.Write($buffer, 0, $buffer.Length)
        $Context.Response.Close()
    }

    if ($context.Request.HttpMethod -eq 'POST') {

        # We can log the request to the terminal
        write-host "$($context.Request.UserHostAddress)  =>  $($context.Request.Url)" -f 'mag'
        $memStream = [System.IO.MemoryStream]::new()
        $context.Request.InputStream.CopyTo($memStream)
    
        $params = @{
            AsyncTask  = [BitmapDecoder]::CreateAsync([System.IO.WindowsRuntimeStreamExtensions]::AsRandomAccessStream($memStream))
            ResultType = [BitmapDecoder]
        }
        $bitmapDecoder = Await @params
    
    
        $params = @{ 
            AsyncTask = $bitmapDecoder.GetSoftwareBitmapAsync()
            ResultType = [SoftwareBitmap]
        }
        $softwareBitmap = Await @params
    
        # Run the OCR
        $result = Await $ocrEngine.RecognizeAsync($softwareBitmap) ([Windows.Media.Ocr.OcrResult])

        $Context.Response.ContentType = "application/json"
        $serialized = $result | ConvertTo-Json -Depth 5 -Compress
        $buffer = [System.Text.Encoding]::UTF8.GetBytes($serialized)
        $context.Response.OutputStream.Write($buffer, 0, $buffer.Length)
        $Context.Response.Close()
    }
}

https://gist.github.com/GitHub30/7fb64dabf813c974d4b7069ab38fba0d