MicrosoftCognitiveTranslator.fs

module MicrosoftCognitiveTranslator

open System
open System.Net
open System.Net.Http
open System.Web
    
type Translator() =
    let AsyncGetAccessToken () =
        let CognitiveServicesAccountKey = "<your cognitive services key>" // see portal.azure.com
        let ServiceUrl = new System.Uri("https://api.cognitive.microsoft.com/sts/v1.0/issueToken")
        async {
            let client = new HttpClient()
            let request = new HttpRequestMessage()
            request.Method <- HttpMethod.Post
            request.RequestUri <- ServiceUrl
            request.Content <- new StringContent("")
            request.Headers.TryAddWithoutValidation("Ocp-Apim-Subscription-Key", CognitiveServicesAccountKey) |> ignore

            use! response = Async.AwaitTask <| client.SendAsync(request)
            response.EnsureSuccessStatusCode() |> ignore

            let! token = Async.AwaitTask <| response.Content.ReadAsStringAsync()
            return token
        }

    let Authtoken = AsyncGetAccessToken() |> Async.RunSynchronously

    // track how many bytes we translate
    let mutable BytesTranslated = 0

    member this.Translate(text : string, fromLanguageCode, toLanguageCode) =
        let encoded = HttpUtility.UrlEncode(text)
        let uri = sprintf "https://api.microsofttranslator.com/v2/http.svc/Translate?text=%s&from=%s&to=%s&appid=Bearer%%20%s" encoded fromLanguageCode toLanguageCode Authtoken

        let httpWebRequest = WebRequest.Create(uri) :?> HttpWebRequest
        try
            let response = httpWebRequest.GetResponse()
            let stream = response.GetResponseStream()
            let dcs = new System.Runtime.Serialization.DataContractSerializer(Type.GetType("System.String"))
            let translation = dcs.ReadObject stream :?> string
            BytesTranslated <- BytesTranslated + text.Length
            translation
        with | _ -> Unchecked.defaultof<string>

An approximate translation from the C# code I was using in one of my projects. FWIW, the C# is twice as many LOC.