使用Elm从POST请求下载文件

module Main exposing (..)

import Browser
import Html exposing (Html, button, div, text)
import Html.Events exposing (onClick)
import Http
import File
import File.Download as Download

type Msg
    = DownloadFile

type alias Model =
    { fileUrl : String
    }

init : Model
init =
    { fileUrl = "https://example.com/file.pdf" -- 替换为实际的文件URL
    }

update : Msg -> Model -> Model
update msg model =
    case msg of
        DownloadFile ->
            let
                request =
                    { method = "POST"
                    , headers = []
                    , body = Http.emptyBody
                    , url = model.fileUrl
                    }
            in
            Http.send handleResponse request

handleResponse : Result Http.Error (Http.Response Blob) -> Msg
handleResponse result =
    case result of
        Ok response ->
            case response.status of
                200 ->
                    let
                        fileName =
                            "file.pdf" -- 替换为实际的文件名

                        download =
                            Download.bytes fileName (Download.blob response.body)
                    in
                    Download.send download

                _ ->
                    -- 处理其他状态码的逻辑
                    DownloadFile

        Err error ->
            -- 处理请求错误的逻辑
            DownloadFile

view : Model -> Html Msg
view model =
    div []
        [ button [ onClick DownloadFile ] [ text "下载文件" ]
        ]

main =
    Browser.sandbox { init = init, update = update, view = view }