为什么我收到 F# 错误 FS0039：命名空间或模块“Http”未定义

在 Visual Studio 2015 和 2017 中，我尝试使用 FSharp Interactive 中的几个 F# 示例中的 Http 类，并且不断收到：

错误 FS0039：未定义命名空间或模块“Http”

这是示例：

open FSharp.Data
let response = Http.RequestString("http://api.themoviedb.org/3/search/movie", silentHttpErrors = true)

这显然是由于 FSharp.Data 的版本造成的。有没有办法为 FSharp Interactive 指定正确的版本？哪个版本的 FSharp.Data 包含 Http 模块？

根据评论，我编写了一个脚本来安装 Paket，对其进行初始化，然后在脚本运行时选择安装依赖项。

/// install.paket.fsx
open System
open System.IO

printfn "Initialising..."
Environment.CurrentDirectory <- __SOURCE_DIRECTORY__
// invisibly run a command (paket.exe in this case)
let init paket =
    let psi = new System.Diagnostics.ProcessStartInfo(paket)
    psi.Arguments <- "init"
    psi.UseShellExecute <- false
    let p = System.Diagnostics.Process.Start(psi)
    p.WaitForExit()
    p.ExitCode

if not (File.Exists "paket.exe") then
    printfn "installing paket"
    let url = "http://fsprojects.github.io/Paket/stable"
    use wc = new Net.WebClient()
    let tmp = Path.GetTempFileName()
    let stable = wc.DownloadString(url)
    wc.DownloadFile(stable, tmp)
    File.Move(tmp,Path.GetFileName stable)
    printfn "paket installed"
    System.Threading.Thread.Sleep(100)
    printfn "initialising paket"
    init "paket.exe" |> ignore
    System.Threading.Thread.Sleep(200)
    printfn "paket initialised"
else
    printfn "paket already exists"

/// install.dependencies.fsx

open System.IO
printfn "Installing dependencies"
System.Environment.CurrentDirectory <- __SOURCE_DIRECTORY__
#r "paket.exe"

open Paket
let dependencies = Paket.Dependencies.Locate(__SOURCE_DIRECTORY__)

printfn "%s" dependencies.DependenciesFile

if not (File.Exists "packages/Newtonsoft.Json/lib/net40/Newtonsoft.Json.dll") then
    printfn "installing nuget depenencies"
    // either use the dependencies.Install to add dependencies in the paket.dependencies file
    //dependencies.Install true |> ignore
    // or install them by name
    // I remove the existing versions
    dependencies.Remove "FSharp.Data"
    dependencies.Remove "Newtonsoft.Json 8.0.3"
    // then add them (because I'm pedantic about the way the dependencies file looks)
    dependencies.Add "FSharp.Data"
    dependencies.Add "Newtonsoft.Json 8.0.3"
    printfn "nuget depenencies installed"
else
    printfn "nuget depenencies already exist"

printfn "Dependencies installed"

请注意 Newtonsoft.Json 使用 8.0.3，最新版本带来了 20 多个附加依赖项，因此我找到了一个非常独立的旧版本。如果您想要最新版本，可以省略版本号。

然后，我在共享的utilities.fsx中使用这些脚本来实现可重用的功能

System.Environment.CurrentDirectory <- __SOURCE_DIRECTORY__
#load "install.paket.fsx"
#load "install.dependencies.fsx"

#r "packages/fsharp.data/lib/net40/fsharp.data.dll"
#r "packages/Newtonsoft.Json/lib/net40/Newtonsoft.Json.dll"

open FSharp.Data
open FSharp.Data.HtmlAttribute
open FSharp.Data.HtmlNode
open FSharp.Data.HttpRequestHeaders
open Newtonsoft.Json
open System.Net
open System.IO
// utilities like authentication, Http requests and JSON (de)serialization

最后，我通过加载实用程序来引用目标脚本中的全部内容：

System.Environment.CurrentDirectory <- __SOURCE_DIRECTORY__
#load "utilities.fsx"
open Utilities

它负责处理所有依赖项。这些可以从 Visual Studio 运行Alt + Enter组合键或从命令行使用fsi.exe MyScript.fsx