POST request using F# - https

Question

I want to make a POST request with a body containing a simple key value pair
like { "Id":"VVE87BDA-B0A1-48F3-A7C7-F3482CE2UIJ" }
How can I do this in F# ??

Answer 1

Have a look at FSharp.Data library
Http.RequestString
( "http://httpbin.org/post",
headers = [ ContentType HttpContentTypes.Json ],
body = TextRequest """ {"test": 42} """)

Answer 2

You can also do this through .NET libraries like in C# or VB. Here's how it works with HttpWebRequest (assuming you aren't using task or async):
let obj = {| Id = "VVE87BDA-B0A1-48F3-A7C7-F3482CE2UIJ" |}
let req = WebRequest.CreateHttp "http://www.example.com"
req.Method <- "POST"
req.ContentType <- "application/json"
do (
use reqStream = req.GetRequestStream()
use sw = new StreamWriter(reqStream )
obj |> JsonConvert.SerializeObject |> sw.Write
)
use resp = req.GetResponse()
use respStream = resp.GetResponseStream()
use sr = new StreamReader(respStream)
let respBody = sr.ReadToEnd()
printfn "%s" respBody
async version:
let obj = {| Id = "VVE87BDA-B0A1-48F3-A7C7-F3482CE2UIJ" |}
let req = WebRequest.CreateHttp "http://www.example.com"
req.Method <- "POST"
req.ContentType <- "application/json"
do! async {
use! reqStream = req.GetRequestStreamAsync() |> Async.AwaitTask
use sw = new StreamWriter(reqStream )
do! obj |> JsonConvert.SerializeObject |> sw.WriteAsync |> Async.AwaitTask
}
use! resp = req.AsyncGetResponse()
use respStream = resp.GetResponseStream()
use sr = new StreamReader(respStream)
let! respBody = sr.ReadToEndAsync() |> Async.AwaitTask
printfn "%s" respBody
In either case it's best to make sure reqStream goes out of scope and gets disposed before the GetResponse call, to make sure the request data gets fully written.