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POST EndPoint with a Json body cannot be reached
websharperpostjsonbody

Hi,

I am having issues with a simple POST endpoint that cannot reach. The endpoint is decorated by the 'Json' attribute.

Here is a simple site to illustrate the issue:

module Site2 =

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type EndPoint2 =
    | [<EndPoint "GET /get">] Get
    | [<EndPoint "POST /post_query"; Query "query">] PostQuery of query: string
    | [<EndPoint "POST /post_body"; Json "body">] PostBody of body: JsonBody
    | [<EndPoint "POST /post_simple">] PostSimple

and JsonBody = { test: string; }

[<Website>]
let Main =

    let mainWebsite = Application.MultiPage (fun context action ->
        match action with
        | EndPoint2.Get -> Content.Json ("Get works!")
        | EndPoint2.PostQuery query -> Content.Json ("PostQuery works!")
        | EndPoint2.PostBody body -> Content.Json ("PostBody works!")
        | EndPoint2.PostSimple -> Content.Json ("PostSimple works!")
    )

    Sitelet.Sum [ mainWebsite ]

Here are my tests:

GET http://localhost:9000/get -> works fine

POST http://localhost:9000/post_query/?query=test -> works fine

POST http://localhost:9000/post_simple with the following body: { "test": "some string" } -> works fine

POST http://localhost:9000/post_body with the following body: { "test": "some string" } -> does not work, results in a 404 code.

Any idea what is wrong here? I am using WebSharper.3.6.19.242

Thank you, Youenn

.

This is strange, I copied your code into a new Self-Hosted Client-Server Application (I assume that's what you're using due to the port 9000) and I am not having this issue; I correctly receive "PostBody works!".

What version of WebSharper.Owin are you using? I'm on 3.6.14.133.

By on 4/24/2017 6:10 AM ()

I managed to find what was the issue. I illustrated it in this gist:

If you run it as it is, the POST with a JSON body won't work. However, if you comment lines 59, 60, and 61, it will work as expected.

I suspect the fact that we read the body prevents it from being used later, but not sure.

Do you have an idea why?

By on 4/27/2017 11:42 AM ()

Ah, right. Indeed, if the body stream has been read before WebSharper steps in, then it is not available anymore, and WebSharper sees an empty body. You need to copy the content into a MemoryStream so that it can be subsequently re-read:

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if not environment.Request.Body.CanSeek then
    let s = new MemoryStream() :> Stream
    do! awaitTask <| environment.Request.Body.CopyToAsync s
    environment.Request.Body <- s
environment.Request.Body.Seek(0L, SeekOrigin.Begin) |> ignore

// Your 3 lines here...

environment.Request.Body.Seek(0L, SeekOrigin.Begin) |> ignore

And also, you need to place the whole body of the function inside the async block instead of before it (although I admit I don't completely understand why).

Here is my fixed version of your gist.

By on 5/1/2017 5:21 AM ()

Ah ok, it makes sense! Thanks for your help, I'll update my code accordingly.

By on 5/2/2017 2:54 AM ()

Hi Loic, you are right, I am using the Self-Hosted Client-Server Applicationa and WebSharper.Owin.3.6.14.133 too.. I'll try to set up a completely new, separate project and see if I still have the problem.

By on 4/26/2017 1:39 PM ()

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