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HttpFs.SamplePostApplication

README.md

How to make a POST request.

Following code uses httpbin service to make a POST request.

There are two pages to look at.

  1. /post Returns POST data.

  2. /forms/post HTML form that submits to /post.

Script is going to reproduce request made by /forms/post page.

Most common Content Type for forms is application/x-www-form-urlencoded.

|> withHeader (ContentType "application/x-www-form-urlencoded")

Also, keep in mind that form may redirect you to another page, allow redirects by removing:

|> withAutoFollowRedirectsDisabled

Create a request:

let request =
    createRequest Post "http://httpbin.org/post"
    |> withBody body
    |> withHeader (Referer "https://github.com/relentless/Http.fs")
    |> withHeader (UserAgent "Mozilla/5.0 (Windows NT 6.3; WOW64; rv:36.0) Gecko/20100101 Firefox/36.0")    
    |> withHeader (Accept "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8")       
    |> withHeader (AcceptLanguage "Accept-Language: en-US")
    |> withHeader (ContentType "application/x-www-form-urlencoded")    
    |> withHeader (Custom {name="DNT"; value="1"}) // Custom header. Do Not Track Enabled 
    |> withAutoDecompression (DecompressionScheme.GZip ||| DecompressionScheme.Deflate) // Accept both.
    |> withResponseCharacterEncoding "utf-8"
    |> withKeepAlive true

let resp = request |> getResponse
printfn "StatusCode: %d" resp.StatusCode

Create request body.

KeyValuePair is a simple type to store form values.

/// Any Key-value pair to store values. 
type KeyValuePair = {Key:string; Value:string}

// Set up parameters for small pizza with bacon and onions.
let bodyParams :KeyValuePair list = [
    {Key = "custname"; Value = "John Doe"}
    {Key = "custtel"; Value = "123456789"}
    {Key = "custemail"; Value = "example@example.com"}
     // Radio button
    {Key = "size"; Value = "small"}
     // Checkboxes
    {Key = "topping"; Value = "bacon"}
    {Key = "topping"; Value = "cheese"}

    {Key = "delivery"; Value = "4:00"}
    {Key = "comments"; Value = ""}
    ]

Form body must be encoded.

HttpUtility.UrlEncode is in the System.Web namespace, remember to add reference to the project.

/// Function to convert parameter list to Body.
let bodyFunc (acc:string) (tArg:KeyValuePair) = 
    // Encode characters like spaces before transmitting.
    let rName = tArg.Key |> HttpUtility.UrlEncode
    let rValue = tArg.Value |> HttpUtility.UrlEncode

    let mix = HttpUtility.UrlEncode rName + "=" + rValue
    match acc with
    | "" -> mix // Skip first.
    | _ -> acc + "&" + mix  // application/x-www-form-urlencoded

Use Seq.fold on bodyParams to make request body.

// Create body.
let body = bodyParams |> Seq.fold bodyFunc ""

Actual request body: custname=John+Doe&custtel=123456789&custemail=example%40example.com&size=small&topping=bacon&topping=cheese&delivery=4%3a00&comments=

Make POST request.

let resp = request |> getResponse

resp returns StatusCode 200 and EntityBody as following:

{
  "args": {}, 
  "data": "", 
  "files": {}, 
  "form": {
    "comments": "", 
    "custemail": "example@example.com", 
    "custname": "John Doe", 
    "custtel": "123456789", 
    "delivery": "4:00", 
    "size": "small", 
    "topping": [
      "bacon", 
      "cheese"
    ]
      }, 
  "headers": {
    "Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8", 
    "Accept-Encoding": "gzip, deflate", 
    "Accept-Language": "Accept-Language: en-US", 
    "Content-Length": "133", 
    "Content-Type": "application/x-www-form-urlencoded", 
    "Dnt": "1", 
    "Host": "httpbin.org", 
    "Referer": "https://github.com/relentless/Http.fs", 
    "User-Agent": "Mozilla/5.0 (Windows NT 6.3; WOW64; rv:36.0) Gecko/20100101 Firefox/36.0"
  }, 
  "json": null, 
  "origin": "xx.xxx.xxx.xxx", 
  "url": "http://httpbin.org/post"
}