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JuankGlezz
Asked: 2020-05-23 10:45:00 +0800 CST 2020-05-23 10:45:00 +0800 CST

make the POST request from the controller

  • 772

I have the need to make a POST request from the controller before loading the view, I want to do this due to a certain condition that is required of me.

The condition is:

If I have more than one product in the contract, show a "Menu" with the contracted products, otherwise, if I only have 1, show the view of that product and not the "Menu".

The Menu controller code is:

public ActionResult MenuApps(){
  if (WSKernel.Suscriptions_WebDevices_Get(productosDatos, out productosRespuesta)) {
    model.Productos = productosRespuesta.ListSuscriptions_WebDevices;
    //si solo se cuenta con un solo producto, hacer redireccion directa al unico producto
    if (model.Productos != null && model.Productos.Length == 1){
      switch (model.Productos[0].AdmixProduct){
        case "Producto1":
          return Redirect("http://localhost/Producto1");
        case "Producto2":
          return Redirect("http://localhost/Producto2");
      }
    }
  }else{//sin productos}
}

But the do return Redirect("http://localhost/Producto2");makes a request HTTPbecause GETI want to send information and I want the user not to see it just because I need him to always log in correctly.

On the other hand, where I want to redirect is another project that is already finished and this one is configured to receive information by POST.

How can I make the POST request and redirect to the page from the controller?

c#

1 Answers

  1. Best Answer
    1. Firstly my idea was to return a script with an AJAX request from Javascript, but I had the problem that I couldn't redirect to the page, so it wasn't what I needed.
    2. I proposed to return a view with a form, but the problem was that the blank page always appeared and when I made the request, it was not very well seen either.

    After several attempts and a lot of searching I found this post where he explains the attempts he made, but apparently my second idea was on the right track, only on the page he does it with a Helper.

    The idea of Helper​​is simple:
    for each key value you want to post, we create a hidden field, create the form, then add the necessary script to do the automatic submission by calling it vPostForm.submit()from the JavaScript code .

    Therefore the code would be as follows:

    private static String PreparePOSTForm(string url, NameValueCollection data)
{
    //Set a name for the form
    string formID = "PostForm";
    //Build the form using the specified data to be posted.
    StringBuilder strForm = new StringBuilder();
    strForm.Append("<form id=\"" + formID + "\" name=\"" + 
                   formID + "\" action=\"" + url + 
                   "\" method=\"POST\">");

    foreach (string key in data)
    {
        strForm.Append("<input type=\"hidden\" name=\"" + key + 
                       "\" value=\"" + data[key] + "\">");
    }

    strForm.Append("</form>");
    //Build the JavaScript which will do the Posting operation.
    StringBuilder strScript = new StringBuilder();
    strScript.Append("<script language="'javascript'">");
    strScript.Append("var v" + formID + " = document." + 
                     formID + ";");
    strScript.Append("v" + formID + ".submit();");
    strScript.Append("</script>");
    //Return the form and the script concatenated.
    //(The order is important, Form then JavaScript)
    return strForm.ToString() + strScript.ToString();
}

    Now to consume this private method you need the following:

    public static void RedirectAndPOST(Page page, string destinationUrl, NameValueCollection data)
{
  //Prepare the Posting form
  string strForm = PreparePOSTForm(destinationUrl, data);
  //Add a literal control the specified page holding 
  //the Post Form, this is to submit the Posting form with the request.
  page.Controls.Add(new LiteralControl(strForm));
}

    ok now in my controller i would use something like this:

    Dictionary<string, object> postData = new Dictionary<string, object>();
postData.Add("first", "someValueOne");
postData.Add("second", "someValueTwo");
return this.RedirectAndPost("http://TheUrlToPostDataTo", postData);

    Now yes, the condition that had to be respected is fulfilled:

    If I have more than one product in the contract, show a "Menu" with the contracted products, otherwise, if I only have 1, show the view of that product and not the "Menu".

    Samer Abu Rabie code and credit

    If you want to do something simpler in MVC there is a Nuget package like Fluentx.Mvc (Recommended) , in which you no longer need to create the helper in a file, you only need to import the package withusing Fluentx.Mvc;

    To use it is the same way.

    Dictionary<string, object> postData = new Dictionary<string, object>();
postData.Add("first", "someValueOne");
postData.Add("second", "someValueTwo");
return this.RedirectAndPost("http://TheUrlToPostDataTo", postData);
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