Cloud Pages - API request inside of an IF statement

Question

I'm using the following code in a Cloud Page to submit an HTTP Post request. I was able to get the Script.Util.HttpRequest() methods to work on their own. But now I want to only submit the request if the querystring contains a specific value. Every combination I've tried of running the script inside of an ampscript if statement results in a 500 error, and the debugging code isn't providing me with any information.

<script runat="server">
 Platform.Load("core","1");
 try {
</script>

  %%[if RequestParameter('Q1')=="right" then]%%
<script runat="server">
  var req = new Script.Util.HttpRequest("{requestURL}");
  req.emptyContentHandling = 0;
  req.retries = 2;
  req.continueOnError = true;
  req.contentType = "application/x-www-form-urlencoded";
  req.method = "POST";
  req.postData = "{payload)";
var resp = req.send();

  Platform.Response.Write(resp.content);
  Platform.Response.Write(resp.headers["returnHeader"]);
</script>
%%[endif]%%
  
<script runat="server">
 }
 catch (err) {
  Variable.SetValue("@errorMessage", Stringify(err.message) + Stringify(err.description));
 }
</script> 
<script runat="client">
 console.log(`%%=v(@errorMessage)=%%`);
</script>

Answer 1

I am not sure why you make a switch to AMPscript in the script. You can just run it all in SSJS:

<script runat="server">
 Platform.Load("core","1");
 try {

  if (Request.GetFormField('Q1') == 'right') {

    var req = new Script.Util.HttpRequest("{requestURL}");
    req.emptyContentHandling = 0;
    req.retries = 2;
    req.continueOnError = true;
    req.contentType = "application/x-www-form-urlencoded";
    req.method = "POST";
    req.postData = "{payload)";
    var resp = req.send();

    Write(resp.content);
    Write(resp.headers["returnHeader"]);
  }
  
 }
 catch (err) {
  Write('<script>console.log(' + Stringify(err.message) + Stringify(err.description)) + ')</script>');
 }
</script>

As you can see it is actually less code this way and should be much more performant. To handle your console.log part (since in a try/catch, the JS var would only be local and not global so could not be passed same way you passed AMPscript variable) I added the information into a Write() inside the catch block to output the client-side script to the page with the information you needed - which will then be performed and push that info to the console.

I removed runat="client" as I do not believe this is actual code and by default <script> is run at client-side, which is why for SSJS you need to specify runat=server.

Answer 2

Here is an error in syntax writing:

req.postData = "{payload)";

You have to write a form url encoded string, something like:

req.postData = "foo=bar&me=Daniel";