Flash message persistance seems to only work with a 302

Phoenix Forum Questions / Help
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1

I’m working on getting some flash messages to appear correctly after a failed captcha. I have a CaptchPlug that will validate the captcha and if the user gets it wrong or there was some error with the verification process, it’ll put a flash message up telling the user what happened.

I have this code here that runs on failure:

conn
        |> Controller.put_flash(
          :error,
          "There was an error verifying you're not a robot. Please try again."
        )
        |> Conn.put_status(:conflict)
        |> Controller.text("")
        |> Conn.halt()

The client side code makes a JS http request to an endpoint and it will get back a 409 (conflict) and trigger a page reload. I expect the reloaded page to show the flash message. However when the page reloads, there’s no message to be seen. BUT when I change the put_status to return a 302 instead, I can do the exact same thing as I did with the 409 (without the browser reloading itself) and reload the page and the flash message appears. The only difference between the two tests is a 409 vs. a 302 status code (browser is performing the exact same requests either way), but the message doesn’t appear unless I use a 302.

Is there some logic that surrounds flash messages and status codes? Is there a better way to get at what I’m trying to do?

Thanks

2

Only 3xx status codes will put the flash message in the session. All other ones are meant to render the flash message within the request, which set the flash message.

3

Thanks. Ended up returning a 300 and letting the client JS catch/handle it to reload the page.