title: How are server side errors handled in Post/Redirect/Get pattern?
body: <p>For the successful use case, the Post/Redirect/Get (PRG) work flow is pretty simple: simply redirect (client-side) to the desired page. But what about cases when errors are encountered during server-side validation and we want to preserve the inputs when we display the input page again?</p>
  
  <p>As far as I can tell, there are two approaches: simply re-render the input page after the form POST submission (i.e. no redirection) during errors (thus disregarding the PRG pattern); or, redirect to the input page, and store the previous inputs somewhere it can be retrieved later (e.g. session), during rendering. Both have drawbacks: in the first, we are presented with the problems PRG pattern helps us to avoid (e.g. bookmarkability, double submission); the second approach leads to inconsistent GETs (first GET will find the stored inputs, subsequent GETs might not). Are there other alternatives to those mentioned here? I am hoping for inputs from the community on how this case is best handled. </p>