code: func (wfe *WebFrontEndImpl) parseJWSRequest(request *http.Request) (*jose.JSONWebSignature, *probs.ProblemDetails) {
  	// Verify that the POST request has the expected headers
  	if prob := wfe.validPOSTRequest(request); prob != nil {
  		return nil, prob
  	}
  
  	// Read the POST request body's bytes. validPOSTRequest has already checked
  	// that the body is non-nil
  	bodyBytes, err := ioutil.ReadAll(request.Body)
  	if err != nil {
  		wfe.stats.httpErrorCount.With(prometheus.Labels{"type": "UnableToReadReqBody"}).Inc()
  		return nil, probs.ServerInternal("unable to read request body")
  	}
  
  	return wfe.parseJWS(bodyBytes)
  }
docs: // parseJWSRequest extracts a JSONWebSignature from an HTTP POST request's body using parseJWS.