How to display descriptive error message?

I have a problem in displaying the error message in Ruby on Rails. I am using:

rescue => Exception ex
 #display ex.message

The output I get when I tried to display it in an alert messagebox is this:

"DBI::DatabaseError: 37000 (50000) [Microsoft][ODBC SQL Server Driver][SQL Server]Canno开发者_JAVA百科t approve records for the specified date..: Exec uspTestProc 279, 167, 2."

It displays some words that are not friendly to users. What I want is to display only these words: "Cannot approve records for the specified date"

Common practice in Rails is to use the "flash" session variable within the Controller:

# error catching logic goes here
flash[:error] = "There was an error!"

# notice logic goes here
flash[:notice] = "I am sending you a notice."

Then display it (possibly within a catchall layout):

<% if flash[:error] %>
<div id="error"><%= flash[:error] %></div>
<% end %>

<% if flash[:notice] %>
<div id="notice"><%= flash[:notice] %></div>
<% end %>

Was that what you are looking for?

I think an error like that can be catch by rescue_from

class ApplicationController

  rescue_from MyException do
    render :text => 'We have some issue in our database'
  end
end

In any language, I would usually always handle the exceptions and show the user a dumbed down version.

Users shouldn't get to see the inner workings of something and exceptions are a great way to show them a big mess of nonsense.

I:

• Log the actual exception because I, or the system maintainer needs to know exactly what happened, with a tracelog if possible.
• Show the user either a tailored exception for specific to the problem - "You've entered the wrong data!"
• Or a generic error - "Oh noes! something went hideously wrong!!1" - if it wasn't caused by the user or I haven't got a case for handling it (yet).