title: How to change UserDoesNotExist SELECT behavior in Flask-peewee - python & mysql
body: <p>Im using <a href="http://flask-peewee.readthedocs.org/en/latest/" rel="noreferrer">flask-peewee</a> to make an API and I'd like to return back a 404 json if user doesn't exist in the table but seems like it's throwing 500 error instead of 404 error json: </p>
  
  <p>Here is the <strong>Error</strong> I'm getting:</p>
  
  <pre><code>UserDoesNotExist: instance matching query does not exist:
  SQL: SELECT t1.`id`, t1.`username`, t1.`password`, t1.`email`, t1.`token`, t1.`join_date`, t1.`active`, t1.`admin` FROM `user` AS t1 WHERE ((t1.`active` = %s) AND (t1.`username` = %s))
  [Wed Sep 18 20:26:24 2013] [error] [client 173.225.41.154] PARAMS: [True, u'fery3']
  </code></pre>
  
  <p>Code:</p>
  
  <pre><code>@app.route('/api/login/',  methods=['POST'])
  def authenticate1():
      if request.method == 'POST' and request.form['username']:
          active = User.select().where(User.active==True)
          user2 = User.select().where(User.username==request.form['username']).get()
          try:
              user = active.where(User.username==request.form['username']).get()
          except exceptions:  # includes simplejson.decoder.JSONDecodeError
              return make_response(jsonify( { 'error': 'Bad request' } ), 400)
          else:
              if not user.check_password(request.form['password']):
                  return make_response(jsonify( { 'error': 'Bad request','message': 'Wrong Username or Password'} ), 400)
          return make_response(jsonify( { "meta":{'model':'login','code':'200','status':'ok','message':'successfully loggedin'},'objects':[{'username': user2.username,'email':user2.email,'token' : user2.token }] } ), 200)
  </code></pre>