导航管理界面时，我的实时应用出现错误

Question

When I navigate to a certain resource in the admin interface for my app I get a status 500 error. Why might this be?

Here is from my logs:

2011-06-16T21:33:35+00:00 app[web.1]: Started GET "/admin/timeline_events" for 151.205.162.106 at 2011-06-16 14:33:35 -0700
2011-06-16T21:33:35+00:00 app[web.1]: 
2011-06-16T21:33:35+00:00 app[web.1]: NoMethodError (undefined method `map' for nil:NilClass):

How would I find where map is in my app?

OK, so I think it's this code in my application helper that might be causing this

def render_timeline(events, title)
  events.map do |event|
    render(:partial => "timeline_events/#{event.event_type}", :locals => {:event => event, :title => title})
  end.join.html_safe
end

The code basically renders different partials depending on what type of event it is to create a feed.

Answer 1

It looks like you're calling the method but passing nil as the events argument.

Make sure that when there are no events to be rendered, you pass in an empty array instead of nil .

You can catch this in the body of the method by adding:

events ||= []

as the first line, or you can use default arguments:

def render_timeline(events = [], title)

or you can just change how you generate the events argument so it never returns nil .