I have a simple RoR project where I have a table (Story) with stories
and links. I added a 3rd param in another table (permalink) and linked
it.
Now I want to access the records from Story using the permalink
In the console I can do the following:
s = Story.find_by_permalink(“weblog”)
=> #<Story id: 1, name: “my weblog”, link: “http://mywelog.com”,
created_at: “2008-01-06 02:25:36”, updated_at: “2008-01-12 19:29:41”,
permalink: “weblog”>
this is the result I was expecting.
Now moving on to the controller, I have in there:
def show
@story = Story.find_by_permalink(params[:permalink])
end
and in the view I have:
My Story
<%= @story.name %>
<%= link_to @story.link, @story.link %>
I also updated the routes.rb file, adding in there:
map.story ‘story/show/:permalink’, :controller => ‘story’, :action =>
‘show’
Now when I run the server, and type in:
http://localhost:3000/story/show/weblog
I get the following error:
NoMethodError in Story#show
Showing story/show.rhtml where line #2 raised:
You have a nil object when you didn’t expect it!
The error occurred while evaluating nil.name
Extracted source (around line #2):
1:
My Story
2:
<%= @story.name %>
3:
<%= link_to @story.link, @story.link %>
RAILS_ROOT: /home/hkhan/digg
Application Trace | Framework Trace | Full Trace
app/views/story/show.rhtml:2:in
`_run_erb_47app47views47story47show46rhtml’
/usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_view/base.rb:637:in
send' /usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_view/base.rb:637:in
compile_and_render_template’
/usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_view/base.rb:365:in
render_template' /usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_view/base.rb:316:in
render_file’
/usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/base.rb:1100:in
render_for_file' /usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/base.rb:836:in
render_with_no_layout’
/usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/layout.rb:262:in
render_without_benchmark' /usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/benchmarking.rb:51:in
render’
/usr/local/lib/ruby/1.8/benchmark.rb:293:in measure' /usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/benchmarking.rb:51:in
render’
/usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/base.rb:1153:in
default_render' /usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/base.rb:1159:in
perform_action_without_filters’
/usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/filters.rb:697:in
call_filters' /usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/filters.rb:689:in
perform_action_without_benchmark’
/usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/benchmarking.rb:68:in
perform_action_without_rescue' /usr/local/lib/ruby/1.8/benchmark.rb:293:in
measure’
/usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/benchmarking.rb:68:in
perform_action_without_rescue' /usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/rescue.rb:199:in
perform_action_without_caching’
/usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/caching.rb:678:in
perform_action' /usr/local/lib/ruby/gems/1.8/gems/activerecord-2.0.2/lib/active_record/connection_adapters/abstract/query_cache.rb:33:in
cache’
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.0.2/lib/active_record/query_cache.rb:8:in
cache' /usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/caching.rb:677:in
perform_action’
/usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/base.rb:524:in
send' /usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/base.rb:524:in
process_without_filters’
/usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/filters.rb:685:in
process_without_session_management_support' /usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/session_management.rb:123:in
process’
/usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/base.rb:388:in
process' /usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/dispatcher.rb:171:in
handle_request’
/usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/dispatcher.rb:115:in
dispatch' /usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/dispatcher.rb:126:in
dispatch_cgi’
/usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/dispatcher.rb:9:in
dispatch' /usr/local/lib/ruby/gems/1.8/gems/rails-2.0.2/lib/webrick_server.rb:112:in
handle_dispatch’
/usr/local/lib/ruby/gems/1.8/gems/rails-2.0.2/lib/webrick_server.rb:78:in
service' /usr/local/lib/ruby/1.8/webrick/httpserver.rb:104:in
service’
/usr/local/lib/ruby/1.8/webrick/httpserver.rb:65:in run' /usr/local/lib/ruby/1.8/webrick/server.rb:173:in
start_thread’
/usr/local/lib/ruby/1.8/webrick/server.rb:162:in start' /usr/local/lib/ruby/1.8/webrick/server.rb:162:in
start_thread’
/usr/local/lib/ruby/1.8/webrick/server.rb:95:in start' /usr/local/lib/ruby/1.8/webrick/server.rb:92:in
each’
/usr/local/lib/ruby/1.8/webrick/server.rb:92:in start' /usr/local/lib/ruby/1.8/webrick/server.rb:23:in
start’
/usr/local/lib/ruby/1.8/webrick/server.rb:82:in start' /usr/local/lib/ruby/gems/1.8/gems/rails-2.0.2/lib/webrick_server.rb:62:in
dispatch’
/usr/local/lib/ruby/gems/1.8/gems/rails-2.0.2/lib/commands/servers/webrick.rb:66
/usr/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in
gem_original_require' /usr/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in
require’
/usr/local/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:496:in
require' /usr/local/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:342:in
new_constants_in’
/usr/local/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:496:in
require' /usr/local/lib/ruby/gems/1.8/gems/rails-2.0.2/lib/commands/server.rb:39 /usr/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in
gem_original_require’
/usr/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in
`require’
script/server:3
app/views/story/show.rhtml:2:in
_run_erb_47app47views47story47show46rhtml' /usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_view/base.rb:637:in
send’
/usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_view/base.rb:637:in
compile_and_render_template' /usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_view/base.rb:365:in
render_template’
/usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_view/base.rb:316:in
render_file' /usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/base.rb:1100:in
render_for_file’
/usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/base.rb:836:in
render_with_no_layout' /usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/layout.rb:262:in
render_without_benchmark’
/usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/benchmarking.rb:51:in
render' /usr/local/lib/ruby/1.8/benchmark.rb:293:in
measure’
/usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/benchmarking.rb:51:in
render' /usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/base.rb:1153:in
default_render’
/usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/base.rb:1159:in
perform_action_without_filters' /usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/filters.rb:697:in
call_filters’
/usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/filters.rb:689:in
perform_action_without_benchmark' /usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/benchmarking.rb:68:in
perform_action_without_rescue’
/usr/local/lib/ruby/1.8/benchmark.rb:293:in measure' /usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/benchmarking.rb:68:in
perform_action_without_rescue’
/usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/rescue.rb:199:in
perform_action_without_caching' /usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/caching.rb:678:in
perform_action’
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.0.2/lib/active_record/connection_adapters/abstract/query_cache.rb:33:in
cache' /usr/local/lib/ruby/gems/1.8/gems/activerecord-2.0.2/lib/active_record/query_cache.rb:8:in
cache’
/usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/caching.rb:677:in
perform_action' /usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/base.rb:524:in
send’
/usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/base.rb:524:in
process_without_filters' /usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/filters.rb:685:in
process_without_session_management_support’
/usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/session_management.rb:123:in
process' /usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/base.rb:388:in
process’
/usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/dispatcher.rb:171:in
handle_request' /usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/dispatcher.rb:115:in
dispatch’
/usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/dispatcher.rb:126:in
dispatch_cgi' /usr/local/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/dispatcher.rb:9:in
dispatch’
/usr/local/lib/ruby/gems/1.8/gems/rails-2.0.2/lib/webrick_server.rb:112:in
handle_dispatch' /usr/local/lib/ruby/gems/1.8/gems/rails-2.0.2/lib/webrick_server.rb:78:in
service’
/usr/local/lib/ruby/1.8/webrick/httpserver.rb:104:in service' /usr/local/lib/ruby/1.8/webrick/httpserver.rb:65:in
run’
/usr/local/lib/ruby/1.8/webrick/server.rb:173:in start_thread' /usr/local/lib/ruby/1.8/webrick/server.rb:162:in
start’
/usr/local/lib/ruby/1.8/webrick/server.rb:162:in start_thread' /usr/local/lib/ruby/1.8/webrick/server.rb:95:in
start’
/usr/local/lib/ruby/1.8/webrick/server.rb:92:in each' /usr/local/lib/ruby/1.8/webrick/server.rb:92:in
start’
/usr/local/lib/ruby/1.8/webrick/server.rb:23:in start' /usr/local/lib/ruby/1.8/webrick/server.rb:82:in
start’
/usr/local/lib/ruby/gems/1.8/gems/rails-2.0.2/lib/webrick_server.rb:62:in
dispatch' /usr/local/lib/ruby/gems/1.8/gems/rails-2.0.2/lib/commands/servers/webrick.rb:66 /usr/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in
gem_original_require’
/usr/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in
require' /usr/local/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:496:in
require’
/usr/local/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:342:in
new_constants_in' /usr/local/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:496:in
require’
/usr/local/lib/ruby/gems/1.8/gems/rails-2.0.2/lib/commands/server.rb:39
/usr/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in
gem_original_require' /usr/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in
require’
script/server:3
Request
Parameters:
{“id”=>“weblog”}
Show session dump
:csrf_id: d13a9d7dbf67db04912fb3bdfe1dc0bc
flash: !map:ActionController::Flash::FlashHash {}
Response
Headers:
{“cookie”=>[],
“Cache-Control”=>“no-cache”}
Any ideas???