Unable to get past Tutorial 1 in RubyOnRails

Unable to get past Tutorial 1 in RubyOnRails

On 29 April 2006 I met some one in a Microsoft sponsored developersâ??
community gahering. I was told that ruby on rails is a free software,
easy to use, and in no time will have my mind blown with all the
wonderful prospects and possibilities.

After almost a week, I am still unable to get past tutorial 1 and still
unable to make any tutorials work so far.

I have watched a few videos and demos from the web and I have browsed
through half a book on programming ruby.

I have tried
http://www.onlamp.com/pub/a/onlamp/2005/01/20/rails.html?page=1
Encountered some problems such as â??Port 80 for Apache was being used by
some other process�, and being unable to connect to my mySql in the
local host.

So I switched to a newer version of the tutorial in
http://instantrails.rubyforge.org/tutorial/index.html
I encountered similar problems.

So, I moved on to try the tutorial in the site
http://rails.homelinux.org/ for 4 days on rails.
I couldnâ??t even get into day 1, so to say.

I also tried the tutorial on
http://wiki.rubyonrails.org/rails/pages/Tutorial and didnâ??t get to point
of â??Congratulations, youâ??re on Rails!â?
I browsed through the 6 part tutorials, but didnâ??t gained much.
After that I went back to
http://instantrails.rubyforge.org/tutorial/index.html
Un-installed and re-installed a few times until I came to the part where
â??Editâ? a recipe was introduced and got stuck.

So, I turned to the Forum for help, stating my problem as best I could.

I was advised to look at the codes in the pre-installed â??cookbookâ?. I
went through the processes and found that each of the step work.

Since the â??Editâ? part didnâ??t work in my exercise in â??cookbook2â?, I
copied the whole folder â??Appâ? from â??cookbookâ? to â??cookbook2â? so the
codes are idential.

I removed the database â??cookcook2â? and used the MySQL-Front 3.2 to
create a new database â??cookbook2â? and check to make sure that the tables
and fields resembled those of the pre-installed â??cookbookâ?.

I was able to log into the website to create the required categories so
that they wouldnâ??t be empty when I tried to create new recipes.

Some one please help!

I was able to to enter the website to create a new recipe, using
http://localhost:3000/recipe/new

Problem came when I pressed to â??Createâ? button.

This brought me to the url: http://localhost:3000/recipe/list

Error message:
NoMethodError in Recipe#list
Showing app/views/recipe/list.rhtml where line #23 raised:
You have a nil object when you didn’t expect it!
The error occured while evaluating nil.name
Extracted source (around line #23):
20:
21:
22:


23: <%= link_to recipe.category.name,
24: :action => “list”,
25: :category => “#{recipe.category.name}” %>
26:
RAILS_ROOT: ./script/…/config/…
Application Trace | Framework Trace | Full Trace
#{RAILS_ROOT}/app/views/recipe/list.rhtml:23
#{RAILS_ROOT}/app/views/recipe/list.rhtml:8
Request
Parameters: None
Show session dump
Response
Headers: {“cookie”=>[], “Cache-Control”=>“no-cache”}

the error basically means that the category is nil (i.e.
cookbook.nil.name)

hope this helps.

Yes, this is correct. Go look at your recipes table and make sure that
every
recipe has an assigned category.

Curt

Curt H. wrote:

Yes, this is correct. Go look at your recipes table and make sure that
every
recipe has an assigned category.

Curt

Hi, All

I found my mistake in the database setting.

The field “title” in the table [recipes] doesnot allow null and I set
the default to [null].

Once I corrected this mistake, the application is running.

Thanks for your advice that led me me to discover the mistake.

Now, I can proceed to a new tutorial.

Regards,

Ling.

Greetings.

Thanks for the reply. At this stage I still donâ??t know enough of the
syntax of ruby. Even though I have guessed that it means category or
recipe is nil, I still donâ??t know how to resolve the problem.

What puzzles me is that the codes work in â??cookbookâ? but not in
â??cookbook2â?.

The same problem occurred when I tried to show the list of recipes when
there were none. Isnâ??t it possible to display an empty list in ruby?

Can some one help? Or do I need to finish reading the book â??Programming
in ruby� before I can work the tutorial 1?

Regards,

Ling.

The codes behind the module â??list.rhtmlâ? is repordued as follows:

<% @recipes.each do |recipe| %>
<% if (@category == nil) || (@category == recipe.category.name)%>


Recipe

Category

Date


<%= link_to recipe.title,
:action => “show”,
:id => recipe.id %>
    <%= link_to "(delete)",
                {:action => "delete", :id => recipe.id},
                :confirm => "Really delete #{recipe.title}?" %>
    </font>
  </td>
  <td>
    <%= link_to recipe.category.name,
                :action => "list",
                :category => "#{recipe.category.name}" %>
  </td>
  <td><%= recipe.date %></td>
 </tr>

<% end %>
<% end %>

cyx wrote:

the error basically means that the category is nil (i.e.
cookbook.nil.name)

hope this helps.

Thanks. Curt.

I have created 3 categories before I tried to create the first recipe.

I chose a category from the drop down. So there was a category for the
new recipe to be created.

It appears that the recipe list was empty up till then.

When I pressed the “Create” button, the error message as shown appeared.

The same message appeared when I tried to display the recipes when there
were none.

So, what is the problem?

Regards,

Ling

Curt H. wrote:

Yes, this is correct. Go look at your recipes table and make sure that
every
recipe has an assigned category.

Curt

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