Rails can't access struct variables

[Yagiz Nizipli]

Hello,

I am using Rails 4.0 and Ruby 2.0, in terminal I can easily access a IP's information, but on Rails this code gives an error to the structs variable.

<% lat = GeoIP.new("#{Rails.root}/public/GeoLiteCity.dat").city("#{user.ip}") %>
<%= lat.country_code2 %>

In this code, "country_code2" gives an "undefined method `country_code2' for nil:NilClass" error, but when I do

<% lat = GeoIP.new("#{Rails.root}/public/GeoLiteCity.dat").city("#{user.ip}") %>
<%= lat %>

It prints the struct properly. Is this a gem issue or a Rails misconfiguration?

[Clifford Heath]

I haven't tested GeoIP with Rails 4 yet, but the message
"undefined method `country_code2' for nil:NilClass"
means that your variable "lat" is nil, which will be because
the call to city() didn't find the "user.ip" that you passed.
So I suspect it's just a user error.

On 11/07/2013, at 12:32 AM, ynizipli [e-mail] wrote:

Hello,

I am using Rails 4.0 and Ruby 2.0, in terminal I can easily access a IP's information, but on Rails this code gives an error to the structs variable.

<% lat = GeoIP.new("#{Rails.root}/public/GeoLiteCity.dat").city("#{user.ip}") %>
<%= lat.country_code2 %>

In this code, "country_code2" gives an "undefined method `country_code2' for nil:NilClass" error, but when I do

<% lat = GeoIP.new("#{Rails.root}/public/GeoLiteCity.dat").city("#{user.ip}") %>
<%= lat %>

It prints the struct properly. Is this a gem issue or a Rails misconfiguration?

—
Reply to this email directly or view it on GitHub.

[Yagiz Nizipli]

Hello,

When I print the variable @lat, it prints correctly. But separating the struct and accessing its sub-variables is the part which creates an error.

Yagiz Nizipli
Sabanci University

On Thursday, July 11, 2013 at 12:40 AM, Clifford Heath wrote:

I haven't tested GeoIP with Rails 4 yet, but the message
"undefined method `country_code2' for nil:NilClass"
means that your variable "lat" is nil, which will be because
the call to city() didn't find the "user.ip" that you passed.
So I suspect it's just a user error.

On 11/07/2013, at 12:32 AM, ynizipli <[e-mail] (mailto:[e-mail])> wrote:

Hello,

I am using Rails 4.0 and Ruby 2.0, in terminal I can easily access a IP's information, but on Rails this code gives an error to the structs variable.

<% lat = GeoIP.new("#{Rails.root}/public/GeoLiteCity.dat").city("#{user.ip}") %>
<%= lat.country_code2 %>

In this code, "country_code2" gives an "undefined method `country_code2' for nil:NilClass" error, but when I do

<% lat = GeoIP.new("#{Rails.root}/public/GeoLiteCity.dat").city("#{user.ip}") %>
<%= lat %>

It prints the struct properly. Is this a gem issue or a Rails misconfiguration?

—
Reply to this email directly or view it on GitHub.

—
Reply to this email directly or view it on GitHub (#30 (comment)).

[Clifford Heath]

On 11/07/2013, at 8:46 AM, ynizipli [e-mail] wrote:

When I print the variable @lat, it prints correctly. But separating the struct and accessing its sub-variables is the part which creates an error.

Sorry, but I don't believe you. Read your original code and error message:

<% lat = GeoIP.new("#{Rails.root}/public/GeoLiteCity.dat").city("#{user.ip}") %>
<%= lat.country_code2 %>

gives an "undefined method `country_code2' for nil:NilClass"

Ruby is telling you that "lat" is nil, and nil doesn't have a country_code2 message.
Try including the debugger gem, put a "debugger" call in between those two lines,
and look at the value of lat.

You should not assume that calling "city" will always return an object that responds
to country_code2. Sometimes it returns nil, as in this case, so your code should check
for that.

[Yagiz Nizipli]

Result of:

<% lat = GeoIP.new("#{Rails.root}/public/GeoLiteCity.dat").city("#{user.ip}") %>
<%= lat %>

[ { #<struct GeoIP::City request="85.162.251.16", ip="85.162.251.16", country_code2="SK", country_code3="SVK", country_name="Slovakia", continent_code="EU", region_name="", city_name="", postal_code="", latitu......

Result of:

<% lat = GeoIP.new("#{Rails.root}/public/GeoLiteCity.dat").city("#{user.ip}") %>
<%= lat.country_code2 %>

undefined method `country_code2' for nil:NilClass

<%= lat.country_code2 %> is highlighted.

[Clifford Heath]

Ok, that's new evidence - you hadn't established that before. Wierd... I'll investigate.

[Yagiz Nizipli]

What can I do to help?

[Clifford Heath]

I've updated my Ruby2.0.0 to p247, and can't reproduce your problem (but I'm not in Rails). However, the result of printing "lat" above starts with the characters [{#struct... whereas lat.inspect just says #<struct...

I honestly don't think that this is a problem with GeoIP. Something is going on within your ERB templates however, since the error message definitely indicates that "lat" is Nil in the case where "country_code2" is undefined. Perhaps put both lines inside one <%= ... %> pair?

I'l re-open this is you can show that it's really a problem with GeoIP. At the moment I have no evidence that it is.