How do I use Active Support core extensions?

问题

I have Active Support 3.0.3 installed and Rails 3.0.3 with Ruby 1.8.7.

When I try to use 1.week.ago I get

NoMethodError: undefined method 'week' for 1:Fixnum
from (irb):2

The other core extensions seem to work. I tried it on a friend's computer (same install specs and legacy versions are on his) with the same results.

What gives?

All of this is in IRB.

回答1:

Since using Rails should handle this automatically I'm going to assume you're trying to add Active Support to a non-Rails script.

Read "How to Load Core Extensions".

Active Support's methods got broken into smaller groups in Rails 3, so we don't end up loading a lot of unneeded stuff with a simple require 'activesupport'. Now we have to do things like require 'active_support/core_ext/object/blank'

If you don't care about granularity, you can choose to load bigger chunks. If you want everything in one big gulp use...

For 1.9.2:

rvm 1.9.2
irb -f
irb(main):001:0> require 'active_support/all'
=> true
irb(main):002:0> 1.week.ago
=> 2010-11-14 17:56:16 -0700
irb(main):003:0> 

For 1.8.7:

rvm 1.8.7
irb -f
irb(main):001:0> require 'rubygems'
=> true
irb(main):002:0> require 'active_support/all'
=> true
irb(main):003:0> 1.week.ago
=> Sun Nov 14 17:54:19 -0700 2010
irb(main):004:0> 

回答2:

You can granularly add libraries via the already mentioned

require 'active_support/core_ext/some_class/some_file'

There is also another level up where you can

require 'active_support/core_ext/some_class'

But, at the moment, this is unfortunately not available for Time, Date and DateTime.

A way around this is to require 'active_support/time' which will give you Time, Date and DateTime which would solve the OP was asking for without requiring everything.

---

My Rails patch, which adds active_support/core_ext/date and date_time, made it into Rails v4.0.0, so now you can require these individually. YAY!

回答3:

In my case the following link worked:

https://bundler.io/blog/2019/01/04/an-update-on-the-bundler-2-release.html

$ cat Gemfile.lock | grep -A 1 "BUNDLED WITH"
BUNDLED WITH
   1.17.3

$ gem install bundler -v '1.17.3'

回答4:

Does this work from the console? This is working for me:

$ sw_vers
ProductName:    Mac OS X
ProductVersion: 10.6.5
BuildVersion:   10H574

$ rails c
Loading development environment (Rails 3.0.3)
>> 1.week.ago
=> Sun, 14 Nov 2010 16:57:18 UTC +00:00

回答5:

You can :
require 'active_support/core_ext'
or :
require 'active_support/all'

来源：https://stackoverflow.com/questions/4238867/how-do-i-use-active-support-core-extensions