# How to overwrite a method?

**URL:** <https://discuss.rubyonrails.org/t/how-to-overwrite-a-method/36144>\
**Category:** rubyonrails-talk\
**Created:** [November 7, 2008, 11:17am UTC](https://discuss.rubyonrails.org/t/how-to-overwrite-a-method/36144 "2008-11-07T11:17:02Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Frederick\_Cheung](https://sea2.discourse-cdn.com/rubyonrails/user_avatar/discuss.rubyonrails.org/frederick_cheung/32/3901_2.png) [@Frederick\_Cheung](https://discuss.rubyonrails.org/u/Frederick_Cheung)\
**Post date:** [November 7, 2008, 11:17am UTC](https://discuss.rubyonrails.org/t/how-to-overwrite-a-method/36144/1 "2008-11-07T11:17:02Z")

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> Hi,
> 
> The following file within rails /activeresource/lib/active\_resource/formats/xml\_format.rb
> 
> Has the method def extension &nbsp;&nbsp;"xml" end
> 
> How can I overwrite this so that it returns PHP without editing any  
> core file?

just reopen that class class WhateverItIs &nbsp;&nbsp;&nbsp;def extension &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;"php" &nbsp;&nbsp;&nbsp;end end