Blow up when things are wrong

When something unexpected happens, you should know about it immediately to make debugging and fixing the problem easier. Discusses ActiveRecord persistence APIs.

Transcript

1. Blow up when
   things are wrong
   ActiveRecord edition
   Vesa Vänskä, Kisko Labs
   Helsinki Ruby Brigade, Rails Girls
   

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2. When something
   is wrong, you
   should know
   about it as fast as
   possible
   

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3. #save vs #save!
   

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4. foo.save!
   # or
   if foo.save
   # success
   else
   # fail
   end
   

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5. The case of
   updating
   attributes
   

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6. Validations Callbacks
   #update_attributes ✔ ✔
   #update_attribute ✖ ✔
   

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7. Question
   

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8. Which of #decrement,
   #decrement!, and
   #decrement_counter
   skip validations/
   callbacks?
   

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9. Validations Callbacks
   #decrement ✔ ✖
   #decrement! ✖ ✔
   #decrement_counter ✖ ✖
   

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10. http://guides.rubyonrails.org/
    active_record_validations_callba
    cks.html
    

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11. ATK
    Do Not Want
    RubyGem
    https://github.com/
    garybernhardt/do_not_want
    

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12. Making it simpler
    

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13. In Rails 3.2.7 the
    #update_attribute method was
    actually deprecated
    

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14. 14.6.2012 – #update_attribute is deprecated in 3.2
    branch
    14.6.2012 – #update_attribute was removed from 4.0
    branch
    24.7.2012 – #update_column was deprecated in 4.0
    branch
    26.7.2012 – Rails 3.2.7 release
    30.7.2012 – #update_column is undeprecated in 4.0
    branch
    1.8.2012 – #update_attribute is undeprecated in 3.2
    branch
    25.8.2012 – #update_attribute is put back in 4.0
    branch
    9.8.2012 – Rails 3.2.8 release
    

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15. • https://github.com/rails/rails/commit/
    b081f6b59fb3f15d12043072ad9b331ffd2bc56e
    • https://github.com/rails/rails/pull/6738
    • https://github.com/rails/rails/pull/1190
    • https://github.com/rails/rails/commit/
    4ac81de52fbcdabc68f6d1fa8a5ee9ff7fff7df1
    • https://github.com/rails/rails/commit/
    50bdb924ba26999a468ec4844917cefec39ba08c
    • https://github.com/rails/rails/commit/
    81542f95d25825a7d3eff87d6f706661bf553b18
    Links
    

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16. I
    

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17. What is the
    current status?
    

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18. After all this
    •In Rails 4 the recommended way
    is to use #update with a hash
    •#update_attributes is aliased to
    #update
    •#update_attribute is still skipping
    validations
    

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19. Vesa's laws of
    updating attributes
    1. Use #update_attributes or use
    setters and #save/#save!
    2. All other methods of updating
    attributes need an accompanying
    comment that explains why you
    didn't follow the first rule.
    

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20. Useless ActiveResource
    information
    •ActiveResource #update_attribute
    will run validations normally
    

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21. Extra Ruby tip
    

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22. {foo: "bar"}[:foo]
    {foo: "bar"}.fetch(:foo)
    

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23. {foo: "bar"}[:foo] #=> "bar"
    {foo: "bar"}.fetch(:foo)
    #=> "bar"
    

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24. {foo: "bar"}[:whatevs]
    {foo: "bar"}.fetch(:whatevs)
    

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25. {foo: "bar"}[:whatevs] #=> nil
    {foo: "bar"}.fetch(:whatevs)
    #=> KeyError: key not
    found: :whatevs
    

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26. {foo: "bar"}
    .fetch(:whatevs, :not_found)
    #=> :not_found
    {foo: "bar"}
    .fetch(:whatevs) { 1 + 1 }
    #=> 2
    

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27. Thank you!
    twitter.com/vesan
    vesavanska.com
    

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