Rails Best Practices Characteristics of good code 1) Maintainability 2) Readability 3) Flexibility 4) Easy Delegation

2. Rails Best Practices

3. What’s Good Code?
Good code is like a Good Joke!!
It needs no explanation!!

4. How to write Good Code?
Follow Best Practices
Characteristics of a good code:
 Maintainability
 Readability
 Flexibility
 Easy Delegation

5. Fat Model, Skinny Controller

6. SQL Injection
 Prevent SQL injection by using ? to set the params of
the query
 Bad Practice
 Good Practice

7. N + 1 queries problem
Consider the following code which finds 10 clients and prints their postcodes
Total queries executed here are 11. 1 to fine 10clients and then 10(1
per each client to find its address)

8. Solution to N+1 queries
problem
Eager Loading
Use “includes”. With includes, ActiveRecord ensures that all of the
specified associations are loaded using minimum possible queries.

9. Use Scopes
 Bad Practice
 Good Practice

10. Use Query Attribute
 Do you always check if ActiveRecord’s attributes exists
or are blank? present?
 Rails provides a cleaner way by query attribute
 Bad Practice
 Good Practice
 Each attribute of ActiveRecord’s model has a query
method, so you don’t need to use present? blank?

11. Annotate your models
 Don’t go to schema.rb file everytime to find the table
structure information.
 We have a easier way. Use gem annotate
https://github.com/ctran/annotate_models
 It will automatically add comments at the top and
bottom of your models to list the table structures
information

12. Use model association
Good Practice
Bad Practice:

13. Protect Mass Assignment
Problem :
Solution: You can use attr_protected to declare a blacklist of variables you
don’t want it to be assigned

14. DRY Code
 Don’t repeat the code in controller. You can avoid that
using before_filter
 Eg: Bad practice

15. Removing repeated code
 As you saw in previous slide, below statement was
repeated in all actions. We can avoid it if we use before
filter
 Good Practice

16. References
 http://guides.rubyonrails.org/
 http://rails-bestpractices.com/
 Gem for code metric tool for rails-projects
https://github.com/railsbp/rails_best_practices
 Online service to find security issues in rails project
http://rails-brakeman.com/
 https://github.com/presidentbeef/brakeman

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