How to list all methods for an object in Ruby

Question

How do I list all the methods that a particular object has access to   I have a  current user object  defined in the application controller   def current user    current user     User find session  user id   if session  user id  end   And want to see what methods I have available to me in the view file  Specifically  I want to see what methods a  has many association provides   I know what  has many should provide  but want to check that

User · Answer

If You are looking list of methods which respond by an instance (in your case @current_user). According to ruby documentation methods

Returns a list of the names of public and protected methods of obj. This will include all the methods accessible in obj's ancestors. If the optional parameter is false, it returns an array of obj's public and protected singleton methods, the array will not include methods in modules included in obj.

@current_user.methods
@current_user.methods(false) #only public and protected singleton methods and also array will not include methods in modules included in @current_user class or parent of it.

Alternatively, You can also check that a method is callable on an object or not?.

@current_user.respond_to?:your_method_name

If you don't want parent class methods then just subtract the parent class methods from it.

@current_user.methods - @current_user.class.superclass.new.methods #methods that are available to @current_user instance.

User · Answer

You can do   current user methods   For better listing  puts   n current user methods      current user methods sort join   n   to s   n n

User · Answer

To expound upon  clyfe s answer  You can get a list of your instance methods using the following code  assuming that you have an Object Class named  Parser     Parser new methods - Object new methods

User · Answer

Module instance methods     Returns an array containing the names of the public and protected instance methods in the receiver  For a module  these are the public and protected methods  for a class  they are the instance  not singleton  methods  With no argument  or with an argument that is false  the instance methods in mod are returned  otherwise the methods in mod and mod   s superclasses are returned    module A   def method1    end end class B   def method2    end end class C  lt  B   def method3    end end  A instance methods                   gt    method1  B instance methods false             gt    method2  C instance methods false             gt    method3  C instance methods true  length      gt  43

User · Answer

Or just User methods false  to return only the methods defined within that class

User · Answer

What about one of these   object methods sort Class methods sort

User · Answer

Suppose User has many Posts   u   User first u posts methods u posts methods - Object methods

User · Answer

The following will list the methods that the User class has that the base Object class does not have      gt  gt  User methods - Object methods   gt    field types    maximum    create     active connections    to dropdown        content columns    su pw     default timezone    encode quoted value         reloadable     update    reset sequence name    default timezone          validate find options    find on conditions without deprecation         validates size of    execute simple calculation    attr protected         reflections    table name prefix         Note that methods is a method for Classes and for Class instances    Here s the methods that my User class has that are not in the ActiveRecord base class    gt  gt  User methods - ActiveRecord  Base methods   gt    field types    su pw     set login attr    create user and conf user         original table name    field type    authenticate    set default order        id name     id name column    original locking column    default order        subclass associations           I ran the statements in the console    Note that the methods created as a result of the  many  has many relationships defined in the User class are not in the results of the methods call   Added Note that  has many does not add methods directly  Instead  the ActiveRecord machinery uses the Ruby method missing and responds to techniques to handle method calls on the fly  As a result  the methods are not listed in the methods method result

[ruby-on-rails] How to list all methods for an object in Ruby?

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