Use the pretty_generate() function, built into later versions of JSON. For example:
require 'json'
my_object = { :array => [1, 2, 3, { :sample => "hash"} ], :foo => "bar" }
puts JSON.pretty_generate(my_object)
Which gets you:
{
"array": [
1,
2,
3,
{
"sample": "hash"
}
],
"foo": "bar"
}
rename_column :table, :old_column, :new_column
You'll probably want to create a separate migration to do this. (Rename FixColumnName as you will.):
script/generate migration FixColumnName
# creates db/migrate/xxxxxxxxxx_fix_column_name.rb
Then edit the migration to do your will:
# db/migrate/xxxxxxxxxx_fix_column_name.rb
class FixColumnName < ActiveRecord::Migration
def self.up
rename_column :table_name, :old_column, :new_column
end
def self.down
# rename back if you need or do something else or do nothing
end
end
For Rails 3.1 use:
While, the up and down methods still apply, Rails 3.1 receives a change method that "knows how to migrate your database and reverse it when the migration is rolled back without the need to write a separate down method".
See "Active Record Migrations" for more information.
rails g migration FixColumnName
class FixColumnName < ActiveRecord::Migration
def change
rename_column :table_name, :old_column, :new_column
end
end
If you happen to have a whole bunch of columns to rename, or something that would have required repeating the table name over and over again:
rename_column :table_name, :old_column1, :new_column1
rename_column :table_name, :old_column2, :new_column2
...
You could use change_table to keep things a little neater:
class FixColumnNames < ActiveRecord::Migration
def change
change_table :table_name do |t|
t.rename :old_column1, :new_column1
t.rename :old_column2, :new_column2
...
end
end
end
Then just db:migrate as usual or however you go about your business.
For Rails 4:
While creating a Migration for renaming a column, Rails 4 generates a change method instead of up and down as mentioned in the above section. The generated change method is:
$ > rails g migration ChangeColumnName
which will create a migration file similar to:
class ChangeColumnName < ActiveRecord::Migration
def change
rename_column :table_name, :old_column, :new_column
end
end
Best Answer
I just had this problem. I was not providing a body for the email, and was sending the attachment only. Unfortunately, it appears that SendGrid gets confused by this, sending an empty email (which is expected) with an empty attachment (which is neither expected nor desired).
Therefore, the solution: provide a body for the email. In your specific case, an
/app/views/application_mailer/welcome.text.erbtemplate with a simple text, saying "See attached" or whatever appropriate.