Rails has an except/except! method that returns the hash with those keys removed. If you’re already using Rails, there’s no sense in creating your own version of this. class Hash # Returns a hash that includes everything but the given keys. # hash = { a: true, b: false, c: nil} # hash.except(:c) # => … Read more
db:migrate runs (single) migrations that have not run yet. db:create creates the database db:drop deletes the database db:schema:load creates tables and columns within the existing database following schema.rb. This will delete existing data. db:setup does db:create, db:schema:load, db:seed db:reset does db:drop, db:setup db:migrate:reset does db:drop, db:create, db:migrate Typically, you would use db:migrate after having made … Read more
remove_column :table_name, :column_name For instance: remove_column :users, :hobby would remove the hobby Column from the users table.
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” }
Use rand(range) From Ruby Random Numbers: If you needed a random integer to simulate a roll of a six-sided die, you’d use: 1 + rand(6). A roll in craps could be simulated with 2 + rand(6) + rand(6). Finally, if you just need a random float, just call rand with no arguments. As Marc-André Lafortune … Read more
It looks like in Ubuntu that header is part of the libpq-dev package (at least in the following Ubuntu versions: 11.04 (Natty Narwhal), 10.04 (Lucid Lynx), 11.10 (Oneiric Ocelot), 12.04 (Precise Pangolin), 14.04 (Trusty Tahr) and 18.04 (Bionic Beaver)): … /usr/include/postgresql/libpq-fe.h … So try installing libpq-dev or its equivalent for your OS: For Ubuntu/Debian systems: … Read more
rake db:rollback STEP=1 Is a way to do this, if the migration you want to rollback is the last one applied. You can substitute 1 for however many migrations you want to go back. For example: rake db:rollback STEP=5 Will also rollback all the migration that happened later (4, 3, 2 and also 1). To … Read more
What happens When the user views a form to create, update, or destroy a resource, the Rails app creates a random authenticity_token, stores this token in the session, and places it in a hidden field in the form. When the user submits the form, Rails looks for the authenticity_token, compares it to the one stored … Read more
The problem is still your pg_hba.conf file*. This line: local all postgres peer Should be: local all postgres md5 After altering this file, don’t forget to restart your PostgreSQL server. If you’re on Linux, that would be sudo service postgresql restart. Locating hba.conf Note that the location of this file isn’t very consistent. You can … Read more
For Rails 3.2 or Rails 4+ You should use request.original_url to get the current URL. Source code on current repo found here. This method is documented at original_url method, but if you’re curious, the implementation is: def original_url base_url + original_fullpath end For Rails 3: You can write “#{request.protocol}#{request.host_with_port}#{request.fullpath}”, since request.url is now deprecated. For … Read more