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class Api::Users::Show < ApiAction
get "/api/users/:user_id" do
user = UserQuery.find(user_id)
json UserSerializer.new(user)
end
end
get "/sign_in"
for non REST routes.user_id
method is generated because there is a user_id
route parameter.json
to render JSON. Extract
serializers
for reusable JSON responses.# Set up the model
class User < BaseModel
table do
column last_active_at : Time
column last_name : String
column nickname : String?
end
end
?
to the type when the column can be nil
. Crystal will then
help you remember not to call methods on it that won't work.last_active_at
and last_name
since they are not marked as nilable).# Add some methods to help query the database
class UserQuery < User::BaseQuery
def recently_active
last_active_at.gt(1.week.ago)
end
def sorted_by_last_name
last_name.lower.desc_order
end
end
# Query the database
UserQuery.new.recently_active.sorted_by_last_name
User::BaseQuery
is automatically generated when you define a model. Inherit
from it to customize queries.lower
method on a String
column to make sure Postgres sorts
everything in lowercase.gt
to get users last active greater than 1 week ago. Lucky has lots
of powerful abstractions for creating complex queries, and type specific
methods (like lower
).class Users::Index < BrowserAction
get "/users" do
users = UserQuery.new.sorted_by_last_name
render IndexPage, users: users
end
end
class Users::IndexPage < MainLayout
needs users : UserQuery
def content
render_new_user_button
render_user_list
end
private def render_new_user_button
link "New User", to: Users::New
end
private def render_user_list
ul class: "user-list" do
users.each do |user|
li do
link user.name, to: Users::Show.with(user.id)
text " - "
text user.nickname || "No Nickname"
end
end
end
end
end
needs users : UserQuery
tells the compiler that it must be passed users
of the type UserQuery
.Users::New
. Pass
params using with
: Users::Show.with(user.id)
. No more trying to remember path
helpers and whether the helper is pluralized or not - If you forget to pass a
param to a route, Lucky will let you know at compile-time.column nickname : String?
as nilable, Lucky would fail
to compile the page if you just did text user.nickname
since it disallows
printing nil
. So instead we add a fallback "No Nickname"
. No more
accidentally printing empty text in HTML!You need to make sure to install the Crystal dependencies.
shards install
crystal spec
from the project root.See CONTRIBUTING.md
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based heavily on Sentry. Thanks @samueleaton!