feat: create links - route + controller + model + migration

.gitignore

@@ -4,3 +4,4 @@
 /.shards/
 *.dwarf
 *.db
+.env.*

db/migrations/20240512214223_create_links.sql

@@ -0,0 +1,14 @@
+-- +micrate Up
+-- SQL in section 'Up' is executed when this migration is applied
+CREATE TABLE links (
+	id INTEGER PRIMARY KEY AUTOINCREMENT,
+	slug VARCHAR(100) UNIQUE NOT NULL,
+	url TEXT NOT NULL,
+	click_counter INTEGER DEFAULT 0,
+	created_at INTEGER DEFAULT CURRENT_TIMESTAMP NOT NULL,
+	updated_at INTEGER DEFAULT CURRENT_TIMESTAMP NOT NULL
+);
+
+-- +micrate Down
+-- SQL section 'Down' is executed when this migration is rolled back
+DROP TABLE links;

shard.yml

@@ -1,4 +1,4 @@
-name: pa
+name: url-shortener
 version: 0.1.0
 
 authors:
@@ -6,7 +6,7 @@ authors:
 
 targets:
   pa:
-    main: src/pa.cr
+    main: src/url-shortener.cr
 
 dependencies:
   kemal:

src/controllers/link.cr

@@ -0,0 +1,25 @@
+require "../lib/controller.cr"
+
+module App::Controllers::Link
+  class Create < App::Lib::BaseController
+    include App::Models
+    include App::Lib
+
+    def call(env)
+      params = env.params.json["link"].as(Hash)
+
+      link = Link.new
+      link.url = params["url"].as_s
+      link.slug = Random::Secure.urlsafe_base64(4)
+
+      changeset = Database.insert(link)
+
+      if !changeset.valid?
+        errors = {"errors" => map_changeset_errors(changeset.errors)}
+        raise App::UnprocessableEntityException.new(env, errors.to_json)
+      end
+
+      App::Serializers::Link.new(link).to_json
+    end
+  end
+end

src/controllers/ping.cr

@@ -1,7 +1,7 @@
 require "../lib/controller.cr"
 
-module Pa::Controllers::Ping
+module App::Controllers::Ping
-  class Get < Pa::Lib::BaseController
+  class Get < App::Lib::BaseController
     def call(env)
       response = {"pong" => "ok"}
       response.to_json

src/lib/controller.cr

@@ -1,4 +1,11 @@
-module Pa::Lib
+module App::Lib
   abstract class BaseController
+     def map_changeset_errors(errors)
+      errors.reduce({} of String => Array(String)) do |memo, error|
+        memo[error[:field]] = memo[error[:field]]? || [] of String
+        memo[error[:field]] << error[:message]
+        memo
+      end
+    end
   end
 end

src/lib/database.cr

@@ -1,7 +1,7 @@
 require "sqlite3"
 require "crecto"
 
-module Pa::Lib
+module App::Lib
   class Database
     extend Crecto::Repo
 
@@ -9,8 +9,7 @@ module Pa::Lib
     Multi = Crecto::Repo::Multi
 
     config do |conf|
-      conf.adapter = Crecto::Adapters::SQLite3
+      conf.uri = ENV["DATABASE_URL"]
-      conf.database = ENV["DATABASE_URL"]
     end
   end
 end

src/lib/errors.cr

@@ -0,0 +1,33 @@
+require "kemal"
+
+module App
+  class UnauthorizedException < Kemal::Exceptions::CustomException
+    def initialize(context)
+      context.response.status_code = 401
+      super(context)
+    end
+  end
+
+  class ForbiddenException < Kemal::Exceptions::CustomException
+    def initialize(context)
+      context.response.status_code = 403
+      super(context)
+    end
+  end
+
+  class NotFoundException < Kemal::Exceptions::CustomException
+    def initialize(context)
+      context.response.status_code = 404
+      super(context)
+    end
+  end
+
+  class UnprocessableEntityException < Kemal::Exceptions::CustomException
+    def initialize(context, @content = "")
+      context.response.status_code = 422
+      super(context)
+    end
+
+    getter :content
+  end
+end

src/models/link.cr

@@ -0,0 +1,14 @@
+require "sqlite3"
+require "crecto"
+
+module App::Models
+  class Link < Crecto::Model
+    schema :links do
+      field :slug, String
+      field :url, String
+      field :click_counter, Int64
+    end
+
+    validate_required [:slug, :url]
+  end
+end

src/routes.cr

@@ -1,7 +1,15 @@
 require "./controllers/**"
 
-module Pa
+module App
+  before_all do |env|
+    env.response.content_type = "application/json"
+  end
+
   get "/api/ping" do |env|
     Controllers::Ping::Get.new.call(env)
   end
+
+  post "/api/links" do |env|
+    Controllers::Link::Create.new.call(env)
+  end
 end

src/serializers/link.cr

@@ -0,0 +1,17 @@
+require "json"
+
+require "../models/link"
+
+module App::Serializers
+  class Link
+    def initialize(@link : App::Models::Link)
+    end
+
+    def to_json(builder : JSON::Builder)
+      builder.object do
+        builder.field("origin", @link.url)
+        builder.field("link", "#{ENV["APP_URL"]}/#{@link.slug}")
+      end
+    end
+  end
+end

src/url-shortener.cr

@@ -1,7 +1,10 @@
 require "kemal"
 
 require "./config/*"
-require "./services/*"
+require "./lib/*"
+require "./models/*"
+require "./serializers/*"
+
 require "./routes"
 
 error 500 { |env| {"status" => 500, "error" => "Internal Server Error"}.to_json }

src/version.cr

@@ -1,3 +1,3 @@
-module Pa
+module App
   VERSION = "0.1.0"
 end