feat: Repository is non-generic

Closes #3

Author: vladfaust

README.md

@@ -87,26 +87,24 @@ end
 
 db = DB.open(ENV["DATABASE_URL"])
 query_logger = Core::QueryLogger.new(STDOUT)
-
-user_repo = Core::Repository(User).new(db, query_logger)
-post_repo = Core::Repository(Post).new(db, query_logger)
+repo = Core::Repository.new(db, query_logger)
 
 user = User.new(name: "Fo")
 user.valid? # => false
 user.errors # => [{:name => "length must be >= 3"}]
 user.name = "Foo"
 user.valid? # => true
 
-user.id = user_repo.insert(user) # See ^1
+user.id = repo.insert(user) # See ^1
 # INSERT INTO users (name, created_at) VALUES ($1, $2) RETURNING id
 
 post = Post.new(author: user, content: "Foo Bar")
-post.id = post_repo.insert(post) # See ^1
+post.id = repo.insert(post) # See ^1
 # INSERT INTO posts (author_id, content, created_at) VALUES ($1, $2, $3) RETURNING id
 
 alias Query = Core::Query
 
-posts = post_repo.query(Query(Post).where(author: user))
+posts = repo.query(Query(Post).where(author: user))
 # SELECT * FROM posts WHERE author_id = $1
 
 posts.first.content # => "Foo Bar"
@@ -116,7 +114,7 @@ query = Query(User)
   .select(:*, :"COUNT(posts.id) AS posts_count")
   .group_by(%i(users.id posts.id))
   .one
-user = user_repo.query(query).first
+user = repo.query(query).first
 # SELECT *, COUNT (posts.id) AS posts_count
 # FROM users JOIN posts AS posts ON posts.author_id = users.id
 # GROUP BY users.id, posts.id LIMIT 1
@@ -125,10 +123,10 @@ user.posts_count # => 1
 
 user.name = "Bar"
 user.changes # => {:name => "Bar"}
-user_repo.update(user)
+repo.update(user)
 # UPDATE users SET name = $1 WHERE id = $2 RETURNING id
 
-post_repo.delete(posts.first)
+repo.delete(posts.first)
 # DELETE FROM posts WHERE id = $1
 ```
 

spec/repository_spec.cr

@@ -5,14 +5,13 @@ db = DB.open(ENV["DATABASE_URL"] || raise "No DATABASE_URL is set!")
 query_logger = Core::QueryLogger.new(nil)
 
 describe Repo do
-  user_repo = Repo(User).new(db, query_logger)
-  post_repo = Repo(Post).new(db, query_logger)
+  repo = Repo.new(db, query_logger)
 
   user_created_at = uninitialized Time
 
   describe "#insert" do
     user = User.new(name: "Test User")
-    result = user_repo.insert(user)
+    result = repo.insert(user)
     query = Query(User).last
 
     it "sets created_at field" do
@@ -29,12 +28,12 @@ describe Repo do
       user.id = db.scalar(query.select(:id).to_s).as(Int32)
 
       post = Post.new(author: user, content: "Some content")
-      post_repo.insert(post).should be_truthy
+      repo.insert(post).should be_truthy
     end
 
     pending "returns fresh id" do
       previous_id = db.scalar(query.select(:id).to_s).as(Int32)
-      user_repo.insert(user).should eq(previous_id + 1)
+      repo.insert(user).should eq(previous_id + 1)
     end
   end
 
@@ -46,7 +45,7 @@ describe Repo do
       .order_by(:"users.id DESC")
       .limit(1)
 
-    user = user_repo.query(complex_query).first
+    user = repo.query(complex_query).first
 
     it "returns a valid instance" do
       user.id.should be_a(Int32)
@@ -59,28 +58,28 @@ describe Repo do
 
     pending "handles DB errors" do
       expect_raises do
-        user_repo.query("INVALID QUERY")
+        repo.query("INVALID QUERY")
       end
     end
   end
 
   describe "#update" do
-    user = user_repo.query(Query(User).last).first
+    user = repo.query(Query(User).last).first
 
     it "ignores empty changes" do
-      user_repo.update(user).should eq nil
+      repo.update(user).should eq nil
     end
 
     pending "handles DB errors" do
       user.id = nil
       expect_raises do
-        user_repo.update(user)
+        repo.update(user)
       end
     end
 
     user.name = "Updated User"
-    update = user_repo.update(user)
-    updated_user = user_repo.query(Query(User).last).first
+    update = repo.update(user)
+    updated_user = repo.query(Query(User).last).first
 
     it "actually updates" do
       updated_user.name.should eq "Updated User"
@@ -92,13 +91,13 @@ describe Repo do
   end
 
   describe "#delete" do
-    post = post_repo.query(Query(Post).last).first
+    post = repo.query(Query(Post).last).first
     post_id = post.id
-    delete = post_repo.delete(post)
+    delete = repo.delete(post)
 
     it do
       delete.should be_truthy
-      post_repo.query(Query(Post).where(id: post_id)).empty?.should eq true
+      repo.query(Query(Post).where(id: post_id)).empty?.should eq true
     end
 
     pending "returns an amount of affected rows" do
@@ -108,7 +107,7 @@ describe Repo do
     pending "handles DB errors" do
       # It's already deleted, so
       expect_raises do
-        post_repo.delete(post)
+        repo.delete(post)
       end
     end
   end

src/core/repository.cr

@@ -9,7 +9,7 @@ require "./query_logger"
 #
 # ```
 # logger = Core::QueryLogger.new(STDOUT)
-# repo = Core::Repository(User).new(db, logger)
+# repo = Core::Repository.new(db, logger)
 #
 # user = User.new(name: "Foo")
 # repo.insert(user) # TODO: [RFC] Return last inserted ID
@@ -30,7 +30,7 @@ require "./query_logger"
 # # DELETE FROM users WHERE id = $1
 # # 1.628ms
 # ```
-class Core::Repository(ModelType)
+class Core::Repository
   # :nodoc:
   property db
   # :nodoc:
@@ -44,23 +44,33 @@ class Core::Repository(ModelType)
   def initialize(@db : DB::Database, @query_logger : QueryLogger)
   end
 
-  # Issue a query to the `#db`. Returns an array of `Model` instances.
+  # Query `#db` returning an array of *model* instances.
+  #
+  # ```
+  # repo.query(User, "SELECT * FROM users") # => Array(User)
+  # ```
   #
   # TODO: Handle errors (PQ::PQError)
-  def query(query : String, *params) : Array(ModelType)
+  def query(model : Model.class, query : String, *params) : Array
     query = prepare_query(query)
     params = prepare_params(*params) if params.any?
 
     query_logger.wrap(query) do
       db.query_all(query, *params) do |rs|
-        rs.read(ModelType)
+        rs.read(model)
       end
     end
   end
 
-  # ditto
-  def query(query : Query)
-    query(query.to_s, query.params)
+  # Query `#db` returning an array of model instances inherited from *query*.
+  #
+  # ```
+  # repo.query(Query(User).all) # => Array(User)
+  # ```
+  #
+  # TODO: Handle errors (PQ::PQError)
+  def query(query : Query(T)) forall T
+    query(T, query.to_s, query.params)
   end
 
   private SQL_INSERT = <<-SQL
@@ -75,19 +85,19 @@ class Core::Repository(ModelType)
   # TODO: Handle errors.
   # TODO: Multiple inserts.
   # TODO: [RFC] Call `#query` and return `Model` instance instead (see https://github.com/will/crystal-pg/issues/101).
-  def insert(instance : ModelType) : Int64
+  def insert(instance : Model) : Int64
     fields = instance.db_fields.dup.tap do |f|
       f.each do |k, _|
-        f[k] = now if ModelType.created_at_fields.includes?(k) && f[k].nil?
-        f.delete(k) if k == ModelType.primary_key
+        f[k] = now if instance.class.created_at_fields.includes?(k) && f[k].nil?
+        f.delete(k) if k == instance.class.primary_key
       end
     end
 
     query = SQL_INSERT % {
-      table_name: ModelType.table_name,
+      table_name: instance.class.table_name,
       keys:       fields.keys.join(", "),
       values:     (1..fields.size).map { "?" }.join(", "),
-      returning:  ModelType.primary_key,
+      returning:  instance.class.primary_key,
     }
 
     query = prepare_query(query)
@@ -111,22 +121,22 @@ class Core::Repository(ModelType)
   # TODO: Handle errors.
   # TODO: Multiple updates.
   # TODO: [RFC] Call `#query` and return `Model` instance instead (see https://github.com/will/crystal-pg/issues/101).
-  def update(instance : ModelType)
+  def update(instance : Model)
     fields = instance.db_fields.select do |k, _|
       instance.changes.keys.includes?(k)
     end.tap do |f|
       f.each do |k, _|
-        f[k] = now if ModelType.updated_at_fields.includes?(k)
+        f[k] = now if instance.class.updated_at_fields.includes?(k)
       end
     end
 
     return unless fields.any?
 
     query = SQL_UPDATE % {
-      table_name:  ModelType.table_name,
+      table_name:  instance.class.table_name,
       set_fields:  fields.keys.map { |k| k.to_s + " = ?" }.join(", "),
-      primary_key: ModelType.primary_key, # TODO: Handle empty primary key
-      returning:   ModelType.primary_key,
+      primary_key: instance.class.primary_key, # TODO: Handle empty primary key
+      returning:   instance.class.primary_key,
     }
 
     query = prepare_query(query)
@@ -146,10 +156,10 @@ class Core::Repository(ModelType)
   #
   # TODO: Handle errors.
   # TODO: Multiple deletes.
-  def delete(instance : ModelType)
+  def delete(instance : Model)
     query = SQL_DELETE % {
-      table_name:  ModelType.table_name,
-      primary_key: ModelType.primary_key,
+      table_name:  instance.class.table_name,
+      primary_key: instance.class.primary_key,
     }
 
     query = prepare_query(query)