Elixir and Angular 2 without Hello, world !, or Implementing work with the tree directory, part 1

If you have not encountered Elixir before, I highly recommend starting with learning a language. I plan to give detailed explanations of the approaches and features used, but it is impossible to cover everything fully within a small series of articles (except for the fact that I myself constantly find something new). There is a basic introduction to the project site for studying, as well as many other resources on the Internet. A very useful forum where the creator of the language responds with great pleasure. By the way, an excellent example answer to the question "is it worth it to study Elixir first or immediately rush to the embrasure" can be seen in this thread on Reddit. As a summary, I can say that the author of the topic was disappointed by the insignificant difference in the performance of the test case written in Ruby and "on Elixir" (as he believed). The code on Ruby was executed in 4.221 seconds, on Elixir - 5.923 seconds. After the code was rewritten using language features (and not just porting one-to-one with Ruby), he began working three (!!!) times faster.

Having said the right things, I will say a seditious one: I rarely do this myself, and usually I rush into battle immediately.

 $ mix phoenix.new atv_api --no-brunch --no-html * creating atv_api/config/config.exs * creating atv_api/config/dev.exs * creating atv_api/config/prod.exs ... * creating atv_api/priv/static/images/phoenix.png * creating atv_api/priv/static/favicon.ico Fetch and install dependencies? [Yn] y * running mix deps.get We are all set! Run your Phoenix application: $ cd atv_api $ mix phoenix.server You can also run your app inside IEx (Interactive Elixir) as: $ iex -S mix phoenix.server Before moving on, configure your database in config/dev.exs and run: $ mix ecto.create $ 

 $ mix phoenix.gen.json Fos fos title:text * creating web/controllers/fos_controller.ex * creating web/views/fos_view.ex * creating test/controllers/fos_controller_test.exs * creating web/views/changeset_view.ex * creating web/models/fos.ex * creating test/models/fos_test.exs * creating priv/repo/migrations/20170215194144_create_fos.exs Add the resource to your api scope in web/router.ex: resources "/fos", FosController, except: [:new, :edit] Remember to update your repository by running migrations: $ mix ecto.migrate 

 defmodule AtvApi.Router do use AtvApi.Web, :router pipeline :api do plug :accepts, ["json"] end scope "/api", AtvApi do pipe_through :api resources "/fos", FosController, except: [:new, :edit] end end 

 defmodule AtvApi.Repo.Migrations.CreateFos do use Ecto.Migration def change do create table(:fos, primary_key: false) do add :id, :text, null: false, primary_key: true add :title, :text timestamps() end end end 

 defmodule AtvApi.Fos do use AtvApi.Web, :model @primary_key {:id, :string, autogenerate: false} schema "fos" do field :title, :string timestamps() end @doc """ Builds a changeset based on the `struct` and `params`. """ def changeset(struct, params \\ %{}) do struct |> cast(params, [:id, :title]) |> validate_required([:id, :title]) end end 

Here you also need to say a few words about what the model is.

In Elixir, there is the concept of "structure" ( struct ). A structure is an extension of an associative array (i.e., storage of key-value pairs, standardly denoted as %{ key => value, ...} , and if the key is an atom, then %{ key: value, ...} ); the structure has an additional key __struct__ , the value of which contains its name, and is limited to only those fields that are specified in the code at the time of compilation . If you try to add a value to a structure with a key that is not described in it at the time of compilation, an error will be generated. The structure is determined using the defstruct construct and gets the name of the module in which it is described:

 iex> defmodule User do ...> defstruct title: "John", age: 27 ...> end 

The list of keywords used with defstruct defines the fields that this structure can and will contain, along with their default values. In the example above, the structure will be named %User{} .

As mentioned, the structure is an extension of the associative array, so all the functions of the Map module will work with them. However, the Enumerable protocol for structures is not implemented, so the Enum module will not work with them.

It remains to add that a model is a structure obtained using meta-programming (more on this later) from the description contained in the do ... end block of the macro macro.Our model described in the module AtvApi.Foswill be of type %Fos{}and contain key fields :id(by default) and :title(explicitly defined).

For more detailed information on structures, welcome to the documentation .

 $ mix test test/models/fos_test.exs Compiling 7 files (.ex) Generated atv_api app 1) test changeset with valid attributes (AtvApi.FosTest) test/models/fos_test.exs:9 Expected truthy, got false code: changeset.valid?() stacktrace: test/models/fos_test.exs:11: (test) . Finished in 0.05 seconds 2 tests, 1 failure Randomized with seed 166025 

 $ mix test test/models/fos_test.exs .. Finished in 0.04 seconds 2 tests, 0 failures Randomized with seed 892257 

 require Logger alias AtvApi.Repo import Ecto.Query ### OECD FOS dictionary ### alias AtvApi.Fos unless Repo.one!(from f in Fos, select: count(f.id)) > 0 do multi = File.read!("priv/repo/oecd_fos.txt") |> String.split("\n") |> Enum.reject(fn(row) -> byte_size(row) < 1 end) |> Enum.sort |> Enum.dedup |> Enum.reduce(Ecto.Multi.new, fn(row, multi) -> [id, title] = row |> String.trim |> String.split(";") changeset = Fos.changeset(%Fos{}, %{id: id, title: title}) Ecto.Multi.insert(multi, id, changeset) end) Repo.transaction(multi) Logger.info "OECD FOS load complete" end ### OECD FOS dictionary ### 

Elixir - (.. , ). — , (.. ) . , , , . require .

, [] , ( tuple ) {:ok, result} {:error, description} , , , , .
For example:

 iex> File.read("file.txt") {:ok, "file contents"} iex> File.read("no_such_file.txt") {:error, :enoent} iex> File.read!("file.txt") "file contents" iex> File.read!("no_such_file.txt") ** (File.Error) could not read file no_such_file.txt: no such file or directory 

 iex(1)> some_map = %{one: 1} %{one: 1} iex(2)> Enum.count(some_map) 1 iex(3)> some_map |> Enum.count() 1 iex(4)> Enum.count(Map.put(some_map, :two, 2)) 2 iex(5)> some_map |> Map.put(:two, 2) |> Enum.count() 2 

( pattern matching ) — Elixir. , , = ( ) — , (match operator). , :

 iex> x = 1 1 iex> x 1 

, :

 iex> 1 = x 1 iex> 2 = x ** (MatchError) no match of right hand side value: 1 

x 1, .
, .

:

 iex> {a, b, c} = {:hello, "world", 42} {:hello, "world", 42} iex> a :hello iex> b "world" 

:

 iex> {a, b, {d, e} = c} = {:hello, "world", {:grey, "hole"}} {:hello, "world", {:grey, "hole"}} iex> a :hello iex> b "world" iex> c {:grey, "hole"} iex> d :grey iex> e "hole" 

, . , :

 iex> {a, b, c} = {:hello, "world"} ** (MatchError) no match of right hand side value: {:hello, "world"} 

, :

 iex> {a, b, c} = [:hello, "world", 42] ** (MatchError) no match of right hand side value: [:hello, "world", 42] 

, . , :ok :

 iex> {:ok, result} = {:ok, 13} {:ok, 13} iex> result 13 iex> {:ok, result} = {:error, :oops} ** (MatchError) no match of right hand side value: {:error, :oops} 

, .

- (pin operator). , , , , Elixir , . , ? pin operator:

 iex> x = 1 1 iex> ^x = 2 ** (MatchError) no match of right hand side value: 2 iex> {y, ^x} = {2, 1} {2, 1} iex> y 2 iex> {y, ^x} = {2, 2} ** (MatchError) no match of right hand side value: {2, 2} 

x 1, :

 iex> {y, 1} = {2, 2} ** (MatchError) no match of right hand side value: {2, 2} 

, Ecto.Changeset , , () () (constraints) ( , — ). Ecto.Changeset " ", .. changeset . changeset cast/3 change/2 . , , , , API, .., — . , , ( ) .

AtvApi.Fos.changeset/2 , Ecto.Changeset , — cast/3 — ( struct ), ( params ) , , , ( [:id, :title] ). , , ( , ). , , :id :

 |> validate_length(:id, min: 6) 

, , valid? false . .
For example:

 iex> valid = AtvApi.Fos.changeset(%AtvApi.Fos{}, %{id: "123", title: "Some title"}) #Ecto.Changeset<action: nil, changes: %{id: "123", title: "Some title"}, errors: [], data: #AtvApi.Fos<>, valid?: true> iex> invalid = valid |> Ecto.Changeset.validate_length(:id, min: 6) #Ecto.Changeset<action: nil, changes: %{id: "123", title: "Some title"}, errors: [id: {"should be at least %{count} character(s)", [count: 6, validation: :length, min: 6]}], data: #AtvApi.Fos<>, valid?: false> iex> AtvApi.Repo.insert!(invalid) # "" ,    ** (Ecto.InvalidChangesetError) could not perform insert because changeset is invalid. Applied changes %{id: "123", title: "Some title"} Params %{"id" => "123", "title" => "Some title"} Errors %{id: [{"should be at least %{count} character(s)", [count: 6, validation: :length, min: 6]}]} Changeset #Ecto.Changeset<action: :insert, changes: %{id: "123", title: "Some title"}, errors: [id: {"should be at least %{count} character(s)", [count: 6, validation: :length, min: 6]}], data: #AtvApi.Fos<>, valid?: false> (ecto) lib/ecto/repo/schema.ex:134: Ecto.Repo.Schema.insert!/4 iex> AtvApi.Repo.insert(invalid) # "" ,   {:error, description} {:error, #Ecto.Changeset<action: :insert, changes: %{id: "123", title: "Some title"}, errors: [id: {"should be at least %{count} character(s)", [count: 6, validation: :length, min: 6]}], data: #AtvApi.Fos<>, valid?: false>} 

 $ mix run priv/repo/seeds.exs [debug] QUERY OK source="fos" db=0.7ms SELECT count(f0."id") FROM "fos" AS f0 [] [debug] QUERY OK db=0.1ms begin [] [debug] QUERY OK db=1.4ms INSERT INTO "fos" ("id","title","inserted_at","updated_at") VALUES ($1,$2,$3,$4) ["010000", "Natural Sciences", {{2017, 2, 21}, {11, 50, 38, 799789}}, {{2017, 2, 21}, {11, 50, 38, 804086}}] [debug] QUERY OK db=0.3ms ... INSERT INTO "fos" ("id","title","inserted_at","updated_at") VALUES ($1,$2,$3,$4) ["0605BQ", "Humanities, multidisciplinary", {{2017, 2, 21}, {11, 50, 38, 973021}}, {{2017, 2, 21}, {11, 50, 38, 973025}}] [debug] QUERY OK db=5.8ms commit [] [info] OECD FOS load complete 

 # mix.exs # ... # Specifies your project dependencies. # # Type `mix help deps` for examples and options. defp deps do [{:phoenix, "~> 1.2.1"}, {:phoenix_pubsub, "~> 1.0"}, {:phoenix_ecto, "~> 3.0"}, {:postgrex, ">= 0.0.0"}, {:gettext, "~> 0.11"}, {:cowboy, "~> 1.0"}, #  -   {:ex_machina, "~> 1.0", only: :test}, {:mix_test_watch, "~> 0.3", only: :dev, runtime: false}] end # ... 

 $ mix deps.get Running dependency resolution... Dependency resolution completed: ex_machina 1.0.2 fs 2.12.0 mix_test_watch 0.3.3 * Getting ex_machina (Hex package) Checking package (https://repo.hex.pm/tarballs/ex_machina-1.0.2.tar) Using locally cached package * Getting mix_test_watch (Hex package) Checking package (https://repo.hex.pm/tarballs/mix_test_watch-0.3.3.tar) Fetched package * Getting fs (Hex package) Checking package (https://repo.hex.pm/tarballs/fs-2.12.0.tar) Fetched package 

 defmodule AtvApi.FactoryFosList do @fos_list [ %{id: "010000", title: "Natural Sciences"}, %{id: "020000", title: "Engineering and Technology"}, %{id: "030000", title: "Medical and Health Sciences"}, # ... %{id: "0604YG", title: "Theater"}, %{id: "0605BQ", title: "Humanities, multidisciplinary"}, ] def fos_list, do: @fos_list end 

 defmodule AtvApi.Factory do use ExMachina.Ecto, repo: AtvApi.Repo import AtvApi.FactoryFosList, only: [fos_list: 0] def fos_factory do %AtvApi.Fos{ id: "0", title: "Some science-technology name", } end def build_all(factory_name, insert? \\ false) do get_list(factory_name) |> Enum.map(fn(rec) -> case insert? do true -> insert(factory_name, rec) false -> build(factory_name, rec) end end) end def insert_all(factory_name) do build_all(factory_name, true) end defp get_list(:fos) do fos_list() end defp get_list(_) do [] end end 

, - — , . "Quote and unquote" , "" "Domain Specific Languages" Elixir.

, , , , ...

… — , , use ExMachina.Ecto, ... . ExMachina.Ecto GitHub . , , .

, , .. ExMachina.Ecto ( require ExMachina.Ecto ) ExMachina.Ecto.__using__/1 , - ( — repo: AtvApi.Repo ; , Elixir [] ). :repo , quote do ... end , (.. AtvApi.FactoryFos ), quote unquote (. ). , params_for/2 , string_params_for/2 . use ExMachina use ExMachine.EctoStrategy, ... , — .. ( ).

, build/2 build_list/3 , . ExMachina.Ecto insert/2 insert_list/3 , , . , ExMachina.Strategy , ExMachina.EctoStrategy use ExMachine.Strategy, function_title: :insert . , insert/2 insert_list/3 — __using__/1 ExMachina.Strategy :function_name .

, , .

AtvApi.Factory.build/2 Elixir:

 $ MIX_ENV=test iex -S mix Erlang/OTP 19 [erts-8.2] [source] [64-bit] [smp:4:4] [async-threads:10] [hipe] [kernel-poll:false] Interactive Elixir (1.4.1) - press Ctrl+C to exit (type h() ENTER for help) iex> AtvApi.Factory.build(:fos, %{id: "0103SY", title: "Optics"}) %AtvApi.Fos{__meta__: #Ecto.Schema.Metadata<:built, "fos">, id: "0103SY", inserted_at: nil, title: "Optics", updated_at: nil} 

build_all/2 , .

: mix.exs Phoenix Framework mix , test/support . MIX_ENV=test .

  defp get_list(:fos) do fos_list() end defp get_list(_) do [] end 

 $ mix test.watch Running tests... ..... Finished in 0.05 seconds 5 tests, 0 failures Randomized with seed 806690 

Elixir ExUnit . , — , .

.

ExUnit :

 # File: assertion_test.exs # 1)  ExUnit. ExUnit.start # 2)     ( , test case) #   (use) "ExUnit.Case". defmodule AssertionTest do # 3)  :   "async: true",  #        . #   ,        #  . use ExUnit.Case, async: true # 4)     "test"  "def" test "the truth" do assert true end end 

:

 $ elixir assertion_test.exs warning: this check/guard will always yield the same result assertion_test.exs:17 . Finished in 0.03 seconds (0.03s on load, 0.00s on tests) 1 test, 0 failures Randomized with seed 598489 

Mix test/test_helper.exs . .

ExUnit.Case . async .

. setup_all setup ( ):

 defmodule ExampleTest do use ExUnit.Case setup do {:ok, [hello: :world]} end test "context contains key-value pairs", context do assert context[:hello] == :world end end 

, , :

  test "context is a map and pattern matching", %{hello: hello} do assert hello == :world end 

setup , — , .

, ExUnit.Case (callbacks) ExUnit.Callbacks . setup_all setup , on_exit/2 .

. , (. ).

setup_all . setup . , setup_all setup .

on_exit/2 , , setup .

setup_all {:ok, keywords} , - keywords setup_all , setup .

setup setup .

:ok .

setup_all - , , setup .

:

 defmodule AssertionTest do use ExUnit.Case, async: true # "setup_all"          setup_all do IO.puts " AssertionTest" # No metadata :ok end # "setup"     setup do IO.puts "   'setup'" on_exit fn -> IO.puts "     " end #        [hello: "world"] end #  ,    #    setup context do IO.puts " : #{context[:test]}" :ok end #        setup :invoke_local_or_imported_function test "always pass" do assert true end test "another one", context do assert context[:hello] == "world" end defp invoke_local_or_imported_function(context) do [from_named_setup: true] end end 

ExUnit.Assertions . , ExUnit.Case , .

assert/1 refute/1 .

, , , .

Phoenix Framework , - , .. , , .

, , .

 defmodule AtvApi.FosControllerTest do use AtvApi.ConnCase import AtvApi.Factory import AtvApi.FactoryFosList, only: [fos_list: 0] setup %{conn: conn} do insert_all(:fos) fos = fos_list() |> Enum.sort |> Poison.encode! |> Poison.decode! {:ok, conn: put_req_header(conn, "accept", "application/json"), fos: fos} end test "lists all entries on index", %{conn: conn, fos: fos} do conn = get conn, fos_path(conn, :index) assert json_response(conn, 200)["data"] == fos end end 

 $ mix phoenix.routes fos_path GET /api/fos AtvApi.FosController :index fos_path GET /api/fos/:id AtvApi.FosController :show fos_path POST /api/fos AtvApi.FosController :create fos_path PATCH /api/fos/:id AtvApi.FosController :update PUT /api/fos/:id AtvApi.FosController :update fos_path DELETE /api/fos/:id AtvApi.FosController :delete 

 $ mix phoenix.routes Compiling 6 files (.ex) fos_path GET /api/fos AtvApi.FosController :index 

 $ mix test test/controllers/fos_controller_test.exs Compiling 6 files (.ex) 1) test lists all entries on index (AtvApi.FosControllerTest) test/controllers/fos_controller_test.exs:19 Assertion with == failed code: json_response(conn, 200)["data"] == fos left: [%{"id" => "010000", "title" => "Natural Sciences"}, %{"id" => "020000", "title" => "Engineering and Technology"}, %{"id" => "030000", "title" => "Medical and Health Sciences"}, ... %{"id" => "0101PO", "title" => "Mathematics, interdisciplinary applications"}, %{"id" => "0101PQ", "title" => "Mathematics"}, %{"id" => "0101UR", ...}, %{...}, ...] right: [%{"id" => "010000", "title" => "Natural Sciences"}, %{"id" => "010100", "title" => "Mathematics"}, %{"id" => "0101PN", "title" => "Mathematics, applied"}, ... %{"id" => "010600", "title" => "Biological sciences"}, %{"id" => "0106BD", "title" => "Biodiversity conservation"}, %{"id" => "0106CO", ...}, %{...}, ...] stacktrace: test/controllers/fos_controller_test.exs:21: (test) Finished in 0.1 seconds 1 test, 1 failure Randomized with seed 415134 

 defmodule AtvApi.FosController do use AtvApi.Web, :controller alias AtvApi.Fos import Ecto.Query def index(conn, _params) do fos = Repo.all(from f in Fos, order_by: f.id) render(conn, "index.json", fos: fos) end end 

 $ mix test test/controllers/fos_controller_test.exs Compiling 1 file (.ex) . Finished in 0.2 seconds 1 test, 0 failures Randomized with seed 347227 

 defmodule AtvApi.Repo.Migrations.CreateGrnti do use Ecto.Migration def change do create table(:grnti, primary_key: false) do add :id, :integer, null: false, primary_key: true add :title, :text add :has_children, :boolean, default: false, null: false timestamps() end end end 

 defmodule AtvApi.Grnti do use AtvApi.Web, :model schema "grnti" do field :title, :string field :has_children, :boolean, default: false timestamps() end @doc """ Builds a changeset based on the `struct` and `params`. """ def changeset(struct, params \\ %{}) do struct |> cast(params, [:id, :title, :has_children]) |> validate_required([:id, :title, :has_children]) end end 

 $ mix test test/models/grnti_test.exs . 1) test changeset with valid attributes (AtvApi.GrntiTest) test/models/grnti_test.exs:9 Expected truthy, got false code: changeset.valid?() stacktrace: test/models/grnti_test.exs:11: (test) Finished in 0.05 seconds 2 tests, 1 failure Randomized with seed 788882 

 $ mix test test/models/grnti_test.exs .. Finished in 0.04 seconds 2 tests, 0 failures Randomized with seed 692361 

 $ mix ecto.migrate 17:54:26.080 [info] == Running AtvApi.Repo.Migrations.CreateGrnti.change/0 forward 17:54:26.080 [info] create table grnti 17:54:26.097 [info] == Migrated in 0.0s 

 ### Grnti dictionary ### alias AtvApi.Grnti unless Repo.one!(from g in Grnti, select: count(g.id)) > 0 do multi = File.read!("priv/repo/grnti.txt") |> String.split("\n") |> Enum.reject(fn(row) -> byte_size(row) < 2 end) |> Enum.reduce(%{}, fn(row, acc) -> {id, parent_id, title} = case <<String.trim(row)::binary>> do <<a::binary-size(2), ".", b::binary-size(2), ".", c::binary-size(2), " ", title::binary>> -> { String.to_integer("#{a}#{b}#{c}"), String.to_integer("#{a}#{b}00"), title } <<a::binary-size(2), ".", b::binary-size(2), " ", title::binary>> -> { String.to_integer("#{a}#{b}00"), String.to_integer("#{a}0000"), title } <<a::binary-size(2), " ", title::binary>> -> { String.to_integer("#{a}0000"), -1, title } end parent = case Map.get(acc, parent_id) do nil -> {"", true} {p_title, _} -> {p_title, true} end current = case Map.get(acc, id) do nil -> {title, false} {_, has_children} -> {title, has_children} end acc |> Map.put(id, current) |> Map.put(parent_id, parent) end) |> Enum.reduce(Ecto.Multi.new, fn({id, {title, has_children}}, multi) -> if id > -1 do changeset = Grnti.changeset(%Grnti{}, %{id: id, title: String.trim(title), has_children: has_children}) Ecto.Multi.insert(multi, "#{id}", changeset) else multi end end) Repo.transaction(multi) Logger.info "GRNTI load complete" end ### Grnti dictionary ### 

Elixir <<>> . .

. , : Erlang , — , , Elixir .

— , — , :

 defmodule ImageTyper @png_signature <<137::size(8), 80::size(8), 78::size(8), 71::size(8), 13::size(8), 10::size(8), 26::size(8), 10::size(8)>> @jpg_signature <<255::size(8), 216::size(8)>> def type(<<@png_signature, rest::binary>>), do: :png def type(<<@jpg_signature, rest::binary>>), do: :jpg def type(_), do :unknown end 

ImageTyper.type/1 , , : :png | :jpg | :unknown .

 $ mix run priv/repo/seeds.exs [debug] QUERY OK source="fos" db=0.9ms queue=0.1ms SELECT count(f0."id") FROM "fos" AS f0 [] [debug] QUERY OK source="grnti" db=3.6ms SELECT count(g0."id") FROM "grnti" AS g0 [] [debug] QUERY OK db=0.1ms begin [] [debug] QUERY OK db=2.1ms INSERT INTO "grnti" ("has_children","id","title","inserted_at","updated_at") VALUES ($1,$2,$3,$4,$5) [false, 443135, "   ", {{2017, 2, 22}, {16, 51, 9, 581608}}, {{2017, 2, 22}, {16, 51, 9, 585864}}] [debug] QUERY OK db=0.3ms INSERT INTO "grnti" ("has_children","id","title","inserted_at","updated_at") VALUES ($1,$2,$3,$4,$5) [false, 722335, "  ", {{2017, 2, 22}, {16, 51, 9, 593526}}, {{2017, 2, 22}, {16, 51, 9, 593531}}] [debug] QUERY OK db=0.1ms INSERT INTO "grnti" ("has_children","id","title","inserted_at","updated_at") VALUES ($1,$2,$3,$4,$5) [true, 761300, " ", {{2017, 2, 22}, {16, 51, 9, 593995}}, {{2017, 2, 22}, {16, 51, 9, 594000}}] ... [debug] QUERY OK db=0.4ms INSERT INTO "grnti" ("has_children","id","title","inserted_at","updated_at") VALUES ($1,$2,$3,$4,$5) [false, 107161, "", {{2017, 2, 22}, {16, 51, 56, 376371}}, {{2017, 2, 22}, {16, 51, 56, 376375}}] [debug] QUERY OK db=0.3ms INSERT INTO "grnti" ("has_children","id","title","inserted_at","updated_at") VALUES ($1,$2,$3,$4,$5) [false, 292931, "     ", {{2017, 2, 22}, {16, 51, 56, 376969}}, {{2017, 2, 22}, {16, 51, 56, 376972}}] [debug] QUERY OK db=5.0ms commit [] [info] GRNTI load complete 

 defmodule AtvApi.FactoryGrntiList do @grnti_list [ %{id: 000000, has_children: true, title: "   "}, %{id: 000800, has_children: false, title: "   "}, %{id: 000900, has_children: false, title: "  "}, %{id: 001100, has_children: false, title: "   "}, # ... %{id: 032323, has_children: false, title: "    (   XII .)"}, %{id: 032325, has_children: false, title: "     (  XII .   XVI .)"}, ] def grnti_list, do: @grnti_list end 

 defmodule AtvApi.Factory do use ExMachina.Ecto, repo: AtvApi.Repo import AtvApi.FactoryFosList, only: [fos_list: 0] import AtvApi.FactoryGrntiList, only: [grnti_list: 0] def fos_factory do %AtvApi.Fos{ id: "0", title: "Some science-technology name", } end def grnti_factory do %AtvApi.Grnti{ id: 0, title: "Some grnti chapter name", has_children: false, } end def build_all(factory_name, insert? \\ false) do get_list(factory_name) |> Enum.map(fn(rec) -> case insert? do true -> insert(factory_name, rec) false -> build(factory_name, rec) end end) end def insert_all(factory_name) do build_all(factory_name, true) end defp get_list(:fos) do fos_list() end defp get_list(:grnti) do grnti_list() end defp get_list(_) do [] end end 

, , . , , :

  defp get_list(factory) do case factory do :fos -> fos_list() :grnti -> grnti_list() _ -> [] end end 

, - , . , , API:

  # ################################################### # # proceed API request results # # ################################################### # # check for task defp proceed_response(task_uuid, response, state) do # could be rewriten inline, but this is for better code readability task = Map.get(state, task_uuid) proceed_response(task, task_uuid, response, state) end # no task with such uuid - do nothing defp proceed_response(task, _task_uuid, _response, state) when is_nil(task) do state end # Got a normal HTTP response defp proceed_response(task, task_uuid, {:ok, %HTTPoison.Response{body: body, status_code: 200}} = _response, state) do json_decode_result = Poison.decode(body) proceed_response(task, task_uuid, json_decode_result, state) end # API task ID defp proceed_response(task, task_uuid, {:ok, %{"errorId" => 0, "taskId" => api_task_id} = _json_body}, state) do Process.send_after(self(), {:api_get_task_result, task_uuid}, task.result_request_interval) put_in(state, [task_uuid, :api_task_id], api_task_id) end # Set a timer to try again if the task is still processing defp proceed_response(task, task_uuid, {:ok, %{"errorId" => 0, "status" => "processing"} = _json_body}, state) do Process.send_after(self(), {:api_get_task_result, task_uuid}, task.result_retry_interval) state end # Deal with result if the task is done and task type is Image # in case of push: true defp proceed_response( %{type: "ImageToTextTask"} = task, task_uuid, {:ok, %{"errorId" => 0, "status" => "ready", "solution" => %{"text" => text}} = _json_body}, state) do state |> put_in([task_uuid, :result], %{text: text}) |> put_in([task_uuid, :status], :ready) |> push_data(task, task_uuid, {:ready, task_uuid, %{text: text}}) end # Any other - probably an error defp proceed_response(_task, task_uuid, error, state) do parse_error(task_uuid, error, state) end 

if\else .
. , {"errorId" => 0, "taskId" => 12345} , API , {"errorId" => 0, "status" => "processing"} , , , {"errorId" => 0, "status" => "ready", "solution" => {"text" => "some_text"}} . , , , , , JSON {"errorId" => 0, "status" => "ready", "solution" => %{"image" => image_string}} (, , JSON, ). , API — - proceed_response/3 .

— . , :

 $ iex Erlang/OTP 19 [erts-8.2] [source] [64-bit] [smp:4:4] [async-threads:10] [hipe] [kernel-poll:false] Interactive Elixir (1.4.1) - press Ctrl+C to exit (type h() ENTER for help) iex> defmodule ListSum do ...> def list_sum(list), do: list_sum(list, 0) ...> def list_sum([head | tail], acc), do: list_sum(tail, acc + head) ...> def list_sum([], acc), do: acc ...> end {:module, ListSum, <<70, 79, 82, 49, 0, 0, 5, 180, 66, 69, 65, 77, 69, 120, 68, 99, 0, 0, 0, 223, 131, 104, 2, 100, 0, 14, 101, 108, 105, 120, 105, 114, 95, 100, 111, 99, 115, 95, 118, 49, 108, 0, 0, 0, 4, 104, 2, ...>>, {:list_sum, 2}} iex> ListSum.list_sum([1, 5, 10, 20]) 36 

 defmodule AtvApi.Router do use AtvApi.Web, :router pipeline :api do plug :accepts, ["json"] end scope "/api", AtvApi do pipe_through :api get "/fos", FosController, :index get "/grnti/:id", GrntiController, :show end end 

 $ mix phoenix.routes Compiling 6 files (.ex) fos_path GET /api/fos AtvApi.FosController :index grnti_path GET /api/grnti/:id AtvApi.GrntiController :show 

  # ... def get_descendants(:grnti, -1) do grnti_list() |> Enum.filter(fn(%{id: id}) -> rem(id, 10000) == 0 end) end # ... 

 $ MIX_ENV=test iex -S mix Erlang/OTP 19 [erts-8.2] [source] [64-bit] [smp:4:4] [async-threads:10] [hipe] [kernel-poll:false] Interactive Elixir (1.4.1) - press Ctrl+C to exit (type h() ENTER for help) iex> AtvApi.Factory.get_descendants(:grnti, -1) [%{has_children: true, id: 0, title: "   "}, %{has_children: true, id: 20000, title: ""}, %{has_children: true, id: 30000, title: ".  "}] 

 defmodule AtvApi.GrntiControllerTest do use AtvApi.ConnCase import AtvApi.Factory setup %{conn: conn} do insert_all(:grnti) {:ok, conn: put_req_header(conn, "accept", "application/json")} end test "the root level descendants", %{conn: conn} do id = -1 grnti_subtree = get_descendants(:grnti, id) conn = get conn, grnti_path(conn, :show, id) assert json_response(conn, 200)["data"] == grnti_subtree |> Poison.encode! |> Poison.decode! end end 

 defmodule AtvApi.GrntiController do use AtvApi.Web, :controller alias AtvApi.Grnti def show(conn, %{"id" => id}) do conn |> put_resp_content_type("text/plain") |> send_resp(200, "request_ok") end end 

 defmodule AtvApi.Grnti do # ... def descendants(parent_id) when parent_id == -1 do from g in AtvApi.Grnti, where: fragment("mod(?, ?)", g.id, 10000) == 0, order_by: g.id end end 

 defmodule AtvApi.GrntiController do # ... def show(conn, %{"id" => parent_id}) do grnti = parent_id |> Grnti.descendants |> Repo.all render(conn, "index.json", grnti: grnti) end end 

 defmodule AtvApi.Grnti do # ... def descendants(parent_id) when is_binary(parent_id) do parent_id |> String.to_integer |> descendants end def descendants(parent_id) when parent_id == -1 do from g in AtvApi.Grnti, where: fragment("mod(?, ?)", g.id, 10000) == 0, order_by: g.id end end 

defmodule AtvApi.GrntiView do
use AtvApi.Web, :view

def render("index.json", %{grnti: grnti}) do
%{data: render_many(grnti, AtvApi.GrntiView, "grnti.json")}
end

def render("grnti.json", %{grnti: grnti}) do
%{id: grnti.id,
title: grnti.title,
has_children: grnti.has_children}
end
end

 defmodule AtvApi.Factory do # ... def get_descendants(:grnti, -1) do grnti_list() |> Enum.filter(fn(%{id: id}) -> rem(id, 10000) == 0 end) end def get_descendants(:grnti, parent_id) when rem(parent_id, 10000) == 0 do grnti_list() |> Enum.filter(fn(%{id: id}) -> rem(id, 100) == 0 and id > parent_id and id < parent_id + 10000 end) end defp get_list(:fos) do # .. end 

 defmodule AtvApi.GrntiControllerTest do use AtvApi.ConnCase import AtvApi.Factory setup %{conn: conn, id: id} do insert_all(:grnti) conn = put_req_header(conn, "accept", "application/json") descendants = :grnti |> get_descendants(id) |> Poison.encode! |> Poison.decode! conn = get conn, grnti_path(conn, :show, id) {:ok, conn: conn, descendants: descendants} end @tag id: -1 test "shows chosen root level subtree", %{conn: conn, descendants: descendants} do assert json_response(conn, 200)["data"] == descendants end end 

  # ... @tag id: 000000 test "shows chosen second level subtree - id: 000000", %{conn: conn, descendants: descendants} do assert json_response(conn, 200)["data"] == descendants end @tag id: 020000 test "shows chosen second level subtree - id: 020000", %{conn: conn, descendants: descendants} do assert json_response(conn, 200)["data"] == descendants end @tag id: 030000 test "shows chosen second level subtree - id: 030000", %{conn: conn, descendants: descendants} do assert json_response(conn, 200)["data"] == descendants end #... 

  # ... def descendants(parent_id) when parent_id == -1 do from g in AtvApi.Grnti, where: fragment("mod(?, ?)", g.id, 10000) == 0, order_by: g.id end def descendants(parent_id) when rem(parent_id, 10000) == 0 do from g in AtvApi.Grnti, where: g.id > ^parent_id, where: g.id < ^(parent_id + 10000), where: fragment("mod(?, ?)", g.id, 100) == 0, order_by: g.id end # ... 

 defmodule AtvApi.Factory do # ... def get_descendants(:grnti, parent_id) when rem(parent_id, 10000) == 0 do grnti_list() |> Enum.filter(fn(%{id: id}) -> rem(id, 100) == 0 and id > parent_id and id < parent_id + 10000 end) end def get_descendants(:grnti, parent_id) when rem(parent_id, 100) == 0 do grnti_list() |> Enum.filter(fn(%{id: id}) -> id > parent_id and id < parent_id + 100 end) end defp get_list(:fos) do # .. end 

  # ... @tag id: 000900 test "shows chosen second level subtree - id: 000900", %{conn: conn, descendants: descendants} do assert json_response(conn, 200)["data"] == descendants end @tag id: 021500 test "shows chosen second level subtree - id: 021500", %{conn: conn, descendants: descendants} do assert json_response(conn, 200)["data"] == descendants end @tag id: 032300 test "shows chosen second level subtree - id: 032300", %{conn: conn, descendants: descendants} do assert json_response(conn, 200)["data"] == descendants end #... 

  # ... def descendants(parent_id) when rem(parent_id, 10000) == 0 do from g in AtvApi.Grnti, where: g.id > ^parent_id, where: g.id < ^(parent_id + 10000), where: fragment("mod(?, ?)", g.id, 100) == 0, order_by: g.id end def descendants(parent_id) when rem(parent_id, 100) == 0 do from g in AtvApi.Grnti, where: g.id > ^parent_id, where: g.id < ^(parent_id + 100), order_by: g.id end # ... 

 defmodule AtvApi.GrntiControllerTest do use AtvApi.ConnCase import AtvApi.Factory setup %{conn: conn, id: id} do insert_all(:grnti) conn = conn |> put_req_header("accept", "application/json") |> get(grnti_path(conn, :show, id)) {:ok, conn: conn} end describe "Controller must return descendants of" do setup %{id: id} do descendants = :grnti |> get_descendants(id) |> Poison.encode! |> Poison.decode! {:ok, descendants: descendants} end @tag id: -1 test "the root level", %{conn: conn, descendants: descendants} do assert json_response(conn, 200)["data"] == descendants end @tag id: 000000 test "the chapter with id: 000000", %{conn: conn, descendants: descendants} do assert json_response(conn, 200)["data"] == descendants end @tag id: 020000 test "the chapter with id: 020000", %{conn: conn, descendants: descendants} do assert json_response(conn, 200)["data"] == descendants end @tag id: 030000 test "the chapter with id: 030000", %{conn: conn, descendants: descendants} do assert json_response(conn, 200)["data"] == descendants end @tag id: 000900 test "the chapter with id: 000900", %{conn: conn, descendants: descendants} do assert json_response(conn, 200)["data"] == descendants end @tag id: 021500 test "the chapter with id: 021500", %{conn: conn, descendants: descendants} do assert json_response(conn, 200)["data"] == descendants end @tag id: 032300 test "the chapter with id: 032300", %{conn: conn, descendants: descendants} do assert json_response(conn, 200)["data"] == descendants end end end 

 defmodule AtvApi.GrntiControllerTest do use AtvApi.ConnCase # ... describe "Request must be declined with status code 422 and appropriate JSON error message in case of" do @tag id: "somestring" test "id as a non-digit symbol string", %{conn: conn} do assert json_response(conn, 422)["error"] == %{message: "Unprocessable Entity"} end @tag id: -2 test "id is less than -1 and equal -2", %{conn: conn} do assert json_response(conn, 422)["error"] == %{message: "Unprocessable Entity"} end @tag id: -100 test "id is less than -1 and equal -100", %{conn: conn} do assert json_response(conn, 422)["error"] == %{message: "Unprocessable Entity"} end @tag id: 1000000 test "id is greater than 999999 and equal 1000000", %{conn: conn} do assert json_response(conn, 422)["error"] == %{message: "Unprocessable Entity"} end @tag id: 90000000 test "id is greater than 999999 and equal 90000000", %{conn: conn} do assert json_response(conn, 422)["error"] == %{message: "Unprocessable Entity"} end @tag id: 030955 test "id is a third level section code and equal 030955", %{conn: conn} do assert json_response(conn, 422)["error"] == %{message: "Unprocessable Entity"} end @tag id: 020129 test "id is a third level section code and equal 020129", %{conn: conn} do assert json_response(conn, 422)["error"] == %{message: "Unprocessable Entity"} end end end 

 defmodule AtvApi.GrntiController do use AtvApi.Web, :controller alias AtvApi.Grnti def show(conn, %{"id" => parent_id}) do case Integer.parse(parent_id) do :error -> show(conn, :error) {int, _} -> show(conn, int) end end def show(conn, parent_id) when is_integer(parent_id) and parent_id > -2 and parent_id < 1000000 and ( rem(parent_id, 100) == 0 or parent_id == -1 ) do grnti = parent_id |> Grnti.descendants() |> Repo.all() render(conn, "index.json", grnti: grnti) end def show(conn, _parent_id) do conn |> put_resp_content_type("application/json") |> send_resp(422, ~S({"error":{"message":"Unprocessable Entity"}})) end end 

show/2 , , .. URL. , show/2 . . , , guard , . , , Content-Type: application/json , (sigil) .