The document outlines the development of an API for selling stickers through a smartphone application that integrates with the LINE Creators Market. It details the technology stack (Perl, nginx, RESTful JSON API), data requirements for stickers, and authentication processes via LINE's access token. Additionally, it discusses data validation using JSON schema and the importance of maintaining accurate documentation.

1. アプリで簡単にスタンプを
販売するためのAPI開発

2. ⾃⼰紹介
Adam
Millerchip
LINE Fukuoka 株式会社
Creators Market Engineer
ミラーチップ・アダム

3. LINE Creators Market
Make and sell stickers for LINE
Buy stickers from LINE STORE
https://store.line.me/

4. LINE Creators Market
Existing Web Service
https://creator.line.me/

5. Create Stickers

6. Why make a smartphone application?
Create Stickers
• Create images on phone
• Upload them automatically
• No need to log in to website
Smartphone application
• Create images using image editing software
• Upload manually to website
Web application

7. LINE Creators Studio
Application Requirements
What data to send to LINE?
• Sticker Images
• Title, Main Image, Price, Author…
• Web service:
• Sticker inspection
• Bank details + payment system
• Sales statistics
• Etc.
Send to LINE STORE

8. Technology
Design decisions:
• Refuse existing system
• Create a new API for the mobile app to use
• RESTful JSON API
• Authentication
• Documentation: JSON Schema
Technologies introduced for this API:
• Perl
• HTTP Webserver (nginx)
• Plack (PSGI) app
• Amon2 web framework
Existing technology

9. GET POST PUT DELETE
LINE Creators Studio: JSON API
RESTful JSON API
RESTful
JSON
HTTP Response Code
200 OK
204 No Content
400 Bad Request
401 Unauthorized
403 Forbidden
405 Method Not Allowed
…
{“event”: “Developer Meetup”, “number”: 18 }

10. LINE Creators Studio: JSON API
RESTful JSON API
get '/api/v1/languages' => ‘Languages#list';
get '/api/v1/sellable_areas' => 'SellableAreas#list';
get '/api/v1/my/price_tiers'
=> ‘My::PriceTiers#list’;
post '/api/v1/token'
=> 'Token#create';
post '/api/v1/token/refresh'
=> 'Token#refresh';
delete_ '/api/v1/token'
=> 'Token#remove';
sub list {
my ($class, $c) = @_;
my @languages = LCM::Language->sticker_languages;
return $c->render_json([
map {
name => $_->name,
code => $_->code,
}, @languages
]);
}
Language Controller
Amon2::Web::Dispatcher::RouterBoom

11. LINE Creators Studio: JSON API
RESTful JSON API
get '/api/v1/my/author_names' => 'My::AuthorNames#list';
post '/api/v1/my/author_names' => 'My::AuthorNames#create';
put '/api/v1/my/author_names' => 'My::AuthorNames#update';
curl -i -X GET https://example.com/api/v1/my/author_names
-H "Authorization: Bearer $ACCESS_TOKEN"
HTTP/1.1 200 OK
Server: nginx
Date: Fri, 14 Jul 2017 08:49:24 GMT
Content-Type: application/json; charset=utf-8
Content-Length: 57
Connection: keep-alive
Keep-Alive: timeout=3
X-Content-Type-Options: nosniff
08:49:24 GMT; path=/
[{"name":"Adam Creator","can_edit":true,"language":"en"}]

12. LINE Creators Studio: JSON API
RESTful JSON API
get '/api/v1/my/author_names' => 'My::AuthorNames#list';
post '/api/v1/my/author_names' => 'My::AuthorNames#create';
put '/api/v1/my/author_names' => 'My::AuthorNames#update';
sub list {
my ($class, $c) = @_;
my $author = $c->seller->get_author;
my @response = results_for($c, $author);
return $c->render_json(@response);
}

13. LINE Creators Studio: JSON API
RESTful JSON API
$ curl -i -X PUT
https://example.com/api/v1/my/author_names
-d '[
{
"language": "en",
"name": "Adam Creator"
},
{
"language": "ja",
"name": "アダムクリエーター"
}
]'
-H "Content-Type: application/json"
-H "Authorization: Bearer $ACCESS_TOKEN"
HTTP/1.1 200 OK
Server: nginx
Date: Fri, 14 Jul 2017 08:57:46 GMT
Content-Type: application/json; charset=utf-
8
Content-Length: 128
Connection: keep-alive
Keep-Alive: timeout=3
X-Content-Type-Options: nosniff
[
{"name":"Adam Creator”, “can_edit":true,
"language":"en"},
{“language":"ja", “name":"アダムクリエータ
ー", "can_edit":true}
]
get '/api/v1/my/author_names' => 'My::AuthorNames#list';
post '/api/v1/my/author_names' => 'My::AuthorNames#create';
put '/api/v1/my/author_names' => 'My::AuthorNames#update';

14. LINE Creators Studio: JSON API
RESTful JSON API
$ curl -X GET -i https://example.com/api/v1/my/author_names -H
"Authorization: Bearer $ACCESS_TOKEN"
HTTP/1.1 200 OK
Server: nginx
Date: Fri, 14 Jul 2017 09:04:52 GMT
Content-Type: application/json; charset=utf-8
Content-Length: 128
Connection: keep-alive
Keep-Alive: timeout=3
X-Content-Type-Options: nosniff
09:04:52 GMT; path=/
[{"language":"en","name":"Adam
Creator","can_edit":true},{"language":"ja","name":"アダムクリエーター
","can_edit":true}
get '/api/v1/my/author_names' => 'My::AuthorNames#list';
post '/api/v1/my/author_names' => 'My::AuthorNames#create';
put '/api/v1/my/author_names' => 'My::AuthorNames#update';

15. LINE Creators Studio: JSON API
RESTful JSON API
get '/api/v1/my/author_names' => 'My::AuthorNames#list';
post '/api/v1/my/author_names' => 'My::AuthorNames#create';
put '/api/v1/my/author_names' => 'My::AuthorNames#update';
sub update {
my ($class, $c) = @_;
my $author = $c->seller->get_author() or return $c->res_400;
my $body = $c->req->body_as_json() or return $c->res_400;
my %author_params = params_for($body);
# return HTTP 422 unless _validate(%author_params);
$author->update(%author_params);
my @results = results_for($c, $author->meta);
return $c->render_json(@results);
}

16. LINE Creators Studio: JSON API
RESTful JSON API
curl -i -X POST
https://example.com/api/v1/my/author_names -d
‘[
// { … JSON data … }
]’
-H "Content-Type: application/json”
-H "Authorization: Bearer $ACCESS_TOKEN"
HTTP/1.1 400 Bad Request
Date: Fri, 14 Jul 2017 09:29:12 GMT
Content-Type: application/json; charset=utf-8
Content-Length: 52
{"message":"'author_name' resource already exists."}
sub create {
my ($class, $c) = @_;
if ($c->seller->get_author) {
return $c->res_400(sprintf q{'%s' resource already exists.}, RESOURCE_NAME);
}
Creator Name (AuthorNames) Controller
get '/api/v1/my/author_names' => 'My::AuthorNames#list';
post '/api/v1/my/author_names' => 'My::AuthorNames#create';
put '/api/v1/my/author_names' => 'My::AuthorNames#update';

17. LINE Creators Studio: Access Token
Authentication
Web: LINE Login - OAuth
https://developers.line.me/line-login/overview
https://developers.line.me/ios/overview
https://developers.line.me/android/overview
LINE Login sends LINE access token to server
Session, Cookies
App: SDK Provides access token directly
App must send access token to server
Creators Market API access token

18. New Technology: Access Token
Login via SDK
Creators Studio
Click Login
LINE access token
Line SDK
Creators Market API
Auth Server (LINE)
Issue LINE access token
Creators Studio
LINE access token
Resource Server (LINE)
verify token
API access token
Resource Server (LINE)
use token
Creators Market API

19. JSON (or YAML) file
LINE Creators Studio: JSON Schema
JSON Schema
Use prmd to generate markdown documentation
Use JSV::Validator to validate objects
http://json-schema.org/
https://github.com/interagent/prmd
'$schema': http://json-schema.org/draft-
04/hyper-schema
title: Language
description: Language
stability: prototype
strictProperties: true
type: object
id: schemata/language
properties:
code:
type: string
example: en
description: Code identifying the
language
name:
type: string
example: English
description: Human readable name
required: [ 'code', 'name' ]
links:
- description: List existing languages.
href: '/languages'
http_header:
Authorization: Bearer <token>
method: GET
rel: instances
title: List
Documentation separated from code
Can forget to update (but tests help)

20. New Technology: JSON Schema
JSON Schema: prmd
https://github.com/interagent/prmd
properties:
code:
type: string
example: en
description: Code identifying the language
name:
type: string
example: English
description: Human readable name
required: [ 'code', 'name' ]
links:
- description: List existing languages.
href: '/languages'
http_header:
Authorization: Bearer <token>
method: GET
rel: instances
title: List
$ prmd combine schemata | prmd doc > Readme.md

21. New Technology: JSON Schema
JSON Schema: JSV::Validator
https://metacpan.org/pod/JSV::Validator
properties:
code:
type: string
example: en
description: Code identifying the
language
name:
type: string
example: English
description: Human readable name
required: [ 'code', 'name' ]
links:
- description: List existing languages.
href: '/languages'
http_header:
Authorization: Bearer <token>
method: GET
rel: instances
title: List
use JSV::Validator;
use Test::Kantan;
use YAML::XS;
my $validator = JSV::Validator->new;
my $schema = YAML::XS::LoadFile('language.yml');
When 'Request is `GET /api/v1/languages`';
$mech->get_ok('/api/v1/languages');
Then 'Response is as expected';
my @languages = @{ $mech->json_content };
foreach (@languages) {
expect($validator->validate($schema, $_))->to_be_true;
};

22. LINE Creators Studio
Summary
• HTTP Webserver (nginx)
• Perl・Plack・Amon2
• JSON RESTful API
• Authentication: LINE SDK, LINE Social REST API + API Access Token
• JSON Schema (but YAML)
• Documentation
• Data validation in tests
RESTful API to existing service

23. Thank you.