Elm Twitch Api

Decoders and a few other helpers for using Twitch.tv APIs.

Partial coverage of the APIs I have used.

• Includes most the Helix (new Twitch API).
• Some additional decoders for unofficial hosts.

Most modules provide decoders for a specific api request. Notable exceptions include:

• Twitch.Helix - generic types and decoders
• Twitch.Helix.Request - HTTP request helper
• Twitch.Kraken.Request - HTTP request helper
• Twitch.Template - template url helpers

Decoder Modules

Decoder modules provide stock decoders for each field in an api response. These decoders are usually trivial, and can be easily replaced if you want to decode as a different type. Most of them are of the form.

id : Decoder UserId
id = (field "id" Helix.userId)

The library provides:

• The correctly spelled field name (at least according to the test suite)
• A sensible basic decode type
• In a few cases, more complex decode types

Notably, video durations are of the form "1h22m33s", and the Twitch.Helix.Video.duration decoder returns it as milliseconds.

Most ids are numbers as strings; the library uses an aliased string with a custom name for documentation purposes, but treats the ids as opaque tokens.

Decoder example

import Twitch.Helix.User as User
import Json.Decode exposing (..)

users : Decoder (List User)
users = User.response user

user : Decoder User
user =
  map3 User
    User.id
    User.login
    User.displayName

Request helpers

fetchUserByNameUrl : String -> String
fetchUserByNameUrl login =
  "https://api.twitch.tv/helix/users?login=" ++ login

fetchUserByName : String -> String -> Cmd Msg
fetchUserByName auth login =
  Twitch.Helix.send <|
    { clientId = TwitchId.clientId -- your id
    -- I keep mine in a separate module
    -- so it can be excluded from version control
    , auth = auth
    , decoder = users -- your function, see above
    , tagger = User
    , url = (fetchUserByNameUrl login)
    }

Example applications using this library:

• https://github.com/JustinLove/following_videos (Following Videos) (a bit obsolete)
• https://github.com/JustinLove/hostable (Hostable)
• https://github.com/JustinLove/hosting-clips (Hosting Clips)
• https://github.com/JustinLove/schedule-from-videos (Schedule From Videos)
• https://github.com/JustinLove/stream-credits (Stream Credits)