jsonapi-http
Make HTTP requests with jsonapi decoding/encoding in Elm.
This package makes use of the packages jsonapi and remotedata.
You will be able to send HTTP requests that expect a jsonapi object as a response.
Getting started
Here is an example of the creation of a post, that expects a post as a return value. The posts we send and receive will follow the jsonapi specification.
type alias User =
{ id : String
, name : String
}
type alias Post =
{ id : String
, title : String
, body : String
, creator : User
}
type alias PostPayload =
{ title : String
, body : String
}
createPost : (RemoteData.RemoteData Http.Error.RequestError Post) -> PostPayload -> Cmd msg
createPost msg body =
Http.Request.request
{ headers = []
, url = { url = "/api/post", method = Http.Methods.POST }
, body = encodeBody body
, documentDecoder = JsonApi.Decode.resource "posts" postDecoder
}
|> Task.map (RemoteData.map JsonApi.Document.resource)
|> Task.perform msg
encodeBody : PostPayload -> Json.Encode.Value
encodeBody body =
JsonApi.Encode.Document.build
|> JsonApi.Encode.Document.withResource
(JsonApi.Resource.build "posts"
|> JsonApi.Resource.withAttributes
[ ( "body", Json.Encode.string body.body )
, ( "title", Json.Encode.string body.title )
]
)
|> JsonApi.Encode.document
postDecoder : JsonApi.Resource.Resource -> Json.Decode.Decoder Post
postDecoder res =
Json.Decode.map4 Post
(Json.Decode.succeed (JsonApi.Resource.id res))
(Json.Decode.field "title" Json.Decode.string)
(Json.Decode.field "body" Json.Decode.string)
(JsonApi.Decode.relationship "creator" res User.userDecoder)
userDecoder : JsonApi.Resource.Resource -> Json.Decode.Decoder User
userDecoder res =
Json.Decode.map2 User
(Json.Decode.succeed (JsonApi.Resource.id res))
(Json.Decode.field "name" Json.Decode.string)Here is how to use the functions defined above to create a new post and retrieve this newly created post from the server.
type Msg =
OnPostCreated (RemoteData.RemoteData Http.Error.RequestError Post)
type alias Model =
{ post : RemoteData.RemoteData Http.Error.RequestError Post }
newPost : PostPayload
newPost =
{ title = "My new post"
, body = "This is a new post"
}
init : ( Model, Cmd Msg )
init =
( { post = RemoteData.Loading }
, createPost OnPostCreated newPost
)
update : Msg -> Model -> ( Model, Cmd Msg )
update msg model =
case msg of
OnPostCreated post ->
( { model | post = post }
, Cmd.none
)
view : Model -> Html Msg
view model =
case model.post of
RemoteData.NotAsked ->
text "The post will be created soon"
RemoteData.Loading ->
text "Still a few seconds to wait!"
RemoteData.Failure error ->
viewError error
RemoteData.Success post ->
div []
[ div [ class "post-title" ] [ text post.title ]
, div [ class "post-body" ] [ text post.body ]
, div [ class "post-creator" ] [ text post.creator.name ]
]
viewError : Http.Error.RequestError -> Html Msg
viewError error =
case error of
Http.Error.HttpError httpError ->
text "This is a HTTP error as we already know them..."
Http.Error.CustomError msg ->
text ("Custom error " ++ msg)
Http.Error.JsonApiError errors ->
text "This is an error coming from the jsonapi paylaod"
subscriptions : Model -> Sub Msg
subscriptions =
Sub.none
