defmodule GraphQL.Plug.Endpoint do
import Plug.Conn
alias Plug.Conn
@behaviour Plug
def init(opts) do
schema = case Keyword.get(opts, :schema) do
{mod, func} -> apply(mod, func, [])
s -> s
end
%{schema: schema}
end
def call(%Conn{method: m} = conn, opts) when m in ["GET", "POST"] do
%{schema: schema} = conn.assigns[:graphql_options] || opts
query = query(conn)
cond do
query && use_graphiql?(conn) -> handle_graphiql_call(conn, schema, query)
query -> handle_call(conn, schema, query)
true -> handle_error(conn, "Must provide query string.")
end
end
def call(%Conn{method: _} = conn, _) do
handle_error(conn, "GraphQL only supports GET and POST requests.")
end
defp handle_call(conn, schema, query) do
conn
|> put_resp_content_type("application/json")
|> execute(schema, query)
end
defp handle_graphiql_call(conn, schema, query) do
{:ok, data} = GraphQL.execute(schema, query)
{:ok, result} = Poison.encode(%{data: data})
conn
|> put_resp_content_type("text/html")
|> send_resp(200, graphiql_html(query, nil, result))
end
defp handle_error(conn, message) do
{:ok, errors} = Poison.encode %{errors: [%{message: message}]}
conn
|> put_resp_content_type("application/json")
|> send_resp(400, errors)
end
defp execute(conn, schema, query) do
case GraphQL.execute(schema, query) do
{:ok, data} ->
case Poison.encode(%{data: data}) do
{:ok, json} -> send_resp(conn, 200, json)
{:error, errors} -> send_resp(conn, 400, errors)
end
{:error, errors} ->
case Poison.encode(errors) do
{:ok, json} -> send_resp(conn, 400, json)
{:error, errors} -> send_resp(conn, 400, errors)
end
end
end
defp query(%Conn{params: %{"query" => query}}) do
if query && String.strip(query) != "", do: query, else: nil
end
defp query(_) do
nil
end
defp use_graphiql?(conn) do
case get_req_header(conn, "accept") do
[accept_header | _] ->
String.contains?(accept_header, "text/html") &&
!Map.has_key?(conn.params, "raw")
_ ->
false
end
end
@graphiql_version "0.4.4"
defp graphiql_html(query, variables \\ "", result) do
"""
"""
end
end