GraphQL utils.
def deps do
[
{:straw_hat_graphql, "~> 0.1"}
]
end
The package come with predefined types that you could use in your project. Most of those types dictate how your data structure and responses from your mutations will look like but it will help you to speed up your development.
defmodule YourApp.AbsintheSchema do
use Absinthe.Schema
use Absinthe.Schema.Notation
# Should be include it before you use it
import_types StrawHat.GraphQL.Types
import_types StrawHat.GraphQL.Scalars
# ...
end
Check StrawHat.GraphQL.Types
and StrawHat.GraphQL.Scalars
for more
information about the included types.
There is some types for doing paginations. We follow Scrivener for formatting the response.
Note: For now there is some boilerplate code for the paginations. We are aware of using macros but to be honest sometimes is better a repeated code that shoot ourself in the foot, still thinking about creating macros for this.
object :person do
interface :straw_hat_node
field :id, non_null(:id)
# ... more fields
end
# We recommend to use `_pagination`, this is another place where we could macros.
object :people_pagination do
# This will force you to defined the schemas
interface(:straw_hat_pagination)
field(:page, non_null(:straw_hat_pagination_page))
field(:total_entries, non_null(:integer))
field(:total_pages, non_null(:integer))
# This is where it gets tricky and probably we could use macros
# the reason is that we can't put this field inside `:straw_hat_pagination`
# because the type is not the same for all the objects.
field(:entries, list_of(:person))
end
Now let's create the query.
field :people, :people_pagination do
arg(:pagination, non_null(:straw_hat_pagination_page_input))
resolve(&PeopleResolver.get_people/2)
end
Mutations is something that comes really handy and with a really nice API.
Note: For now there is some boilerplate code for the mutations. We are aware of using macros but to be honest sometimes is better a repeated code that shoot ourself in the foot, still thinking about creating macros for this.
First, you need to create the mutation response which normally should extend
from the interface of mutation_response
object :person do
interface :straw_hat_node
field :id, non_null(:id)
# ... more fields
end
# We recommend to use `_payload`, this is another place where we could macros
object :person_payload do
# This will force you to defined the schemas
interface :straw_hat_mutation_response
field :successful, non_null(:boolean)
field :errors, list_of(:straw_hat_error)
# This is where it gets tricky and probably we could use macros
# the reason is that we can't put this field inside `:straw_hat_mutation_response`
# because the type is not the same for all mutations.
field :payload, :person
end
Now we create the mutation
object :person_mutations do
field :person_update, :person_payload do
arg :person, non_null(:person_input)
# other resolvers, maybe authorization
resolve &MyApp.PersonResolvers.update_person/2
end
end
Now what is left is the resolver function itself
defmodule MyApp.PersonResolvers do
alias StrawHat.GraphQL.MutationResponse
def update_person(%{person: person_params}, _) do
response = MyApp.Person.update_person(person_params)
# We do not want to force anything the responses from your modules
# it up to you, make sure you call the correct function for format
# the data structure
case response do
{:ok, response} -> MutationResponse.succeeded(response)
{:error, reason} -> MutationResponse.failed(reason)
end
end
end
If you want to avoid doing the pattern matching constantly which it is up to your application design, you could create a function that does it for you
defmodule MyApp.ResolverHelpers
alias StrawHat.GraphQL.MutationResponse
def response_with({:ok, response}), do: MutationResponse.succeeded(response)
def response_with({:error, reason}), do: MutationResponse.failed(reason)
def response_with(_), do: raise(ArgumentError)
end
then your resolver becomes
import MyApp.ResolverHelpers
def update_person(%{person: person_params}, _) do
person_params
|> MyApp.Person.update_person()
|> response_with()
end
And now you are go to go. Or use StrawHat.GraphQL.MutationResponse.response_with/1
but be aware that it is constrain by the inputs.
Any suggestion and code pattern that you notice in your app, open an issue and let's talk about it.