A friendlier Ruby client for consuming GraphQL-based APIs. Built on top of your usual graphql-client, but with better defaults, more consistent error handling, and using the faraday HTTP client.
Add the following line to your Gemfile.
gem 'graphlient'
Create a new instance of Graphlient::Client
with a URL and optional headers.
client = Graphlient::Client.new('https://test-graphql.biz/graphql',
headers: {
'Authorization' => 'Bearer 123'
}
)
The schema is available automatically via .schema
.
client.schema # GraphQL::Schema
Make queries with query
, which takes a String or a block for the query definition.
With a String.
response = client.query <<~GRAPHQL
query {
invoice(id: 10) {
id
total
line_items {
price
item_type
}
}
}
GRAPHQL
With a block.
response = client.query do
query do
invoice(id: 10) do
id
total
line_items do
price
item_type
end
end
end
end
This will call the endpoint setup in the configuration with POST
, the Authorization
header and query
as follows.
query {
invoice(id: 10) {
id
total
line_items {
price
item_type
}
}
}
A successful response object always contains data which can be iterated upon. The following example returns the first line item's price.
response.data.invoice.line_items.first.price
You can also execute mutations the same way.
response = client.query do
mutation do
createInvoice(input: { fee_in_cents: 12_345 }) do
id
fee_in_cents
end
end
end
The successful response contains data in response.data
. The following example returns the newly created invoice's ID.
response.data.create_invoice.first.id
To reduce requests to graphql API you can cache schema:
client = Client.new(url, schema_path: 'config/your_graphql_schema.json')
client.schema.dump! # you only need to call this when graphql schema changes
Unlike graphql-client, Graphlient will always raise an exception unless the query has succeeded.
- Graphlient::Errors::ClientError: all client-side query validation failures based on current schema
- Graphlient::Errors::GraphQLError: all GraphQL API errors, with a humanly readable collection of problems
- Graphlient::Errors::ExecutionError: all GraphQL execution errors, with a humanly readable collection of problems
- Graphlient::Errors::ServerError: all transport errors raised by Faraday
All errors inherit from Graphlient::Errors::Error
if you need to handle them in bulk.
Graphlient can execute parameterized queries and mutations by providing variables as query parameters.
The following query accepts an array of IDs.
With a String.
query = <<-GRAPHQL
query($ids: [Int]) {
invoices(ids: $ids) {
id
fee_in_cents
}
}
GRAPHQL
variables = { ids: [42] }
client.query(query, variables)
With a block.
client.query(ids: [42]) do
query(ids: [:int]) do
invoices(ids: :ids) do
id
fee_in_cents
end
end
end
Graphlient supports following Scalar types for parameterized queries by default:
:id
maps toID
:boolean
maps toBoolean
:float
maps toFloat
:int
maps toInt
:string
maps toString
You can use any of the above types with !
to make it required or use them in []
for array parameters.
For any other custom types, graphlient will simply use to_s
of the symbol provided for the type, so query(ids: [:InvoiceType!])
will result in query($ids: [InvoiceType!])
.
The following mutation accepts a custom type that requires fee_in_cents
.
client.query(input: { fee_in_cents: 12_345 }) do
mutation(input: :createInvoiceInput!) do
createInvoice(input: :input) do
id
fee_in_cents
end
end
end
You can parse
and execute
queries separately with optional variables. This is highly recommended as parsing a query and validating a query on every request adds performance overhead. Parsing queries early allows validation errors to be discovered before request time and avoids many potential security issues.
# parse a query, returns a GraphQL::Client::OperationDefinition
query = client.parse do
query(ids: [:int]) do
invoices(ids: :ids) do
id
fee_in_cents
end
end
end
# execute a query, returns a GraphQL::Client::Response
client.execute query, ids: [42]
Graphlient uses graphql-client, which recommends building queries as static module members along with dynamic variables during execution. This can be accomplished with graphlient the same way.
Create a new instance of Graphlient::Client
with a URL and optional headers.
module SWAPI
Client = Graphlient::Client.new('https://test-graphql.biz/graphql',
headers: {
'Authorization' => 'Bearer 123'
},
allow_dynamic_queries: false
)
end
The schema is available automatically via .schema
.
SWAPI::Client.schema # GraphQL::Schema
Define a query.
module SWAPI
InvoiceQuery = Client.parse do
query(id: :int) do
invoice(id: :id) do
id
fee_in_cents
end
end
end
end
Execute the query.
response = SWAPI::Client.execute(SWAPI::InvoiceQuery, id: 42)
Note that in the example above the client is created with allow_dynamic_queries: false
(only allow static queries), while graphlient defaults to allow_dynamic_queries: true
(allow dynamic queries). This option is marked deprecated, but we're proposing to remove it and default it to true
in graphql-client#128.
You can directly use Graphlient::Query
to generate raw GraphQL queries.
query = Graphlient::Query.new do
query do
invoice(id: 10) do
line_items
end
end
end
query.to_s
# "\nquery {\n invoice(id: 10){\n line_items\n }\n }\n"
You can include Graphlient::Extensions::Query
in your class. This will add a new method_missing
method to your context which will be used to generate GraphQL queries.
include Graphlient::Extensions::Query
query = query do
invoice(id: 10) do
line_items
end
end
query.to_s
# "\nquery{\n invoice(id: 10){\n line_items\n }\n }\n"
You can swap the default Faraday adapter for Net::HTTP
.
client = Graphlient::Client.new('https://test-graphql.biz/graphql',
http: Graphlient::Adapters::HTTP::HTTPAdapter
)
Use Graphlient inside your RSpec tests in a Rails application or with Rack::Test
against your actual application.
require 'spec_helper'
describe App do
include Rack::Test::Methods
def app
# ...
end
let(:client) do
Graphlient::Client.new('http://test-graphql.biz/graphql') do |client|
client.http do |h|
h.connection do |c|
c.use Faraday::Adapter::Rack, app
end
end
end
end
context 'an invoice' do
let(:result) do
client.query do
query do
invoice(id: 10) do
id
end
end
end
end
it 'can be retrieved' do
expect(result.data.invoice.id).to eq 10
end
end
end
Alternately you can stub_request
with Webmock.
describe App do
let(:url) { 'http://example.com/graphql' }
let(:client) { Graphlient::Client.new(url) }
before do
stub_request(:post, url).to_return(
status: 200,
body: DummySchema.execute(GraphQL::Introspection::INTROSPECTION_QUERY).to_json
)
end
it 'retrieves schema' do
expect(client.schema).to be_a GraphQL::Schema
end
end
MIT License, see LICENSE