Class: GraphQL::Field
- Inherits:
-
Object
- Object
- GraphQL::Field
- Includes:
- Define::InstanceDefinable
- Defined in:
- lib/graphql/field.rb,
lib/graphql/field/resolve.rb
Overview
Fields belong to ObjectTypes and InterfaceTypes.
They're usually created with the field
helper. If you create it by hand, make sure #name is a String.
A field must have a return type, but if you want to defer the return type calculation until later, you can pass a proc for the return type. That proc will be called when the schema is defined.
For complex field definition, you can pass a block to the field
helper, eg field :name do ... end
.
This block is equivalent to calling GraphQL::Field.define { ... }
.
Resolve
Fields have resolve
functions to determine their values at query-time.
The default implementation is to call a method on the object based on the field name.
You can specify a custom proc with the resolve
helper.
There are some shortcuts for common resolve
implementations:
- Provide
property:
to call a method with a different name than the field name - Provide
hash_key:
to resolve the field by doing a key lookup, egobj[:my_hash_key]
Arguments
Fields can take inputs; they're called arguments. You can define them with the argument
helper.
They can have default values which will be provided to resolve
if the query doesn't include a value.
Only certain types maybe used for inputs:
- Scalars
- Enums
- Input Objects
- Lists of those types
Input types may also be non-null -- in that case, the query will fail if the input is not present.
Complexity
Fields can have complexity values which describe the computation cost of resolving the field.
You can provide the complexity as a constant with complexity:
or as a proc, with the complexity
helper.
Defined Under Namespace
Modules: Resolve
Instance Attribute Summary collapse
-
#arguments ⇒ Hash<String => GraphQL::Argument>
Map String argument names to their Argument implementations.
-
#complexity ⇒ Numeric, Proc
The complexity for this field (default: 1), as a constant or a proc like
->(query_ctx, args, child_complexity) { } # Numeric
. -
#mutation ⇒ GraphQL::Relay::Mutation?
The mutation this field was derived from, if it was derived from a mutation.
-
#name ⇒ String
The name of this field on its ObjectType (or InterfaceType).
-
#resolve_proc ⇒ Object
readonly
Returns the value of attribute resolve_proc.
Instance Method Summary collapse
- #hash_key=(new_hash_key) ⇒ Object
-
#initialize ⇒ Field
constructor
A new instance of Field.
- #property=(new_property) ⇒ Object
-
#resolve(object, arguments, context) ⇒ Object
Get a value for this field.
-
#resolve=(new_resolve_proc) ⇒ Object
Provide a new callable for this field's resolve function.
- #to_s ⇒ Object
-
#type ⇒ Object
Get the return type for this field.
- #type=(new_return_type) ⇒ Object
Methods included from Define::InstanceDefinable
Constructor Details
#initialize ⇒ Field
Returns a new instance of Field.
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# File 'lib/graphql/field.rb', line 147 def initialize @complexity = 1 @arguments = {} @resolve_proc = build_default_resolver end |
Instance Attribute Details
#arguments ⇒ Hash<String => GraphQL::Argument>
Returns Map String argument names to their Argument implementations.
|
# File 'lib/graphql/field.rb', line 138
|
#complexity ⇒ Numeric, Proc
Returns The complexity for this field (default: 1), as a constant or a proc like ->(query_ctx, args, child_complexity) { } # Numeric
.
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# File 'lib/graphql/field.rb', line 147 def initialize @complexity = 1 @arguments = {} @resolve_proc = build_default_resolver end |
#mutation ⇒ GraphQL::Relay::Mutation?
Returns The mutation this field was derived from, if it was derived from a mutation.
|
# File 'lib/graphql/field.rb', line 141
|
#name ⇒ String
Returns The name of this field on its ObjectType (or InterfaceType).
|
# File 'lib/graphql/field.rb', line 135
|
#resolve_proc ⇒ Object (readonly)
Returns the value of attribute resolve_proc.
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# File 'lib/graphql/field.rb', line 133 def resolve_proc @resolve_proc end |
Instance Method Details
#hash_key=(new_hash_key) ⇒ Object
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# File 'lib/graphql/field.rb', line 208 def hash_key=(new_hash_key) ensure_defined @hash_key = new_hash_key self.resolve = nil # reset resolve proc end |
#property=(new_property) ⇒ Object
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# File 'lib/graphql/field.rb', line 201 def property=(new_property) ensure_defined @property = new_property self.resolve = nil # reset resolve proc end |
#resolve(object, arguments, context) ⇒ Object
Get a value for this field
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# File 'lib/graphql/field.rb', line 160 def resolve(object, arguments, context) ensure_defined resolve_proc.call(object, arguments, context) end |
#resolve=(new_resolve_proc) ⇒ Object
Provide a new callable for this field's resolve function. If nil
,
a new resolve proc will be build based on its #name, #property or #hash_key.
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# File 'lib/graphql/field.rb', line 168 def resolve=(new_resolve_proc) ensure_defined @resolve_proc = new_resolve_proc || build_default_resolver end |
#to_s ⇒ Object
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# File 'lib/graphql/field.rb', line 214 def to_s "<Field name:#{name || "not-named"} desc:#{description} resolve:#{resolve_proc}>" end |
#type ⇒ Object
Get the return type for this field.
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# File 'lib/graphql/field.rb', line 180 def type @clean_type ||= begin ensure_defined GraphQL::BaseType.(@dirty_type) end end |
#type=(new_return_type) ⇒ Object
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# File 'lib/graphql/field.rb', line 173 def type=(new_return_type) ensure_defined @clean_type = nil @dirty_type = new_return_type end |