moonbitstack/moongql/exec

README
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AppliedDirective
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Argument
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DataLoader
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Definition
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Directive
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DirectiveDef
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Document
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EntityDef
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EntityResolver
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EnumType
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Federation
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Field
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FieldDirectiveHook
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FragmentDefinition
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FromGql
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GqlError
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GqlSyntaxError
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GqlType
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GqlWs
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ObjectType
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OperationDefinition
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OperationType
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Pos
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QueryField
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ResolveInfo
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ResolverError
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Resolvers
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ScalarType
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Schema
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Selection
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Subscribers
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SubscriptionResult
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ToGql
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Token
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TokenKind
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TypeKind
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TypeRef
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UnionType
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Value
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VariableDefinition
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create_source_event_stream
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execute
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execute_subscription
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field_error
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graphiql_html
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graphql_app
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graphql_handler
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graphql_ws_handler
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parse
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read
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tokenize
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validate

moonbitstack/moongql/exec does not have a README file

FromGql

pub(open) trait FromGql {
  fn from_gql(Json) -> Self raise ResolverError
}

A MoonBit value read from an argument or a parent value: async-graphql's InputType. A refusal is a ResolverError saying what was expected.

impl FromGql for Bool

impl FromGql for Int

impl FromGql for Int64

impl FromGql for Double

impl FromGql for String

impl FromGql for Option[T]

impl FromGql for Array[T]

impl FromGql for Json

ToGql

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pub(open) trait ToGql {
  fn to_gql(Self) -> Json
}

A MoonBit value as a GraphQL result: async-graphql's OutputType. Implemented for the built-in scalars, Int64 (written as a string, since GraphQL's Int is 32-bit), Json, T? and Array[T]; the #gql generator writes it for each annotated type.

impl ToGql for Bool

impl ToGql for Int

impl ToGql for Int64

impl ToGql for Double

impl ToGql for String

impl ToGql for Option[T]

impl ToGql for Array[T]

impl ToGql for Json

ResolverError

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pub(all) suberror ResolverError {
  ResolverError(String)
  ResolverErrorExt(String, Map[String, Json])
}

An error raised by a field resolver; its message is reported in the response errors list with the field's response path.

ResolverError::expected

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fn ResolverError::expected(want : String, got : Json) -> ResolverError

The refusal of a value that is not a want, as every [FromGql] here writes it: expected Int, got "x".

ResolveInfo

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pub(all) struct ResolveInfo {
  parent : Json
  args : Map[String, Json]
  ctx : Json
  field_name : String
}

The information a field resolver receives: the resolved parent object (as JSON), the coerced arguments, the shared context value, and the field's name. A resolver returns the field's value as JSON (an object for composite types, whose sub-fields are then resolved against it) and may raise ResolverError to surface a field error.

ResolveInfo::arg

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fn ResolveInfo::arg(self : ResolveInfo, name : String) -> Json

Read a named argument as JSON, or Json::null() when it was not supplied.

ResolveInfo::read

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fn[T : FromGql] ResolveInfo::read(self : ResolveInfo, name : String) -> T raise ResolverError

The argument name as any [FromGql] type; a missing argument reads as null, so it is None for a T?. A refusal names the argument.

Resolvers

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pub struct Resolvers {
  map : Map[String, (ResolveInfo) -> Json raise ResolverError]
}

A registry of field resolvers, keyed by "TypeName.fieldName". Fields with no registered resolver fall back to the default resolver, which reads the field's name off the parent JSON object (matching graphql-core's default_field_resolver).

Resolvers::field

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fn Resolvers::field(self : Resolvers, type_name : String, field_name : String, resolver : (ResolveInfo) -> Json raise ResolverError) -> Unit

Resolvers::new

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fn Resolvers::new() -> Resolvers

Create an empty resolver registry.

Subscribers

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pub struct Subscribers {
  map : Map[String, (ResolveInfo) -> Array[Json] raise ResolverError]
}

A registry of subscription source resolvers, keyed by "TypeName.fieldName" on the subscription root type. A source returns the ordered stream of event payloads; each payload is the resolved value of the root field for one event, and its sub-selection is resolved against it like any object value.

Subscribers::field

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fn Subscribers::field(self : Subscribers, type_name : String, field_name : String, source : (ResolveInfo) -> Array[Json] raise ResolverError) -> Unit

Register a source stream for the root subscription field field_name on type_name. The source is called once per operation and yields the ordered events to deliver.

Subscribers::new

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fn Subscribers::new() -> Subscribers

Create an empty subscription source registry.

SubscriptionResult

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pub(all) enum SubscriptionResult {
  RequestError(Array[@moonbitstack/moongql/lang.GqlError
GqlError])
  EventStream(Array[Json])
}

The outcome of establishing a subscription (GraphQL spec §6.2.3 CreateSourceEventStream + MapSourceToResponseEvent): either the request failed before any event could be produced — a parse, validation, or source-resolution error the client should receive instead of a stream — or the source yielded its ordered { data, errors } response payloads. Keeping the two apart lets a transport (the graphql-transport-ws handler) send a single error message for the former and a run of next messages for the latter, which the flat "one error response in the payload list" shape cannot distinguish.

build_response

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fn build_response(data : Json?, errors : Array[@moonbitstack/moongql/lang.GqlError
GqlError], extensions? : Map[String, Json]) -> Json

Assemble the final { errors?, data?, extensions? } response object. data is omitted for request-level failures (no execution began) and included (possibly null) once execution starts; errors is omitted when empty, and so is the server's extensions map (§7.1, the entry reserved for whatever a server wants to say alongside the result — timings, a trace id, a cache hint).

create_source_event_stream

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fn create_source_event_stream(schema : @moonbitstack/moongql/schema.Schema
Schema, resolvers : Resolvers, subscribers : Subscribers, query : String, variables? : Map[String, Json], operation_name? : String, root_value? : Json, context? : Json) -> SubscriptionResult

Establish a subscription and materialise its event payloads. Parses and validates query, requires a single-root-field subscription operation, invokes the registered source, and maps every event through execute_subscription_event. Any failure before the first event — parse/validation error, a non-subscription operation, more than one root field, an introspection root, a missing source, or a source ResolverError — is a RequestError; success is an EventStream of ordered response payloads.

execute

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fn execute(schema : @moonbitstack/moongql/schema.Schema
Schema, resolvers : Resolvers, query : String, variables? : Map[String, Json], operation_name? : String, root_value? : Json, context? : Json, extensions? : Map[String, Json]) -> Json

Execute a GraphQL request end to end: parse query, validate it against schema, select the operation, coerce variables, then walk the selection set with resolvers — returning the { data, errors } response as JSON.

variables supplies operation variable values, operation_name picks an operation when the document has several, root_value seeds the root object, context is threaded to every resolver, and extensions is the server's own extensions entry on the response (§7.1), emitted when non-empty. The function never raises: parse and validation failures yield an errors-only response, and field errors are collected alongside partial data.

execute_subscription

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fn execute_subscription(schema : @moonbitstack/moongql/schema.Schema
Schema, resolvers : Resolvers, subscribers : Subscribers, query : String, variables? : Map[String, Json], operation_name? : String, root_value? : Json, context? : Json) -> Array[Json]

Run a subscription operation and collect its ordered response payloads.

A thin wrapper over create_source_event_stream: a RequestError collapses to a single { errors } response (the flat shape callers without a streaming transport expect), and an EventStream is returned as-is. variables, operation_name, root_value and context mirror execute.

field_error

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fn field_error(e : Error) -> ResolverError

Any error a resolver raised, as the field error it becomes; a ResolverError passes through unchanged.

operation_type

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fn operation_type(schema : @moonbitstack/moongql/schema.Schema
Schema, doc : @moonbitstack/moongql/lang.Document
Document, operation_name : String?) -> Result[@moonbitstack/moongql/lang.OperationType
OperationType, @moonbitstack/moongql/lang.GqlError
GqlError]

Which kind of operation a request would run, chosen the way execute chooses it. The server needs this before running anything: a subscription goes over a socket, and GraphQL over HTTP refuses a mutation sent by GET.

read

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fn[T : FromGql] read(value : Json, key : String) -> T raise ResolverError

The member key of an object value as any [FromGql] type, the way a generated input type reads its fields; a missing member reads as null. A refusal names the member.

Source Files

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#FromGql

#ToGql

#ResolverError

#ResolverError::expected

#ResolveInfo

#ResolveInfo::arg

#ResolveInfo::read

#Resolvers

#Resolvers::field

#Resolvers::new

#Subscribers

#Subscribers::field

#Subscribers::new

#SubscriptionResult

#build_response

#create_source_event_stream

#execute

#execute_subscription

#field_error

#operation_type

#read

Source Files

FromGql

ToGql

ResolverError

ResolverError::expected

ResolveInfo

ResolveInfo::arg

ResolveInfo::read

Resolvers

Resolvers::field

Resolvers::new

Subscribers

Subscribers::field

Subscribers::new

SubscriptionResult

build_response

create_source_event_stream

execute

execute_subscription

field_error

operation_type

read