forked from rs/rest-layer
/
types.go
193 lines (182 loc) · 4.99 KB
/
types.go
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package graphql
import (
"fmt"
"log"
"github.com/graphql-go/graphql"
"github.com/rs/rest-layer/resource"
"github.com/rs/rest-layer/schema"
)
type types map[string]*graphql.Object
// getObjectType returns a graphql object type definition from a REST layer schema
func (t types) getObjectType(idx resource.Index, r *resource.Resource) *graphql.Object {
// Memoize types by their name so we don't create several instance of the same resource
name := r.Name()
o := t[name]
if o == nil {
o = graphql.NewObject(graphql.ObjectConfig{
Name: name,
Description: r.Schema().Description,
Fields: getFields(idx, r.Schema()),
})
t[name] = o
t.addConnections(o, idx, r)
}
return o
}
// addConnections adds connections fields to the object afterward to prevent from dead loops
func (t types) addConnections(o *graphql.Object, idx resource.Index, r *resource.Resource) {
// Add sub field references
for name, def := range r.Schema().Fields {
if ref, ok := def.Validator.(*schema.Reference); ok {
sr, found := idx.GetResource(ref.Path, nil)
if !found {
log.Panicf("resource reference not found: %s", ref.Path)
}
o.AddFieldConfig(name, &graphql.Field{
Description: def.Description,
Type: t.getObjectType(idx, sr),
Args: getFArgs(def.Params),
Resolve: getSubFieldResolver(name, sr, def),
})
}
}
// Add sub resources
for _, sr := range r.GetResources() {
name := sr.Name()
o.AddFieldConfig(name, &graphql.Field{
Description: fmt.Sprintf("Connection to %s", name),
Type: graphql.NewList(t.getObjectType(idx, sr)),
Args: listArgs,
Resolve: getSubResourceResolver(sr),
})
}
}
func getSubFieldResolver(parentField string, r *resource.Resource, f schema.Field) graphql.FieldResolveFn {
s, serialize := f.Validator.(schema.FieldSerializer)
return func(p graphql.ResolveParams) (data interface{}, err error) {
parent, ok := p.Source.(map[string]interface{})
if !ok {
return nil, nil
}
var item *resource.Item
// Get sub field resource
item, err = r.Get(p.Context, parent[parentField])
if err != nil {
return nil, err
}
data = item.Payload
if f.Handler != nil {
data, err = f.Handler(p.Context, data, p.Args)
}
if err == nil && serialize {
data, err = s.Serialize(data)
}
return data, err
}
}
func getSubResourceResolver(r *resource.Resource) graphql.FieldResolveFn {
return func(p graphql.ResolveParams) (interface{}, error) {
parent, ok := p.Source.(map[string]interface{})
if !ok {
return nil, nil
}
lookup, page, perPage, err := listParamResolver(r, p, nil)
if err != nil {
return nil, err
}
// Limit the connection to parent's owned
lookup.AddQuery(schema.Query{
schema.Equal{
Field: r.ParentField(),
Value: parent["id"],
},
})
list, err := r.Find(p.Context, lookup, page, perPage)
if err != nil {
return nil, err
}
result := make([]map[string]interface{}, len(list.Items))
for i, item := range list.Items {
result[i] = item.Payload
}
return result, nil
}
}
func getFields(idx resource.Index, s schema.Schema) graphql.Fields {
flds := graphql.Fields{}
// Iter fields
for name, def := range s.Fields {
if def.Hidden {
continue
}
if _, ok := def.Validator.(*schema.Reference); ok {
// Handled by addConnections to prevent dead loops
}
var typ graphql.Output
if def.Schema != nil {
typ = graphql.NewObject(graphql.ObjectConfig{
Name: name,
Fields: getFields(idx, *def.Schema),
})
} else {
typ = getFType(def.Validator)
}
flds[name] = &graphql.Field{
Description: def.Description,
Type: typ,
Args: getFArgs(def.Params),
Resolve: getFResolver(name, def),
}
}
return flds
}
func getFArgs(p schema.Params) graphql.FieldConfigArgument {
if p == nil {
return nil
}
args := graphql.FieldConfigArgument{}
for name, param := range p {
args[name] = &graphql.ArgumentConfig{
Description: param.Description,
Type: getFType(param.Validator),
}
}
return args
}
// getFResolver returns a GraphQL field resolver for REST layer field handler
func getFResolver(fieldName string, f schema.Field) graphql.FieldResolveFn {
s, serialize := f.Validator.(schema.FieldSerializer)
if !serialize && f.Handler == nil {
return nil
}
return func(rp graphql.ResolveParams) (interface{}, error) {
data, ok := rp.Source.(map[string]interface{})
if !ok {
return nil, nil
}
var err error
val := data[fieldName]
if f.Handler != nil {
val, err = f.Handler(rp.Context, val, rp.Args)
}
if err == nil && serialize {
val, err = s.Serialize(val)
}
return val, err
}
}
// getFType translates a REST layer field type into GraphQL type
func getFType(v schema.FieldValidator) graphql.Output {
switch v.(type) {
case *schema.String, schema.String:
return graphql.String
case *schema.Integer, schema.Integer:
return graphql.Int
case *schema.Float, schema.Float:
return graphql.Float
case *schema.Bool, schema.Bool:
return graphql.Boolean
default:
return graphql.String
}
}