feat: add nodes field to relay connections (#471)

This adds a `nodes` field to relay connections. With this added it
allows GraphQL queries like this:

```
  location(id: $id) {
    id
    name
    devices {
      nodes {
        id
        name
      }
    }
  }
```

Which makes it easier to loop through results instead of having to loop
through the `edges` and then `node` to get the actual list of nodes.
This is similar to how GitHub and other public GraphQL APIs provide
things through the relay connection.

This is entirely based off of ent/contrib#602 and can be removed once we
are on a release that includes that PR.

Signed-off-by: Nicole Hubbard <[email protected]>

Author: nicolerenee

entx/generator.go

@@ -44,6 +44,16 @@ func WithFederation() ExtensionOption {
 	}
 }
 
+// WithConnectionNodes adds the templates for adding nodes to relay connections
+func WithConnectionNodes() ExtensionOption {
+	return func(ex *Extension) error {
+		ex.templates = append(ex.templates, PaginationTemplate)
+		ex.gqlSchemaHooks = append(ex.gqlSchemaHooks, addNodesToConnections)
+
+		return nil
+	}
+}
+
 // WithJSONScalar adds the JSON scalar definition
 func WithJSONScalar() ExtensionOption {
 	return func(ex *Extension) error {

entx/gql_hooks.go

@@ -16,6 +16,8 @@ package entx
 
 import (
 	"errors"
+	"slices"
+	"strings"
 
 	"entgo.io/ent/entc"
 	"entgo.io/ent/entc/gen"
@@ -88,6 +90,36 @@ var (
 		}
 		return nil
 	}
+
+	addNodesToConnections = func(_ *gen.Graph, s *ast.Schema) error {
+		for _, t := range s.Types {
+			if !strings.HasSuffix(t.Name, "Connection") {
+				continue
+			}
+
+			existingFields := []string{"edges", "pageInfo", "totalCount"}
+			missingField := false
+			for _, f := range t.Fields {
+				if !slices.Contains(existingFields, f.Name) {
+					missingField = true
+				}
+			}
+			if missingField {
+				continue
+			}
+
+			// If we are here then this type is a connection with only the fields we expect so add nodes
+			nodeType := strings.TrimSuffix(t.Name, "Connection")
+
+			t.Fields = append(t.Fields, &ast.FieldDefinition{
+				Name:        "nodes",
+				Type:        ast.ListType(ast.NamedType(nodeType, nil), nil),
+				Description: "A list of nodes.",
+			})
+		}
+
+		return nil
+	}
 )
 
 // import string mutations from entc

entx/template.go

@@ -19,6 +19,7 @@ import (
 	"strings"
 	"text/template"
 
+	"entgo.io/contrib/entgql"
 	"entgo.io/ent/entc/gen"
 	"github.com/mitchellh/mapstructure"
 )
@@ -30,6 +31,9 @@ var (
 	// EventHooksTemplate adds support for generating event hooks
 	EventHooksTemplate = parseT("template/event_hooks.tmpl")
 
+	// PaginationTemplate adds support for adding the nodes field to relay connections
+	PaginationTemplate = parseT("template/pagination.tmpl")
+
 	// TemplateFuncs contains the extra template functions used by entx.
 	TemplateFuncs = template.FuncMap{
 		"contains":                          strings.Contains,
@@ -41,8 +45,14 @@ var (
 )
 
 func parseT(path string) *gen.Template {
+	funcMap := entgql.TemplateFuncs
+
+	for k, v := range TemplateFuncs {
+		funcMap[k] = v
+	}
+
 	return gen.MustParse(gen.NewTemplate(path).
-		Funcs(TemplateFuncs).
+		Funcs(funcMap).
 		ParseFS(_templates, path))
 }