next version preparation: hero: add a Container.Inject method to inject values outside of HTTP lifecycle, e.g. a database may be used by other services outside of Iris, the hero container (and API's Builder.GetContainer()) should provide it.

Former-commit-id: 89863055a3a3ab108a3f4b753072a35321a3a193

Author: kataras

hero/binding.go

@@ -125,13 +125,15 @@ func getBindingsFor(inputs []reflect.Type, deps []*Dependency, paramsCount int)
 	// Therefore, count the inputs that can be path parameters first.
 	shouldBindParams := make(map[int]struct{})
 	totalParamsExpected := 0
-	for i, in := range inputs {
-		if _, canBePathParameter := context.ParamResolvers[in]; !canBePathParameter {
-			continue
-		}
-		shouldBindParams[i] = struct{}{}
+	if paramsCount != -1 {
+		for i, in := range inputs {
+			if _, canBePathParameter := context.ParamResolvers[in]; !canBePathParameter {
+				continue
+			}
+			shouldBindParams[i] = struct{}{}
 
-		totalParamsExpected++
+			totalParamsExpected++
+		}
 	}
 
 	startParamIndex := paramsCount - totalParamsExpected

hero/container.go

@@ -2,7 +2,9 @@ package hero
 
 import (
 	stdContext "context"
+	"errors"
 	"net/http"
+	"reflect"
 	"time"
 
 	"github.com/kataras/iris/v12/context"
@@ -177,3 +179,70 @@ func (c *Container) HandlerWithParams(fn interface{}, paramsCount int) context.H
 func (c *Container) Struct(ptrValue interface{}, partyParamsCount int) *Struct {
 	return makeStruct(ptrValue, c, partyParamsCount)
 }
+
+/*
+func (c *Container) Inject(ctx context.Context, toPtr ...interface{}) error {
+	types := make([]reflect.Type, 0, len(toPtr))
+	for _, ptr := range toPtr {
+		types = append(types, indirectType(typeOf(ptr)))
+	}
+
+	bindings := getBindingsFor(types, c.Dependencies, -1)
+
+	for _, b := range bindings {
+		v, err := b.Dependency.Handle(ctx, b.Input)
+		if err != nil {
+			if err == ErrSeeOther {
+				continue
+			}
+
+			return err
+		}
+
+		reflect.ValueOf(toPtr).Set(v)
+	}
+
+	return nil
+}*/
+
+// ErrMissingDependency may returned only from the `Container.Inject` method
+// when not a matching dependency found for "toPtr".
+var ErrMissingDependency = errors.New("missing dependency")
+
+// Inject SHOULD only be used outside of HTTP handlers (performance is not priority for this method)
+// as it does not pre-calculate the available list of bindings for the "toPtr" and the registered dependencies.
+//
+// It sets a static-only matching dependency to the value of "toPtr".
+// The parameter "toPtr" SHOULD be a pointer to a value corresponding to a dependency,
+// like input parameter of a handler or field of a struct.
+//
+// If no matching dependency found, the `Inject` method returns an `ErrMissingDependency` and
+// "toPtr" keeps its original state (e.g. nil).
+//
+// Example Code:
+// c.Register(&LocalDatabase{...})
+// [...]
+// var db Database
+// err := c.Inject(&db)
+func (c *Container) Inject(toPtr interface{}) error {
+	val := reflect.Indirect(valueOf(toPtr))
+	typ := val.Type()
+
+	for _, d := range c.Dependencies {
+		if d.Static && matchDependency(d, typ) {
+			v, err := d.Handle(nil, &Input{Type: typ})
+			if err != nil {
+				if err == ErrSeeOther {
+					continue
+				}
+
+				return err
+			}
+
+			val.Set(v)
+			return nil
+		}
+	}
+
+	return ErrMissingDependency
+}

hero/container_test.go

@@ -46,14 +46,54 @@ var (
 	}
 )
 
-func TestHeroHandler(t *testing.T) {
+func TestContainerHandler(t *testing.T) {
 	app := iris.New()
 
-	b := New()
-	postHandler := b.Handler(fn)
+	c := New()
+	postHandler := c.Handler(fn)
 	app.Post("/{id:int}", postHandler)
 
 	e := httptest.New(t, app)
 	path := fmt.Sprintf("/%d", expectedOutput.ID)
 	e.POST(path).WithJSON(input).Expect().Status(httptest.StatusOK).JSON().Equal(expectedOutput)
 }
+
+func TestContainerInject(t *testing.T) {
+	c := New()
+
+	expected := testInput{Name: "test"}
+	c.Register(expected)
+	c.Register(&expected)
+
+	// struct value.
+	var got1 testInput
+	if err := c.Inject(&got1); err != nil {
+		t.Fatal(err)
+	}
+	if !reflect.DeepEqual(expected, got1) {
+		t.Fatalf("[struct value] expected: %#+v but got: %#+v", expected, got1)
+	}
+
+	// ptr.
+	var got2 *testInput
+	if err := c.Inject(&got2); err != nil {
+		t.Fatal(err)
+	}
+
+	if !reflect.DeepEqual(&expected, got2) {
+		t.Fatalf("[ptr] expected: %#+v but got: %#+v", &expected, got2)
+	}
+
+	// register implementation, expect interface.
+	expected3 := &testServiceImpl{prefix: "prefix: "}
+	c.Register(expected3)
+
+	var got3 testService
+	if err := c.Inject(&got3); err != nil {
+		t.Fatal(err)
+	}
+
+	if !reflect.DeepEqual(expected3, got3) {
+		t.Fatalf("[service] expected: %#+v but got: %#+v", expected3, got3)
+	}
+}

hero/reflect.go

@@ -7,14 +7,23 @@ import (
 )
 
 func valueOf(v interface{}) reflect.Value {
-	if v, ok := v.(reflect.Value); ok {
+	if val, ok := v.(reflect.Value); ok {
 		// check if it's already a reflect.Value.
-		return v
+		return val
 	}
 
 	return reflect.ValueOf(v)
 }
 
+func typeOf(typ interface{}) reflect.Type {
+	if v, ok := typ.(reflect.Type); ok {
+		// check if it's already a reflect.Type.
+		return v
+	}
+
+	return reflect.TypeOf(typ)
+}
+
 // indirectType returns the value of a pointer-type "typ".
 // If "typ" is a pointer, array, chan, map or slice it returns its Elem,
 // otherwise returns the typ as it's.
@@ -82,9 +91,8 @@ func equalTypes(binding reflect.Type, input reflect.Type) bool {
 	// if accepts an interface, check if the given "got" type does
 	// implement this "expected" user handler's input argument.
 	if input.Kind() == reflect.Interface {
-		// fmt.Printf("expected interface = %s and got to set on the arg is: %s\n", expected.String(), got.String())
-		// return got.Implements(expected)
-		// return expected.AssignableTo(got)
+		// fmt.Printf("expected interface = %s and got to set on the arg is: %s\n", binding.String(), input.String())
+		// return input.Implements(binding)
 		return binding.AssignableTo(input)
 	}