Iterator preserves last delta link (#192)

* Iterator preserves delta link

* Update CHANGELOG

CHANGELOG.md

@@ -11,6 +11,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+## [0.36.2] - 2023-05-01
+
+### Added
+
+- `PageIterator` exposes `odata.nextLink` and `odata.deltaLink` of most recent page.
+
 ## [0.36.1] - 2023-04-17
 
 ### Added

internal/user_delta_response.go

@@ -0,0 +1,65 @@
+package internal
+
+import (
+	i04eb5309aeaafadd28374d79c8471df9b267510b4dc2e3144c378c50f6fd7b55 "github.com/microsoft/kiota-abstractions-go/serialization"
+)
+
+// UsersDeltaResponse
+type UsersDeltaResponse struct {
+	//
+	UsersResponse
+	//
+	odataDeltaLink *string
+}
+
+// NewDeltasResponse instantiates a new usersResponse and sets the default values.
+func NewUsersDeltaResponse() *UsersDeltaResponse {
+	m := &UsersDeltaResponse{
+		UsersResponse: *NewUsersResponse(),
+	}
+	return m
+}
+
+// GetOdataDeltaLink gets the @odata.nextLink property value.
+func (m *UsersDeltaResponse) GetOdataDeltaLink() *string {
+	if m == nil {
+		return nil
+	} else {
+		return m.odataDeltaLink
+	}
+}
+
+// GetFieldDeserializers the deserialization information for the current model
+func (m *UsersDeltaResponse) GetFieldDeserializers() map[string]func(i04eb5309aeaafadd28374d79c8471df9b267510b4dc2e3144c378c50f6fd7b55.ParseNode) error {
+	res := m.UsersResponse.GetFieldDeserializers()
+	res["@odata.deltaLink"] = func(n i04eb5309aeaafadd28374d79c8471df9b267510b4dc2e3144c378c50f6fd7b55.ParseNode) error {
+		val, err := n.GetStringValue()
+		if err != nil {
+			return err
+		}
+		if val != nil {
+			m.SetOdataDeltaLink(val)
+		}
+		return nil
+	}
+	return res
+}
+
+// Serialize serializes information the current object
+func (m *UsersDeltaResponse) Serialize(writer i04eb5309aeaafadd28374d79c8471df9b267510b4dc2e3144c378c50f6fd7b55.SerializationWriter) error {
+	{
+		err := writer.WriteStringValue("@odata.deltaLink", m.GetOdataDeltaLink())
+		if err != nil {
+			return err
+		}
+	}
+
+	return m.UsersResponse.Serialize(writer)
+}
+
+// SetOdataDeltaLink sets the @odata.deltaLink property value.
+func (m *UsersDeltaResponse) SetOdataDeltaLink(value *string) {
+	if m != nil {
+		m.odataDeltaLink = value
+	}
+}

page_iterator.go

@@ -3,10 +3,11 @@ package msgraphgocore
 import (
 	"context"
 	"errors"
-	abstractions "github.com/microsoft/kiota-abstractions-go"
-	"github.com/microsoft/kiota-abstractions-go/serialization"
 	"net/url"
 	"reflect"
+
+	abstractions "github.com/microsoft/kiota-abstractions-go"
+	"github.com/microsoft/kiota-abstractions-go/serialization"
 )
 
 // PageIterator represents an iterator object that can be used to get subsequent pages of a collection.
@@ -21,8 +22,9 @@ type PageIterator[T interface{}] struct {
 
 // PageResult represents a page object built from a graph response object
 type PageResult[T interface{}] struct {
-	oDataNextLink *string
-	value         []T
+	oDataNextLink  *string
+	oDataDeltaLink *string
+	value          []T
 }
 
 func (p *PageResult[T]) getValue() []T {
@@ -87,6 +89,10 @@ func (pI *PageIterator[T]) Iterate(context context.Context, callback func(pageIt
 			return nil
 		}
 
+		if pI.currentPage.getOdataNextLink() == nil || *pI.currentPage.getOdataNextLink() == "" {
+			return nil
+		}
+
 		nextPage, err := pI.next(context)
 		if err != nil {
 			return err
@@ -109,13 +115,19 @@ func (pI *PageIterator[T]) SetReqOptions(reqOptions []abstractions.RequestOption
 	pI.reqOptions = reqOptions
 }
 
+// GetOdataNextLink returns the @odata.nextLink value in the current page result.
+func (pI *PageIterator[T]) GetOdataNextLink() *string {
+	return pI.currentPage.oDataNextLink
+}
+
+// GetOdataDeltaLink returns the @odata.deltaLink value in current paged result.
+func (pI *PageIterator[T]) GetOdataDeltaLink() *string {
+	return pI.currentPage.oDataDeltaLink
+}
+
 func (pI *PageIterator[T]) next(context context.Context) (PageResult[T], error) {
 	var page PageResult[T]
 
-	if pI.currentPage.getOdataNextLink() == nil || *pI.currentPage.getOdataNextLink() == "" {
-		return page, nil
-	}
-
 	resp, err := pI.fetchNextPage(context)
 	if err != nil {
 		return page, err
@@ -174,11 +186,11 @@ func (pI *PageIterator[T]) enumerate(callback func(item T) bool) bool {
 	for i := pI.pauseIndex; i < len(pageItems); i++ {
 		keepIterating = callback(pageItems[i])
 
+		// Set pauseIndex so that we know where to resume from.
+		// Resumes from the next item
+		pI.pauseIndex = i + 1
+
 		if !keepIterating {
-			// Callback returned false, pause! stop enumerating page items. Set pauseIndex so that we know
-			// where to resume from.
-			// Resumes from the next item
-			pI.pauseIndex = i + 1
 			break
 		}
 	}
@@ -191,6 +203,11 @@ type PageWithOdataNextLink interface {
 	GetOdataNextLink() *string
 }
 
+// PageWithOdataDeltaLink represents a contract with the GetOdataDeltaLink() method
+type PageWithOdataDeltaLink interface {
+	GetOdataDeltaLink() *string
+}
+
 func convertToPage[T interface{}](response interface{}) (PageResult[T], error) {
 	var page PageResult[T]
 
@@ -216,6 +233,11 @@ func convertToPage[T interface{}](response interface{}) (PageResult[T], error) {
 		return page, errors.New("response does not have next link accessor")
 	}
 
+	deltablePage, ok := response.(PageWithOdataDeltaLink)
+	if ok {
+		page.oDataDeltaLink = deltablePage.GetOdataDeltaLink()
+	}
+
 	page.oDataNextLink = parsablePage.GetOdataNextLink()
 	page.value = collected
 

page_iterator_test.go

@@ -33,6 +33,10 @@ func ParsableCons(pn serialization.ParseNode) (serialization.Parsable, error) {
 	return internal.NewUsersResponse(), nil
 }
 
+func ParsableDeltaCons(pn serialization.ParseNode) (serialization.Parsable, error) {
+	return internal.NewUsersDeltaResponse(), nil
+}
+
 func TestConstructorWithInvalidRequestAdapter(t *testing.T) {
 	graphResponse := internal.NewUsersResponse()
 
@@ -160,13 +164,82 @@ func TestIterateCanBePausedAndResumed(t *testing.T) {
 	})
 
 	assert.Equal(t, res, []string{"0", "1", "2", "3", "4"})
+	assert.Equal(t, pageIterator.GetOdataNextLink(), response.GetOdataNextLink())
 
 	pageIterator.Iterate(context.Background(), func(item internal.User) bool {
 		res2 = append(res2, *item.GetId())
 
 		return true
 	})
 	assert.Equal(t, res2, []string{"10"})
+	assert.Empty(t, pageIterator.GetOdataNextLink())
+
+	pageIterator.Iterate(context.Background(), func(item internal.User) bool {
+		assert.Fail(t, "Should not re-iterate over items")
+		return true
+	})
+}
+
+func TestGetOdataNextLink(t *testing.T) {
+	testServer := httptest.NewServer(nethttp.HandlerFunc(func(w nethttp.ResponseWriter, req *nethttp.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		fmt.Fprint(w, `
+			{
+				"@odata.nextLink": "",
+				"value": [
+	        		{
+	            		"id": "10"
+	        		}
+	        	]
+        	}
+        `)
+	}))
+	defer testServer.Close()
+
+	graphResponse := buildGraphResponse()
+	mockPath := testServer.URL + "/next-page"
+	graphResponse.SetOdataNextLink(&mockPath)
+
+	pageIterator, _ := NewPageIterator[internal.User](graphResponse, reqAdapter, ParsableDeltaCons)
+	pageIterator.Iterate(context.Background(), func(item internal.User) bool {
+		return true
+	})
+
+	assert.Empty(t, pageIterator.GetOdataNextLink())
+}
+
+func TestGetOdataDeltaLink(t *testing.T) {
+	testServer := httptest.NewServer(nethttp.HandlerFunc(func(w nethttp.ResponseWriter, req *nethttp.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		fmt.Fprint(w, `
+			{
+				"@odata.nextLink": "",
+				"@odata.deltaLink": "delta-page-2",
+				"value": [
+	        		{
+	            		"id": "10"
+	        		}
+	        	]
+        	}
+        `)
+	}))
+	defer testServer.Close()
+
+	dl := "delta-page-1"
+	mockPath := testServer.URL + "/next-page"
+
+	graphResponse := &internal.UsersDeltaResponse{
+		UsersResponse: *buildGraphResponse(),
+	}
+	graphResponse.SetOdataDeltaLink(&dl)
+	graphResponse.SetOdataNextLink(&mockPath)
+
+	pageIterator, _ := NewPageIterator[internal.User](graphResponse, reqAdapter, ParsableDeltaCons)
+	pageIterator.Iterate(context.Background(), func(item internal.User) bool {
+		return true
+	})
+
+	assert.Equal(t, *pageIterator.GetOdataDeltaLink(), "delta-page-2")
 }
 
 func buildGraphResponse() *internal.UsersResponse {