From dbf5f354ee9788bbf459aa43a2326d20d682ae8b Mon Sep 17 00:00:00 2001
From: Seongmin Lee <git@boltless.me>
Date: Fri, 24 Oct 2025 00:28:31 +0900
Subject: [PATCH] appview/pagination: context based pagination
Change-Id: rsqppswwxxkzwqrlswzqksqltykklzwt

introduce helper methods: `IntoContext` and `FromContext`
these will help using pagination obj form context easier and make it
less error-prune by using private empty struct as a key instead of raw
string

Signed-off-by: Seongmin Lee <git@boltless.me>
---
 appview/issues/issues.go               |  6 +-----
 appview/middleware/middleware.go       |  2 +-
 appview/notifications/notifications.go |  6 +-----
 appview/pagination/page.go             | 23 +++++++++++++++++++++++
 appview/state/gfi.go                   |  5 +----
 5 files changed, 27 insertions(+), 15 deletions(-)

diff --git a/appview/issues/issues.go b/appview/issues/issues.go
index fb1acc0a..ff39b8e5 100644
--- a/appview/issues/issues.go
+++ b/appview/issues/issues.go
@@ -770,11 +770,7 @@ func (rp *Issues) RepoIssues(w http.ResponseWriter, r *http.Request) {
 		isOpen = true
 	}
 
-	page, ok := r.Context().Value("page").(pagination.Page)
-	if !ok {
-		l.Error("failed to get page")
-		page = pagination.FirstPage()
-	}
+	page := pagination.FromContext(r.Context())
 
 	user := rp.oauth.GetUser(r)
 	f, err := rp.repoResolver.Resolve(r)
diff --git a/appview/middleware/middleware.go b/appview/middleware/middleware.go
index 2d7366ab..c1fb754e 100644
--- a/appview/middleware/middleware.go
+++ b/appview/middleware/middleware.go
@@ -105,7 +105,7 @@ func Paginate(next http.Handler) http.Handler {
 			}
 		}
 
-		ctx := context.WithValue(r.Context(), "page", page)
+		ctx := pagination.IntoContext(r.Context(), page)
 		next.ServeHTTP(w, r.WithContext(ctx))
 	})
 }
diff --git a/appview/notifications/notifications.go b/appview/notifications/notifications.go
index a4047521..c0962e77 100644
--- a/appview/notifications/notifications.go
+++ b/appview/notifications/notifications.go
@@ -49,11 +49,7 @@ func (n *Notifications) notificationsPage(w http.ResponseWriter, r *http.Request
 	l := n.logger.With("handler", "notificationsPage")
 	user := n.oauth.GetUser(r)
 
-	page, ok := r.Context().Value("page").(pagination.Page)
-	if !ok {
-		l.Error("failed to get page")
-		page = pagination.FirstPage()
-	}
+	page := pagination.FromContext(r.Context())
 
 	total, err := db.CountNotifications(
 		n.db,
diff --git a/appview/pagination/page.go b/appview/pagination/page.go
index b3dc781b..d84f07d5 100644
--- a/appview/pagination/page.go
+++ b/appview/pagination/page.go
@@ -1,5 +1,7 @@
 package pagination
 
+import "context"
+
 type Page struct {
 	Offset int // where to start from
 	Limit  int // number of items in a page
@@ -12,6 +14,27 @@ func FirstPage() Page {
 	}
 }
 
+type ctxKey struct{}
+
+func IntoContext(ctx context.Context, page Page) context.Context {
+	return context.WithValue(ctx, ctxKey{}, page)
+}
+
+func FromContext(ctx context.Context) Page {
+	if ctx == nil {
+		return FirstPage()
+	}
+	v := ctx.Value(ctxKey{})
+	if v == nil {
+		return FirstPage()
+	}
+	page, ok := v.(Page)
+	if !ok {
+		return FirstPage()
+	}
+	return page
+}
+
 func (p Page) Previous() Page {
 	if p.Offset-p.Limit < 0 {
 		return FirstPage()
diff --git a/appview/state/gfi.go b/appview/state/gfi.go
index b0106813..d7909e57 100644
--- a/appview/state/gfi.go
+++ b/appview/state/gfi.go
@@ -18,10 +18,7 @@ import (
 func (s *State) GoodFirstIssues(w http.ResponseWriter, r *http.Request) {
 	user := s.oauth.GetUser(r)
 
-	page, ok := r.Context().Value("page").(pagination.Page)
-	if !ok {
-		page = pagination.FirstPage()
-	}
+	page := pagination.FromContext(r.Context())
 
 	goodFirstIssueLabel := fmt.Sprintf("at://%s/%s/%s", consts.TangledDid, tangled.LabelDefinitionNSID, "good-first-issue")
 
-- 
2.43.0