api: factorize pagination offset calculation

Every list handler duplicated the same clamping of per_page against the
configured defaults and the offset computation. Move it to a PageParams
method so the rules live in one place and stay consistent across
endpoints.

Signed-off-by: Robin Jarry <robin@jarry.cc>

Author: rjarry

pkg/api/api.go

@@ -28,6 +28,19 @@ type PageParams struct {
 	PerPage int `query:"per_page" minimum:"1" doc:"Results per page"`
 }
 
+func (p PageParams) offsetPage(cfg *config.Config) (int, int) {
+	perPage := p.PerPage
+	if perPage < 1 {
+		perPage = cfg.Http.ApiPageSize
+	}
+	if perPage > cfg.Http.ApiPageMax {
+		perPage = cfg.Http.ApiPageMax
+	}
+	offset := (p.Page - 1) * perPage
+
+	return offset, perPage
+}
+
 type SearchParams struct {
 	Q     string `query:"q" doc:"Search term"`
 	Order string `query:"order" doc:"Ordering field"`

pkg/api/bundles.go

@@ -93,14 +93,7 @@ func (h *handler) ListBundles(
 		return nil, huma.Error500InternalServerError("Internal error.")
 	}
 
-	perPage := input.PerPage
-	if perPage < 1 {
-		perPage = h.cfg.Http.ApiPageSize
-	}
-	if perPage > h.cfg.Http.ApiPageMax {
-		perPage = h.cfg.Http.ApiPageMax
-	}
-	offset := (input.Page - 1) * perPage
+	offset, perPage := input.offsetPage(h.cfg)
 
 	var bundles []db.Bundle
 	if err := q.Model(&bundles).

pkg/api/checks.go

@@ -81,14 +81,7 @@ func (h *handler) ListChecks(
 		return nil, huma.Error500InternalServerError("Internal error.")
 	}
 
-	perPage := input.PerPage
-	if perPage < 1 {
-		perPage = h.cfg.Http.ApiPageSize
-	}
-	if perPage > h.cfg.Http.ApiPageMax {
-		perPage = h.cfg.Http.ApiPageMax
-	}
-	offset := (input.Page - 1) * perPage
+	offset, perPage := input.offsetPage(h.cfg)
 
 	var checks []db.Check
 	if err := q.Select(&checks).

pkg/api/comments.go

@@ -77,14 +77,7 @@ func (h *handler) ListPatchComments(
 		return nil, huma.Error500InternalServerError("Internal error.")
 	}
 
-	perPage := input.PerPage
-	if perPage < 1 {
-		perPage = h.cfg.Http.ApiPageSize
-	}
-	if perPage > h.cfg.Http.ApiPageMax {
-		perPage = h.cfg.Http.ApiPageMax
-	}
-	offset := (input.Page - 1) * perPage
+	offset, perPage := input.offsetPage(h.cfg)
 
 	var comments []db.PatchComment
 	if err := q.Model(&comments).Relation("Submitter").
@@ -223,14 +216,7 @@ func (h *handler) ListCoverComments(
 		return nil, huma.Error500InternalServerError("Internal error.")
 	}
 
-	perPage := input.PerPage
-	if perPage < 1 {
-		perPage = h.cfg.Http.ApiPageSize
-	}
-	if perPage > h.cfg.Http.ApiPageMax {
-		perPage = h.cfg.Http.ApiPageMax
-	}
-	offset := (input.Page - 1) * perPage
+	offset, perPage := input.offsetPage(h.cfg)
 
 	var comments []db.CoverComment
 	if err := q.Model(&comments).Relation("Submitter").

pkg/api/covers.go

@@ -62,14 +62,7 @@ func (h *handler) ListCovers(
 		return nil, huma.Error500InternalServerError("Internal error.")
 	}
 
-	perPage := input.PerPage
-	if perPage < 1 {
-		perPage = h.cfg.Http.ApiPageSize
-	}
-	if perPage > h.cfg.Http.ApiPageMax {
-		perPage = h.cfg.Http.ApiPageMax
-	}
-	offset := (input.Page - 1) * perPage
+	offset, perPage := input.offsetPage(h.cfg)
 
 	var covers []db.Cover
 	if err := sq.Model(&covers).

pkg/api/events.go

@@ -59,14 +59,7 @@ func (h *handler) ListEvents(
 		return nil, huma.Error500InternalServerError("Internal error.")
 	}
 
-	perPage := input.PerPage
-	if perPage < 1 {
-		perPage = h.cfg.Http.ApiPageSize
-	}
-	if perPage > h.cfg.Http.ApiPageMax {
-		perPage = h.cfg.Http.ApiPageMax
-	}
-	offset := (input.Page - 1) * perPage
+	offset, perPage := input.offsetPage(h.cfg)
 
 	order := "event.date DESC"
 	if input.Order == "date" {

pkg/api/patches.go

@@ -80,14 +80,7 @@ func (h *handler) ListPatches(
 		return nil, huma.Error500InternalServerError("Internal error.")
 	}
 
-	perPage := input.PerPage
-	if perPage < 1 {
-		perPage = h.cfg.Http.ApiPageSize
-	}
-	if perPage > h.cfg.Http.ApiPageMax {
-		perPage = h.cfg.Http.ApiPageMax
-	}
-	offset := (input.Page - 1) * perPage
+	offset, perPage := input.offsetPage(h.cfg)
 
 	var patches []db.Patch
 	if err := sq.Model(&patches).

pkg/api/people.go

@@ -59,14 +59,7 @@ func (h *handler) ListPeople(
 		return nil, huma.Error500InternalServerError("Internal error.")
 	}
 
-	perPage := input.PerPage
-	if perPage < 1 {
-		perPage = h.cfg.Http.ApiPageSize
-	}
-	if perPage > h.cfg.Http.ApiPageMax {
-		perPage = h.cfg.Http.ApiPageMax
-	}
-	offset := (input.Page - 1) * perPage
+	offset, perPage := input.offsetPage(h.cfg)
 
 	var people []db.Person
 	if err := sq.Model(&people).Relation("User").

pkg/api/projects.go

@@ -119,14 +119,7 @@ func (h *handler) ListProjects(
 		return nil, huma.Error500InternalServerError("Internal error.")
 	}
 
-	perPage := input.PerPage
-	if perPage < 1 {
-		perPage = h.cfg.Http.ApiPageSize
-	}
-	if perPage > h.cfg.Http.ApiPageMax {
-		perPage = h.cfg.Http.ApiPageMax
-	}
-	offset := (input.Page - 1) * perPage
+	offset, perPage := input.offsetPage(h.cfg)
 
 	var projects []db.Project
 	if err := sq.OrderExpr("id ASC").Offset(offset).Limit(perPage).Scan(ctx, &projects); err != nil {

pkg/api/series.go

@@ -68,14 +68,7 @@ func (h *handler) ListSeries(
 		return nil, huma.Error500InternalServerError("Internal error.")
 	}
 
-	perPage := input.PerPage
-	if perPage < 1 {
-		perPage = h.cfg.Http.ApiPageSize
-	}
-	if perPage > h.cfg.Http.ApiPageMax {
-		perPage = h.cfg.Http.ApiPageMax
-	}
-	offset := (input.Page - 1) * perPage
+	offset, perPage := input.offsetPage(h.cfg)
 
 	var series []db.Series
 	if err := sq.Model(&series).