refactored for maintainability

internal/handlers/pageopt_helpers.go

@@ -0,0 +1,45 @@
+package handlers
+
+import (
+	"net/http"
+
+	"git.haelnorr.com/h/golib/hws"
+	"git.haelnorr.com/h/oslstats/internal/db"
+	"git.haelnorr.com/h/oslstats/internal/validation"
+	"github.com/uptrace/bun"
+)
+
+// pageOptsFromForm calls r.ParseForm and gets the pageOpts from the formdata.
+// It renders a Bad Request error page on fail
+// PageOpts will be nil on fail
+func pageOptsFromForm(s *hws.Server, w http.ResponseWriter, r *http.Request) *db.PageOpts {
+	getter, ok := validation.ParseFormOrError(s, w, r)
+	if !ok {
+		return nil
+	}
+	return getPageOpts(s, w, r, getter)
+}
+
+// pageOptsFromQuery gets the pageOpts from the request query and renders a Bad Request error page on fail
+// PageOpts will be nil on fail
+func pageOptsFromQuery(s *hws.Server, w http.ResponseWriter, r *http.Request) *db.PageOpts {
+	return getPageOpts(s, w, r, validation.NewQueryGetter(r))
+}
+
+func getPageOpts(s *hws.Server, w http.ResponseWriter, r *http.Request, g validation.Getter) *db.PageOpts {
+	page := g.Int("page").Min(1).Value
+	perPage := g.Int("per_page").Min(1).Max(100).Value
+	order := g.String("order").TrimSpace().ToUpper().AllowedValues([]string{"ASC", "DESC"}).Value
+	orderBy := g.String("order_by").TrimSpace().ToLower().Value
+	valid := g.ValidateAndError(s, w, r)
+	if !valid {
+		return nil
+	}
+	pageOpts := &db.PageOpts{
+		Page:    page,
+		PerPage: perPage,
+		Order:   bun.Order(order),
+		OrderBy: orderBy,
+	}
+	return pageOpts
+}