Merge default Range.

pkg/headerutil/headerutil.go

@@ -46,3 +46,27 @@ func ParseRange(header string) (*Range, error) {
 
 	return &rangeHeader, nil
 }
+
+// WithDefaults returns a new Range instance with the defaults taken from d.
+func (r *Range) WithDefaults(d Range) Range {
+	if r == nil {
+		return d
+	}
+
+	// Make a copy.
+	c := *r
+
+	if c.Max == nil {
+		c.Max = d.Max
+	}
+
+	if c.Sort == nil {
+		c.Sort = d.Sort
+	}
+
+	if c.Order == nil {
+		c.Order = d.Order
+	}
+
+	return c
+}

releases.go

@@ -57,7 +57,7 @@ type ReleasesQuery struct {
 	Version *int
 
 	// If provided, uses the limit and sorting parameters specified in the range.
-	Range *headerutil.Range
+	Range headerutil.Range
 }
 
 // Scope implements the Scope interface.
@@ -72,18 +72,24 @@ func (q ReleasesQuery) Scope(db *gorm.DB) *gorm.DB {
 		scope = append(scope, FieldEquals("version", *version))
 	}
 
-	if r := q.Range; r != nil {
-		scope = append(scope, Range(r))
-	} else {
-		scope = append(scope, Order("version desc"))
-	}
+	scope = append(scope, Range(q.Range.WithDefaults(q.DefaultRange())))
 
 	// Preload all the things.
 	scope = append(scope, Preload("App", "Config", "Slug", "Processes"))
 
 	return scope.Scope(db)
 }
 
+// DefaultRange returns the default headerutil.Range used if values aren't
+// provided.
+func (q ReleasesQuery) DefaultRange() headerutil.Range {
+	sort, order := "version", "desc"
+	return headerutil.Range{
+		Sort:  &sort,
+		Order: &order,
+	}
+}
+
 // ReleasesFirst returns the first matching release.
 func (s *store) ReleasesFirst(scope Scope) (*Release, error) {
 	var release Release

releases_test.go

@@ -15,7 +15,7 @@ func TestReleasesQuery(t *testing.T) {
 		order   = "desc"
 	)
 
-	rangeHeader := &headerutil.Range{
+	rangeHeader := headerutil.Range{
 		Sort:  &sort,
 		Max:   &max,
 		Order: &order,

server/heroku/heroku.go

@@ -5,6 +5,7 @@ import (
 	"net/http"
 
 	"github.com/remind101/empire"
+	"github.com/remind101/empire/pkg/headerutil"
 	"github.com/remind101/empire/server/authorization"
 	"github.com/remind101/pkg/httpx"
 	"github.com/remind101/pkg/httpx/middleware"
@@ -119,3 +120,17 @@ func NoContent(w http.ResponseWriter) error {
 	w.WriteHeader(http.StatusNoContent)
 	return nil
 }
+
+// RangeHeader parses the Range header and returns an headerutil.Range.
+func RangeHeader(r *http.Request) (headerutil.Range, error) {
+	header := r.Header.Get("Range")
+	if header == "" {
+		return headerutil.Range{}, nil
+	}
+
+	rangeHeader, err := headerutil.ParseRange(header)
+	if err != nil {
+		return headerutil.Range{}, err
+	}
+	return *rangeHeader, nil
+}

server/heroku/releases.go

@@ -6,7 +6,6 @@ import (
 
 	"github.com/bgentry/heroku-go"
 	"github.com/remind101/empire"
-	"github.com/remind101/empire/pkg/headerutil"
 	"github.com/remind101/pkg/httpx"
 	"golang.org/x/net/context"
 )
@@ -72,12 +71,9 @@ func (h *GetReleases) ServeHTTPContext(ctx context.Context, w http.ResponseWrite
 		return err
 	}
 
-	var rangeHeader *headerutil.Range
-	if header := r.Header.Get("Range"); header != "" {
-		rangeHeader, err = headerutil.ParseRange(header)
-		if err != nil {
-			return err
-		}
+	rangeHeader, err := RangeHeader(r)
+	if err != nil {
+		return err
 	}
 
 	rels, err := h.Releases(empire.ReleasesQuery{App: a, Range: rangeHeader})

store.go

@@ -85,15 +85,15 @@ func Limit(limit int) Scope {
 }
 
 // Range returns a Scope that limits and orders the results.
-func Range(r *headerutil.Range) Scope {
+func Range(r headerutil.Range) Scope {
 	var scope ComposedScope
 
-	if max := r.Max; max != nil {
-		scope = append(scope, Limit(*max))
+	if r.Max != nil {
+		scope = append(scope, Limit(*r.Max))
 	}
 
-	if sort := r.Sort; sort != nil {
-		order := fmt.Sprintf("%s %s", *sort, *(r.Order))
+	if r.Sort != nil && r.Order != nil {
+		order := fmt.Sprintf("%s %s", *r.Sort, *r.Order)
 		scope = append(scope, Order(order))
 	}