Move parameters into struct form

Signed-off-by: Knut Ahlers <knut@ahlers.me>

cache.go

@@ -1,22 +1,7 @@
 package main
 
 import (
-	"crypto/sha256"
-	"fmt"
 	"io"
-	"strings"
-
-	"github.com/golang/geo/s2"
 )
 
-type cacheFunction func(center s2.LatLng, zoom int, marker []marker, x, y int, disableAttribution bool) (io.ReadCloser, error)
-
-func cacheKeyHelper(center s2.LatLng, zoom int, marker []marker, x, y int, disableAttribution bool) string {
-	markerString := []string{}
-	for _, m := range marker {
-		markerString = append(markerString, m.String())
-	}
-	hashString := fmt.Sprintf("%s|%d|%s|%dx%d|%v", center.String(), zoom, strings.Join(markerString, "+"), x, y, disableAttribution)
-
-	return fmt.Sprintf("%x", sha256.Sum256([]byte(hashString)))
-}
+type cacheFunction func(generateMapConfig) (io.ReadCloser, error)

cache_filesystem.go

@@ -7,12 +7,10 @@ import (
 	"os"
 	"path"
 	"time"
-
-	"github.com/golang/geo/s2"
 )
 
-func filesystemCache(center s2.LatLng, zoom int, marker []marker, x, y int, disableAttribution bool) (io.ReadCloser, error) {
-	cacheKey := cacheKeyHelper(center, zoom, marker, x, y, disableAttribution)
+func filesystemCache(opts generateMapConfig) (io.ReadCloser, error) {
+	cacheKey := opts.getCacheKey()
 	cacheFileName := path.Join(cfg.CacheDir, cacheKey[0:2], cacheKey+".png")
 
 	if info, err := os.Stat(cacheFileName); err == nil && info.ModTime().Add(cfg.ForceCache).After(time.Now()) {
@@ -20,7 +18,7 @@ func filesystemCache(center s2.LatLng, zoom int, marker []marker, x, y int, disa
 	}
 
 	// No cache hit, generate a new map
-	mapReader, err := generateMap(center, zoom, marker, x, y, disableAttribution)
+	mapReader, err := generateMap(opts)
 	if err != nil {
 		return nil, err
 	}

main.go

@@ -65,36 +65,34 @@ func main() {
 
 func handleMapRequest(res http.ResponseWriter, r *http.Request) {
 	var (
-		center             *s2.LatLng
-		disableAttribution bool = r.URL.Query().Get("no-attribution") == "true"
 		err       error
 		mapReader io.ReadCloser
-		markers            []marker
-		x, y               int
-		zoom               int
+		opts      = generateMapConfig{
+			DisableAttribution: r.URL.Query().Get("no-attribution") == "true",
+		}
 	)
 
-	if center, err = parseCoordinate(r.URL.Query().Get("center")); err != nil {
+	if opts.Center, err = parseCoordinate(r.URL.Query().Get("center")); err != nil {
 		http.Error(res, fmt.Sprintf("Unable to parse 'center' parameter: %s", err), http.StatusBadRequest)
 		return
 	}
 
-	if zoom, err = strconv.Atoi(r.URL.Query().Get("zoom")); err != nil {
+	if opts.Zoom, err = strconv.Atoi(r.URL.Query().Get("zoom")); err != nil {
 		http.Error(res, fmt.Sprintf("Unable to parse 'zoom' parameter: %s", err), http.StatusBadRequest)
 		return
 	}
 
-	if x, y, err = parseSize(r.URL.Query().Get("size"), true); err != nil {
+	if opts.Width, opts.Height, err = parseSize(r.URL.Query().Get("size"), true); err != nil {
 		http.Error(res, fmt.Sprintf("Unable to parse 'size' parameter: %s", err), http.StatusBadRequest)
 		return
 	}
 
-	if markers, err = parseMarkerLocations(r.URL.Query()["markers"]); err != nil {
+	if opts.Markers, err = parseMarkerLocations(r.URL.Query()["markers"]); err != nil {
 		http.Error(res, fmt.Sprintf("Unable to parse 'markers' parameter: %s", err), http.StatusBadRequest)
 		return
 	}
 
-	if mapReader, err = cacheFunc(*center, zoom, markers, x, y, disableAttribution); err != nil {
+	if mapReader, err = cacheFunc(opts); err != nil {
 		log.Errorf("Map render failed: %s (Request: %s)", err, r.URL.String())
 		http.Error(res, fmt.Sprintf("I experienced difficulties rendering your map: %s", err), http.StatusInternalServerError)
 		return
@@ -106,14 +104,14 @@ func handleMapRequest(res http.ResponseWriter, r *http.Request) {
 	io.Copy(res, mapReader)
 }
 
-func parseCoordinate(coord string) (*s2.LatLng, error) {
+func parseCoordinate(coord string) (s2.LatLng, error) {
 	if coord == "" {
-		return nil, errors.New("No coordinate given")
+		return s2.LatLng{}, errors.New("No coordinate given")
 	}
 
 	parts := strings.Split(coord, ",")
 	if len(parts) != 2 {
-		return nil, errors.New("Coordinate not in format lat,lon")
+		return s2.LatLng{}, errors.New("Coordinate not in format lat,lon")
 	}
 
 	var (
@@ -122,15 +120,15 @@ func parseCoordinate(coord string) (*s2.LatLng, error) {
 	)
 
 	if lat, err = strconv.ParseFloat(parts[0], 64); err != nil {
-		return nil, errors.New("Latitude not parseable as float")
+		return s2.LatLng{}, errors.New("Latitude not parseable as float")
 	}
 
 	if lon, err = strconv.ParseFloat(parts[1], 64); err != nil {
-		return nil, errors.New("Longitude not parseable as float")
+		return s2.LatLng{}, errors.New("Longitude not parseable as float")
 	}
 
 	pt := s2.LatLngFromDegrees(lat, lon)
-	return &pt, nil
+	return pt, nil
 }
 
 func parseSize(size string, validate bool) (x, y int, err error) {
@@ -203,7 +201,7 @@ func parseMarkerLocations(markers []string) ([]marker, error) {
 					return nil, fmt.Errorf("Unparsable chunk found in marker: %q", p)
 				}
 				result = append(result, marker{
-					pos:   *pos,
+					pos:   pos,
 					color: col,
 					size:  size,
 				})

map.go

@@ -2,9 +2,11 @@ package main
 
 import (
 	"bytes"
+	"crypto/sha256"
 	"fmt"
 	"image/color"
 	"io"
+	"strings"
 
 	staticMap "github.com/Luzifer/go-staticmaps"
 	"github.com/fogleman/gg"
@@ -43,20 +45,45 @@ func (m marker) String() string {
 	return fmt.Sprintf("%s|%.0f|%d,%d,%d,%d", m.pos.String(), m.size, r, g, b, a)
 }
 
-func generateMap(center s2.LatLng, zoom int, marker []marker, x, y int, disableAttribution bool) (io.Reader, error) {
+type generateMapConfig struct {
+	Center             s2.LatLng
+	Zoom               int
+	Markers            []marker
+	Width              int
+	Height             int
+	DisableAttribution bool
+}
+
+func (g generateMapConfig) getCacheKey() string {
+	markerString := []string{}
+	for _, m := range g.Markers {
+		markerString = append(markerString, m.String())
+	}
+	hashString := fmt.Sprintf("%s|%d|%s|%dx%d|%v",
+		g.Center.String(),
+		g.Zoom,
+		strings.Join(markerString, "+"),
+		g.Width,
+		g.Height,
+		g.DisableAttribution)
+
+	return fmt.Sprintf("%x", sha256.Sum256([]byte(hashString)))
+}
+
+func generateMap(opts generateMapConfig) (io.Reader, error) {
 	ctx := staticMap.NewContext()
 	ctx.SetUserAgent(fmt.Sprintf("Mozilla/5.0+(compatible; staticmap/%s; https://github.com/Luzifer/staticmap)", version))
 
-	ctx.SetSize(x, y)
-	ctx.SetCenter(center)
-	ctx.SetZoom(zoom)
+	ctx.SetSize(opts.Width, opts.Height)
+	ctx.SetCenter(opts.Center)
+	ctx.SetZoom(opts.Zoom)
 
-	if disableAttribution {
+	if opts.DisableAttribution {
 		ctx.OverrideAttribution("")
 	}
 
-	if marker != nil {
-		for _, m := range marker {
+	if opts.Markers != nil {
+		for _, m := range opts.Markers {
 			ctx.AddMarker(staticMap.NewMarker(m.pos, m.color, float64(m.size)))
 		}
 	}