Error handling

cmd/kartograph-map-generator/main.go

@@ -5,6 +5,7 @@ import (
 	"f00860/kartograph-map-editor/pkg/web"
 	"flag"
 	"fmt"
+	"log"
 	"time"
 )
 
@@ -29,7 +30,12 @@ func main() {
 		return
 	}
 
-	world := generator.New(size, wastelands, mountains, ruins, seed)
+	world, err := generator.New(size, wastelands, mountains, ruins, seed)
+
+	if err != nil {
+		log.Fatal(err)
+		return
+	}
 
 	switch output {
 	case "svg":

pkg/generator/svg.go

@@ -7,6 +7,17 @@ import (
 	"github.com/ajstarks/svgo"
 )
 
+func ErrorSVG(err error, width int, height int) string {
+	buf := bytes.NewBufferString("")
+	canvas := svg.New(buf)
+
+	canvas.Start(width, height)
+	canvas.Text(width/2, height/2, err.Error(), "text-anchor:middle;font-size:3px;font-family:Courier New;font-weight:light;")
+	canvas.End()
+
+	return buf.String()
+}
+
 func (w World) SVG() string {
 	// DIN-A5
 	width := 148 * 3

pkg/generator/world.go

@@ -91,7 +91,7 @@ func (w World) JSON() string {
 	return string(output)
 }
 
-func New(size int, numWastelands int, numMountains int, numRuins int, seed string) World {
+func New(size int, numWastelands int, numMountains int, numRuins int, seed string) (World, error) {
 	InitSeed(seed)
 
 	w := World{
@@ -102,7 +102,9 @@ func New(size int, numWastelands int, numMountains int, numRuins int, seed strin
 		Seed:       seed,
 	}
 
-	// TODO: Return error wenn kein Platz mehr da ist
+	if size < 3 || size > 25 {
+		return World{}, errors.New("Spielfeldgröße nicht im Bereich 3..25.")
+	}
 
 	// All empty for start
 	for i := 0; i < w.Size*w.Size; i++ {
@@ -114,6 +116,10 @@ func New(size int, numWastelands int, numMountains int, numRuins int, seed strin
 	var wastelands []int
 
 	if numWastelands > 0 {
+		if numWastelands > size*size {
+			return World{}, errors.New("Zu viele Ödlandfelder.")
+		}
+
 		startPos := roll(w.Size-1) + roll(w.Size-1)*w.Size
 		w.place(WastelandTerritory, startPos)
 		wastelands = append(wastelands, startPos)
@@ -150,6 +156,10 @@ func New(size int, numWastelands int, numMountains int, numRuins int, seed strin
 				candidates = append(candidates, pos)
 			}
 		}
+
+		if len(candidates) < 1 {
+			return World{}, errors.New("Zu viele Berge.")
+		}
 		w.place(MountainTerritory, randomItem(candidates))
 	}
 
@@ -165,10 +175,13 @@ func New(size int, numWastelands int, numMountains int, numRuins int, seed strin
 				candidates = append(candidates, pos)
 			}
 		}
+		if len(candidates) < 1 {
+			return World{}, errors.New("Zu viele Ruinen.")
+		}
 		w.place(RuinsTerritory, randomItem(candidates))
 	}
 
-	return w
+	return w, nil
 }
 
 func InitSeed(seed string) {

pkg/web/service.go

@@ -3,6 +3,7 @@ package web
 import (
 	"embed"
 	"f00860/kartograph-map-editor/pkg/generator"
+	"fmt"
 	"html/template"
 	"io"
 	"log"
@@ -33,7 +34,7 @@ func Start(address string, port int) {
 	}
 }
 
-func worldFromRequest(req *http.Request) generator.World {
+func worldFromRequest(req *http.Request) (generator.World, error) {
 	size, err := strconv.Atoi(req.URL.Query().Get("s"))
 	if err != nil {
 		size = 11
@@ -59,16 +60,30 @@ func worldFromRequest(req *http.Request) generator.World {
 }
 
 func mapHandler(w http.ResponseWriter, req *http.Request) {
-	world := worldFromRequest(req)
 	log.Printf("GET /map.svg?%v (%v)", req.URL.Query().Encode(), req.RemoteAddr)
+
+	var SVGContent string
+
+	world, err := worldFromRequest(req)
+	if err != nil {
+		SVGContent = generator.ErrorSVG(err, 100, 100)
+	} else {
+		SVGContent = world.SVG()
+	}
+
 	w.Header().Set("Content-Type", "image/svg+xml")
-	w.Header().Set("Content-Length", strconv.Itoa(len(world.SVG())))
+	w.Header().Set("Content-Length", strconv.Itoa(len(SVGContent)))
-	io.WriteString(w, world.SVG())
+	io.WriteString(w, SVGContent)
 }
 
 func printHandler(w http.ResponseWriter, req *http.Request) {
-	world := worldFromRequest(req)
 	log.Printf("GET /print?%v (%v)", req.URL.Query().Encode(), req.RemoteAddr)
+
+	world, err := worldFromRequest(req)
+	if err != nil {
+		fmt.Print(err)
+		return
+	}
 	tpl, err := template.ParseFS(templateFiles, "templates/print.tpl.html")
 
 	if err != nil {
@@ -80,7 +95,7 @@ func printHandler(w http.ResponseWriter, req *http.Request) {
 
 func indexHandler(w http.ResponseWriter, req *http.Request) {
 	seed := generator.RandomSeed()
-	world := generator.New(11, 7, 5, 6, seed)
+	world, _ := generator.New(11, 7, 5, 6, seed)
 	log.Printf("GET / (%v) Seed: %v", req.RemoteAddr, seed)
 	tpl, err := template.ParseFS(templateFiles, "templates/index.tpl.html")
 

pkg/web/static/generator.js

@@ -7,19 +7,20 @@ document.addEventListener('DOMContentLoaded', function() {
 
         let map = document.querySelector('.map')
         // Generate new random seed
-        let newMapUrl = '/map.svg?seed=' + seed +
+        let newMapParams = '?seed=' + seed +
             '&s=' + size +
             '&w=' + wastelands +
             '&m=' + mountains +
             '&r=' + ruins
-        document.querySelector('.map').setAttribute('src', newMapUrl);
+        document.querySelector('.map').setAttribute('src', '/map.svg' + newMapParams);
-        document.querySelector('#map-link').setAttribute('href', newMapUrl);
+        document.querySelector('#print-button').setAttribute('data-target', '/print' + newMapParams);
+        document.querySelector('#map-button').setAttribute('data-target', '/map.svg' + newMapParams);
+        document.querySelector('#map-link').setAttribute('data-target', '/map.svg' + newMapParams);
     };
 
     let actionButtons = document.querySelectorAll('button[class="action"]');
     Array.prototype.forEach.call(actionButtons, function(action, i) {
         action.addEventListener('click', function(e) {
-            console.log("adsf");
             document.location.href = e.target.getAttribute('data-target');
         });
     });

pkg/web/templates/index.tpl.html

@@ -49,8 +49,8 @@
             <input type="button" name="refresh" value="Neu generieren">
         </form>
 
-        <button class="action" data-target="/print?seed={{ .Seed }}&s={{ .Size }}&w={{ .Wastelands }}&r={{ .Ruins }}&m={{ .Mountains }}">Drucken</button>
+        <button class="action" id="print-button" data-target="/print?seed={{ .Seed }}&s={{ .Size }}&w={{ .Wastelands }}&r={{ .Ruins }}&m={{ .Mountains }}">Drucken</button>
-        <button class="action" data-target="/map.svg?seed={{ .Seed }}&s={{ .Size }}&w={{ .Wastelands }}&r={{ .Ruins }}&m={{ .Mountains }}">Direktlink</button>
+        <button class="action" id="map-button" data-target="/map.svg?seed={{ .Seed }}&s={{ .Size }}&w={{ .Wastelands }}&r={{ .Ruins }}&m={{ .Mountains }}">Direktlink</button>
 
         <p>2011 <a href="https://aaron-fischer.net/">Aaron Fischer</a></p>
     </body>