💄 QR-Code for Vote-ID

go.mod

@@ -17,6 +17,7 @@ require (
 	github.com/mattn/go-colorable v0.1.13 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
 	github.com/russross/blackfriday/v2 v2.1.0 // indirect
+	github.com/skip2/go-qrcode v0.0.0-20200617195104-da1b6568686e // indirect
 	github.com/stretchr/testify v1.9.0 // indirect
 	github.com/valyala/bytebufferpool v1.0.0 // indirect
 	github.com/valyala/fasttemplate v1.2.2 // indirect

go.sum

@@ -21,6 +21,8 @@ github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZb
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/russross/blackfriday/v2 v2.1.0 h1:JIOH55/0cWyOuilr9/qlrm0BSXldqnqwMsf35Ld67mk=
 github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
+github.com/skip2/go-qrcode v0.0.0-20200617195104-da1b6568686e h1:MRM5ITcdelLK2j1vwZ3Je0FKVCfqOLp5zO6trqMLYs0=
+github.com/skip2/go-qrcode v0.0.0-20200617195104-da1b6568686e/go.mod h1:XV66xRDqSt+GTGFMVlhk3ULuV0y9ZmzeVGR4mloJI3M=
 github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
 github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 github.com/urfave/cli/v2 v2.27.2 h1:6e0H+AkS+zDckwPCUrZkKX38mRaau4nL2uipkJpbkcI=

http/main.go

@@ -3,6 +3,7 @@ package http
 import (
 	"fmt"
 	"net/http"
+	"os"
 	"strconv"
 	"strings"
 	"time"
@@ -18,6 +19,14 @@ import (
 	"github.com/labstack/echo/middleware"
 )
 
+var BASE_URL = os.Getenv("BASE_URL")
+
+func init() {
+	if BASE_URL == "" {
+		BASE_URL = "http://localhost"
+	}
+}
+
 // Serve takes a bind-address and starts the HTTP server.
 func Serve(bindAddr string) error {
 	e := echo.New()
@@ -31,6 +40,7 @@ func Serve(bindAddr string) error {
 	e.GET("/v", handleVotingForm)
 	e.POST("/v", handleNewVoting)
 	e.GET("/v/:id", handleShowVoting)
+	e.GET("v/:vid/:id", handleShowVote)
 	e.POST("/v/:id", handleVote)
 
 	return e.Start(bindAddr)
@@ -125,10 +135,30 @@ func handleVote(ctx echo.Context) error {
 		return err
 	}
 	store.PlaceVote(id, vid, elector, c)
+	return ctx.Redirect(http.StatusFound, fmt.Sprintf("/v/%s/%s", vid, id))
+}
+
+func handleShowVote(ctx echo.Context) error {
+	var (
+		id  = ctx.Param("id")
+		vid = ctx.Param("vid")
+	)
+
+	url := fmt.Sprintf(
+		"%s/v/%s/%s",
+		BASE_URL,
+		vid,
+		id,
+	)
+	qrCode, err := generateQrCode(url)
+	if err != nil {
+		return err
+	}
 	return ctx.Render(http.StatusFound, "thanks", map[string]interface{}{
-		"Title": "cvote | thx",
+		"Title":  "cvote | nom nom nom",
-		"Id":    id,
+		"Id":     id,
-		"Vid":   vid,
+		"Vid":    vid,
+		"QRCode": qrCode,
 	})
 }
 

http/qr.go

@@ -0,0 +1,15 @@
+package http
+
+import (
+	b64 "encoding/base64"
+
+	"github.com/skip2/go-qrcode"
+)
+
+func generateQrCode(url string) (string, error) {
+	qrCode, err := qrcode.Encode(url, qrcode.Medium, 256)
+	if err != nil {
+		return "", err
+	}
+	return b64.StdEncoding.EncodeToString(qrCode), nil
+}

tmpl/thanks.html

@@ -16,9 +16,12 @@
         {{ .Id }}
       </p>
       <hr class="m-4">
-      <form action="/v/{{ .Vid }}" method="GET">
+      <div class="w-full flex justify-center">
-        <button type="submit" class="w-full hover:bg-blue-800 focus:ring-4 focus:outline-none focus:ring-blue-300 font-medium rounded-lg text-sm px-5 py-2.5 text-center bg-purple-600 hover:bg-purple-700 focus:ring-blue-800 text-white hover:text-yellow-200 text-xl">Go back</button>
+        <img src="data:image/png;base64,{{ .QRCode }}" alt="QR-Code" class="center pb-4">
-      </form>
+      </div>
+      <a href="/v/{{ .Vid }}" class="w-full block hover:bg-blue-800 focus:ring-4 focus:outline-none focus:ring-blue-300 font-medium rounded-lg text-sm px-5 py-2.5 text-center bg-purple-600 hover:bg-purple-700 focus:ring-blue-800 text-white hover:text-yellow-200 text-xl">
+        Go back
+      </a>
     </div>
   </div>
 </div>