Add QR support (#13)

* Remove ioutil

* Add qr codes

go.mod

@@ -27,6 +27,7 @@ require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/jackc/pgx/v4 v4.17.2
 	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/skip2/go-qrcode v0.0.0-20200617195104-da1b6568686e
 	github.com/stretchr/testify v1.8.0 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
 )

go.sum

@@ -102,6 +102,8 @@ github.com/shopspring/decimal v1.2.0 h1:abSATXmQEYyShuxI4/vyW3tV1MrKAJzCZ/0zLUXY
 github.com/shopspring/decimal v1.2.0/go.mod h1:DKyhrW/HYNuLGql+MJL6WCR6knT2jwCFRcu2hWCYk4o=
 github.com/sirupsen/logrus v1.4.1/go.mod h1:ni0Sbl8bgC9z8RoU9G6nDWqqs/fq4eDPysMBDgk/93Q=
 github.com/sirupsen/logrus v1.4.2/go.mod h1:tLMulIdttU9McNUspp0xgXVQah82FyeX6MwdIuYE2rE=
+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/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.2.0/go.mod h1:qt09Ya8vawLte6SNmTgCsAVtYtaKzEcn8ATUoHMkEqE=

pkg/client/client.go

@@ -5,7 +5,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net/http"
 	"path"
 	"time"
@@ -131,7 +130,7 @@ func marshal(m proto.Message) (io.Reader, error) {
 }
 
 func unmarshalBody(resp *http.Response, m proto.Message) error {
-	b, err := ioutil.ReadAll(resp.Body)
+	b, err := io.ReadAll(resp.Body)
 	if err != nil {
 		return err
 	}

pkg/links/api.go

@@ -1,7 +1,7 @@
 package links
 
 import (
-	"io/ioutil"
+	"io"
 	"log"
 	"net/http"
 	"net/url"
@@ -54,7 +54,7 @@ func (s *server) get() authHandler {
 func (s *server) put() authHandler {
 	return func(w http.ResponseWriter, r *http.Request, sub string) {
 		l := mux.Vars(r)["link"]
-		data, err := ioutil.ReadAll(r.Body)
+		data, err := io.ReadAll(r.Body)
 		if err != nil {
 			internalError(w, err)
 			return

pkg/links/api_test.go

@@ -5,7 +5,6 @@ import (
 	"encoding/base64"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net/http"
 	"net/http/httptest"
 	"strings"
@@ -244,9 +243,9 @@ func marshal(t *testing.T, m proto.Message) io.Reader {
 
 func unmarshal(t *testing.T, r io.Reader, m proto.Message) {
 	t.Helper()
-	b, err := ioutil.ReadAll(r)
+	b, err := io.ReadAll(r)
 	if err != nil {
-		t.Fatalf("ioutil.ReadAll failed: %v", err)
+		t.Fatalf("os.ReadAll failed: %v", err)
 	}
 	if err := protojson.Unmarshal(b, m); err != nil {
 		t.Fatalf("protojson.Unmarshal failed: %v", err)

pkg/links/redirect.go

@@ -5,6 +5,8 @@ import (
 	"net/http"
 	"net/url"
 	"strings"
+
+	qrcode "github.com/skip2/go-qrcode"
 )
 
 // Index is used for special handling for the root path; it is stored
@@ -23,6 +25,17 @@ func (s *server) redirect() http.HandlerFunc {
 			key = Index
 		}
 
+		// If prefixed with the /qr/ path, show a QR instead of redirecting.
+		qr := false
+		if key == "qr" {
+			qr = true
+			if len(paths) == 0 {
+				key = Index
+			} else {
+				key, paths = paths[0], paths[1:]
+			}
+		}
+
 		// Look up the key, and unmarshal the LinkEntry from the DB
 		key = strings.ReplaceAll(key, "-", "")
 		le, err := s.store.Get(r.Context(), key)
@@ -58,7 +71,21 @@ func (s *server) redirect() http.HandlerFunc {
 		if rq := r.URL.RawQuery; rq != "" {
 			loc.RawQuery = rq
 		}
+		if qr {
+			writeQR(w, loc)
+			return
+		}
 		log.Printf("redirecting %s to %s", r.URL, loc)
 		http.Redirect(w, r, loc.String(), http.StatusFound)
 	}
 }
+
+func writeQR(w http.ResponseWriter, u *url.URL) {
+	png, err := qrcode.Encode(u.String(), qrcode.High, 256)
+	if err != nil {
+		log.Printf("qrcode.Encode(%s) failed: %v", u, err)
+		internalError(w, err)
+	}
+	w.Header().Set("Content-Type", "image/png")
+	w.Write(png)
+}

pkg/links/redirect_test.go

@@ -109,3 +109,45 @@ func TestRedirect(t *testing.T) {
 		}
 	}
 }
+
+func TestQR(t *testing.T) {
+	tests := []struct {
+		key   string
+		value string
+		get   string
+	}{{
+		key:   Index,
+		value: "https://example.com",
+		get:   "/qr",
+	}, {
+		key:   "foo",
+		value: "https://example.com",
+		get:   "/qr/foo",
+	}}
+
+	for _, tc := range tests {
+		t.Logf("test %q", tc.key)
+
+		s := NewMemStore()
+		s.Put(context.Background(), tc.key, &pb.Link{Uri: tc.value})
+
+		req, err := http.NewRequest("GET", tc.get, nil)
+		if err != nil {
+			t.Errorf("NewRequest(%v) failed: %v", tc.get, err)
+			continue
+		}
+
+		rr := httptest.NewRecorder()
+		srv := NewHandler(s, nil)
+		srv.ServeHTTP(rr, req)
+		res := rr.Result()
+
+		if res.StatusCode != http.StatusOK {
+			t.Errorf("result %+v: got code %v, want OK", res, res.StatusCode)
+			continue
+		}
+		if ct := res.Header["Content-Type"]; len(ct) != 1 || ct[0] != "image/png" {
+			t.Errorf("got Content-Type %v, want image/png", ct)
+		}
+	}
+}

test.sh

@@ -56,6 +56,10 @@ echo "Testing hyphens..."
 result=$(curl -s "${ADDR}/f-o-o" -o /dev/null -w "${TEST_OUTPUT}")
 test "${result}" = "302 http://www.example.com/"
 
+echo "Testing QR code..."
+result=$(curl -s "${ADDR}/qr/foo" -o /dev/null -w '%{http_code} %{content_type}')
+test "${result}" = "200 image/png"
+
 echo "Testing get redirect..."
 "${TEST_DIR}/client" --priv "${PRIV}" \
          --addr "${ADDR}" \