commit 29de7cf4ac35505a9488121ceb59cb5437081d1a Author: Paul-Christian Volkmer Date: Wed Jan 12 15:19:10 2022 +0100 Import existing source code diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..dbe539b --- /dev/null +++ b/.gitignore @@ -0,0 +1,3 @@ +.idea + +idicon \ No newline at end of file diff --git a/Dockerfile b/Dockerfile new file mode 100644 index 0000000..0dd8204 --- /dev/null +++ b/Dockerfile @@ -0,0 +1,32 @@ +FROM golang:1.16-alpine AS build-env + +ENV USER=appuser +ENV UID=8000 + +RUN adduser \ + --disabled-password \ + --gecos "" \ + --home "/null" \ + --shell "/sbin/nologin" \ + --no-create-home \ + --uid "${UID}" \ + "${USER}" + +WORKDIR /tmp/build +ADD . /tmp/build +# -ldlflags '-s' to strip binary +RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o app -ldflags '-w -s' + +### + +FROM scratch + +COPY --from=build-env /etc/passwd /etc/passwd +COPY --from=build-env /etc/group /etc/group +COPY --from=build-env /tmp/build/app /usr/local/bin/idicon + +USER appuser:appuser + +EXPOSE 8000 + +ENTRYPOINT ["/usr/local/bin/idicon"] \ No newline at end of file diff --git a/LICENSE b/LICENSE new file mode 100644 index 0000000..4818d1a --- /dev/null +++ b/LICENSE @@ -0,0 +1,21 @@ +The MIT License + +Copyright (c) 2021 Paul-Christian Volkmer + +Permission is hereby granted, free of charge, to any person obtaining a copy +of this software and associated documentation files (the "Software"), to deal +in the Software without restriction, including without limitation the rights +to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +copies of the Software, and to permit persons to whom the Software is +furnished to do so, subject to the following conditions: + +The above copyright notice and this permission notice shall be included in all +copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE +SOFTWARE. \ No newline at end of file diff --git a/README.adoc b/README.adoc new file mode 100644 index 0000000..2d1ff95 --- /dev/null +++ b/README.adoc @@ -0,0 +1,41 @@ += IdIcon + +Simple implementation of an identicon service. + +== Usage + +HTTP `GET` is used to request an identicon image. + +.... +curl http://localhost:8000/avatar/23463b99b62a72f26ed677cc556c44e8?s=100&c=v2 +.... + +Instead of requesting identicons for MD5 hashes of usernames or mail addresses, it is possible to use plain username and mail address. The will result in the same generated identicon. + +Use request query parameter `s` to request images with specified size. Default value is 80px. The size is limited to a maximum value of 512px. +Query parameter `c` will set color scheme. Available values are `v1` and `v2`. + +=== Server settings + +You can use `COLORSCHEME` in environment to define the default color scheme to be used. Fallback value will be `v2`. + +== Development and local start + +A *Golang* setup is required for development. File `idicon.go` contains the source code. Type + +.... +$ go run +.... + +to run the application on port 8000. + +=== Docker build + +Use `Dockerfile` to build a new image based on `scratch` image and start this image by typing + +.... +$ docker build -t idicon . +$ docker run -p 8000:8000 idicon +.... + +This will build the image and will start a new container listening on port 8000 for requests. diff --git a/go.mod b/go.mod new file mode 100644 index 0000000..cce1834 --- /dev/null +++ b/go.mod @@ -0,0 +1,5 @@ +module idicon + +go 1.16 + +require github.com/gorilla/mux v1.8.0 diff --git a/go.sum b/go.sum new file mode 100644 index 0000000..5350288 --- /dev/null +++ b/go.sum @@ -0,0 +1,2 @@ +github.com/gorilla/mux v1.8.0 h1:i40aqfkR1h2SlN9hojwV5ZA91wcXFOvkdNIeFDP5koI= +github.com/gorilla/mux v1.8.0/go.mod h1:DVbg23sWSpFRCP0SfiEN6jmj59UnW/n46BH5rLB71So= diff --git a/idicon.go b/idicon.go new file mode 100644 index 0000000..69cf797 --- /dev/null +++ b/idicon.go @@ -0,0 +1,138 @@ +package main + +import ( + "crypto/md5" + "encoding/hex" + "github.com/gorilla/mux" + "image" + "image/color" + "image/draw" + "image/png" + "log" + "net/http" + "os" + "regexp" + "strconv" + "strings" +) + +func colorV1(hash [16]byte) color.RGBA { + r := 32 + (hash[0]%16)/2<<4 + g := 32 + (hash[2]%16)/2<<4 + b := 32 + (hash[len(hash)-1]%16)/2<<4 + + if r > g && r > b { + r += 48 + } else if g > r && g > b { + g += 48 + } else if b > r && b > g { + b += 48 + } + return color.RGBA{r, g, b, 255} +} + +func colorV2(hash [16]byte) color.RGBA { + var palette = []color.RGBA{ + {0x3c, 0x38, 0x36, 0xff}, + {0xcc, 0x24, 0x1d, 0xff}, + {0x98, 0x97, 0x1a, 0xff}, + {0xd7, 0x99, 0x21, 0xff}, + {0x45, 0x85, 0x88, 0xff}, + {0xb1, 0x62, 0x86, 0xff}, + {0x68, 0x9d, 0x6a, 0xff}, + {0xa8, 0x99, 0x84, 0xff}, + } + return palette[hash[15]%8] +} + +func genIdIcon(id string, size int, f func([16]byte) color.RGBA) *image.NRGBA { + id = strings.ToLower(id) + blocks := 5 + if size > 512 { + size = 512 + } + + hash := hashBytes(id) + data := make([]bool, blocks*blocks) + for i := 0; i < len(hash)-1; i++ { + data[i] = hash[i]%2 != hash[i+1]%2 + } + return drawImage(mirrorData(data, blocks), blocks, size, f(hash)) +} + +func hashBytes(id string) [16]byte { + hash := [16]byte{} + md5RegExp := regexp.MustCompile("[a-f0-9]{32}") + if !md5RegExp.Match([]byte(id)) { + hash = md5.Sum([]byte(id)) + } else { + dec, _ := hex.DecodeString(id) + for idx, b := range dec { + hash[idx] = b + } + } + return hash +} + +func mirrorData(data []bool, blocks int) []bool { + for x := 0; x < blocks; x++ { + min := x*blocks + 1 + for y := 0; y < blocks; y++ { + a := ((blocks - x - 1) * blocks) + y + b := min + y - 1 + if data[a] { + data[b] = true + } + } + } + return data +} + +func drawImage(data []bool, blocks int, size int, c color.Color) *image.NRGBA { + img := image.NewNRGBA(image.Rect(0, 0, size, size)) + + draw.Draw(img, img.Bounds(), &image.Uniform{color.Gray{240}}, image.Point{0, 0}, draw.Src) + + blockSize := size / (blocks + 1) + border := (size - (blocks * blockSize)) / 2 + + for x := border; x < blockSize*blocks+border; x++ { + bx := (x - border) / blockSize + for y := border; y < blockSize*blocks+border; y++ { + by := (y - border) / blockSize + idx := bx*blocks + by + if data[idx] && (bx < blocks || by < blocks) { + img.Set(x, y, c) + } + } + } + + return img +} + +func RequestHandler(w http.ResponseWriter, r *http.Request) { + id := mux.Vars(r)["id"] + + size, err := strconv.Atoi(r.URL.Query().Get("s")) + if err != nil { + size = 80 + } + + colorScheme := r.URL.Query().Get("c") + if colorScheme == "" { + colorScheme = os.Getenv("COLORSCHEME") + } + + w.Header().Add("Content-Type", "image/png") + if colorScheme == "v1" { + err = png.Encode(w, genIdIcon(id, size, colorV1)) + } else { + err = png.Encode(w, genIdIcon(id, size, colorV2)) + } +} + +func main() { + router := mux.NewRouter() + router.HandleFunc("/avatar/{id}", RequestHandler) + log.Fatal(http.ListenAndServe(":8000", router)) +} diff --git a/idicon_test.go b/idicon_test.go new file mode 100644 index 0000000..ce9bc15 --- /dev/null +++ b/idicon_test.go @@ -0,0 +1,91 @@ +package main + +import ( + "bytes" + _ "embed" + "github.com/gorilla/mux" + "image/png" + "net/http" + "net/http/httptest" + "reflect" + "testing" +) + +//go:embed testdata/1a79a4d60de6718e8e5b326e338ae533_v1.png +var v1 []byte + +//go:embed testdata/1a79a4d60de6718e8e5b326e338ae533_v2.png +var v2 []byte + +func testRouter() *mux.Router { + router := mux.NewRouter() + router.HandleFunc("/avatar/{id}", RequestHandler) + return router +} + +func TestCorrectContentType(t *testing.T) { + req, err := http.NewRequest("GET", "/avatar/example", nil) + if err != nil { + t.Fatal(err) + } + + rr := httptest.NewRecorder() + testRouter().ServeHTTP(rr, req) + + if ctype := rr.Header().Get("Content-Type"); ctype != "image/png" { + t.Errorf("content type header does not match: got %v want image/png", ctype) + } +} + +func TestCorrectResponseForV1ColorScheme(t *testing.T) { + req, err := http.NewRequest("GET", "/avatar/1a79a4d60de6718e8e5b326e338ae533?c=v1", nil) + if err != nil { + t.Fatal(err) + } + + rr := httptest.NewRecorder() + testRouter().ServeHTTP(rr, req) + + if !reflect.DeepEqual(rr.Body.Bytes(), v1) { + t.Errorf("returned image does not match expected image") + } +} + +func TestCorrectResponseForV2ColorScheme(t *testing.T) { + req, err := http.NewRequest("GET", "/avatar/1a79a4d60de6718e8e5b326e338ae533?c=v2", nil) + if err != nil { + t.Fatal(err) + } + + rr := httptest.NewRecorder() + testRouter().ServeHTTP(rr, req) + + if !reflect.DeepEqual(rr.Body.Bytes(), v2) { + t.Errorf("returned image does not match expected image") + } +} + +func TestIgnoreCase(t *testing.T) { + w1 := bytes.NewBuffer([]byte{}) + png.Encode(w1, genIdIcon("example", 80, colorV1)) + + w2 := bytes.NewBuffer([]byte{}) + png.Encode(w2, genIdIcon("Example", 80, colorV1)) + + if bytes.Compare(w1.Bytes(), w2.Bytes()) != 0 { + t.Errorf("resulting images do not match") + } +} + +func TestStringMatchesHash(t *testing.T) { + w1 := bytes.NewBuffer([]byte{}) + // MD5 of lowercase 'example' + png.Encode(w1, genIdIcon("1a79a4d60de6718e8e5b326e338ae533", 80, colorV2)) + + w2 := bytes.NewBuffer([]byte{}) + png.Encode(w2, genIdIcon("Example", 80, colorV2)) + + if bytes.Compare(w1.Bytes(), w2.Bytes()) != 0 { + t.Errorf("resulting images do not match") + } +} diff --git a/testdata/1a79a4d60de6718e8e5b326e338ae533_v1.png b/testdata/1a79a4d60de6718e8e5b326e338ae533_v1.png new file mode 100644 index 0000000..2ef33b1 Binary files /dev/null and b/testdata/1a79a4d60de6718e8e5b326e338ae533_v1.png differ diff --git a/testdata/1a79a4d60de6718e8e5b326e338ae533_v2.png b/testdata/1a79a4d60de6718e8e5b326e338ae533_v2.png new file mode 100644 index 0000000..1d63a34 Binary files /dev/null and b/testdata/1a79a4d60de6718e8e5b326e338ae533_v2.png differ