reprogl

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package handlers
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import (
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	"bufio"
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	"bytes"
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	"errors"
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	"image"
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	"image/png"
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	"io/fs"
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	"net/http"
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	"os"
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	"os/exec"
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	"strconv"
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	"time"
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	"github.com/go-chi/chi/v5"
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	"xelbot.com/reprogl/container"
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	"xelbot.com/reprogl/models"
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	"xelbot.com/reprogl/utils/avatar"
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	"xelbot.com/reprogl/utils/hashid"
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)
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func AvatarGenerator(app *container.Application) http.HandlerFunc {
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	return func(w http.ResponseWriter, r *http.Request) {
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		hash := chi.URLParam(r, "hash")
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		writeAvatar(w, app, hash, 80)
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	}
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}
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func AvatarGeneratorWithSize(app *container.Application) http.HandlerFunc {
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	return func(w http.ResponseWriter, r *http.Request) {
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		hash := chi.URLParam(r, "hash")
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		sizeStr := chi.URLParam(r, "size")
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		size, err := strconv.Atoi(sizeStr)
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		if err != nil {
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			app.NotFound(w)
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			return
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		}
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		writeAvatar(w, app, hash, size)
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	}
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}
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func writeAvatar(w http.ResponseWriter, app *container.Application, hash string, size int) {
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	hashModel, err := hashid.Decode(hash, true)
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	if err != nil {
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		app.NotFound(w)
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		return
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	}
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	img, err := avatar.GenerateAvatar(hashModel, app, size)
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	if err != nil {
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		if errors.Is(err, models.RecordNotFound) || errors.Is(err, avatar.InvalidSize) {
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			app.NotFound(w)
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		} else {
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			app.ServerError(w, err)
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		}
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		return
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	}
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	expires := time.Now().Add(container.AvatarTTL * time.Second)
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	cacheControl(w, container.AvatarTTL)
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	setExpires(w, expires)
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	w.Header().Set("Content-Type", "image/png")
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	rawImage, err := pngquantPipe(img)
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	if err != nil {
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		panic(err)
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	}
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	saveToFile(hash, size, rawImage)
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	_, err = w.Write(rawImage)
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	if err != nil {
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		app.ServerError(w, err)
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	}
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}
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func pngquantPipe(avatarImage image.Image) ([]byte, error) {
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	buf := new(bytes.Buffer)
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	err := png.Encode(buf, avatarImage)
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	if err != nil {
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		return []byte{}, err
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	}
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	quantBuf := new(bytes.Buffer)
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	cmd := exec.Command("/usr/bin/pngquant", "-s1", "--quality=60-80", "-")
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	cmd.Stdin = bufio.NewReader(buf)
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	cmd.Stderr = os.Stderr
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	cmd.Stdout = quantBuf
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	err = cmd.Run()
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	if err != nil {
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		return []byte{}, err
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	}
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	return quantBuf.Bytes(), nil
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}
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func saveToFile(hash string, size int, rawImage []byte) {
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	var postfix string
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	if size != 80 {
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		postfix = ".w" + strconv.Itoa(size)
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	}
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	filename := "public/images/avatar/" + hash + postfix + ".png"
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	f, err := os.Open(filename)
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	if errors.Is(err, fs.ErrNotExist) {
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		_ = os.WriteFile(filename, rawImage, 0644)
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	}
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	_ = f.Close()
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}
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