From 6c1eed0ff4872d6d5a478294e57ce0e8b90dcab3 Mon Sep 17 00:00:00 2001
From: Mike Crute <mike@crute.us>
Date: Mon, 16 Oct 2023 19:53:08 -0700
Subject: bin/webp: add webp server binary

---
 bin/webp/go.mod  |   8 +++++
 bin/webp/go.sum  |   6 ++++
 bin/webp/main.go | 106 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 120 insertions(+)
 create mode 100644 bin/webp/go.mod
 create mode 100644 bin/webp/go.sum
 create mode 100644 bin/webp/main.go

diff --git a/bin/webp/go.mod b/bin/webp/go.mod
new file mode 100644
index 0000000..ad9ea20
--- /dev/null
+++ b/bin/webp/go.mod
@@ -0,0 +1,8 @@
+module code.crute.us/mcrute/golib/bin/webp
+
+go 1.20
+
+require (
+	github.com/chai2010/webp v1.1.1
+	golang.org/x/image v0.0.0-20211028202545-6944b10bf410
+)
diff --git a/bin/webp/go.sum b/bin/webp/go.sum
new file mode 100644
index 0000000..27fb1cf
--- /dev/null
+++ b/bin/webp/go.sum
@@ -0,0 +1,6 @@
+github.com/chai2010/webp v1.1.1 h1:jTRmEccAJ4MGrhFOrPMpNGIJ/eybIgwKpcACsrTEapk=
+github.com/chai2010/webp v1.1.1/go.mod h1:0XVwvZWdjjdxpUEIf7b9g9VkHFnInUSYujwqTLEuldU=
+golang.org/x/image v0.0.0-20211028202545-6944b10bf410 h1:hTftEOvwiOq2+O8k2D5/Q7COC7k5Qcrgc2TFURJYnvQ=
+golang.org/x/image v0.0.0-20211028202545-6944b10bf410/go.mod h1:023OzeP/+EPmXeapQh35lcL3II3LrY8Ic+EFFKVhULM=
+golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
diff --git a/bin/webp/main.go b/bin/webp/main.go
new file mode 100644
index 0000000..c00a6d8
--- /dev/null
+++ b/bin/webp/main.go
@@ -0,0 +1,106 @@
+package main
+
+// webp is a small HTTP server that listens on a Unix socket and
+// receives an uncompressed TIFF image as a POST value; it returns a
+// webp encoded image. The `quality` header is an integer ranging from
+// 0-100 indicating the webp quality, it is required. The `lossless` and
+// `exact` headers specify that the image is lossless and to preserve
+// RGB values in transparent areas, respectively. These headers may
+// only be set to "true" and their absence implies that they are false.
+//
+// This program exists because there is no pure-Go implementation of
+// a webp encoder and using CGO is not desirable for most binaries.
+// Furthermore, forking a cwebp binary per image conversion may not
+// scale well for a given application, especially if this forking occurs
+// on a per-user-request basis. Additionally cwebp requires that the
+// image be loaded from disk which may not be desirable while this
+// program works purely with byte streams.
+//
+// This program should be shipped with, started, managed, and killed
+// by the parent process that needs webp support. It supports clean
+// shutdown in response to SIGTERM. Errors and requests are logged to
+// stderr.
+//
+// Uncompressed TIFF was used as the transit format because it supports
+// all image color spaces as well as transparency. Compression is
+// unneeded because it wastes CPU cycles on the encode and decode side
+// for an IPC call, which has no appreciable bandwidth limit.
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"net"
+	"net/http"
+	"os"
+	"os/signal"
+	"strconv"
+	"syscall"
+
+	"github.com/chai2010/webp"
+	"golang.org/x/image/tiff"
+)
+
+func writeError(w http.ResponseWriter, code int, message string, args ...any) {
+	w.WriteHeader(code)
+	w.Write([]byte(fmt.Sprintf(message+"\n", args...)))
+	log.Printf("error: %d: %s", code, fmt.Sprintf(message, args...))
+}
+
+type webpConverterHandler struct{}
+
+func (h *webpConverterHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	img, err := tiff.Decode(r.Body)
+	if err != nil {
+		writeError(w, http.StatusBadRequest, "decode failed: %s", err)
+		return
+	}
+
+	quality, err := strconv.Atoi(r.Header.Get("quality"))
+	if err != nil {
+		writeError(w, http.StatusBadRequest, "unable to parse quality header: %s", err)
+		return
+	}
+
+	w.WriteHeader(http.StatusOK)
+	err = webp.Encode(w, img, &webp.Options{
+		Lossless: r.Header.Get("lossless") == "true",
+		Exact:    r.Header.Get("exact") == "true",
+		Quality:  float32(quality),
+	})
+	if err != nil {
+		log.Printf("error encoding web: %s", err)
+	}
+
+	log.Printf(`"%s %s" %s`, r.Method, r.URL.String(), r.Header.Get("Content-Length"))
+}
+
+func main() {
+	if len(os.Args) != 2 {
+		log.Fatalf("usage: %s <socket path>", os.Args[0])
+	}
+
+	sig := make(chan os.Signal)
+	signal.Notify(sig, syscall.SIGTERM)
+
+	spath := os.Args[1]
+	os.Remove(spath)
+
+	server := http.Server{
+		Handler:  &webpConverterHandler{},
+		ErrorLog: log.Default(),
+	}
+
+	listener, err := net.Listen("unix", spath)
+	if err != nil {
+		log.Fatalf("error: %s", err)
+	}
+
+	log.Printf("listening on %s", spath)
+	go server.Serve(listener)
+
+	<-sig
+	log.Printf("process received SIG_TERM, quitting")
+	server.Shutdown(context.Background())
+	os.Remove(spath)
+}
-- 
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