Initial commit.

7 files changed, 331 insertions, 0 deletions

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
new file mode 100644
index 0000000..3961181
--- /dev/null
+++ b/.github/workflows/build.yml
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+name: "Build"
+on:
+  pull_request:
+  push:
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2.4.0
+    - uses: cachix/install-nix-action@v15
+      with:
+        extra_nix_config: |
+          access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
+    - run: nix build
+    - name: Create Release
+      id: create_release
+      uses: actions/create-release@v1
+      env:
+        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      with:
+        tag_name: ${{ github.ref }}
+        release_name: Release ${{ github.ref }}
+        draft: false
+        prerelease: false
+    - name: Upload Release Asset
+      id: upload-release-asset
+      uses: actions/upload-release-asset@v1
+      env:
+        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      with:
+        upload_url: ${{ steps.create_release.outputs.upload_url }} # This pulls from the CREATE RELEASE step above, referencing it's ID to get its outputs object, which include a `upload_url`. See this blog post for more info: https://jasonet.co/posts/new-features-of-github-actions/#passing-data-to-future-steps 
+        asset_path: ./result/bin/ddcutil-daemon
+        asset_name: ddcutil-daemon
+        asset_content_type: application/octet-stream
diff --git a/README.md b/README.md
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index 0000000..6d97db7
--- /dev/null
+++ b/README.md
@@ -0,0 +1,50 @@
+# Description
+
+HTTP service to control monitor brightness.
+
+# Requirements
+
+* go 1.17.11
+* ddcutil 1.2.2
+* linux 5.13.16
+
+# Build
+
+``` shell
+nix build
+```
+
+# Run
+
+```
+sudo result/bin/ddcutil-daemon
+```
+
+The `ddcutil` binary should run with root privileges, so we use `sudo`.
+
+# Usage
+
+Get current brightness cached value:
+```shell
+curl 127.0.0.1:49281/set
+```
+
+Set brightness to specific value:
+```shell
+curl --request POST --data '{'value': 5}' 127.0.0.1:49281/set
+```
+
+Increase brightness:
+```shell
+curl --request POST --data '{"value": 5}' 127.0.0.1:49281/increase
+```
+
+Decrease brightness:
+```shell
+curl --request POST --data '{"value": 5}' 127.0.0.1:49281/decrease
+```
+
+Toggle brightness between current and minimal values:
+```shell
+curl --request POST 127.0.0.1:49281/toggle
+```
diff --git a/ddcutil-daemon.json b/ddcutil-daemon.json
new file mode 100644
index 0000000..33e9a05
--- /dev/null
+++ b/ddcutil-daemon.json
@@ -0,0 +1,4 @@
+{
+    "listen": "127.0.0.1:49281",
+    "vcp": "10"
+}
diff --git a/flake.lock b/flake.lock
new file mode 100644
index 0000000..858d802
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,25 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1697886341,
+        "narHash": "sha256-AdE67xPty9M9wn36nPVp6aDntIdigrs7UbyaGv1VAaM=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "44881e03af1c730cbb1d72a4d41274a2c957813a",
+        "type": "github"
+      },
+      "original": {
+        "id": "nixpkgs",
+        "type": "indirect"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 0000000..44823ef
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,39 @@
+{
+  description = "HTTP service to control monitor brightness";
+
+  outputs = { self, nixpkgs, ... }:
+    let system = "x86_64-linux";
+    in {
+      packages.${system} = {
+        default = nixpkgs.legacyPackages.${system}.callPackage
+          ({ lib, go, buildGoModule }:
+            buildGoModule rec {
+              pname = "ddcutil-daemon";
+              version = "0.0.1";
+              src = ./.;
+              # preConfigure phase to compile a statically linked executable
+              preConfigure = ''
+                export CGO_ENABLED=0
+                export GOOS=linux
+                export GOARCH=amd64
+              '';
+              ldflags = let t = "github.com/kitnil/ddcutil-daemon";
+              in [
+                "-s" # stripped binary
+                "-X ${t}.Version=${version}"
+                "-X ${t}.Branch=unknown"
+                "-X ${t}.BuildUser=nix@nixpkgs"
+                "-X ${t}.BuildDate=unknown"
+                "-X ${t}.GoVersion=${lib.getVersion go}"
+              ];
+              vendorSha256 = null;
+              meta = with lib; {
+                description = "HTTP service to control monitor brightness.";
+                homepage = "https://github.com/kitnil/ddcutil-daemon";
+                license = licenses.asl20;
+                platforms = platforms.unix;
+              };
+            }) { };
+      };
+    };
+}
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..f018c57
--- /dev/null
+++ b/go.mod
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+module github.com/kitnil/ddcutil-daemon
+
+go 1.17
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..60de258
--- /dev/null
+++ b/main.go
@@ -0,0 +1,176 @@
+package main
+
+import (
+	"encoding/json"
+	"io"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"os"
+	"os/exec"
+	"strconv"
+	"strings"
+)
+
+type Configuration struct {
+	Listen string
+	Vcp string
+}
+
+var configuration = Configuration{
+	Listen: "127.0.0.1:49281",
+	Vcp: "10"}
+
+type Brightness struct {
+	Lock         bool
+	Value        int
+	ToggledValue int
+}
+
+var currentBrightness Brightness
+
+func update() {
+	if currentBrightness.Lock == false {
+		currentBrightness.Lock = true
+		cmd := exec.Command("ddcutil", "getvcp", "--brief", configuration.Vcp)
+		log.Println(cmd.String())
+		out, err := cmd.CombinedOutput()
+		if err != nil {
+			log.Println(err)
+			return
+		}
+		outString := strings.Split(strings.Trim(string(out), "\n"), " ")
+		currentBrightness.Value, err = strconv.Atoi(outString[len(outString)-2])
+		if err != nil {
+			log.Println(err)
+			return
+		}
+		log.Println("Current brightness is", currentBrightness.Value)
+		currentBrightness.Lock = false
+	} else {
+		log.Println("Active lock, no operation performed")
+		return
+	}
+}
+
+func get(w http.ResponseWriter, r *http.Request) {
+	if r.Method == "GET" {
+                log.Println("Current brightness cached value is",
+			currentBrightness.Value)
+	}
+}
+
+func ddcutilSetBrightness(brightness Brightness) {
+	if currentBrightness.Lock == false {
+		currentBrightness.Lock = true
+		cmd := exec.Command("ddcutil", "setvcp", configuration.Vcp,
+			strconv.Itoa(brightness.Value))
+		log.Println(cmd.String())
+		_, err := cmd.CombinedOutput()
+		if err != nil {
+			log.Println(err)
+			return
+		}
+		currentBrightness.Value = brightness.Value
+		currentBrightness.Lock = false
+	} else {
+		log.Println("Active lock, no operation performed")
+		return
+	}
+}
+
+func set(w http.ResponseWriter, r *http.Request) {
+	if r.Method == "POST" {
+		body, err := io.ReadAll(r.Body)
+		if err != nil {
+			log.Println(err)
+			return
+		}
+		var brightness Brightness
+		json.Unmarshal([]byte(body), &brightness)
+		ddcutilSetBrightness(brightness)
+	}
+}
+
+func decrease(w http.ResponseWriter, r *http.Request) {
+	if r.Method == "POST" {
+		body, err := io.ReadAll(r.Body)
+		if err != nil {
+			log.Println(err)
+			return
+		}
+		var brightness Brightness
+		json.Unmarshal([]byte(body), &brightness)
+		newValue := Brightness{Value: currentBrightness.Value - brightness.Value}
+		if newValue.Value < 0 {
+			log.Println("Brightness is minimum")
+		} else {
+			ddcutilSetBrightness(newValue)
+			log.Println("Current brightness is", currentBrightness.Value)
+		}
+	} else {
+		log.Println("Active lock, no operation performed")
+		return
+	}
+}
+
+func increase(w http.ResponseWriter, r *http.Request) {
+	if r.Method == "POST" {
+		body, err := io.ReadAll(r.Body)
+		if err != nil {
+			log.Println(err)
+			return
+		}
+		var brightness Brightness
+		json.Unmarshal([]byte(body), &brightness)
+		newValue := Brightness{Value: currentBrightness.Value + brightness.Value}
+		if newValue.Value > 100 {
+			log.Println("Brightness is maximum")
+		} else {
+			ddcutilSetBrightness(newValue)
+			log.Println("Current brightness is", currentBrightness.Value)
+		}
+	} else {
+		log.Println("Active lock, no operation performed")
+		return
+	}
+}
+
+func toggle(w http.ResponseWriter, r *http.Request) {
+	if r.Method == "POST" {
+		if currentBrightness.Value == 0 {
+			ddcutilSetBrightness(Brightness{Value: currentBrightness.ToggledValue})
+			log.Println("Current brightness is", currentBrightness.Value)
+		} else {
+			currentBrightness.ToggledValue = currentBrightness.Value
+			ddcutilSetBrightness(Brightness{Value: 0})
+			log.Println("Current brightness is", currentBrightness.Value)
+		}
+	}
+}
+
+func main() {
+	jsonFile, err := os.Open("ddcutil-daemon.json")
+	if err != nil {
+		log.Fatalln(err)
+	}
+	byteValue, err := ioutil.ReadAll(jsonFile)
+	if err != nil {
+		log.Fatalln(err)
+	}
+	var configuration Configuration
+	json.Unmarshal(byteValue, &configuration)
+	jsonFile.Close()
+
+	currentBrightness.Lock = false
+	update()
+	http.HandleFunc("/update", func(w http.ResponseWriter, r *http.Request) {
+		update()
+	})
+	http.HandleFunc("/get", get)
+	http.HandleFunc("/set", set)
+	http.HandleFunc("/decrease", decrease)
+	http.HandleFunc("/increase", increase)
+	http.HandleFunc("/toggle", toggle)
+	log.Fatal(http.ListenAndServe(configuration.Listen, nil))
+}