kitproj · alexec · Nov 15, 2025 · Nov 15, 2025 · Nov 15, 2025 · Nov 15, 2025
diff --git a/.github/workflows/go.yml b/.github/workflows/go.yml
@@ -0,0 +1,28 @@
+# This workflow will build a golang project
+# For more information see: https://docs.github.com/en/actions/automating-builds-and-tests/building-and-testing-go
+
+name: Go
+
+on:
+  push:
+    branches: [ "main" ]
+  pull_request:
+    branches: [ "main" ]
+
+jobs:
+
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Set up Go
+      uses: actions/setup-go@v4
+      with:
+        go-version: '1.24'
+
+    - name: Build
+      run: go build -v ./...
+
+    - name: Test
+      run: go test -v ./...
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
@@ -0,0 +1,49 @@
+name: release
+
+on:
+  push:
+    # run only against tags
+    tags:
+      - "*"
+
+permissions:
+  contents: write
+
+jobs:
+  release:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+      - run: git fetch --force --tags
+      - name: Set up Go
+        uses: actions/setup-go@v3
+        with:
+          go-version: ">=1.22.0"
+          cache: true
+
+      - run: go generate -v ./...
+      - run: go vet -v ./...
+      - run: go test -v ./...
+
+      # https://gist.github.com/asukakenji/f15ba7e588ac42795f421b48b8aede63
+      - run: CGO_ENABLED=0 GOOS=darwin GOARCH=amd64 go build -o diffs-cli_${{ github.ref_name }}_darwin_amd64 .
+      - run: CGO_ENABLED=0 GOOS=darwin GOARCH=arm64 go build -o diffs-cli_${{ github.ref_name }}_darwin_arm64 .
+      - run: CGO_ENABLED=0 GOOS=linux GOARCH=386 go build -o diffs-cli_${{ github.ref_name }}_linux_386 .
+      - run: CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o diffs-cli_${{ github.ref_name }}_linux_amd64 .
+      - run: CGO_ENABLED=0 GOOS=linux GOARCH=arm64 go build -o diffs-cli_${{ github.ref_name }}_linux_arm64 .
+
+      # create checksums.txt
+      - run: shasum -a 256 diffs-cli_* > checksums.txt
+
+      - name: Create a Release in a GitHub Action
+        uses: softprops/action-gh-release@v2
+        with:
+          files: |
+            diffs-cli_${{ github.ref_name }}_darwin_amd64
+            diffs-cli_${{ github.ref_name }}_darwin_arm64
+            diffs-cli_${{ github.ref_name }}_linux_386
+            diffs-cli_${{ github.ref_name }}_linux_amd64
+            diffs-cli_${{ github.ref_name }}_linux_arm64
+            checksums.txt
diff --git a/.gitignore b/.gitignore
@@ -7,6 +7,7 @@
 *.dll
 *.so
 *.dylib
+diffs-cli
 
 # Test binary, built with `go test -c`
 *.test

diff --git a/README.md b/README.md
@@ -1,2 +1,21 @@
 # diffs-cli
-Diffs CLI
+
+A tiny Go program that shows git diffs in the current directory and all git repositories in subdirectories.
+
+## Usage
+
+```bash
+# Build
+go build -o diffs-cli .
+
+# Run (default port 8080, current directory)
+./diffs-cli
+
+# Run on custom port
+./diffs-cli -port 9000
+
+# Scan a different directory
+./diffs-cli -C /path/to/workspace
+```
+
+Then open http://localhost:8080 (or your custom port) in a browser to view the diffs.
diff --git a/diffs.html b/diffs.html
@@ -0,0 +1,25 @@
+<!DOCTYPE html>
+<html>
+<head>
+    <meta charset="UTF-8">
+    <title>Diffs</title>
+</head>
+<body>
+    <h1>Git Diffs</h1>
+    <pre id="diff">Loading diffs...</pre>
+    <script>
+        fetch('/', {
+            headers: {
+                'Accept': 'text/x-diff'
+            }
+        })
+        .then(response => response.text())
+        .then(data => {
+            document.getElementById('diff').textContent = data || 'No changes';
+        })
+        .catch(error => {
+            document.getElementById('diff').textContent = 'Error loading diffs: ' + error;
+        });
+    </script>
+</body>
+</html>
diff --git a/go.mod b/go.mod
@@ -0,0 +1,3 @@
+module github.com/kitproj/diffs-cli
+
+go 1.24.4
diff --git a/handlers.go b/handlers.go
@@ -0,0 +1,90 @@
+package main
+
+import (
+	"context"
+	_ "embed"
+	"net/http"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"time"
+)
+
+//go:embed diffs.html
+var diffsHTML []byte
+
+func diffsHandler(w http.ResponseWriter, r *http.Request) {
+	accept := r.Header.Get("Accept")
+
+	if strings.Contains(accept, "text/x-diff") {
+		serveDiffsText(w, r)
+	} else {
+		serveDiffsHTML(w, r)
+	}
+}
+
+func serveDiffsHTML(w http.ResponseWriter, _ *http.Request) {
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	_, _ = w.Write(diffsHTML)
+}
+
+func findGitRepos(root string) ([]string, error) {
+	var repos []string
+
+	err := filepath.Walk(root, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return nil
+		}
+
+		if info.IsDir() && info.Name() == ".git" {
+			repoPath := filepath.Dir(path)
+			repos = append(repos, repoPath)
+			return filepath.SkipDir
+		}
+
+		return nil
+	})
+
+	return repos, err
+}
+
+func serveDiffsText(w http.ResponseWriter, r *http.Request) {
+	ctx, cancel := context.WithTimeout(r.Context(), 3*time.Second)
+	defer cancel()
+
+	writer := &maxSizeWriter{Writer: w, maxSize: 5 * 1024 * 1024}
+
+	repos, err := findGitRepos(".")
+	if err != nil {
+		http.Error(w, "Failed to find git repositories: "+err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	w.Header().Set("Content-Type", "text/x-diff; charset=utf-8")
+
+	for _, repoPath := range repos {
+		relPath, _ := filepath.Rel(".", repoPath)
+		if relPath == "." {
+			relPath = ""
+		}
+
+		repoName := relPath
+		if repoName == "" {
+			repoName = filepath.Base(repoPath)
+		}
+
+		cmd := exec.CommandContext(ctx, "bash", "-c", `
+git diff --src-prefix=a/`+repoName+`/ --dst-prefix=b/`+repoName+`/ HEAD
+git ls-files --others --exclude-standard | while IFS= read -r file; do
+  if [ -n "$file" ]; then
+    git diff --no-index --src-prefix=a/`+repoName+`/ --dst-prefix=b/`+repoName+`/ /dev/null "$file" 2>/dev/null || true
+  fi
+done
+		`)
+		cmd.Dir = repoPath
+		cmd.Stdout = writer
+		cmd.Stderr = writer
+		_ = cmd.Run()
+	}
+}
-Original file line number
+Diff line change
@@ Expand Up / @@ -7,6 +7,7 @@ @@
     *.dll
     *.so
     *.dylib
+    diffs-cli
     # Test binary, built with `go test -c`
     *.test
@@ Expand Down @@