From 35af4bab99da94845ebd6e9b2efae6a544d39b35 Mon Sep 17 00:00:00 2001
From: Collin Williams <96917990+bluedragon1221@users.noreply.github.com>
Date: Fri, 22 May 2026 10:23:58 -0500
Subject: LOTS OF TEMP STUFF

---
 modules/services/nixos/ganyupload/AGENTS.md |  65 +++++++++
 modules/services/nixos/ganyupload/main.go   | 212 +++++++++++++++++++++++++++-
 2 files changed, 270 insertions(+), 7 deletions(-)
 create mode 100644 modules/services/nixos/ganyupload/AGENTS.md

(limited to 'modules/services/nixos/ganyupload')

diff --git a/modules/services/nixos/ganyupload/AGENTS.md b/modules/services/nixos/ganyupload/AGENTS.md
new file mode 100644
index 0000000..c4d9192
--- /dev/null
+++ b/modules/services/nixos/ganyupload/AGENTS.md
@@ -0,0 +1,65 @@
+# Ganyupload - Agent Instructions
+
+## Quick Context
+- Simple Go file upload service using standard `net/http`.
+- Single `main.go`, two Nix files (`default.nix`, `pkg.nix`), one README.
+- Embedded README is served on GET /.
+- Used as a NixOS module: `collinux.services.ganyupload` enables it, configures port and upload directory via systemd environment.
+
+## How to Build and Test
+
+### Build
+```bash
+nix build
+```
+
+Alternatively, from the repo root:
+```bash
+nix build .#nixosConfigurations.<hostname>.config.system.build.toplevel
+```
+
+### Test
+No dedicated test file. Verify locally by running with environment variables:
+```bash
+PORT=8080 UPLOAD_DIR=/tmp/upload go run main.go
+```
+
+Then test uploads:
+```bash
+curl -X PUT --data-binary @file.txt http://localhost:8080/file.txt
+curl http://localhost:8080/  # Read embedded README
+```
+
+## Code Style
+
+**Go:**
+- Keep `main.go` clean; use `gofmt -w .`.
+- Match existing error handling (early return, `log.Printf` for warnings, `log.Fatalf` for fatal errors).
+- Path traversal prevention is critical; do not weaken `filepath.Clean` + `..` prefix checks.
+
+**Nix:**
+- Follow `/home/collin/nixos/AGENTS.md` conventions (2-space indent, common arg pattern, `lib.mkIf` for gating).
+- `default.nix` imports `mkCaddyCfg.nix` to integrate with Caddy reverse proxy; do not remove that import.
+
+## Key Implementation Notes
+
+1. **Embedded README:** The README file is embedded at compile time using `//go:embed README`. If you update README, rebuild to reflect changes.
+2. **Environment Variables:**
+   - `UPLOAD_DIR`: Defaults to `.`, overridden by systemd service to `/media/ganyupload`.
+   - `PORT`: Defaults to `8080`, set by systemd to the configured `cfg.port`.
+3. **NixOS Integration:** The service runs as user/group `ganyupload` with home `/var/lib/ganyupload`. Ensure the service has write permission to `UPLOAD_DIR`.
+4. **Caddy Integration:** `default.nix` imports `mkCaddyCfg.nix` to configure Caddy as a reverse proxy. Changes to hostname or port must be reflected in both Nix config and the Caddy rule.
+
+## Common Tasks
+
+- **Update Go code:** Edit `main.go`, test locally, then nix build to verify.
+- **Change upload directory or port:** Update `default.nix` (systemd environment or `cfg.port`).
+- **Update README:** Edit README file, then rebuild (`nix build`) so the embedded version updates.
+- **Debug NixOS module:** Check `/etc/systemd/system/ganyupload.service` for actual service config after rebuild.
+
+## Validation
+
+After changes:
+1. Run `nix build` from this directory or `nix build .#nixosConfigurations.<hostname>.config.system.build.toplevel` from repo root.
+2. If applicable, test via `PORT=8080 UPLOAD_DIR=/tmp go run main.go`.
+3. Verify no Nix lint issues (use repo-level `yo test` or `nix run nixpkgs#alejandra -- .` for formatting).
diff --git a/modules/services/nixos/ganyupload/main.go b/modules/services/nixos/ganyupload/main.go
index 6aa219e..75852c2 100644
--- a/modules/services/nixos/ganyupload/main.go
+++ b/modules/services/nixos/ganyupload/main.go
@@ -2,11 +2,14 @@ package main
 
 import (
 	_ "embed"
+	"fmt"
+	"html"
 	"io"
 	"log"
 	"net/http"
 	"os"
 	"path/filepath"
+	"sort"
 	"strings"
 )
 
@@ -15,6 +18,42 @@ var readme string
 
 var uploadDir = "."
 
+// cleanPath safely cleans and validates a path to prevent traversal attacks
+func cleanPath(filename string) (string, error) {
+	// Remove leading slash
+	filename = strings.TrimPrefix(filename, "/")
+	if filename == "" {
+		return "", nil
+	}
+
+	// Clean the path
+	filename = filepath.Clean(filename)
+
+	// Reject if it tries to go up
+	if strings.HasPrefix(filename, "..") || strings.Contains(filename, "/../") {
+		return "", fmt.Errorf("invalid filename: path traversal not allowed")
+	}
+
+	return filename, nil
+}
+
+// isPathSafe checks that the resolved fullPath stays within uploadDir
+func isPathSafe(uploadDir, fullPath string) bool {
+	// Resolve both paths to absolute to catch symlink attacks
+	absUploadDir, err := filepath.Abs(uploadDir)
+	if err != nil {
+		return false
+	}
+	absFullPath, err := filepath.Abs(fullPath)
+	if err != nil {
+		return false
+	}
+
+	// Ensure the resolved path starts with uploadDir
+	return strings.HasPrefix(absFullPath, absUploadDir+string(filepath.Separator)) ||
+		absFullPath == absUploadDir
+}
+
 func handleRoot(w http.ResponseWriter, r *http.Request) {
 	if r.Method != http.MethodGet {
 		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
@@ -32,27 +71,37 @@ func handleUpload(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	// Handle GET requests for downloads and directory listing
+	if r.Method == http.MethodGet {
+		handleDownload(w, r)
+		return
+	}
+
 	if r.Method != http.MethodPut {
 		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
 		return
 	}
 
 	// Extract filename from URL path, preventing path traversal
-	filename := strings.TrimPrefix(r.URL.Path, "/")
-	if filename == "" {
-		http.Error(w, "filename required", http.StatusBadRequest)
+	filename, err := cleanPath(r.URL.Path)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
 		return
 	}
 
-	// Prevent path traversal
-	filename = filepath.Clean(filename)
-	if strings.HasPrefix(filename, "..") {
-		http.Error(w, "invalid filename", http.StatusBadRequest)
+	if filename == "" {
+		http.Error(w, "filename required", http.StatusBadRequest)
 		return
 	}
 
 	fullPath := filepath.Join(uploadDir, filename)
 
+	// Verify the path is safe
+	if !isPathSafe(uploadDir, fullPath) {
+		http.Error(w, "invalid path", http.StatusBadRequest)
+		return
+	}
+
 	// Ensure the directory exists
 	dir := filepath.Dir(fullPath)
 	if err := os.MkdirAll(dir, 0755); err != nil {
@@ -85,6 +134,155 @@ func handleUpload(w http.ResponseWriter, r *http.Request) {
 	log.Printf("uploaded %s (%d bytes)", filename, written)
 }
 
+func handleDownload(w http.ResponseWriter, r *http.Request) {
+	// Extract filename from URL path
+	filename, err := cleanPath(r.URL.Path)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+
+	fullPath := filepath.Join(uploadDir, filename)
+
+	// Verify the path is safe
+	if !isPathSafe(uploadDir, fullPath) {
+		http.Error(w, "invalid path", http.StatusBadRequest)
+		return
+	}
+
+	fileInfo, err := os.Stat(fullPath)
+	if err != nil {
+		if os.IsNotExist(err) {
+			http.Error(w, "not found", http.StatusNotFound)
+		} else {
+			log.Printf("failed to stat: %v", err)
+			http.Error(w, "internal server error", http.StatusInternalServerError)
+		}
+		return
+	}
+
+	// If it's a directory, list its contents
+	if fileInfo.IsDir() {
+		handleDirList(w, r, uploadDir, filename, fullPath)
+		return
+	}
+
+	// Serve the file
+	http.ServeFile(w, r, fullPath)
+}
+
+func handleDirList(w http.ResponseWriter, r *http.Request, uploadDir, relPath, fullPath string) {
+	entries, err := os.ReadDir(fullPath)
+	if err != nil {
+		log.Printf("failed to read directory: %v", err)
+		http.Error(w, "internal server error", http.StatusInternalServerError)
+		return
+	}
+
+	// Sort entries by name
+	sort.Slice(entries, func(i, j int) bool {
+		return entries[i].Name() < entries[j].Name()
+	})
+
+	// Build breadcrumb navigation
+	pathParts := strings.Split(strings.Trim(relPath, "/"), "/")
+	if relPath == "" {
+		pathParts = []string{}
+	}
+
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	w.WriteHeader(http.StatusOK)
+
+	fmt.Fprintf(w, `<!DOCTYPE html>
+<html>
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>Directory: %s</title>
+    <style>
+        body { font-family: monospace; margin: 2rem; }
+        h1 { margin-bottom: 0.5rem; }
+        .breadcrumb { margin-bottom: 2rem; font-size: 0.9rem; }
+        .breadcrumb a { text-decoration: none; color: #0066cc; }
+        .breadcrumb a:hover { text-decoration: underline; }
+        table { border-collapse: collapse; width: 100%%; }
+        td { padding: 0.5rem; border-bottom: 1px solid #ccc; }
+        td:first-child { text-align: left; }
+        td:last-child { text-align: right; color: #666; }
+        a { text-decoration: none; color: #0066cc; }
+        a:hover { text-decoration: underline; }
+        .directory { color: #0066cc; font-weight: bold; }
+    </style>
+</head>
+<body>
+    <h1>Directory: %s</h1>
+`, html.EscapeString(relPath), html.EscapeString(relPath))
+
+	// Breadcrumb navigation
+	fmt.Fprint(w, `    <div class="breadcrumb">`)
+	fmt.Fprintf(w, `<a href="/">home</a>`)
+	if len(pathParts) > 0 {
+		accumulated := ""
+		for _, part := range pathParts {
+			accumulated = accumulated + "/" + part
+			fmt.Fprintf(w, ` / <a href="%s">%s</a>`, html.EscapeString(accumulated), html.EscapeString(part))
+		}
+	}
+	fmt.Fprint(w, `</div>`)
+
+	// Directory listing
+	fmt.Fprint(w, `    <table>
+`)
+	for _, entry := range entries {
+		name := entry.Name()
+		safeName := html.EscapeString(name)
+
+		if entry.IsDir() {
+			// For directories, add trailing slash to the link
+			linkPath := relPath + "/" + name
+			if relPath == "" {
+				linkPath = "/" + name
+			}
+			linkPath = strings.TrimPrefix(linkPath, "/")
+			fmt.Fprintf(w, `        <tr><td><a href="/%s" class="directory">%s/</a></td><td>-</td></tr>
+`, html.EscapeString(linkPath), safeName)
+		} else {
+			info, _ := entry.Info()
+			linkPath := relPath + "/" + name
+			if relPath == "" {
+				linkPath = "/" + name
+			}
+			linkPath = strings.TrimPrefix(linkPath, "/")
+			size := formatSize(info.Size())
+			fmt.Fprintf(w, `        <tr><td><a href="/%s">%s</a></td><td>%s</td></tr>
+`, html.EscapeString(linkPath), safeName, size)
+		}
+	}
+	fmt.Fprint(w, `    </table>
+</body>
+</html>
+`)
+}
+
+func formatSize(bytes int64) string {
+	const (
+		KB = 1024
+		MB = KB * 1024
+		GB = MB * 1024
+	)
+
+	switch {
+	case bytes < KB:
+		return fmt.Sprintf("%d B", bytes)
+	case bytes < MB:
+		return fmt.Sprintf("%.1f KB", float64(bytes)/KB)
+	case bytes < GB:
+		return fmt.Sprintf("%.1f MB", float64(bytes)/MB)
+	default:
+		return fmt.Sprintf("%.1f GB", float64(bytes)/GB)
+	}
+}
+
 func main() {
 	if envUploadDir := os.Getenv("UPLOAD_DIR"); envUploadDir != "" {
 		uploadDir = envUploadDir
-- 
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