Initial implementation of GitHub download proxy service

- Add flexible URL template configuration via environment variables
- Implement automatic repository path parsing and extraction
- Add 404 response handling for all non-200 status codes
- Support both SecNex and GitHub URL formats through URL template
- Include comprehensive documentation and Docker support
- Add proper Go project structure with .gitignore

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

app/main.go

@@ -0,0 +1,150 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"path"
+	"strings"
+
+	"git.secnex.io/secnex/masterlog"
+)
+
+type Config struct {
+	Port string
+	Url  string
+}
+
+func main() {
+	config := loadConfig()
+
+	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		proxyHandler(w, r, config)
+	})
+
+	masterlog.Info("Starting server", map[string]interface{}{
+		"port": config.Port,
+		"url":  config.Url,
+	})
+
+	if err := http.ListenAndServe(config.Port, nil); err != nil {
+		masterlog.Error("Error starting server", map[string]interface{}{"error": err})
+		os.Exit(1)
+	}
+}
+
+func loadConfig() *Config {
+	config := &Config{
+		Url:  getEnv("URL", "https://git.secnex.io/secnex/%s/raw/branch/main/%s"),
+		Port: getEnv("PORT", ":8080"),
+	}
+
+	return config
+}
+
+func getEnv(key, defaultValue string) string {
+	if value := os.Getenv(key); value != "" {
+		return value
+	}
+	return defaultValue
+}
+
+func proxyHandler(w http.ResponseWriter, r *http.Request, config *Config) {
+	// Only handle GET requests
+	if r.Method != http.MethodGet {
+		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
+		return
+	}
+
+	// Extract repository and file path from URL
+	// Expected format: /repositoryName/path/to/file
+	cleanPath := path.Clean(r.URL.Path)
+	if cleanPath == "/" || cleanPath == "" {
+		http.Error(w, "Repository name required", http.StatusBadRequest)
+		return
+	}
+
+	pathParts := strings.Split(strings.TrimPrefix(cleanPath, "/"), "/")
+	if len(pathParts) < 1 {
+		http.Error(w, "Invalid path format", http.StatusBadRequest)
+		return
+	}
+
+	repository := pathParts[0]
+	filePath := strings.Join(pathParts[1:], "/")
+
+	// Log the incoming request
+	masterlog.Info("Incoming request", map[string]interface{}{
+		"method":        r.Method,
+		"repository":    repository,
+		"file_path":     filePath,
+		"original_path": r.URL.Path,
+	})
+
+	// Build target URL based on server type
+	var targetURL string
+	targetURL = fmt.Sprintf(config.Url, repository, filePath)
+
+	// Create HTTP client with timeout
+	client := &http.Client{}
+	req, err := http.NewRequestWithContext(r.Context(), http.MethodGet, targetURL, nil)
+	if err != nil {
+		masterlog.Error("Error creating request", map[string]interface{}{"error": err})
+		http.Error(w, "Failed to create request", http.StatusInternalServerError)
+		return
+	}
+
+	// Copy headers from original request
+	for key, values := range r.Header {
+		// Skip certain headers that shouldn't be forwarded
+		if strings.ToLower(key) == "host" {
+			continue
+		}
+		for _, value := range values {
+			req.Header.Add(key, value)
+		}
+	}
+
+	resp, err := client.Do(req)
+	if err != nil {
+		masterlog.Error("Error fetching target URL", map[string]interface{}{"error": err, "url": targetURL})
+		http.Error(w, "Not Found", http.StatusNotFound)
+		return
+	}
+	defer resp.Body.Close()
+
+	// Check if response is successful
+	if resp.StatusCode != http.StatusOK {
+		masterlog.Info("Target returned non-200 status", map[string]interface{}{
+			"url":         targetURL,
+			"status_code": resp.StatusCode,
+		})
+		http.Error(w, "Not Found", http.StatusNotFound)
+		return
+	}
+
+	// Copy headers from target response
+	for key, values := range resp.Header {
+		for _, value := range values {
+			w.Header().Add(key, value)
+		}
+	}
+
+	// Set status code to 200
+	w.WriteHeader(http.StatusOK)
+
+	// Copy the response body
+	_, err = io.Copy(w, resp.Body)
+	if err != nil {
+		masterlog.Error("Error copying response", map[string]interface{}{"error": err})
+		// Can't send error response after headers have been written
+		return
+	}
+
+	masterlog.Info("Successfully proxied request", map[string]interface{}{
+		"url":            targetURL,
+		"status_code":    http.StatusOK,
+		"content_length": resp.ContentLength,
+	})
+}