gh-downloader/app/main.go

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,
	})
}