From 69c4ccfc9736276b8463465da8a566ad7ace0c2b Mon Sep 17 00:00:00 2001
From: Seednode <git@seedno.de>
Date: Sat, 4 Feb 2023 23:44:31 -0600
Subject: [PATCH] Added support for persistent index file

---
 README.md      | 17 +++++++-------
 cmd/root.go    |  2 ++
 cmd/version.go |  2 +-
 cmd/web.go     | 64 ++++++++++++++++++++++++++++++++++++++++++++++++--
 4 files changed, 74 insertions(+), 11 deletions(-)

diff --git a/README.md b/README.md
index d7d05eb..56664ec 100644
--- a/README.md
+++ b/README.md
@@ -92,14 +92,15 @@ Available Commands:
   version     Print version
 
 Flags:
-  -c, --cache         only scan directories once, at startup (or when filters are applied)
-  -d, --debug         store list of files served and number of times they were served
-  -f, --filter        enable filtering via query parameters
-  -h, --help          help for roulette
-  -p, --port uint16   port to listen on (default 8080)
-  -r, --recursive     recurse into subdirectories
-  -s, --sort          enable sorting via query parameters
-  -v, --verbose       log accessed files to stdout
+  -c, --cache          generate directory cache at startup
+  -d, --debug          expose stats endpoint
+  -f, --filter         enable filtering
+  -h, --help           help for roulette
+  -i, --index string   path to persistent index file
+  -p, --port uint16    port to listen on (default 8080)
+  -r, --recursive      recurse into subdirectories
+  -s, --sort           enable sorting
+  -v, --verbose        log accessed files to stdout
 
 Use "roulette [command] --help" for more information about a command.
 ```
diff --git a/cmd/root.go b/cmd/root.go
index 4da3778..a80484f 100644
--- a/cmd/root.go
+++ b/cmd/root.go
@@ -15,6 +15,7 @@ var (
 	cache     bool
 	debug     bool
 	filtering bool
+	indexFile string
 	port      uint16
 	recursive bool
 	sorting   bool
@@ -47,6 +48,7 @@ func init() {
 	rootCmd.Flags().BoolVarP(&cache, "cache", "c", false, "generate directory cache at startup")
 	rootCmd.Flags().BoolVarP(&debug, "debug", "d", false, "expose stats endpoint")
 	rootCmd.Flags().BoolVarP(&filtering, "filter", "f", false, "enable filtering")
+	rootCmd.Flags().StringVarP(&indexFile, "index", "i", "", "path to persistent index file")
 	rootCmd.Flags().Uint16VarP(&port, "port", "p", 8080, "port to listen on")
 	rootCmd.Flags().BoolVarP(&recursive, "recursive", "r", false, "recurse into subdirectories")
 	rootCmd.Flags().BoolVarP(&sorting, "sort", "s", false, "enable sorting")
diff --git a/cmd/version.go b/cmd/version.go
index dafe543..23cf362 100644
--- a/cmd/version.go
+++ b/cmd/version.go
@@ -10,7 +10,7 @@ import (
 	"github.com/spf13/cobra"
 )
 
-var Version = "0.34.2"
+var Version = "0.35.0"
 
 func init() {
 	rootCmd.AddCommand(versionCmd)
diff --git a/cmd/web.go b/cmd/web.go
index c9948d9..d5204b6 100644
--- a/cmd/web.go
+++ b/cmd/web.go
@@ -5,7 +5,9 @@ Copyright © 2023 Seednode <seednode@seedno.de>
 package cmd
 
 import (
+	"encoding/gob"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"log"
@@ -25,6 +27,10 @@ import (
 	"github.com/yosssi/gohtml"
 )
 
+var (
+	ErrIndexNotExist = errors.New(`specified index does not exist`)
+)
+
 const (
 	LogDate            string = `2006-01-02T15:04:05.000-07:00`
 	Prefix             string = `/src`
@@ -87,6 +93,10 @@ func (i *Index) generateCache(args []string) {
 	i.mutex.Unlock()
 
 	fileList(args, &Filters{}, "", i)
+
+	if indexFile != "" {
+		i.Export(indexFile)
+	}
 }
 
 func (i *Index) IsEmpty() bool {
@@ -97,6 +107,39 @@ func (i *Index) IsEmpty() bool {
 	return length == 0
 }
 
+func (i *Index) Export(path string) error {
+	file, err := os.OpenFile(path, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0600)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	enc := gob.NewEncoder(file)
+
+	enc.Encode(&i.list)
+
+	return nil
+}
+
+func (i *Index) Import(path string) error {
+	file, err := os.OpenFile(path, os.O_RDONLY, 0600)
+	if os.IsNotExist(err) {
+		return ErrIndexNotExist
+	} else if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	dec := gob.NewDecoder(file)
+
+	err = dec.Decode(&i.list)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
 type ServeStats struct {
 	mutex sync.RWMutex
 	list  []string
@@ -577,7 +620,9 @@ func ServePage(args []string) error {
 		units:        regexp.MustCompile(`^[0-9]+(ns|us|µs|ms|s|m|h)$`),
 	}
 
-	rand.Seed(time.Now().UnixNano())
+	//NewRand(NewSource(time.Now().UnixNano()))
+
+	rand.New(rand.NewSource(time.Now().UnixNano()))
 
 	index := &Index{
 		mutex: sync.RWMutex{},
@@ -585,7 +630,22 @@ func ServePage(args []string) error {
 	}
 
 	if cache {
-		index.generateCache(args)
+		skipIndex := false
+
+		if indexFile != "" {
+			err = index.Import(indexFile)
+			switch err {
+			case ErrIndexNotExist:
+			case nil:
+				skipIndex = true
+			default:
+				return err
+			}
+		}
+
+		if !skipIndex {
+			index.generateCache(args)
+		}
 
 		http.Handle("/_/clear_cache", serveCacheClearHandler(args, index))
 	}