From 8bb88ed20a0941aefadcc3a309b55c23659b14e4 Mon Sep 17 00:00:00 2001
From: mzz2017 <2017@duck.com>
Date: Thu, 9 Feb 2023 20:17:45 +0800
Subject: [PATCH] feat: subscription supports file://

---
 README.md                    |  3 +-
 cmd/internal/subscription.go | 59 +++++++++++++++++++++++++++++++++---
 cmd/run.go                   |  3 +-
 common/utils.go              | 16 ++++++++++
 4 files changed, 73 insertions(+), 8 deletions(-)

diff --git a/README.md b/README.md
index 25e1366..851bf49 100644
--- a/README.md
+++ b/README.md
@@ -122,6 +122,5 @@ See [example.dae](https://github.com/v2rayA/dae/blob/main/example.dae).
 1. MACv2 extension extraction.
 1. Log to userspace.
 1. Support include section.
-1. Subscription section supports "file://"
-1. Subscription section supports key.
+1. Subscription section supports key. And support to filter by subscription key.
 1. ...
diff --git a/cmd/internal/subscription.go b/cmd/internal/subscription.go
index 721067e..a03639a 100644
--- a/cmd/internal/subscription.go
+++ b/cmd/internal/subscription.go
@@ -1,6 +1,8 @@
 package internal
 
 import (
+	"bufio"
+	"bytes"
 	"encoding/json"
 	"fmt"
 	"github.com/sirupsen/logrus"
@@ -9,6 +11,8 @@ import (
 	"net"
 	"net/http"
 	"net/url"
+	"os"
+	"path/filepath"
 	"strconv"
 	"strings"
 )
@@ -80,26 +84,71 @@ func resolveSubscriptionAsSIP008(log *logrus.Logger, b []byte) (nodes []string,
 	return nodes, nil
 }
 
-func ResolveSubscription(log *logrus.Logger, subscription string) (nodes []string, err error) {
+func resolveFile(u *url.URL, configDir string) (b []byte, err error) {
+	if u.Host == "" {
+		return nil, fmt.Errorf("not support absolute path")
+	}
+	/// Relative location.
+	// Make sure path safety.
+	path := filepath.Join(configDir, u.Host, u.Path)
+	if err = common.IsFileInSubDir(path, configDir); err != nil {
+		return nil, err
+	}
+	/// Read and resolve
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	// Resolve the first line instruction.
+	fReader := bufio.NewReader(f)
+	b, err = fReader.Peek(1)
+	if err != nil {
+		return nil, err
+	}
+	if string(b[0]) == "@" {
+		// Instruction line. But not support yet.
+		_, _, err = fReader.ReadLine()
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	b, err = io.ReadAll(fReader)
+	if err != nil {
+		return nil, err
+	}
+	return bytes.TrimSpace(b), err
+}
+
+func ResolveSubscription(log *logrus.Logger, configDir string, subscription string) (nodes []string, err error) {
 	u, err := url.Parse(subscription)
 	if err != nil {
 		return nil, fmt.Errorf("failed to parse subscription \"%v\": %w", subscription, err)
 	}
+	log.Debugf("ResolveSubscription: %v", subscription)
+	var (
+		b    []byte
+		resp *http.Response
+	)
 	switch u.Scheme {
 	case "file":
-		// TODO
+		b, err = resolveFile(u, configDir)
+		if err != nil {
+			return nil, fmt.Errorf("failed to resolve file: %w", err)
+		}
+		goto resolve
 	default:
 	}
-	log.Debugf("ResolveSubscription: %v", subscription)
-	resp, err := http.Get(subscription)
+	resp, err = http.Get(subscription)
 	if err != nil {
 		return nil, err
 	}
 	defer resp.Body.Close()
-	b, err := io.ReadAll(resp.Body)
+	b, err = io.ReadAll(resp.Body)
 	if err != nil {
 		return nil, err
 	}
+resolve:
 	if nodes, err = resolveSubscriptionAsSIP008(log, b); err == nil {
 		return nodes, nil
 	} else {
diff --git a/cmd/run.go b/cmd/run.go
index ea3c917..80e7ed5 100644
--- a/cmd/run.go
+++ b/cmd/run.go
@@ -11,6 +11,7 @@ import (
 	"github.com/v2rayA/dae/pkg/logger"
 	"os"
 	"os/signal"
+	"path/filepath"
 	"syscall"
 )
 
@@ -55,7 +56,7 @@ func Run(log *logrus.Logger, param *config.Params) (err error) {
 	nodeList := make([]string, len(param.Node))
 	copy(nodeList, param.Node)
 	for _, sub := range param.Subscription {
-		nodes, err := internal.ResolveSubscription(log, sub)
+		nodes, err := internal.ResolveSubscription(log, filepath.Dir(cfgFile), sub)
 		if err != nil {
 			log.Warnf(`failed to resolve subscription "%v": %v`, sub, err)
 		}
diff --git a/common/utils.go b/common/utils.go
index e6791f6..fc28c01 100644
--- a/common/utils.go
+++ b/common/utils.go
@@ -11,6 +11,7 @@ import (
 	"encoding/hex"
 	"fmt"
 	"net/url"
+	"path/filepath"
 	"reflect"
 	"strconv"
 	"strings"
@@ -307,3 +308,18 @@ func FuzzyDecode(to interface{}, val string) bool {
 	}
 	return true
 }
+
+func IsFileInSubDir(filePath string, dir string) (err error) {
+	fileDir := filepath.Dir(filePath)
+	if len(dir) == 0 {
+		return fmt.Errorf("bad dir: %v", dir)
+	}
+	rel, err := filepath.Rel(dir, fileDir)
+	if err != nil {
+		return err
+	}
+	if strings.HasPrefix(rel, "..") {
+		return fmt.Errorf("file is out of scope: %v", rel)
+	}
+	return nil
+}