Enhance ipinfoLocal.mmdb file lookup (nxtrace#66)

* Enhance ipinfoLocal.mmdb file lookup
* Refactor get NEXTTRACE_IPINFOLOCALPATH env variable into util

Author: breakertt

README.md

@@ -269,9 +269,13 @@ export NO_COLOR=1
 nexttrace --data-provider ip-api.com
 ## Note There are frequency limits for free queries of the ipinfo and IPInsight APIs. You can purchase services from these providers to remove the limits
 ##      If necessary, you can clone this project, add the token provided by ipinfo or IPInsight and compile it yourself
+##      Fill the token to: ipgeo/tokens.go
+
 ## Note For the offline database IPInfoLocal, please download it manually and rename it to ipinfoLocal.mmdb. (You can download it from here: https://ipinfo.io/signup?ref=free-database-downloads)
+##      Current directory, nexttrace binary directory and FHS directories (Unix-like) will be searched.
+##      To customize it, please use environment variables,
+export NEXTTRACE_IPINFOLOCALPATH=/xxx/yyy.mmdb
 ##      For the offline database Ip2region, you can download it manually and rename it to ip2region.db, or let NextTrace download it automatically
-## Fill the token to: ipgeo/tokens.go
 ## Please be aware: Due to the serious abuse of IP.SB, you will often be not able to query IP data from this source
 ## IP-API.com has a stricter restiction on API calls, if you can't query IP data from this source, please try again in a few minutes
 

README_zh_CN.md

@@ -282,11 +282,15 @@ export NO_COLOR=1
 nexttrace --data-provider ip-api.com
 ## 特别的: 其中 ipinfo 和 IPInsight API 对于免费版查询有频率限制，可从这些服务商自行购买服务以解除限制，如有需要可以 clone 本项目添加其提供的 token 自行编译
 ##        TOKEN填写路径：ipgeo/tokens.go
-## 特别的: 对于离线库 IPInfoLocal，请自行下载并命名为 ipinfoLocal.mmdb (可以从这里下载：https://ipinfo.io/signup?ref=free-database-downloads)
+
+## 特别的: 对于离线库 IPInfoLocal，请自行下载并命名为 ipinfoLocal.mmdb
+##        (可以从这里下载：https://ipinfo.io/signup?ref=free-database-downloads)，
+##        默认搜索用户当前路径、程序所在路径、和 FHS 路径（Unix-like）
+##        如果需要自定义路径，请设置环境变量
+export NEXTTRACE_IPINFOLOCALPATH=/xxx/yyy.mmdb
 ##        对于离线库 Ip2region 可NextTrace自动下载，也可自行下载并命名为 ip2region.db
 ## 另外：由于IP.SB被滥用比较严重，会经常出现无法查询的问题，请知悉。
 ##      IP-API.com限制调用较为严格，如有查询不到的情况，请几分钟后再试。
-
 # 纯真IP数据库默认使用 http://127.0.0.1:2060 作为查询接口，如需自定义请使用环境变量
 export NEXTTRACE_CHUNZHENURL=http://127.0.0.1:2060
 ## 可使用 https://github.com/freshcn/qqwry 自行搭建纯真IP数据库服务

ipgeo/ipinfoLocal.go

@@ -2,24 +2,71 @@ package ipgeo
 
 import (
 	"errors"
-	"github.com/oschwald/maxminddb-golang"
 	"net"
 	"os"
+	"path/filepath"
+	"runtime"
 	"strings"
 	"time"
+	
+	"github.com/nxtrace/NTrace-core/util"
+	"github.com/oschwald/maxminddb-golang"
 )
 
 const (
-	ipinfoDataBasePath = "./ipinfoLocal.mmdb"
+	ipinfoDataBaseFilename = "ipinfoLocal.mmdb"
 )
 
+// Cache the path of the ipinfoLocal.mmdb file
+var ipinfoDataBasePath = ""
+
+// We will try to get the path of the ipinfoLocal.mmdb file in the following order:
+// 1. Use the value of the environment variable NEXTTRACE_IPINFOLOCALPATH
+// 2. Search in the current folder and the executable folder
+// 3. Search in /usr/local/share/nexttrace/ and /usr/share/nexttrace/ (for Unix/Linux)
+// If the file is found, the path will be stored in the ipinfoDataBasePath variable
+func getIPInfoLocalPath() (error) {
+	if ipinfoDataBasePath != "" {
+		return nil
+	}
+	// NEXTTRACE_IPINFOLOCALPATH
+	if util.EnvIPInfoLocalPath != "" {
+		if _, err := os.Stat(util.EnvIPInfoLocalPath); err == nil {
+			ipinfoDataBasePath = util.EnvIPInfoLocalPath
+			return nil
+		} else {
+			return errors.New("NEXTTRACE_IPINFOLOCALPATH is set but the file does not exist")
+		}
+	}
+	folders := []string{}
+	// current folder
+	if cur, err := os.Getwd(); err == nil {
+		folders = append(folders, cur + string(filepath.Separator))
+	}
+	// exeutable folder
+	if exe, err := os.Executable(); err == nil {
+		folders = append(folders, filepath.Dir(exe) + string(filepath.Separator))
+	}
+	if runtime.GOOS != "windows" {
+		folders = append(folders, "/usr/local/share/nexttrace/")
+		folders = append(folders, "/usr/share/nexttrace/")
+	}
+	for _, folder := range folders {
+		if _, err := os.Stat(folder + ipinfoDataBaseFilename); err == nil {
+			ipinfoDataBasePath = folder + ipinfoDataBaseFilename
+			return nil
+		}
+	}
+	return errors.New("no ipinfoLocal.mmdb found")
+}
+
 func IPInfoLocal(ip string, _ time.Duration, _ string, _ bool) (*IPGeoData, error) {
-	if _, err := os.Stat(ipinfoDataBasePath); os.IsNotExist(err) {
+	if err := getIPInfoLocalPath(); err != nil {
 		panic("Cannot find ipinfoLocal.mmdb")
 	}
 	region, err := maxminddb.Open(ipinfoDataBasePath)
 	if err != nil {
-		panic("Cannot find ipinfoLocal.mmdb")
+		panic("Cannot open ipinfoLocal.mmdb at " + ipinfoDataBasePath)
 	}
 	defer func(region *maxminddb.Reader) {
 		err := region.Close()

util/util.go

@@ -18,6 +18,7 @@ import (
 
 var Uninterrupted = GetenvDefault("NEXTTRACE_UNINTERRUPTED", "")
 var EnvToken = GetenvDefault("NEXTTRACE_TOKEN", "")
+var EnvIPInfoLocalPath = GetenvDefault("NEXTTRACE_IPINFOLOCALPATH", "")
 var UserAgent = fmt.Sprintf("NextTrace %s/%s/%s", config.Version, runtime.GOOS, runtime.GOARCH)
 var RdnsCache sync.Map
 var PowProviderParam = ""