alist/server/controllers/down.go

package controllers

import (
	"fmt"
	"github.com/Xhofe/alist/conf"
	"github.com/Xhofe/alist/server/common"
	"github.com/Xhofe/alist/utils"
	"github.com/gin-gonic/gin"
	"github.com/go-resty/resty/v2"
	log "github.com/sirupsen/logrus"
	"net/http"
	"net/http/httputil"
	"net/url"
	"os"
	"path/filepath"
	"strings"
)

func Down(c *gin.Context) {
	rawPath := c.Param("path")
	rawPath = utils.ParsePath(rawPath)
	log.Debugf("down: %s", rawPath)
	account, path, driver, err := common.ParsePath(rawPath)
	if err != nil {
		common.ErrorResp(c, err, 500)
		return
	}
	if driver.Config().OnlyProxy || account.Proxy {
		Proxy(c)
		return
	}
	link, err := driver.Link(path, account)
	if err != nil {
		common.ErrorResp(c, err, 500)
		return
	}
	c.Redirect(302, link)
	return
}

func Proxy(c *gin.Context) {
	rawPath := c.Param("path")
	rawPath = utils.ParsePath(rawPath)
	log.Debugf("proxy: %s", rawPath)
	account, path, driver, err := common.ParsePath(rawPath)
	if err != nil {
		common.ErrorResp(c, err, 500)
		return
	}
	// 只有三种情况允许中转：
	// 1. 账号开启中转
	// 2. driver只能中转
	// 3. 是文本类型文件
	if !account.Proxy && !driver.Config().OnlyProxy && utils.GetFileType(filepath.Ext(rawPath)) != conf.TEXT {
		common.ErrorResp(c, fmt.Errorf("[%s] not allowed proxy", account.Name), 403)
		return
	}
	// 中转时有中转机器使用中转机器
	if account.ProxyUrl != "" {
		name := utils.Base(rawPath)
		link := fmt.Sprintf("%s%s?sign=%s", account.ProxyUrl, rawPath, utils.SignWithToken(name, conf.Token))
		c.Redirect(302, link)
		return
	}
	link, err := driver.Link(path, account)
	if err != nil {
		common.ErrorResp(c, err, 500)
		return
	}
	// 本机文件直接返回文件
	if account.Type == "Native" {
		// 对于名称为index.html的文件需要特殊处理
		if utils.Base(rawPath) == "index.html" {
			file, err := os.Open(link)
			if err != nil {
				common.ErrorResp(c, err, 500)
				return
			}
			defer func() {
				_ = file.Close()
			}()
			fileStat, err := os.Stat(link)
			if err != nil {
				common.ErrorResp(c, err, 500)
				return
			}
			http.ServeContent(c.Writer, c.Request, utils.Base(rawPath), fileStat.ModTime(), file)
			return
		}
		c.File(link)
		return
	} else {
		if utils.GetFileType(filepath.Ext(rawPath)) == conf.TEXT {
			Text(c, link)
			return
		}
		driver.Proxy(c, account)
		r := c.Request
		w := c.Writer
		target, err := url.Parse(link)
		if err != nil {
			common.ErrorResp(c, err, 500)
			return
		}
		protocol := "http://"
		if strings.HasPrefix(link, "https://") {
			protocol = "https://"
		}
		targetHost, err := url.Parse(fmt.Sprintf("%s%s", protocol, target.Host))
		proxy := httputil.NewSingleHostReverseProxy(targetHost)
		r.URL = target
		r.Host = target.Host
		proxy.ServeHTTP(w, r)
	}
}

var client *resty.Client

func init() {
	client = resty.New()
	client.SetRetryCount(3)
}

func Text(c *gin.Context, link string) {
	res, err := client.R().Get(link)
	if err != nil {
		common.ErrorResp(c, err, 500)
		return
	}
	text := res.String()
	t := utils.GetStrCoding(res.Body())
	log.Debugf("text type: %s", t)
	if t != utils.UTF8 {
		body, err := utils.GbkToUtf8(res.Body())
		if err != nil {
			common.ErrorResp(c, err, 500)
			return
		}
		text = string(body)
	}
	c.String(200, text)
}