3x-ui/internal/sub/controller.go

package sub

import (
	"bytes"
	"encoding/base64"
	"encoding/json"
	"fmt"
	"html/template"
	"io/fs"
	"net/http"
	"net/url"
	"os"
	"path/filepath"
	"regexp"
	"strings"
	"sync"
	"time"
	"unicode"

	"github.com/gin-gonic/gin"

	"github.com/mhsanaei/3x-ui/v3/internal/logger"
	"github.com/mhsanaei/3x-ui/v3/internal/web/service"
)

// writeSubError translates a service-layer result into an HTTP response.
// A nil error with no rows means the subId doesn't match anything (deleted
// client, never-existed id) and becomes 404. A real error becomes 500. No
// body — VPN clients only look at the status.
func writeSubError(c *gin.Context, err error) {
	if err == nil {
		c.Status(http.StatusNotFound)
		return
	}
	c.Status(http.StatusInternalServerError)
}

// cachedSubTemplate holds a parsed custom subscription template together with
// the modification time of the file it was parsed from, so the cache can be
// invalidated when an admin edits the template on disk.
type cachedSubTemplate struct {
	tmpl    *template.Template
	modTime time.Time
}

// SUBController handles HTTP requests for subscription links and JSON configurations.
type SUBController struct {
	subTitle         string
	subSupportUrl    string
	subProfileUrl    string
	subAnnounce      string
	subEnableRouting bool
	subRoutingRules  string
	subHideSettings  bool

	subIncyEnableRouting bool
	subIncyRoutingRules  string

	subPath            string
	subJsonPath        string
	subClashPath       string
	subClashAutoDetect bool
	clashUserAgent     *regexp.Regexp
	jsonAutoDetect     bool
	jsonUserAgent      *regexp.Regexp
	jsonAlwaysArray    bool
	jsonEnabled        bool
	clashEnabled       bool
	subEncrypt         bool
	updateInterval     string

	subService      *SubService
	subJsonService  *SubJsonService
	subClashService *SubClashService
	settingService  service.SettingService

	subTemplateMu    sync.RWMutex
	subTemplateCache map[string]*cachedSubTemplate
}

type subControllerConfig struct {
	subPath      string
	subJsonPath  string
	subClashPath string

	subClashAutoDetect     bool
	subClashUserAgentRegex string
	subJsonAutoDetect      bool
	subJsonUserAgentRegex  string
	subJsonAlwaysArray     bool
	subJsonEnabled         bool
	subClashEnabled        bool

	subEncrypt     bool
	remarkTemplate string
	updateInterval string

	subJsonMux            string
	subJsonRules          string
	subJsonFinalMask      string
	subClashEnableRouting bool
	subClashRules         string

	subTitle         string
	subSupportURL    string
	subProfileURL    string
	subAnnounce      string
	subEnableRouting bool
	subRoutingRules  string
	subHideSettings  bool

	subIncyEnableRouting bool
	subIncyRoutingRules  string
}

type SUBControllerOption func(*subControllerConfig)

func WithSUBPath(value string) SUBControllerOption {
	return func(config *subControllerConfig) { config.subPath = value }
}

func WithSUBJsonPath(value string) SUBControllerOption {
	return func(config *subControllerConfig) { config.subJsonPath = value }
}

func WithSUBClashPath(value string) SUBControllerOption {
	return func(config *subControllerConfig) { config.subClashPath = value }
}

func WithSUBClashAutoDetect(value bool) SUBControllerOption {
	return func(config *subControllerConfig) { config.subClashAutoDetect = value }
}

func WithSUBClashUserAgentRegex(value string) SUBControllerOption {
	return func(config *subControllerConfig) { config.subClashUserAgentRegex = value }
}

func WithSUBJsonAutoDetect(value bool) SUBControllerOption {
	return func(config *subControllerConfig) { config.subJsonAutoDetect = value }
}

func WithSUBJsonUserAgentRegex(value string) SUBControllerOption {
	return func(config *subControllerConfig) { config.subJsonUserAgentRegex = value }
}

func WithSUBJsonAlwaysArray(value bool) SUBControllerOption {
	return func(config *subControllerConfig) { config.subJsonAlwaysArray = value }
}

func WithSUBJsonEnabled(value bool) SUBControllerOption {
	return func(config *subControllerConfig) { config.subJsonEnabled = value }
}

func WithSUBClashEnabled(value bool) SUBControllerOption {
	return func(config *subControllerConfig) { config.subClashEnabled = value }
}

func WithSUBEncryption(value bool) SUBControllerOption {
	return func(config *subControllerConfig) { config.subEncrypt = value }
}

func WithSUBRemarkTemplate(value string) SUBControllerOption {
	return func(config *subControllerConfig) { config.remarkTemplate = value }
}

func WithSUBUpdateInterval(value string) SUBControllerOption {
	return func(config *subControllerConfig) { config.updateInterval = value }
}

func WithSUBJsonMux(value string) SUBControllerOption {
	return func(config *subControllerConfig) { config.subJsonMux = value }
}

func WithSUBJsonRules(value string) SUBControllerOption {
	return func(config *subControllerConfig) { config.subJsonRules = value }
}

func WithSUBJsonFinalMask(value string) SUBControllerOption {
	return func(config *subControllerConfig) { config.subJsonFinalMask = value }
}

func WithSUBClashEnableRouting(value bool) SUBControllerOption {
	return func(config *subControllerConfig) { config.subClashEnableRouting = value }
}

func WithSUBClashRules(value string) SUBControllerOption {
	return func(config *subControllerConfig) { config.subClashRules = value }
}

func WithSUBTitle(value string) SUBControllerOption {
	return func(config *subControllerConfig) { config.subTitle = value }
}

func WithSUBSupportURL(value string) SUBControllerOption {
	return func(config *subControllerConfig) { config.subSupportURL = value }
}

func WithSUBProfileURL(value string) SUBControllerOption {
	return func(config *subControllerConfig) { config.subProfileURL = value }
}

func WithSUBAnnounce(value string) SUBControllerOption {
	return func(config *subControllerConfig) { config.subAnnounce = value }
}

func WithSUBEnableRouting(value bool) SUBControllerOption {
	return func(config *subControllerConfig) { config.subEnableRouting = value }
}

func WithSUBRoutingRules(value string) SUBControllerOption {
	return func(config *subControllerConfig) { config.subRoutingRules = value }
}

func WithSUBHideSettings(value bool) SUBControllerOption {
	return func(config *subControllerConfig) { config.subHideSettings = value }
}

func WithSUBIncyEnableRouting(value bool) SUBControllerOption {
	return func(config *subControllerConfig) { config.subIncyEnableRouting = value }
}

func WithSUBIncyRoutingRules(value string) SUBControllerOption {
	return func(config *subControllerConfig) { config.subIncyRoutingRules = value }
}

func defaultSUBControllerConfig() subControllerConfig {
	return subControllerConfig{
		subPath:        "/sub/",
		subJsonPath:    "/json/",
		subClashPath:   "/clash/",
		subEncrypt:     true,
		remarkTemplate: service.DefaultRemarkTemplate,
		updateInterval: "12",
	}
}

// NewSUBController creates a new subscription controller with the given configuration.
func NewSUBController(g *gin.RouterGroup, options ...SUBControllerOption) *SUBController {
	config := defaultSUBControllerConfig()
	for _, option := range options {
		option(&config)
	}

	sub := NewSubService(config.remarkTemplate)
	a := &SUBController{
		subTitle:         config.subTitle,
		subSupportUrl:    config.subSupportURL,
		subProfileUrl:    config.subProfileURL,
		subAnnounce:      config.subAnnounce,
		subEnableRouting: config.subEnableRouting,
		subRoutingRules:  config.subRoutingRules,
		subHideSettings:  config.subHideSettings,

		subIncyEnableRouting: config.subIncyEnableRouting,
		subIncyRoutingRules:  config.subIncyRoutingRules,

		subPath:            config.subPath,
		subJsonPath:        config.subJsonPath,
		subClashPath:       config.subClashPath,
		subClashAutoDetect: config.subClashAutoDetect,
		clashUserAgent:     compileUserAgentRegex("Clash/Mihomo", config.subClashUserAgentRegex, service.DefaultSubClashUserAgentRegex),
		jsonAutoDetect:     config.subJsonAutoDetect,
		jsonUserAgent:      compileUserAgentRegex("Xray JSON", config.subJsonUserAgentRegex, service.DefaultSubJsonUserAgentRegex),
		jsonAlwaysArray:    config.subJsonAlwaysArray,
		jsonEnabled:        config.subJsonEnabled,
		clashEnabled:       config.subClashEnabled,
		subEncrypt:         config.subEncrypt,
		updateInterval:     config.updateInterval,

		subService:      sub,
		subJsonService:  NewSubJsonService(config.subJsonMux, config.subJsonRules, config.subJsonFinalMask, sub),
		subClashService: NewSubClashService(config.subClashEnableRouting, config.subClashRules, sub),

		subTemplateCache: map[string]*cachedSubTemplate{},
	}
	a.initRouter(g)
	return a
}

// initRouter registers HTTP routes for subscription links and JSON endpoints
// on the provided router group.
func (a *SUBController) initRouter(g *gin.RouterGroup) {
	gLink := g.Group(a.subPath)
	gLink.GET(":subid", a.subs)
	gLink.HEAD(":subid", a.subs)
	if a.jsonEnabled {
		gJson := g.Group(a.subJsonPath)
		gJson.GET(":subid", a.subJsons)
		gJson.HEAD(":subid", a.subJsons)
	}
	if a.clashEnabled {
		gClash := g.Group(a.subClashPath)
		gClash.GET(":subid", a.subClashs)
		gClash.HEAD(":subid", a.subClashs)
	}
}

// maybeServeSubPage renders the HTML info page when the request comes from a
// browser (Accept: text/html) or explicitly asks for it (?html=1 or ?view=html).
// It reports whether the request was handled. The remark template's per-client
// info is for the content a client app imports — the raw subscription body. A
// browser viewing the HTML info page gets clean, name-only remarks (usage is
// shown in the page summary).
func (a *SUBController) maybeServeSubPage(c *gin.Context) bool {
	accept := c.GetHeader("Accept")
	wantsHTML := strings.Contains(strings.ToLower(accept), "text/html") || c.Query("html") == "1" || strings.EqualFold(c.Query("view"), "html")
	if !wantsHTML {
		return false
	}
	page, ok := a.buildSubPageData(c)
	if !ok {
		return true
	}
	a.serveSubPage(c, page.BasePath, page)
	return true
}

func (a *SUBController) maybeServeSubInfo(c *gin.Context) bool {
	if !strings.EqualFold(c.Query("format"), "info") {
		return false
	}
	page, ok := a.buildSubPageData(c)
	if !ok {
		return true
	}
	info := a.subPageContext(page)
	delete(info, "links")
	info["emails"] = dedupeEmails(page.Emails)
	setNoCacheHeaders(c)
	c.JSON(http.StatusOK, info)
	return true
}

func (a *SUBController) buildSubPageData(c *gin.Context) (PageData, bool) {
	subId := c.Param("subid")
	_, host, _, hostHeader := a.subService.ResolveRequest(c)
	subReq := a.subService.ForRequest(host)
	subReq.subscriptionBody = false
	subs, emails, lastOnline, traffic, err := subReq.getSubs(subId)
	if err != nil || len(subs) == 0 {
		writeSubError(c, err)
		return PageData{}, false
	}
	subURL, subJsonURL, subClashURL := subReq.BuildURLs(a.subPath, a.subJsonPath, a.subClashPath, subId)
	if !a.jsonEnabled {
		subJsonURL = ""
	}
	if !a.clashEnabled {
		subClashURL = ""
	}
	basePath, exists := c.Get("base_path")
	if !exists {
		basePath = "/"
	}
	basePathStr := basePath.(string)
	page := subReq.BuildPageData(subId, hostHeader, traffic, lastOnline, subs, emails, subURL, subJsonURL, subClashURL, basePathStr, a.subTitle, a.subSupportUrl)
	return page, true
}

func dedupeEmails(emails []string) []string {
	out := make([]string, 0, len(emails))
	seen := make(map[string]struct{}, len(emails))
	for _, email := range emails {
		if email == "" {
			continue
		}
		if _, dup := seen[email]; dup {
			continue
		}
		seen[email] = struct{}{}
		out = append(out, email)
	}
	return out
}

// subs handles HTTP requests for subscription links, returning either HTML page or base64-encoded subscription data.
func (a *SUBController) subs(c *gin.Context) {
	userAgent := c.GetHeader("User-Agent")
	if a.maybeServeSubInfo(c) {
		logSubscriptionRoute(userAgent, "info")
		return
	}
	if a.maybeServeSubPage(c) {
		logSubscriptionRoute(userAgent, "html")
		return
	}
	if shouldAutoServeClash(a.subClashAutoDetect, a.clashEnabled, false, userAgent, a.clashUserAgent) && a.serveClashBody(c, false) {
		logSubscriptionRoute(userAgent, "clash")
		return
	}
	if shouldAutoServeJson(a.jsonAutoDetect, a.jsonEnabled, false, userAgent, a.jsonUserAgent) && a.serveJsonBody(c, true, "application/json; charset=utf-8", false) {
		logSubscriptionRoute(userAgent, "json")
		return
	}
	logSubscriptionRoute(userAgent, "raw")
	subId := c.Param("subid")
	scheme, host, hostWithPort, _ := a.subService.ResolveRequest(c)
	subReq := a.subService.ForRequest(host)
	subReq.subscriptionBody = true
	subs, _, _, traffic, err := subReq.getSubs(subId)
	if err != nil || len(subs) == 0 {
		writeSubError(c, err)
	} else {
		var result strings.Builder
		for _, sub := range subs {
			result.WriteString(sub)
			result.WriteString("\n")
		}

		// Add headers
		header := fmt.Sprintf("upload=%d; download=%d; total=%d; expire=%d", traffic.Up, traffic.Down, traffic.Total, traffic.ExpiryTime/1000)
		profileUrl := a.subProfileUrl
		if profileUrl == "" {
			profileUrl = fmt.Sprintf("%s://%s%s", scheme, hostWithPort, c.Request.RequestURI)
		}
		a.ApplyCommonHeaders(c, header, a.updateInterval, a.subTitle, a.subSupportUrl, profileUrl, a.subAnnounce, a.subEnableRouting, a.subRoutingRules, a.subHideSettings)

		if a.subIncyEnableRouting && a.subIncyRoutingRules != "" {
			result.WriteString(a.subIncyRoutingRules)
			result.WriteString("\n")
		}

		if a.subEncrypt {
			c.String(200, base64.StdEncoding.EncodeToString([]byte(result.String())))
		} else {
			c.String(200, result.String())
		}
	}
}

func shouldAutoServeClash(autoDetect, clashEnabled, wantsHTML bool, userAgent string, userAgentRegex *regexp.Regexp) bool {
	return shouldAutoServeFormat(autoDetect, clashEnabled, wantsHTML, userAgent, userAgentRegex)
}

func shouldAutoServeJson(autoDetect, jsonEnabled, wantsHTML bool, userAgent string, userAgentRegex *regexp.Regexp) bool {
	return shouldAutoServeFormat(autoDetect, jsonEnabled, wantsHTML, userAgent, userAgentRegex)
}

func shouldAutoServeFormat(autoDetect, formatEnabled, wantsHTML bool, userAgent string, userAgentRegex *regexp.Regexp) bool {
	if !autoDetect || !formatEnabled || wantsHTML || userAgentRegex == nil {
		return false
	}
	return userAgentRegex.MatchString(userAgent)
}

func logSubscriptionRoute(userAgent, branch string) {
	logger.Debugf("Subscription request routed: branch=%s user_agent=%q", branch, sanitizeUserAgentForLog(userAgent))
}

func sanitizeUserAgentForLog(userAgent string) string {
	clean := strings.Map(func(r rune) rune {
		if unicode.IsControl(r) {
			return ' '
		}
		return r
	}, userAgent)
	runes := []rune(clean)
	if len(runes) > 512 {
		return string(runes[:512])
	}
	return clean
}

func compileUserAgentRegex(name, pattern, defaultPattern string) *regexp.Regexp {
	pattern = strings.TrimSpace(pattern)
	if pattern == "" {
		pattern = strings.TrimSpace(defaultPattern)
	}
	if pattern == "" {
		return nil
	}
	compiled, err := regexp.Compile(pattern)
	if err == nil {
		return compiled
	}
	logger.Warningf("Invalid %s User-Agent regex %q; falling back to default %q: %v", name, pattern, defaultPattern, err)
	if strings.TrimSpace(defaultPattern) == "" {
		return nil
	}
	return regexp.MustCompile(defaultPattern)
}

// serveSubPage renders internal/web/dist/subpage.html for the current subscription
// request. The Vite-built SPA reads window.__SUB_PAGE_DATA__ on mount —
// we inject that here, along with window.X_UI_BASE_PATH so the
// page's static asset references resolve correctly when the panel runs
// behind a URL prefix.
func (a *SUBController) serveSubPage(c *gin.Context, basePath string, page PageData) {
	var body []byte
	if diskBody, diskErr := os.ReadFile("internal/web/dist/subpage.html"); diskErr == nil {
		body = diskBody
	} else {
		readBody, err := fs.ReadFile(distFS, "dist/subpage.html")
		if err != nil {
			c.String(http.StatusInternalServerError, "missing embedded subpage")
			return
		}
		body = readBody
	}

	// Vite emits absolute asset URLs (`/assets/...`); when the panel is
	// installed under a custom URL prefix, rewrite them so the bundle
	// loads from `<basePath>assets/...` where the static handler is
	// actually mounted.
	if basePath != "/" && basePath != "" {
		body = bytes.ReplaceAll(body, []byte(`src="/assets/`), []byte(`src="`+basePath+`assets/`))
		body = bytes.ReplaceAll(body, []byte(`href="/assets/`), []byte(`href="`+basePath+`assets/`))
	}

	subData := a.subPageContext(page)

	// When an admin has configured a custom subscription theme, render it
	// instead of the default SPA. We render into a buffer first so a template
	// that fails mid-execution can't leave a partially-written (corrupt)
	// response — on any error we log and fall through to the default page.
	if themeDir, _ := a.settingService.GetSubThemeDir(); themeDir != "" {
		if tmpl, err := a.loadSubTemplate(themeDir); err != nil {
			logger.Error("sub: custom template parse failed, using default page:", err)
		} else if tmpl == nil {
			logger.Warning("sub: subThemeDir set but no usable template found, using default page:", themeDir)
		} else {
			var buf bytes.Buffer
			if execErr := tmpl.Execute(&buf, subData); execErr != nil {
				logger.Error("sub: custom template execution failed, using default page:", execErr)
			} else {
				setNoCacheHeaders(c)
				c.Data(http.StatusOK, "text/html; charset=utf-8", buf.Bytes())
				return
			}
		}
	}

	subDataJSON, err := json.Marshal(subData)
	if err != nil {
		subDataJSON = []byte("{}")
	}

	// Defense-in-depth string-escape for the basePath embed — admin-
	// controlled but cheap to harden.
	jsEscape := strings.NewReplacer(
		`\`, `\\`,
		`"`, `\"`,
		"\n", `\n`,
		"\r", `\r`,
		"<", `<`,
		">", `>`,
		"&", `&`,
	)
	escapedBase := jsEscape.Replace(basePath)

	inject := []byte(`<script>window.X_UI_BASE_PATH="` + escapedBase + `";` +
		`window.__SUB_PAGE_DATA__=` + string(subDataJSON) + `;</script></head>`)
	out := bytes.Replace(body, []byte("</head>"), inject, 1)

	setNoCacheHeaders(c)
	c.Data(http.StatusOK, "text/html; charset=utf-8", out)
}

// subPageContext builds the shared view-model map: the template context for
// custom sub themes, the window.__SUB_PAGE_DATA__ payload the SPA reads, and
// (without links) the ?format=info JSON body. The panel's "Calendar Type"
// setting decides whether dates render Gregorian or Jalali — surfaced here so
// consumers match the rest of the panel without a round-trip.
func (a *SUBController) subPageContext(page PageData) map[string]any {
	datepicker, _ := a.settingService.GetDatepicker()
	if datepicker == "" {
		datepicker = "gregorian"
	}

	return map[string]any{
		"sId":           page.SId,
		"enabled":       page.Enabled,
		"isOnline":      page.IsOnline,
		"download":      page.Download,
		"upload":        page.Upload,
		"total":         page.Total,
		"used":          page.Used,
		"remained":      page.Remained,
		"expire":        page.Expire,
		"lastOnline":    page.LastOnline,
		"downloadByte":  page.DownloadByte,
		"uploadByte":    page.UploadByte,
		"totalByte":     page.TotalByte,
		"subUrl":        page.SubUrl,
		"subJsonUrl":    page.SubJsonUrl,
		"subClashUrl":   page.SubClashUrl,
		"subTitle":      page.SubTitle,
		"subSupportUrl": page.SubSupportUrl,
		"links":         page.Result,
		"emails":        page.Emails,
		"datepicker":    datepicker,
		"announce":      a.subAnnounce,
	}
}

// setNoCacheHeaders marks a subscription page response as non-cacheable so VPN
// clients and browsers always fetch fresh traffic/expiry data.
func setNoCacheHeaders(c *gin.Context) {
	c.Header("Cache-Control", "no-cache, no-store, must-revalidate")
	c.Header("Pragma", "no-cache")
	c.Header("Expires", "0")
}

// loadSubTemplate returns the parsed custom subscription template located in
// themeDir, preferring sub.html over index.html. Parsed templates are cached and
// only re-parsed when the underlying file's modification time changes, so admin
// edits are picked up without paying a disk read + HTML parse on every request.
//
// It returns (nil, nil) when themeDir is not a usable directory or contains no
// template file — the caller should fall back to the default page. A non-nil
// error means a template file exists but failed to parse.
func (a *SUBController) loadSubTemplate(themeDir string) (*template.Template, error) {
	info, err := os.Stat(themeDir)
	if err != nil || !info.IsDir() {
		return nil, nil
	}

	templatePath := filepath.Join(themeDir, "index.html")
	if _, err := os.Stat(filepath.Join(themeDir, "sub.html")); err == nil {
		templatePath = filepath.Join(themeDir, "sub.html")
	}

	fi, err := os.Stat(templatePath)
	if err != nil {
		return nil, nil
	}
	modTime := fi.ModTime()

	a.subTemplateMu.RLock()
	cached := a.subTemplateCache[templatePath]
	a.subTemplateMu.RUnlock()
	if cached != nil && cached.modTime.Equal(modTime) {
		return cached.tmpl, nil
	}

	tmpl, err := template.ParseFiles(templatePath)
	if err != nil {
		return nil, err
	}

	a.subTemplateMu.Lock()
	a.subTemplateCache[templatePath] = &cachedSubTemplate{tmpl: tmpl, modTime: modTime}
	a.subTemplateMu.Unlock()
	return tmpl, nil
}

// subJsons handles HTTP requests for JSON subscription configurations.
func (a *SUBController) subJsons(c *gin.Context) {
	if strings.EqualFold(c.Query("view"), "raw") {
		if !a.serveJsonBody(c, a.jsonAlwaysArray, "application/json; charset=utf-8", true) {
			writeSubError(c, nil)
		}
		return
	}
	if a.maybeServeSubPage(c) {
		return
	}
	a.serveJson(c, a.jsonAlwaysArray, "text/plain; charset=utf-8")
}

func (a *SUBController) serveJson(c *gin.Context, alwaysReturnArray bool, contentType string) {
	if !a.serveJsonBody(c, alwaysReturnArray, contentType, false) {
		writeSubError(c, nil)
	}
}

func (a *SUBController) serveJsonBody(c *gin.Context, alwaysReturnArray bool, contentType string, rawDownload bool) bool {
	subId := c.Param("subid")
	scheme, host, hostWithPort, _ := a.subService.ResolveRequest(c)
	jsonSub, header, err := a.subJsonService.GetJson(subId, host, alwaysReturnArray)
	if err != nil {
		writeSubError(c, err)
		return true
	}
	if len(jsonSub) == 0 {
		return false
	}
	profileUrl := a.subProfileUrl
	if profileUrl == "" {
		profileUrl = fmt.Sprintf("%s://%s%s", scheme, hostWithPort, c.Request.RequestURI)
	}
	a.ApplyCommonHeaders(c, header, a.updateInterval, a.subTitle, a.subSupportUrl, profileUrl, a.subAnnounce, a.subEnableRouting, a.subRoutingRules, a.subHideSettings)
	if rawDownload {
		c.Writer.Header().Set("Content-Disposition", `attachment; filename="subscription.json"`)
	}

	c.Data(200, contentType, []byte(jsonSub))
	return true
}

func (a *SUBController) subClashs(c *gin.Context) {
	if strings.EqualFold(c.Query("view"), "raw") {
		if !a.serveClashBody(c, true) {
			writeSubError(c, nil)
		}
		return
	}
	if a.maybeServeSubPage(c) {
		return
	}
	if !a.serveClashBody(c, false) {
		writeSubError(c, nil)
	}
}

func (a *SUBController) serveClashBody(c *gin.Context, rawDownload bool) bool {
	subId := c.Param("subid")
	scheme, host, hostWithPort, _ := a.subService.ResolveRequest(c)
	clashSub, header, err := a.subClashService.GetClash(subId, host)
	if err != nil {
		writeSubError(c, err)
		return true
	}
	if len(clashSub) == 0 {
		return false
	}
	profileUrl := a.subProfileUrl
	if profileUrl == "" {
		profileUrl = fmt.Sprintf("%s://%s%s", scheme, hostWithPort, c.Request.RequestURI)
	}
	a.ApplyCommonHeaders(c, header, a.updateInterval, a.subTitle, a.subSupportUrl, profileUrl, a.subAnnounce, a.subEnableRouting, a.subRoutingRules, a.subHideSettings)
	if rawDownload {
		c.Writer.Header().Set("Content-Disposition", `attachment; filename="subscription.yaml"`)
	} else if a.subTitle != "" {
		// Clash clients commonly use Content-Disposition to choose the imported profile name.
		c.Writer.Header().Set("Content-Disposition", fmt.Sprintf(`attachment; filename*=UTF-8''%s`, url.PathEscape(a.subTitle)))
	}
	c.Data(200, "application/yaml; charset=utf-8", []byte(clashSub))
	return true
}

// ApplyCommonHeaders sets common HTTP headers for subscription responses including user info, update interval, and profile title.
func (a *SUBController) ApplyCommonHeaders(
	c *gin.Context,
	header,
	updateInterval,
	profileTitle string,
	profileSupportUrl string,
	profileUrl string,
	profileAnnounce string,
	profileEnableRouting bool,
	profileRoutingRules string,
	profileHideSettings bool,
) {
	c.Writer.Header().Set("Subscription-Userinfo", header)
	c.Writer.Header().Set("Profile-Update-Interval", updateInterval)

	// Basics
	if profileTitle != "" {
		c.Writer.Header().Set("Profile-Title", "base64:"+base64.StdEncoding.EncodeToString([]byte(profileTitle)))
	}
	if profileSupportUrl != "" {
		c.Writer.Header().Set("Support-Url", profileSupportUrl)
	}
	if profileUrl != "" {
		c.Writer.Header().Set("Profile-Web-Page-Url", profileUrl)
	}
	if profileAnnounce != "" {
		c.Writer.Header().Set("Announce", "base64:"+base64.StdEncoding.EncodeToString([]byte(profileAnnounce)))
	}

	// Advanced (Happ)
	if profileEnableRouting {
		c.Writer.Header().Set("Routing-Enable", "true")
	}
	if profileRoutingRules != "" {
		c.Writer.Header().Set("Routing", profileRoutingRules)
	}
	if profileHideSettings {
		c.Writer.Header().Set("Hide-Settings", "1")
	}
}