refactor(middleware): replace path prefix checks with function-based approach

Replace simple path prefix-based enforcement/bypass mechanism with a more
flexible function-based approach. This allows for more complex conditions
to determine when middleware should be enforced or bypassed.

- Add checkReqFunc and checkRespFunc types for flexible condition checking
- Replace enforcedPathPrefixes with separate enforce and bypass check functions
- Add static asset path detection for automatic bypassing
- Separate request and response check logic for better granularity

internal/net/gphttp/middleware/bypass.go

@@ -2,16 +2,19 @@ package middleware
 
 import (
 	"net/http"
-	"strings"
 
 	"github.com/rs/zerolog/log"
-	"github.com/yusing/godoxy/internal/auth"
 	"github.com/yusing/godoxy/internal/route/rules"
 	httputils "github.com/yusing/goutils/http"
 )
 
 type Bypass []rules.RuleOn
 
+type (
+	checkReqFunc  func(r *http.Request) bool
+	checkRespFunc func(resp *http.Response) bool
+)
+
 func (b Bypass) ShouldBypass(w http.ResponseWriter, r *http.Request) bool {
 	for _, rule := range b {
 		if rule.Check(w, r) {
@@ -29,32 +32,93 @@ type checkBypass struct {
 	modReq RequestModifier
 	modRes ResponseModifier
 
-	// when request path matches any of these prefixes, bypass is not applied
-	enforcedPathPrefixes []string
+	modReqCheckEnforceFuncs []checkReqFunc
+	modReqCheckBypassFuncs  []checkReqFunc
+
+	modResCheckEnforceFuncs []checkRespFunc
+	modResCheckBypassFuncs  []checkRespFunc
 }
 
-func (c *checkBypass) isEnforced(r *http.Request) bool {
-	for _, prefix := range c.enforcedPathPrefixes {
-		if strings.HasPrefix(r.URL.Path, prefix) {
+var (
+	_ RequestModifier  = (*checkBypass)(nil)
+	_ ResponseModifier = (*checkBypass)(nil)
+)
+
+// shouldModReqEnforce checks if the modify request should be enforced.
+//
+// Returns true if any of the check functions returns true.
+func (c *checkBypass) shouldModReqEnforce(r *http.Request) bool {
+	for _, f := range c.modReqCheckEnforceFuncs {
+		if f(r) {
 			return true
 		}
 	}
 	return false
 }
 
+// shouldModResEnforce checks if the modify response should be enforced.
+//
+// Returns true if any of the check functions returns true.
+func (c *checkBypass) shouldModResEnforce(resp *http.Response) bool {
+	for _, f := range c.modResCheckEnforceFuncs {
+		if f(resp) {
+			return true
+		}
+	}
+	return false
+}
+
+// shouldModReqBypass checks if the modify request should be bypassed.
+//
+// If enforce checks return true, the bypass checks are not performed.
+// Otherwise, if any of the bypass checks returns true
+// or user defined bypass rules return true, the request is bypassed.
+func (c *checkBypass) shouldModReqBypass(w http.ResponseWriter, r *http.Request) bool {
+	if c.shouldModReqEnforce(r) {
+		return false
+	}
+	for _, f := range c.modReqCheckBypassFuncs {
+		if f(r) {
+			return true
+		}
+	}
+	return c.bypass.ShouldBypass(w, r)
+}
+
+// shouldModResBypass checks if the modify response should be bypassed.
+//
+// If enforce checks return true, the bypass checks are not performed.
+// Otherwise, if any of the bypass checks returns true
+// or user defined bypass rules return true, the response is bypassed.
+func (c *checkBypass) shouldModResBypass(resp *http.Response) bool {
+	if c.shouldModResEnforce(resp) {
+		return false
+	}
+	for _, f := range c.modResCheckBypassFuncs {
+		if f(resp) {
+			return true
+		}
+	}
+	return c.bypass.ShouldBypass(httputils.ResponseAsRW(resp), resp.Request)
+}
+
+// before modifies the request if the request should be modified.
+//
+// Returns true if the request is not done, false otherwise.
 func (c *checkBypass) before(w http.ResponseWriter, r *http.Request) (proceedNext bool) {
-	if c.modReq == nil || (!c.isEnforced(r) && c.bypass.ShouldBypass(w, r)) {
+	if c.modReq == nil || c.shouldModReqBypass(w, r) {
 		return true
 	}
-	log.Debug().Str("middleware", c.name).Str("url", r.Host+r.URL.Path).Msg("modifying request")
+	// log.Debug().Str("middleware", c.name).Str("url", r.Host+r.URL.Path).Msg("modifying request")
 	return c.modReq.before(w, r)
 }
 
+// modifyResponse modifies the response if the response should be modified.
 func (c *checkBypass) modifyResponse(resp *http.Response) error {
-	if c.modRes == nil || (!c.isEnforced(resp.Request) && c.bypass.ShouldBypass(httputils.ResponseAsRW(resp), resp.Request)) {
+	if c.modRes == nil || c.shouldModResBypass(resp) {
 		return nil
 	}
-	log.Debug().Str("middleware", c.name).Str("url", resp.Request.Host+resp.Request.URL.Path).Msg("modifying response")
+	// log.Debug().Str("middleware", c.name).Str("url", resp.Request.Host+resp.Request.URL.Path).Msg("modifying response")
 	return c.modRes.modifyResponse(resp)
 }
 
@@ -63,23 +127,46 @@ func (m *Middleware) withCheckBypass() any {
 		modReq, _ := m.impl.(RequestModifier)
 		modRes, _ := m.impl.(ResponseModifier)
 		return &checkBypass{
-			name:                 m.Name(),
-			bypass:               m.Bypass,
-			enforcedPathPrefixes: getEnforcedPathPrefixes(modReq, modRes),
-			modReq:               modReq,
-			modRes:               modRes,
+			name:                    m.Name(),
+			bypass:                  m.Bypass,
+			modReq:                  modReq,
+			modRes:                  modRes,
+			modReqCheckEnforceFuncs: getModReqCheckEnforceFuncs(modReq),
+			modReqCheckBypassFuncs:  getModReqCheckBypassFuncs(modReq),
+			modResCheckEnforceFuncs: getModResCheckEnforceFuncs(modRes),
+			modResCheckBypassFuncs:  getModResCheckBypassFuncs(modRes),
 		}
 	}
 	return m.impl
 }
 
-func getEnforcedPathPrefixes(modReq RequestModifier, modRes ResponseModifier) []string {
-	if modReq == nil && modRes == nil {
+func getModReqCheckEnforceFuncs(modReq RequestModifier) (checks []checkReqFunc) {
+	if modReq == nil {
+		return nil
+	}
+	if _, ok := modReq.(*oidcMiddleware); ok {
+		checks = append(checks, isOIDCAuthPath)
+	}
+	return checks
+}
+
+func getModReqCheckBypassFuncs(modReq RequestModifier) (checks []checkReqFunc) {
+	if modReq == nil {
 		return nil
 	}
 	switch modReq.(type) {
-	case *oidcMiddleware:
-		return []string{auth.OIDCAuthBasePath}
+	case *oidcMiddleware, *forwardAuthMiddleware, *crowdsecMiddleware, *hCaptcha:
+		checks = append(checks, isStaticAssetPath)
 	}
+	return checks
+}
+
+func getModResCheckEnforceFuncs(modRes ResponseModifier) []checkRespFunc {
+	// TODO: add enforce checks for response modifiers if needed.
+	return nil
+}
+
+func getModResCheckBypassFuncs(modRes ResponseModifier) []checkRespFunc {
+	// TODO: add bypass checks for response modifiers if needed.
 	return nil
 }

internal/net/gphttp/middleware/bypass_static.go

@@ -0,0 +1,74 @@
+package middleware
+
+import (
+	"net/http"
+
+	"github.com/yusing/godoxy/internal/route/rules"
+)
+
+func must[T any](v T, err error) T {
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+var staticAssetsPaths = map[string]struct{}{
+	// Web app manifests
+	"/manifest.json":        {},
+	"/manifest.webmanifest": {},
+	// Service workers
+	"/sw.js":         {},
+	"/registerSW.js": {},
+	// Favicons
+	"/favicon.ico": {},
+	"/favicon.png": {},
+	"/favicon.svg": {},
+	// Apple icons
+	"/apple-icon.png":                   {},
+	"/apple-touch-icon.png":             {},
+	"/apple-touch-icon-precomposed.png": {},
+	// Microsoft / browser config
+	"/browserconfig.xml": {},
+	// Safari pinned tab
+	"/safari-pinned-tab.svg": {},
+	// Crawlers / SEO
+	"/robots.txt":        {},
+	"/sitemap.xml":       {},
+	"/sitemap_index.xml": {},
+	"/ads.txt":           {},
+}
+
+var staticAssetsGlobs = []rules.Matcher{
+	// Workbox (PWA)
+	must(rules.GlobMatcher("/workbox-window.prod.es5-*.js", false)),
+	must(rules.GlobMatcher("/workbox-*.js", false)),
+	// Favicon variants (e.g. favicon-32x32.png)
+	must(rules.GlobMatcher("/favicon-*.png", false)),
+	// Web app manifest icons
+	must(rules.GlobMatcher("/web-app-manifest-*.png", false)),
+	// Android Chrome icons
+	must(rules.GlobMatcher("/android-chrome-*.png", false)),
+	// Apple touch icon variants
+	must(rules.GlobMatcher("/apple-touch-icon-*.png", false)),
+	// Microsoft tile icons
+	must(rules.GlobMatcher("/mstile-*.png", false)),
+	// Generic PWA / app icons
+	must(rules.GlobMatcher("/pwa-*.png", false)),
+	must(rules.GlobMatcher("/icon-*.png", false)),
+	// Sitemaps (e.g. sitemap-1.xml, sitemap-posts.xml)
+	must(rules.GlobMatcher("/sitemap-*.xml", false)),
+}
+
+func isStaticAssetPath(r *http.Request) bool {
+	if _, ok := staticAssetsPaths[r.URL.Path]; ok {
+		return true
+	}
+
+	for _, matcher := range staticAssetsGlobs {
+		if matcher(r.URL.Path) {
+			return true
+		}
+	}
+	return false
+}

internal/net/gphttp/middleware/oidc.go

@@ -28,6 +28,10 @@ type oidcMiddleware struct {
 
 var OIDC = NewMiddleware[oidcMiddleware]()
 
+func isOIDCAuthPath(r *http.Request) bool {
+	return strings.HasPrefix(r.URL.Path, auth.OIDCAuthBasePath)
+}
+
 func (amw *oidcMiddleware) finalize() error {
 	if !auth.IsOIDCEnabled() {
 		log.Error().Msg("OIDC not enabled but OIDC middleware is used")