初始提交: Gitea 项目代码

services/context/context_template.go

@@ -0,0 +1,141 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package context
+
+import (
+	"context"
+	"html"
+	"html/template"
+	"net/http"
+	"strconv"
+	"strings"
+	"time"
+
+	"gitea.dev/modules/httplib"
+	"gitea.dev/modules/public"
+	"gitea.dev/modules/setting"
+	"gitea.dev/modules/util"
+	"gitea.dev/modules/web/middleware"
+	"gitea.dev/services/webtheme"
+)
+
+type TemplateContext map[string]any
+
+var _ context.Context = TemplateContext(nil)
+
+func NewTemplateContext(ctx context.Context, req *http.Request) TemplateContext {
+	return TemplateContext{"_ctx": ctx, "_req": req}
+}
+
+func (c TemplateContext) req() *http.Request {
+	return c["_req"].(*http.Request)
+}
+
+func (c TemplateContext) parentContext() context.Context {
+	return c["_ctx"].(context.Context)
+}
+
+func (c TemplateContext) Deadline() (deadline time.Time, ok bool) {
+	return c.parentContext().Deadline()
+}
+
+func (c TemplateContext) Done() <-chan struct{} {
+	return c.parentContext().Done()
+}
+
+func (c TemplateContext) Err() error {
+	return c.parentContext().Err()
+}
+
+func (c TemplateContext) Value(key any) any {
+	return c.parentContext().Value(key)
+}
+
+func (c TemplateContext) CurrentWebTheme() *webtheme.ThemeMetaInfo {
+	var themeName string
+	if webCtx := GetWebContext(c); webCtx != nil {
+		if webCtx.Doer != nil {
+			themeName = webCtx.Doer.Theme
+		}
+	}
+	if themeName == "" {
+		themeName = middleware.GetSiteCookie(c.req(), middleware.CookieTheme)
+	}
+	return webtheme.GuaranteeGetThemeMetaInfo(themeName)
+}
+
+func (c TemplateContext) CurrentWebBanner() *setting.WebBannerType {
+	// Using revision as a simple approach to determine if the banner has been changed after the user dismissed it.
+	// There could be some false-positives because revision can be changed even if the banner isn't.
+	// While it should be still good enough (no admin would keep changing the settings) and doesn't really harm end users (just a few more times to see the banner)
+	// So it doesn't need to make it more complicated by allocating unique IDs or using hashes.
+	dismissedBannerRevision, _ := strconv.Atoi(middleware.GetSiteCookie(c.req(), middleware.CookieWebBannerDismissed))
+	banner, revision, _ := setting.Config().Instance.WebBanner.ValueRevision(c)
+	if banner.ShouldDisplay() && dismissedBannerRevision != revision {
+		return &banner
+	}
+	return nil
+}
+
+// AppFullLink returns a full URL link with AppSubURL for the given app link (no AppSubURL)
+// If no link is given, it returns the current app full URL with sub-path but without trailing slash (that's why it is not named as AppURL)
+func (c TemplateContext) AppFullLink(link ...string) template.URL {
+	s := httplib.GuessCurrentAppURL(c.parentContext())
+	s = strings.TrimSuffix(s, "/")
+	if len(link) == 0 {
+		return template.URL(s)
+	}
+	return template.URL(s + "/" + strings.TrimPrefix(link[0], "/"))
+}
+
+func (c TemplateContext) ScriptImport(path string, typ ...string) template.HTML {
+	if len(typ) > 0 {
+		if typ[0] == "module" {
+			return template.HTML(`<script nonce="` + c.CspScriptNonce() + `" type="module" src="` + html.EscapeString(public.AssetURI(path)) + `"></script>`)
+		}
+		panic("unsupported script type: " + typ[0])
+	}
+	return template.HTML(`<script nonce="` + c.CspScriptNonce() + `" src="` + html.EscapeString(public.AssetURI(path)) + `"></script>`)
+}
+
+func (c TemplateContext) CspScriptNonce() (ret string) {
+	// Generate a random nonce for each request and cache it in the context to make it usable during the whole rendering process.
+	//
+	// Some "<script>" tags are not in the CSP context, so they don't need nonce,
+	// these tags are written as "<script nonce>" to help developers to know that "no script nonce attribute is missing"
+	// (e.g.: when they grep the codebase for "script" tags)
+
+	ret, _ = c["_cspScriptNonce"].(string)
+	if ret == "" {
+		ret = util.FastCryptoRandomHex(32) // 16 bytes / 128 bits entropy
+		c["_cspScriptNonce"] = ret
+	}
+	return ret
+}
+
+func (c TemplateContext) HeadMetaContentSecurityPolicy() template.HTML {
+	// The CSP problem is more complicated than it looks.
+	// Gitea was designed to support various "customizations", including:
+	// * custom themes (custom CSS and JS)
+	// * custom assets URL (CDN)
+	// * custom plugins and external renders (e.g.: PlantUML render, and the renders might also load some JS/CSS assets)
+	// There is no easy way for end users to make the CSP "source" completely right.
+	//
+	// There can be 2 approaches in the future:
+	// A. Let end users to configure their reverse proxy to add CSP header
+	//    * Browsers will merge and use the stricter rules between Gitea and reverse proxy
+	// B. Introduce some config options in "app.ini"
+	//    * Maybe this approach should be avoided, don't make the config system too complex, just let users use A
+	return template.HTML(`<meta http-equiv="Content-Security-Policy" content="` +
+		// allow all by default (the same as old releases with no CSP)
+		// maybe some images or markup (external) renders need "data:", need to investigate
+		`default-src * data:;` +
+
+		// enforce nonce for all scripts, disallow inline scripts
+		`script-src * 'nonce-` + c.CspScriptNonce() + `';` +
+
+		// it seems that Vue needs the unsafe-inline, and our custom colors (e.g.: label) also need it
+		`style-src * 'unsafe-inline';` +
+		`">`)
+}