From 722dab5286a001a0bd367d42258a8613a944e1c1 Mon Sep 17 00:00:00 2001 From: wxiaoguang Date: Thu, 20 Apr 2023 16:08:58 +0800 Subject: Make HTML template functions support context (#24056) # Background Golang template is not friendly for large projects, and Golang template team is quite slow, related: * `https://github.com/golang/go/issues/54450` Without upstream support, we can also have our solution to make HTML template functions support context. It helps a lot, the above Golang template issue `#54450` explains a lot: 1. It makes `{{Locale.Tr}}` could be used in any template, without passing unclear `(dict "root" . )` anymore. 2. More and more functions need `context`, like `avatar`, etc, we do not need to do `(dict "Context" $.Context)` anymore. 3. Many request-related functions could be shared by parent&children templates, like "user setting" / "system setting" See the test `TestScopedTemplateSetFuncMap`, one template set, two `Execute` calls with different `CtxFunc`. # The Solution Instead of waiting for upstream, this PR re-uses the escaped HTML template trees, use `AddParseTree` to add related templates/trees to a new template instance, then the new template instance can have its own FuncMap , the function calls in the template trees will always use the new template's FuncMap. `template.New` / `template.AddParseTree` / `adding-FuncMap` are all quite fast, so the performance is not affected. The details: 1. Make a new `html/template/Template` for `all` templates 2. Add template code to the `all` template 3. Freeze the `all` template, reset its exec func map, it shouldn't execute any template. 4. When a router wants to render a template by its `name` 1. Find the `name` in `all` 2. Find all its related sub templates 3. Escape all related templates (just like what the html template package does) 4. Add the escaped parse-trees of related templates into a new (scoped) `text/template/Template` 5. Add context-related func map into the new (scoped) text template 6. Execute the new (scoped) text template 7. To improve performance, the escaped templates are cached to `template sets` # FAQ ## There is a `unsafe` call, is this PR unsafe? This PR is safe. Golang has strict language definition, it's safe to do so: https://pkg.go.dev/unsafe#Pointer (1) Conversion of a *T1 to Pointer to *T2 ## What if Golang template supports such feature in the future? The public structs/interfaces/functions introduced by this PR is quite simple, the code of `HTMLRender` is not changed too much. It's very easy to switch to the official mechanism if there would be one. ## Does this PR change the template execution behavior? No, see the tests (welcome to design more tests if it's necessary) --------- Co-authored-by: silverwind Co-authored-by: Jason Song Co-authored-by: Giteabot --- modules/test/context_tests.go | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'modules/test') diff --git a/modules/test/context_tests.go b/modules/test/context_tests.go index e558bf1b9f..4af7651250 100644 --- a/modules/test/context_tests.go +++ b/modules/test/context_tests.go @@ -5,7 +5,6 @@ package test import ( scontext "context" - "html/template" "io" "net/http" "net/http/httptest" @@ -18,6 +17,7 @@ import ( user_model "code.gitea.io/gitea/models/user" "code.gitea.io/gitea/modules/context" "code.gitea.io/gitea/modules/git" + "code.gitea.io/gitea/modules/templates" "code.gitea.io/gitea/modules/translation" "code.gitea.io/gitea/modules/web/middleware" @@ -120,7 +120,7 @@ func (rw *mockResponseWriter) Push(target string, opts *http.PushOptions) error type mockRender struct{} -func (tr *mockRender) TemplateLookup(tmpl string) (*template.Template, error) { +func (tr *mockRender) TemplateLookup(tmpl string) (templates.TemplateExecutor, error) { return nil, nil } -- cgit v1.2.3