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gitea/templates/repo
Lunny Xiao bd820aa9c5
Add context cache as a request level cache (#22294)
To avoid duplicated load of the same data in an HTTP request, we can set
a context cache to do that. i.e. Some pages may load a user from a
database with the same id in different areas on the same page. But the
code is hidden in two different deep logic. How should we share the
user? As a result of this PR, now if both entry functions accept
`context.Context` as the first parameter and we just need to refactor
`GetUserByID` to reuse the user from the context cache. Then it will not
be loaded twice on an HTTP request.

But of course, sometimes we would like to reload an object from the
database, that's why `RemoveContextData` is also exposed.

The core context cache is here. It defines a new context
```go
type cacheContext struct {
	ctx  context.Context
	data map[any]map[any]any
        lock sync.RWMutex
}

var cacheContextKey = struct{}{}

func WithCacheContext(ctx context.Context) context.Context {
	return context.WithValue(ctx, cacheContextKey, &cacheContext{
		ctx:  ctx,
		data: make(map[any]map[any]any),
	})
}
```

Then you can use the below 4 methods to read/write/del the data within
the same context.

```go
func GetContextData(ctx context.Context, tp, key any) any
func SetContextData(ctx context.Context, tp, key, value any)
func RemoveContextData(ctx context.Context, tp, key any)
func GetWithContextCache[T any](ctx context.Context, cacheGroupKey string, cacheTargetID any, f func() (T, error)) (T, error)
```

Then let's take a look at how `system.GetString` implement it.

```go
func GetSetting(ctx context.Context, key string) (string, error) {
	return cache.GetWithContextCache(ctx, contextCacheKey, key, func() (string, error) {
		return cache.GetString(genSettingCacheKey(key), func() (string, error) {
			res, err := GetSettingNoCache(ctx, key)
			if err != nil {
				return "", err
			}
			return res.SettingValue, nil
		})
	})
}
```

First, it will check if context data include the setting object with the
key. If not, it will query from the global cache which may be memory or
a Redis cache. If not, it will get the object from the database. In the
end, if the object gets from the global cache or database, it will be
set into the context cache.

An object stored in the context cache will only be destroyed after the
context disappeared.
2 years ago
..
actions Move helpers to be prefixed with `gt-` (#22879) 2 years ago
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cite Copy citation file content, in APA and BibTex format, on repo home page (#19999) 2 years ago
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wiki Move helpers to be prefixed with `gt-` (#22879) 2 years ago
activity.tmpl Add main landmark to templates and adjust titles (#22670) 2 years ago
blame.tmpl Move helpers to be prefixed with `gt-` (#22879) 2 years ago
branch_dropdown.tmpl Move helpers to be prefixed with `gt-` (#22879) 2 years ago
clone_buttons.tmpl Move helpers to be prefixed with `gt-` (#22879) 2 years ago
clone_script.tmpl Make clone URL use current page's host (#22808) 2 years ago
commit_page.tmpl Add context cache as a request level cache (#22294) 2 years ago
commit_status.tmpl Change commit status icons to SVG (#20736) 3 years ago
commit_statuses.tmpl Move helpers to be prefixed with `gt-` (#22879) 2 years ago
commits.tmpl Move helpers to be prefixed with `gt-` (#22879) 2 years ago
commits_list.tmpl Add context cache as a request level cache (#22294) 2 years ago
commits_list_small.tmpl Add context cache as a request level cache (#22294) 2 years ago
commits_table.tmpl Move helpers to be prefixed with `gt-` (#22879) 2 years ago
create.tmpl Add context cache as a request level cache (#22294) 2 years ago
create_helper.tmpl Add templates to customize text when creating and migrating repositories 2 years ago
empty.tmpl Add main landmark to templates and adjust titles (#22670) 2 years ago
file_info.tmpl Move helpers to be prefixed with `gt-` (#22879) 2 years ago
forks.tmpl Add context cache as a request level cache (#22294) 2 years ago
graph.tmpl Move helpers to be prefixed with `gt-` (#22879) 2 years ago
header.tmpl Move helpers to be prefixed with `gt-` (#22879) 2 years ago
home.tmpl Move helpers to be prefixed with `gt-` (#22879) 2 years ago
icon.tmpl Move helpers to be prefixed with `gt-` (#22879) 2 years ago
packages.tmpl Add main landmark to templates and adjust titles (#22670) 2 years ago
search.tmpl Remove Fomantic-UI's `.hidden` CSS class for menu elements (#22895) 2 years ago
shabox_badge.tmpl Add context cache as a request level cache (#22294) 2 years ago
sub_menu.tmpl Move helpers to be prefixed with `gt-` (#22879) 2 years ago
unicode_escape_prompt.tmpl Move helpers to be prefixed with `gt-` (#22879) 2 years ago
upload.tmpl Refactor `i18n` to `locale` (#20153) 3 years ago
user_cards.tmpl Add context cache as a request level cache (#22294) 2 years ago
view_file.tmpl Move helpers to be prefixed with `gt-` (#22879) 2 years ago
view_list.tmpl Add context cache as a request level cache (#22294) 2 years ago
watchers.tmpl Add main landmark to templates and adjust titles (#22670) 2 years ago