Files
kgpz_web/templating/template_registry.go
Simon Martens 84fa6f7fa4 better logging
2024-11-16 17:30:14 +01:00

116 lines
2.8 KiB
Go

package templating
import (
"html/template"
"io/fs"
"os"
"strings"
"sync"
"github.com/Theodor-Springmann-Stiftung/kgpz_web/helpers"
"github.com/yalue/merged_fs"
)
// INFO: this ist thread-safe and safe to call in a handler or middleware
type TemplateRegistry struct {
routesFS fs.FS
once sync.Once
// INFO: Template & cache keys are directory routing paths, with '/' as root
// INFO: we don't need a mutex here since this is set in Load() protected by Once().
templates map[string]TemplateContext
cache sync.Map
}
func NewTemplateRegistry(routes fs.FS) *TemplateRegistry {
return &TemplateRegistry{
routesFS: routes,
}
}
// INFO: This returns a new TemplateRegistry with the new fs added to the existing fs,
// merging with the existing FS, possibly overwriting existing files.
func (r *TemplateRegistry) Register(path string, fs fs.FS) *TemplateRegistry {
return NewTemplateRegistry(merged_fs.MergeMultiple(fs, r.routesFS))
}
func (r *TemplateRegistry) Load() error {
r.once.Do(func() {
err := r.load()
helpers.Assert(err, "Error loading templates. Exiting.")
})
return nil
}
// TODO: Throw errors
// TODO: what if there is no template in the directory above?
// What if a certain path is or should uncallable since it has no index or body?
func (r *TemplateRegistry) load() error {
// INFO: Parse setrs r.templates, which is why you need to make sure to call Parse() once
templates := make(map[string]TemplateContext)
fs.WalkDir(r.routesFS, ".", func(path string, d fs.DirEntry, err error) error {
if !d.IsDir() {
return nil
}
url := FSPathToPath(path)
tc := NewTemplateContext(url)
if path != "." {
pathelem := strings.Split(path, string(os.PathSeparator))
pathabove := strings.Join(pathelem[:len(pathelem)-1], string(os.PathSeparator))
pathabove = FSPathToPath(pathabove)
global, ok := templates[pathabove]
if ok {
tc.SetGlobals(global.Globals())
}
}
tc.Parse(r.routesFS)
templates[url] = tc
return nil
})
r.templates = templates
return nil
}
// This function takes a template (typically a layout) and adds all the templates of
// a given directory path to it. This is useful for adding a layout to a template.
func (r *TemplateRegistry) Add(path string, t *template.Template) error {
temp, ok := r.cache.Load(path)
if !ok {
r.Load()
tc, ok := r.templates[path]
if !ok {
return NewError(NoTemplateError, path)
}
template, err := tc.Template(r.routesFS)
if err != nil {
return err
}
r.cache.Store(path, template)
return r.Add(path, t)
}
casted := temp.(*template.Template)
for _, st := range casted.Templates() {
_, err := t.AddParseTree(st.Name(), st.Tree)
if err != nil {
return err
}
}
return nil
}
// TODO: get for a specific component
func (r *TemplateRegistry) Get(path string) error {
return nil
}