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gojekyll/plugins/plugins.go
2017-07-08 22:47:50 -04:00

104 lines
2.9 KiB
Go

// Package plugins holds emulated Jekyll plugins.
//
// Unlike Jekyll, these are baked into the executable -- both because as of 2017.07 package "plugin' currently
// works only on Linux, but also because the gojekyll implementation is immature and any possible interfaces
// are far from baked.
package plugins
import (
"fmt"
"github.com/osteele/gojekyll/config"
"github.com/osteele/gojekyll/pages"
"github.com/osteele/liquid"
"github.com/osteele/liquid/render"
)
// Site is the site interface that is available to a plugin.
type Site interface {
AddDocument(pages.Document, bool)
Config() *config.Config
Pages() []pages.Page
}
// Plugin describes the hooks that a plugin can override.
type Plugin interface {
ConfigureTemplateEngine(liquid.Engine) error
Initialize(Site) error
PostRead(site Site) error
}
type plugin struct{}
func (p plugin) ConfigureTemplateEngine(liquid.Engine) error { return nil }
func (p plugin) Initialize(Site) error { return nil }
func (p plugin) PostRead(Site) error { return nil }
// Lookup returns a plugin if it has been registered.
func Lookup(name string) (Plugin, bool) {
p, found := directory[name]
return p, found
}
// Install installs a plugin from the plugin directory.
func Install(names []string, site Site) {
for _, name := range names {
p, found := directory[name]
if found {
if err := p.Initialize(site); err != nil {
panic(err)
}
} else {
fmt.Printf("warning: gojekyll does not emulate the %s plugin.\n", name)
}
}
}
var directory = map[string]Plugin{}
// register installs a plugin in the plugin directory.
func register(name string, p Plugin) {
directory[name] = p
}
func init() {
register("jekyll-feed", jekyllFeedPlugin{})
register("jekyll-seo-tag", jekyllSEOTagPlugin{})
// the following plugins are always active
// no warning but effect; the server runs in this mode anyway
register("jekyll-live-reload", plugin{})
register("jekyll-sass-converter", plugin{})
}
type jekyllFeedPlugin struct{ plugin }
func (p jekyllFeedPlugin) ConfigureTemplateEngine(e liquid.Engine) error {
p.stubbed("jekyll-feed")
e.RegisterTag("feed_meta", p.makeUnimplementedTag("jekyll-feed"))
return nil
}
type jekyllSEOTagPlugin struct{ plugin }
func (p jekyllSEOTagPlugin) ConfigureTemplateEngine(e liquid.Engine) error {
p.stubbed("jekyll-seo-tag")
e.RegisterTag("seo", p.makeUnimplementedTag("jekyll-seo-tag"))
return nil
}
func (p plugin) stubbed(name string) {
fmt.Printf("warning: gojekyll does not emulate the %s plugin. Some tags have been stubbed to prevent errors.\n", name)
}
func (p plugin) makeUnimplementedTag(pluginName string) liquid.Renderer {
warned := false
return func(ctx render.Context) (string, error) {
if !warned {
fmt.Printf("The %q tag in the %q plugin has not been implemented.\n", ctx.TagName(), pluginName)
warned = true
}
return fmt.Sprintf(`<!-- unimplemented tag: %q -->`, ctx.TagName()), nil
}
}