1 files changed, 124 insertions, 0 deletions

diff --git a/echo/controller/generic_template.go b/echo/controller/generic_template.go
new file mode 100644
index 0000000..190182b
--- /dev/null
+++ b/echo/controller/generic_template.go
@@ -0,0 +1,124 @@
+package controller
+
+import (
+        "fmt"
+        "net/http"
+        "net/url"
+        "strconv"
+        "strings"
+        "sync"
+        "time"
+
+        glecho "code.crute.us/mcrute/golib/echo"
+
+        "github.com/labstack/echo/v4"
+)
+
+type FeatureFlags struct {
+        flags map[string]bool
+}
+
+func NewFeatureFlags() *FeatureFlags {
+        return &FeatureFlags{map[string]bool{}}
+}
+
+func (f *FeatureFlags) Need(feature string) string {
+        f.flags[feature] = true
+        return ""
+}
+
+func (f *FeatureFlags) Needs(feature string) bool {
+        v, ok := f.flags[feature]
+        return ok && v
+}
+
+type PageContext struct {
+        c map[string]string
+}
+
+func NewPageContext() *PageContext {
+        return &PageContext{map[string]string{}}
+}
+
+func (c *PageContext) HasKey(key string) bool {
+        _, ok := c.c[key]
+        return ok
+}
+
+func (c *PageContext) Set(key, value string) string {
+        c.c[key] = value
+        return ""
+}
+
+func (c *PageContext) Get(key string) string {
+        return c.c[key]
+}
+
+type GenericTemplateHandler struct {
+        Render func(echo.Context) (interface{}, error)
+        cb     string
+        init   sync.Once
+        cbm    sync.Mutex // Should only be used in Debug
+}
+
+func (h *GenericTemplateHandler) TmplMakeCacheBustUrl(su string) (string, error) {
+        u, err := url.Parse(su)
+        if err != nil {
+                return "", err
+        }
+
+        q := u.Query()
+        q.Add("cb", h.cb)
+        u.RawQuery = q.Encode()
+
+        return u.String(), nil
+}
+
+func (h *GenericTemplateHandler) canonicalizeUrl(c echo.Context, tr glecho.TemplateChecker) string {
+        path := strings.Trim(c.Request().URL.Path, "/")
+        if path == "" {
+                path = "index.tpl"
+        } else if !strings.HasSuffix(path, ".html") {
+                p := fmt.Sprintf("%s.tpl", path)
+                if !tr.HaveTemplate(c, p) {
+                        path = fmt.Sprintf("%s/index.tpl", path)
+                } else {
+                        path = p
+                }
+        } else {
+                path = strings.ReplaceAll(path, ".html", ".tpl")
+        }
+        return path
+}
+
+func (h *GenericTemplateHandler) Handle(c echo.Context) error {
+        // Generate the cache-buster only once at first request
+        h.init.Do(func() {
+                h.cb = strconv.FormatInt(time.Now().Unix(), 16)
+        })
+
+        // If in debug mode use a new cache buster every time to make reloading
+        // assets easier
+        if c.Echo().Debug {
+                h.cbm.Lock()
+                h.cb = strconv.FormatInt(time.Now().Unix(), 16)
+                h.cbm.Unlock()
+        }
+
+        tr, ok := c.Echo().Renderer.(glecho.TemplateChecker)
+        if !ok {
+                // The only reason this should happen is if the app is wired wrong
+                panic("Template renderer must implement TemplateChecker")
+        }
+
+        path := h.canonicalizeUrl(c, tr)
+
+        c.Set("CanonicalPath", path)
+
+        data, err := h.Render(c)
+        if err != nil {
+                return err
+        }
+
+        return c.Render(http.StatusOK, path, data)
+}