From 01424c7dab5fe42a9f00e3c9bb285924e42136fc Mon Sep 17 00:00:00 2001
From: Brian Picciano <mediocregopher@gmail.com>
Date: Sat, 21 May 2022 11:34:03 -0600
Subject: [PATCH] Standardize URL generation across the blog

---
 srv/src/http/assets.go         |  4 +--
 srv/src/http/posts.go          | 10 +++---
 srv/src/http/tpl.go            | 59 ++++++++++++++++++++++------------
 srv/src/http/tpl/redirect.html |  2 +-
 4 files changed, 46 insertions(+), 29 deletions(-)

diff --git a/srv/src/http/assets.go b/srv/src/http/assets.go
index aacef96..2cbe7a2 100644
--- a/srv/src/http/assets.go
+++ b/srv/src/http/assets.go
@@ -172,7 +172,7 @@ func (a *api) postPostAssetHandler() http.Handler {
 			return
 		}
 
-		a.executeRedirectTpl(rw, r, "assets/")
+		a.executeRedirectTpl(rw, r, a.assetsURL(false))
 	})
 }
 
@@ -199,6 +199,6 @@ func (a *api) deletePostAssetHandler() http.Handler {
 			return
 		}
 
-		a.executeRedirectTpl(rw, r, "assets/")
+		a.executeRedirectTpl(rw, r, a.assetsURL(false))
 	})
 }
diff --git a/srv/src/http/posts.go b/srv/src/http/posts.go
index c05f3de..2f96c6d 100644
--- a/srv/src/http/posts.go
+++ b/srv/src/http/posts.go
@@ -25,7 +25,7 @@ type postTplPayload struct {
 
 func (a *api) postToPostTplPayload(storedPost post.StoredPost) (postTplPayload, error) {
 
-	bodyTpl, err := a.parseTpl(storedPost.Body)
+	bodyTpl, err := a.parseTpl(storedPost.ID+"-body.html", storedPost.Body)
 	if err != nil {
 		return postTplPayload{}, fmt.Errorf("parsing post body as template: %w", err)
 	}
@@ -271,7 +271,7 @@ func (a *api) postPostHandler() http.Handler {
 		if first {
 
 			a.params.Logger.Info(r.Context(), "publishing blog post to mailing list")
-			urlStr := a.params.PublicURL.String() + filepath.Join("/posts", p.ID)
+			urlStr := a.postURL(p.ID, true)
 
 			if err := a.params.MailingList.Publish(p.Title, urlStr); err != nil {
 				apiutil.InternalServerError(
@@ -281,9 +281,7 @@ func (a *api) postPostHandler() http.Handler {
 			}
 		}
 
-		redirectPath := fmt.Sprintf("posts/%s?edit", p.ID)
-
-		a.executeRedirectTpl(rw, r, redirectPath)
+		a.executeRedirectTpl(rw, r, a.postURL(p.ID, false)+"?edit")
 	})
 }
 
@@ -310,7 +308,7 @@ func (a *api) deletePostHandler() http.Handler {
 			return
 		}
 
-		a.executeRedirectTpl(rw, r, "posts/")
+		a.executeRedirectTpl(rw, r, a.postsURL(false))
 
 	})
 }
diff --git a/srv/src/http/tpl.go b/srv/src/http/tpl.go
index dcd1551..2e22370 100644
--- a/srv/src/http/tpl.go
+++ b/srv/src/http/tpl.go
@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"html/template"
 	"io/fs"
+	"log"
 	"net/http"
 	"path/filepath"
 	"strings"
@@ -28,37 +29,54 @@ func mustReadTplFile(fileName string) string {
 	return string(b)
 }
 
-func (a *api) parseTpl(tplBody string) (*template.Template, error) {
+func (a *api) blogURL(path string, abs bool) string {
+	// filepath.Join strips trailing slash, but we want to keep it
+	trailingSlash := strings.HasSuffix(path, "/")
 
-	blogURL := func(path string) string {
+	res := filepath.Join("/", path)
 
-		// filepath.Join strips trailing slash, but we want to keep it
-		trailingSlash := strings.HasSuffix(path, "/")
+	if trailingSlash && res != "/" {
+		res += "/"
+	}
 
-		path = filepath.Join("/", path)
+	if abs {
+		res = a.params.PublicURL.String() + res
+	}
 
-		if trailingSlash && path != "/" {
-			path += "/"
-		}
+	return res
+}
 
-		return path
-	}
+func (a *api) postURL(id string, abs bool) string {
+	path := filepath.Join("posts", id)
+	return a.blogURL(path, abs)
+}
+
+func (a *api) postsURL(abs bool) string {
+	return a.blogURL("posts", abs)
+}
+
+func (a *api) assetsURL(abs bool) string {
+	return a.blogURL("assets", abs)
+}
+
+func (a *api) parseTpl(name, tplBody string) (*template.Template, error) {
 
 	tpl := template.New("root")
 
 	tpl = tpl.Funcs(template.FuncMap{
-		"BlogURL": blogURL,
+		"BlogURL": func(path string) string {
+			return a.blogURL(path, false)
+		},
 		"StaticURL": func(path string) string {
 			path = filepath.Join("static", path)
-			return blogURL(path)
+			return a.blogURL(path, false)
 		},
 		"AssetURL": func(id string) string {
 			path := filepath.Join("assets", id)
-			return blogURL(path)
+			return a.blogURL(path, false)
 		},
 		"PostURL": func(id string) string {
-			path := filepath.Join("posts", id)
-			return blogURL(path)
+			return a.postURL(id, false)
 		},
 		"DateTimeFormat": func(t time.Time) string {
 			return t.Format("2006-01-02")
@@ -89,7 +107,7 @@ func (a *api) parseTpl(tplBody string) (*template.Template, error) {
 
 	var err error
 
-	if tpl, err = tpl.New("").Parse(tplBody); err != nil {
+	if tpl, err = tpl.New(name).Parse(tplBody); err != nil {
 		return nil, err
 	}
 
@@ -97,7 +115,7 @@ func (a *api) parseTpl(tplBody string) (*template.Template, error) {
 }
 
 func (a *api) mustParseTpl(name string) *template.Template {
-	return template.Must(a.parseTpl(mustReadTplFile(name)))
+	return template.Must(a.parseTpl(name, mustReadTplFile(name)))
 }
 
 func (a *api) mustParseBasedTpl(name string) *template.Template {
@@ -140,12 +158,13 @@ func executeTemplate(
 }
 
 func (a *api) executeRedirectTpl(
-	rw http.ResponseWriter, r *http.Request, path string,
+	rw http.ResponseWriter, r *http.Request, url string,
 ) {
+	log.Printf("here url:%q", url)
 	executeTemplate(rw, r, a.redirectTpl, struct {
-		Path string
+		URL string
 	}{
-		Path: path,
+		URL: url,
 	})
 }
 
diff --git a/srv/src/http/tpl/redirect.html b/srv/src/http/tpl/redirect.html
index ed12a2e..a50b324 100644
--- a/srv/src/http/tpl/redirect.html
+++ b/srv/src/http/tpl/redirect.html
@@ -1,7 +1,7 @@
 <!DOCTYPE html>
 <html>
   <head>
-    <meta http-equiv="refresh" content="0; url='{{ BlogURL .Payload.Path }}'" />
+    <meta http-equiv="refresh" content="0; url='{{ .Payload.URL }}'" />
   </head>
   <body>
     <p>Redirecting...</p>