Add preview button to edit post page

srv/src/api/api.go

@@ -222,6 +222,7 @@ func (a *api) handler() http.Handler {
 				"DELETE": authMiddleware(auther,
 					formMiddleware(a.deletePostHandler()),
 				),
+				"PREVIEW": formMiddleware(a.previewPostHandler()),
 			}),
 		))
 		v2Mux.Handle("/assets/", http.StripPrefix("/assets",

srv/src/api/posts.go

@@ -16,32 +16,13 @@ import (
 	"github.com/mediocregopher/blog.mediocregopher.com/srv/post"
 )
 
-func (a *api) renderPostHandler() http.Handler {
-
-	tpl := a.mustParseBasedTpl("post.html")
-	renderIndexHandler := a.renderPostsIndexHandler()
-
-	return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
-
-		id := strings.TrimSuffix(filepath.Base(r.URL.Path), ".html")
-
-		if id == "/" {
-			renderIndexHandler.ServeHTTP(rw, r)
-			return
-		}
-
-		storedPost, err := a.params.PostStore.GetByID(id)
-
-		if errors.Is(err, post.ErrPostNotFound) {
-			http.Error(rw, "Post not found", 404)
-			return
-		} else if err != nil {
-			apiutil.InternalServerError(
-				rw, r, fmt.Errorf("fetching post with id %q: %w", id, err),
-			)
-			return
-		}
+type postTplPayload struct {
+	post.StoredPost
+	SeriesPrevious, SeriesNext *post.StoredPost
+	Body                       template.HTML
+}
 
+func (a *api) postToPostTplPayload(storedPost post.StoredPost) (postTplPayload, error) {
 	parserExt := parser.CommonExtensions | parser.AutoHeadingIDs
 	parser := parser.NewWithExtensions(parserExt)
 
@@ -50,11 +31,7 @@ func (a *api) renderPostHandler() http.Handler {
 
 	renderedBody := markdown.ToHTML([]byte(storedPost.Body), parser, htmlRenderer)
 
-		tplPayload := struct {
-			post.StoredPost
-			SeriesPrevious, SeriesNext *post.StoredPost
-			Body                       template.HTML
-		}{
+	tplPayload := postTplPayload{
 		StoredPost: storedPost,
 		Body:       template.HTML(renderedBody),
 	}
@@ -63,11 +40,9 @@ func (a *api) renderPostHandler() http.Handler {
 
 		seriesPosts, err := a.params.PostStore.GetBySeries(series)
 		if err != nil {
-				apiutil.InternalServerError(
-					rw, r,
-					fmt.Errorf("fetching posts for series %q: %w", series, err),
+			return postTplPayload{}, fmt.Errorf(
+				"fetching posts for series %q: %w", series, err,
 			)
-				return
 		}
 
 		var foundThis bool
@@ -91,6 +66,47 @@ func (a *api) renderPostHandler() http.Handler {
 		}
 	}
 
+	return tplPayload, nil
+}
+
+func (a *api) renderPostHandler() http.Handler {
+
+	tpl := a.mustParseBasedTpl("post.html")
+	renderIndexHandler := a.renderPostsIndexHandler()
+
+	return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+
+		id := strings.TrimSuffix(filepath.Base(r.URL.Path), ".html")
+
+		if id == "/" {
+			renderIndexHandler.ServeHTTP(rw, r)
+			return
+		}
+
+		storedPost, err := a.params.PostStore.GetByID(id)
+
+		if errors.Is(err, post.ErrPostNotFound) {
+			http.Error(rw, "Post not found", 404)
+			return
+		} else if err != nil {
+			apiutil.InternalServerError(
+				rw, r, fmt.Errorf("fetching post with id %q: %w", id, err),
+			)
+			return
+		}
+
+		tplPayload, err := a.postToPostTplPayload(storedPost)
+
+		if err != nil {
+			apiutil.InternalServerError(
+				rw, r, fmt.Errorf(
+					"generating template payload for post with id %q: %w",
+					id, err,
+				),
+			)
+			return
+		}
+
 		executeTemplate(rw, r, tpl, tplPayload)
 	})
 }
@@ -169,9 +185,7 @@ func (a *api) editPostHandler() http.Handler {
 	})
 }
 
-func (a *api) postPostHandler() http.Handler {
-
-	return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+func postFromPostReq(r *http.Request) post.Post {
 
 	p := post.Post{
 		ID:          r.PostFormValue("id"),
@@ -185,6 +199,15 @@ func (a *api) postPostHandler() http.Handler {
 	// textareas encode newlines as CRLF for historical reasons
 	p.Body = strings.ReplaceAll(p.Body, "\r\n", "\n")
 
+	return p
+}
+
+func (a *api) postPostHandler() http.Handler {
+
+	return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+
+		p := postFromPostReq(r)
+
 		if err := a.params.PostStore.Set(p, time.Now()); err != nil {
 			apiutil.InternalServerError(
 				rw, r, fmt.Errorf("storing post with id %q: %w", p.ID, err),
@@ -225,3 +248,27 @@ func (a *api) deletePostHandler() http.Handler {
 
 	})
 }
+
+func (a *api) previewPostHandler() http.Handler {
+
+	tpl := a.mustParseBasedTpl("post.html")
+
+	return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+
+		storedPost := post.StoredPost{
+			Post:        postFromPostReq(r),
+			PublishedAt: time.Now(),
+		}
+
+		tplPayload, err := a.postToPostTplPayload(storedPost)
+
+		if err != nil {
+			apiutil.InternalServerError(
+				rw, r, fmt.Errorf("generating template payload: %w", err),
+			)
+			return
+		}
+
+		executeTemplate(rw, r, tpl, tplPayload)
+	})
+}

srv/src/api/tpl/edit-post.html

@@ -1,11 +1,5 @@
 {{ define "body" }}
 
-  <p>
-    <a href="{{ BlogURL "posts/" }}">
-      <button>Back to Posts</button>
-    </a>
-  </p>
-
   <form method="POST" action="{{ BlogURL "posts/" }}">
 
     {{ .CSRFFormInput }}
@@ -87,7 +81,18 @@
       </div>
     </div>
 
-    <input type="submit" value="Save" />
+    <input
+      type="submit"
+      value="Preview"
+      formaction="{{ BlogURL "posts/" }}{{ .Payload.ID }}?method=preview"
+      formtarget="_blank"
+      />
+
+    <input type="submit" value="Save" formaction="{{ BlogURL "posts/" }}" />
+
+    <a href="{{ BlogURL "posts/" }}">
+      <button type="button">Cancel</button>
+    </a>
 
   </form>