diff --git a/lib/host/blog.sx b/lib/host/blog.sx
index 8fbdd1af..7e87fa76 100644
--- a/lib/host/blog.sx
+++ b/lib/host/blog.sx
@@ -84,6 +84,37 @@
(join "" (map host/blog--render-node (rest tree))))
(else (host/blog--render-node tree))))
(str "
(empty post)
")))))
+;; ── related posts (blog × relations) ────────────────────────────────
+;; A "related" link between two posts is a SYMMETRIC pair of edges in the
+;; relations graph (lib/relations): node = "blog:", kind = related. Edges go
+;; both ways so "related posts" reads the same from either side via children alone
+;; — composing two already-migrated domains (blog + relations) on the host.
+(define host/blog--rel-kind (string->symbol "related"))
+(define host/blog--node (fn (slug) (string->symbol (str "blog:" slug))))
+
+(define host/blog-relate!
+ (fn (a b)
+ (begin
+ (relations/relate (host/blog--node a) (host/blog--node b) host/blog--rel-kind)
+ (relations/relate (host/blog--node b) (host/blog--node a) host/blog--rel-kind))))
+(define host/blog-unrelate!
+ (fn (a b)
+ (begin
+ (relations/unrelate (host/blog--node a) (host/blog--node b) host/blog--rel-kind)
+ (relations/unrelate (host/blog--node b) (host/blog--node a) host/blog--rel-kind))))
+
+;; related slugs for a post: blog children under "related", stripped to slug, and
+;; limited to posts that still exist (a deleted post can leave a dangling edge).
+;; Existence is checked against ONE kv-keys read (host/blog-slugs), not a perform
+;; per candidate — keeping IO out of the inner filter.
+(define host/blog-related
+ (fn (slug)
+ (let ((existing (host/blog-slugs)))
+ (let ((kids (relations/children (host/blog--node slug) host/blog--rel-kind)))
+ (filter (fn (s) (contains? existing s))
+ (map (fn (n) (substr (symbol->string n) 5))
+ (filter (fn (n) (starts-with? (symbol->string n) "blog:")) kids)))))))
+
;; ── page shell ──────────────────────────────────────────────────────
;; A page is an SX element tree, rendered via render-page (5.1). The handler
;; builds the tree (running any dynamic logic in the full evaluator, e.g. a posts
@@ -98,6 +129,51 @@
(head (meta :charset "utf-8") (title (unquote title)))
(body (unquote body))))))))
+;; "Related posts" block for the post page: a list of links, or "" when none.
+;; Records (slug+title) are fetched up front so the SX tree is built from
+;; in-memory data — no durable read happens while the page tree is rendered.
+(define host/blog--related-block
+ (fn (slug)
+ (let ((rel (map (fn (s) {:slug s :title (get (host/blog-get s) :title)})
+ (host/blog-related slug))))
+ (if (> (len rel) 0)
+ (let ((items
+ (map (fn (p)
+ (quasiquote
+ (li (a :href (unquote (str "/" (get p :slug) "/"))
+ (unquote (get p :title))))))
+ rel)))
+ (quasiquote
+ (div :style "margin-top:2em"
+ (h3 "Related posts")
+ (unquote (list (quote ul) items)))))
+ ""))))
+
+;; Related-posts editor for the edit page: current links each with a remove
+;; button, plus an "add related" box (relate by slug; the submit validates it).
+(define host/blog--related-editor
+ (fn (slug)
+ (let ((rel (host/blog-related slug)))
+ (quasiquote
+ (div :style "margin-top:2em;border-top:1px solid #ccc;padding-top:1em"
+ (h3 "Related posts")
+ (unquote
+ (if (> (len rel) 0)
+ (list (quote ul)
+ (map (fn (s)
+ (quasiquote
+ (li (a :href (unquote (str "/" s "/")) (unquote s)) " "
+ (form :method "post" :style "display:inline"
+ :action (unquote (str "/" slug "/unrelate"))
+ (input :type "hidden" :name "other" :value (unquote s))
+ (button :type "submit" "remove")))))
+ rel))
+ (quote (p :style "opacity:0.7" "None yet."))))
+ (form :method "post" :action (unquote (str "/" slug "/relate"))
+ (input :name "other" :placeholder "slug to relate")
+ " "
+ (button :type "submit" "Add related")))))))
+
;; ── read handlers ───────────────────────────────────────────────────
;; Post body is rendered per-block (a guarded HTML string) then injected raw.
(define host/blog-post
@@ -105,19 +181,25 @@
(let ((slug (dream-param req "slug")))
(let ((r (host/blog-get slug)))
(if r
- (dream-html
- (host/blog--page (get r :title)
- (quasiquote
- (div
- (article (raw! (unquote (host/blog-render r))))
- (p :style "margin-top:2em;font-size:0.9em;opacity:0.8"
- (a :href (unquote (str "/" slug "/source")) "view source")
- " · "
- (a :href (unquote (str "/" slug "/edit")) "edit")
- " · "
- (a :href "/" "all posts")
- " · "
- (unquote (host/auth-footer req)))))))
+ ;; Compute the rendered body + related block in let bindings BEFORE the
+ ;; quasiquote — host/blog--related-block does durable reads, and IO must
+ ;; happen in the handler body, not while the page tree is being built.
+ (let ((body-html (host/blog-render r))
+ (related-block (host/blog--related-block slug)))
+ (dream-html
+ (host/blog--page (get r :title)
+ (quasiquote
+ (div
+ (article (raw! (unquote body-html)))
+ (unquote related-block)
+ (p :style "margin-top:2em;font-size:0.9em;opacity:0.8"
+ (a :href (unquote (str "/" slug "/source")) "view source")
+ " · "
+ (a :href (unquote (str "/" slug "/edit")) "edit")
+ " · "
+ (a :href "/" "all posts")
+ " · "
+ (unquote (host/auth-footer req))))))))
(dream-html-status 404
(host/blog--page "Not found"
(quasiquote
@@ -266,9 +348,40 @@
(fn (req)
(let ((slug (dream-param req "slug")))
(if (host/blog-exists? slug)
- (begin (host/blog-delete! slug) (host/ok {:slug slug :deleted true}))
+ (begin
+ ;; drop the post's related edges so no dangling links survive it
+ (for-each (fn (o) (host/blog-unrelate! slug o)) (host/blog-related slug))
+ (host/blog-delete! slug)
+ (host/ok {:slug slug :deleted true}))
(host/error 404 "no such post")))))
+;; POST //relate — relate this post to another (form field `other` = slug).
+;; Validated: the other post must exist and differ; otherwise it's a no-op. Always
+;; redirects back to the edit page. Guarded like the other browser write routes.
+(define host/blog-relate-submit
+ (fn (req)
+ (let ((slug (dream-param req "slug"))
+ (other (dream-form-field req "other")))
+ (if (nil? (host/blog-get slug))
+ (dream-html-status 404
+ (host/blog--page "Not found"
+ (quasiquote (div (h1 "404") (p (unquote (str "No post: " slug)))))))
+ (begin
+ (when (and other (not (= other "")) (not (= other slug)) (host/blog-exists? other))
+ (host/blog-relate! slug other))
+ (dream-redirect (str "/" slug "/edit")))))))
+
+;; POST //unrelate — remove the relation to `other`. Idempotent; redirects
+;; back to the edit page.
+(define host/blog-unrelate-submit
+ (fn (req)
+ (let ((slug (dream-param req "slug"))
+ (other (dream-form-field req "other")))
+ (begin
+ (when (and other (not (= other "")))
+ (host/blog-unrelate! slug other))
+ (dream-redirect (str "/" slug "/edit"))))))
+
;; GET //edit — edit form pre-filled with the post's current title, raw
;; sx_content (in a textarea — render-to-html escapes the text child, so the
;; browser shows the source verbatim), and status (current value pre-selected).
@@ -282,7 +395,10 @@
(host/blog--page "Not found"
(quasiquote (div (h1 "404") (p (unquote (str "No post: " slug)))))))
(let ((status (get r :status)))
- (let ((mk-opt
+ ;; related-editor does durable reads — compute it here, not in the
+ ;; quasiquote, so IO stays in the handler body.
+ (let ((related-editor (host/blog--related-editor slug))
+ (mk-opt
(fn (val label)
(if (= val status)
(quasiquote (option :value (unquote val) :selected "selected" (unquote label)))
@@ -303,7 +419,9 @@
(unquote (mk-opt "published" "Published")))
" "
(button :type "submit" "Save")))
- (p (a :href (unquote (str "/" slug "/")) "view post")
+ (unquote related-editor)
+ (p :style "margin-top:1.5em"
+ (a :href (unquote (str "/" slug "/")) "view post")
" · "
(a :href (unquote (str "/" slug "/source")) "view source")))))))))))))
@@ -368,6 +486,8 @@
(dream-post "/new" (host/blog--protect-html resolve host/blog-form-submit))
(dream-get "/:slug/edit" (host/blog--protect-html resolve host/blog-edit-form))
(dream-post "/:slug/edit" (host/blog--protect-html resolve host/blog-edit-submit))
+ (dream-post "/:slug/relate" (host/blog--protect-html resolve host/blog-relate-submit))
+ (dream-post "/:slug/unrelate" (host/blog--protect-html resolve host/blog-unrelate-submit))
(dream-post "/posts" (host/blog--protect resolve host/blog-create))
(dream-put "/posts/:slug" (host/blog--protect resolve host/blog-update-handler))
(dream-delete "/posts/:slug" (host/blog--protect resolve host/blog-delete-handler)))))
diff --git a/lib/host/tests/blog.sx b/lib/host/tests/blog.sx
index 68618b03..e98c9c1f 100644
--- a/lib/host/tests/blog.sx
+++ b/lib/host/tests/blog.sx
@@ -211,6 +211,44 @@
(host-bl-test "GET /logout -> 303"
(dream-status (host-bl-app (host-bl-req "/logout"))) 303)
+;; -- relate posts (blog × relations) --
+;; my-first-post and another-one both exist in the write-test store at this point.
+(host-bl-test "relate no auth -> redirect to login"
+ (dream-status (host-bl-wapp (host-bl-send "POST" "/my-first-post/relate" nil
+ "application/x-www-form-urlencoded" "other=another-one"))) 303)
+(host-bl-test "relate authed -> 303 back to edit"
+ (dream-resp-header (host-bl-wapp (host-bl-send "POST" "/my-first-post/relate" "Bearer good"
+ "application/x-www-form-urlencoded" "other=another-one")) "location")
+ "/my-first-post/edit")
+(host-bl-test "related is symmetric (a -> b)"
+ (contains? (host/blog-related "my-first-post") "another-one") true)
+(host-bl-test "related is symmetric (b -> a)"
+ (contains? (host/blog-related "another-one") "my-first-post") true)
+(host-bl-test "post page shows a Related posts block"
+ (contains? (dream-resp-body (host-bl-wapp (host-bl-req "/my-first-post/"))) "Related posts") true)
+(host-bl-test "post page links the related post"
+ (contains? (dream-resp-body (host-bl-wapp (host-bl-req "/my-first-post/"))) "/another-one/") true)
+(host-bl-test "relate nonexistent other -> no-op"
+ (begin
+ (host-bl-wapp (host-bl-send "POST" "/my-first-post/relate" "Bearer good"
+ "application/x-www-form-urlencoded" "other=ghost-post"))
+ (contains? (host/blog-related "my-first-post") "ghost-post"))
+ false)
+(host-bl-test "unrelate -> removes the link both ways"
+ (begin
+ (host-bl-wapp (host-bl-send "POST" "/my-first-post/unrelate" "Bearer good"
+ "application/x-www-form-urlencoded" "other=another-one"))
+ (list (contains? (host/blog-related "my-first-post") "another-one")
+ (contains? (host/blog-related "another-one") "my-first-post")))
+ (list false false))
+(host-bl-test "delete cleans up related edges"
+ (begin
+ (host-bl-wapp (host-bl-send "POST" "/my-first-post/relate" "Bearer good"
+ "application/x-www-form-urlencoded" "other=another-one"))
+ (host-bl-wapp (host-bl-send "DELETE" "/posts/another-one" "Bearer good" "" ""))
+ (contains? (host/blog-related "my-first-post") "another-one"))
+ false)
+
;; -- experimental unguarded create-only route (POST /new, no auth) --
(define host-bl-oapp (host/make-app (list host/blog-open-create-routes host/blog-routes)))
(host/blog-use-store! (persist/open))