sx-pub Phase 1: DB schema, IPFS wiring, actor + webfinger + collections + status endpoints

Foundation for the sx-pub federated publishing protocol:

- 6 SQLAlchemy models: actor, collections, documents, activities, followers, following
- Conditional DB enablement in sx_docs (DATABASE_URL present → enable DB)
- Python IO helpers: get_or_create_actor (auto-generates RSA keypair),
  list_collections, check_status, seed_default_collections
- 4 defhandler endpoints returning text/sx (no JSON):
  /pub/actor, /pub/webfinger, /pub/collections, /pub/status
- Alembic migration infrastructure for sx service
- Docker compose: DB + pgbouncer + IPFS + env vars

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

sx/sx/handlers/pub-api.sx

@@ -0,0 +1,98 @@
+;; ==========================================================================
+;; sx-pub Phase 1 API endpoints — actor, webfinger, collections, status
+;;
+;; All responses are text/sx. No JSON.
+;; ==========================================================================
+
+
+;; --------------------------------------------------------------------------
+;; Actor
+;; --------------------------------------------------------------------------
+
+(defhandler pub-actor
+  :path "/pub/actor"
+  :method :get
+  :returns "element"
+  (&key)
+  (let ((actor (helper "pub-actor-data")))
+    (do
+      (set-response-header "Content-Type" "text/sx; charset=utf-8")
+      (str
+        "(SxActor"
+        "\n  :id \"https://" (get actor "domain") "/pub/actor\""
+        "\n  :type \"SxPublisher\""
+        "\n  :name \"" (get actor "display-name") "\""
+        "\n  :summary \"" (get actor "summary") "\""
+        "\n  :inbox \"/pub/inbox\""
+        "\n  :outbox \"/pub/outbox\""
+        "\n  :followers \"/pub/followers\""
+        "\n  :following \"/pub/following\""
+        "\n  :public-key-pem \"" (get actor "public-key-pem") "\")"))))
+
+
+;; --------------------------------------------------------------------------
+;; Webfinger
+;; --------------------------------------------------------------------------
+
+(defhandler pub-webfinger
+  :path "/pub/webfinger"
+  :method :get
+  :returns "element"
+  (&key)
+  (let ((resource (helper "request-arg" "resource" ""))
+        (actor (helper "pub-actor-data")))
+    (let ((expected (str "acct:" (get actor "preferred-username") "@" (get actor "domain"))))
+      (if (!= resource expected)
+        (do
+          (set-response-status 404)
+          (str "(Error :message \"Resource not found\")"))
+        (do
+          (set-response-header "Content-Type" "text/sx; charset=utf-8")
+          (str
+            "(SxWebfinger"
+            "\n  :subject \"" expected "\""
+            "\n  :actor \"https://" (get actor "domain") "/pub/actor\""
+            "\n  :type \"SxPublisher\")"))))))
+
+
+;; --------------------------------------------------------------------------
+;; Collections
+;; --------------------------------------------------------------------------
+
+(defhandler pub-collections
+  :path "/pub/collections"
+  :method :get
+  :returns "element"
+  (&key)
+  (let ((collections (helper "pub-collections-data")))
+    (do
+      (set-response-header "Content-Type" "text/sx; charset=utf-8")
+      (let ((items (map (fn (c)
+              (str "\n  (SxCollection"
+                " :slug \"" (get c "slug") "\""
+                " :name \"" (get c "name") "\""
+                " :description \"" (get c "description") "\""
+                " :href \"/pub/" (get c "slug") "\")"))
+              collections)))
+        (str "(SxCollections" (join "" items) ")")))))
+
+
+;; --------------------------------------------------------------------------
+;; Status
+;; --------------------------------------------------------------------------
+
+(defhandler pub-status
+  :path "/pub/status"
+  :method :get
+  :returns "element"
+  (&key)
+  (let ((status (helper "pub-status-data")))
+    (do
+      (set-response-header "Content-Type" "text/sx; charset=utf-8")
+      (str
+        "(SxPubStatus"
+        "\n  :healthy " (get status "healthy")
+        "\n  :db \"" (get status "db") "\""
+        "\n  :ipfs \"" (get status "ipfs") "\""
+        "\n  :actor \"" (get status "actor") "\""
+        "\n  :domain \"" (or (get status "domain") "unknown") "\")"))))