From 380bc3f52515521f3a591d81408157ac34129b3b Mon Sep 17 00:00:00 2001
From: Jaidyn Ann <10477760+JadedCtrl@users.noreply.github.com>
Date: Mon, 9 Dec 2024 22:25:35 -0600
Subject: [PATCH] Implement a basic, bare-bones inbox!

Adding a new interface, the RECEIVE method.
This allows objects to be received on the inbox,
however sans signature validation.
---
 docs/examples/simple-server.lisp | 11 ++++++++++-
 src/activity-servist.lisp        | 21 +++++++++++++++++----
 2 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/docs/examples/simple-server.lisp b/docs/examples/simple-server.lisp
index 0c063e7..65433c4 100644
--- a/docs/examples/simple-server.lisp
+++ b/docs/examples/simple-server.lisp
@@ -27,6 +27,9 @@
 (defvar *store* (make-hash-table :test #'equal)
   "Our “object-store” — stores all ActivityPub objects, mapped by their IRI @ID.")
 
+(defvar *inbox* nil
+  "Our inbox, a simple list containing all received objects.")
+
 (defvar *config*
   '(:host "http://localhost:8080" :address "0.0.0.0" :port 8080 :fetch fetch))
 
@@ -60,13 +63,19 @@ For example: “https://localhost:8080/users/lena”.")
 ;;; Activity-Servist callbacks
 ;;; ————————————————————————————————————————
 (defun fetch (uri)
-  "activity-servist callback: Returns the JSON-LD-OBJECT of the given @ID or URI
+  "activity-servist callback: Returns the JSON-LD OBJECT of the given @ID or URI
 from our object-store.
 This example server simply stores objects in a hash-table mapping IDs to objects."
   (let ((id (or (uri->id uri) uri)))
     (gethash id *store*)))
 
 
+(defmethod as:receive ((obj json-ld:object))
+  "activity-servist callback: Recieve a JSON-LD OBJECT (posted to the server's
+inbox, and decide what to do with it!"
+  (setq *inbox* (append *inbox* (list obj))))
+
+
 
 ;;; ID-management
 ;;; ————————————————————————————————————————
diff --git a/src/activity-servist.lisp b/src/activity-servist.lisp
index df30fc9..06e18d2 100644
--- a/src/activity-servist.lisp
+++ b/src/activity-servist.lisp
@@ -21,6 +21,8 @@
   (:export
    ;; Functions
    :server :start-server
+   ;; Methods
+   :receive
    ;; Globals
    *config*))
 
@@ -75,6 +77,15 @@ Returns the ActivityPub object associated with the given URI."
         (funcall func uri)
         (error "No FETCH function found in ACTIVITY-SERVIST:*CONFIG*."))))
 
+(defgeneric receive (obj)
+  (:documentation
+   "Called when an OBJECT is “sent” to activity-servist’s HTTP inbox.
+This is done by other servers, and is how activities and objects get federated
+with ActivityPub.
+To receive objects, you should overload this generic with (at the bare minimum)
+a method accepting JSON-LD:OBJECTs. Doing so is required — not defining this
+method will cause an error when an object is sent to the inbox."))
+
 
 
 ;;; Host-info response
@@ -145,9 +156,11 @@ can be found). Uses the callback :FETCH, defined in *CONFIG*."
 ;;; Inbox requests
 ;;; ————————————————————————————————————————
 (defun http-inbox (env path-items params)
-  (let* ((raw-contents (alexandria:read-stream-content-into-byte-vector (getf env :raw-body)))
-         (contents (babel:octets-to-string raw-contents)))
-    '(400 (:content-type "text/plain") ("You tried!"))))
+  "If one tries to send an activity to our inbox, pass it along to
+the overloaded RECEIVE method."
+  (let* ((contents (body-contents (getf env :raw-body))))
+    (receive (json-ld:parse contents))
+    '(200 (:content-type "text/plain") ("You win!"))))
 
 
 
@@ -228,7 +241,7 @@ can be found). Uses the callback :FETCH, defined in *CONFIG*."
 ;;; ————————————————————————————————————————
 (defun server (env)
   "Returns the response data for Clack, given the request property-list ENV."
-  (setq *logs* (append *logs* (list env (body-contents (getf env :raw-body)))))
+  (setq *logs* (append *logs* (list env)))
   (let* ((path   (pathname-sans-parameters (getf env :request-uri)))
          (params (pathname-parameters      (getf env :request-uri)))
          (response-function