feat/process follow type

app/boxes.py

@@ -1,9 +1,26 @@
 #!/usr/bin/env python3
 from app import models
 from app.database import AsyncSession
+from app.activitypub import ME
 from loguru import logger
 from uuid import uuid4
+from app.config import MANUALLY_APPROVES_FOLLOWERS
+from app.config import AP_CONTENT_TYPE
+from app.config import BASE_URL
+from app.config import USER_AGENT
+from app.httpsig import auth
 
+import app.activitypub as ap
+import uuid
+import httpx
+
+
+def allocate_outbox_id() -> str:
+    return str(uuid.uuid4())
+
+
+def build_object_id(id) -> str:
+    return f"{BASE_URL}/tail/{id}"
 
 async def save_incoming(
         db_session: AsyncSession,
@@ -23,7 +40,63 @@ async def save_incoming(
         ap_id=ap_id,
         ap_object=payload,
     )
+    await process_incoming(db_session, payload)
     db_session.add(incoming_activity)
     await db_session.commit()
     await db_session.refresh(incoming_activity)
     return incoming_activity
+
+
+async def process_incoming(
+        db_session: AsyncSession,
+        ap_object: dict,
+) -> bool:
+
+    if "Follow" == ap_object["type"]:
+        await _handle_follow(db_session, ap_object)
+    return True
+
+
+async def _handle_follow(
+        db_session: AsyncSession,
+        ap_object: dict,
+) -> None:
+    if ME["id"] != ap_object["object"]:
+        # await db_session.delete(ap_object)
+        logger.warning("no match follow object!" + ap_object["object"])
+        return
+
+    if MANUALLY_APPROVES_FOLLOWERS:
+        # TODO
+        return
+
+    await _send_accept(db_session, ap_object)
+
+
+async def _send_accept(
+        db_session: AsyncSession,
+        ap_object: dict,
+) -> None :
+
+    reply_id = allocate_outbox_id()
+    out = {
+        "@context": ap.AS_CTX,
+        "id": build_object_id(reply_id),
+        "type": "Accept",
+        "actor": ME["id"],
+        "object": ap_object["id"],
+    }
+
+    async with httpx.AsyncClient() as client:
+        resp = await client.post(
+            ap_object["actor"] + "/inbox",
+            headers={
+                "User-Agent": USER_AGENT,
+                "Content-Type": AP_CONTENT_TYPE,
+            },
+            json=out,
+            auth=auth,
+        )
+
+    resp.raise_for_status()
+    logger.info(resp)

app/config.py

@@ -49,3 +49,5 @@ KEY_PATH = (ROOT_DIR / "data" / "key.pem")
 
 USER_AGENT = "Fediverse Application/Foxhole-0.0.1"
 AP_CONTENT_TYPE = "application/activity+json"
+
+MANUALLY_APPROVES_FOLLOWERS = CONFIG.manually_approves_followers

app/httpsig.py

@@ -1,11 +1,14 @@
 #!/usr/bin/env python3
 import base64
+from urllib.request import HTTPSHandler
 import httpx
 import json
 import fastapi
+import hashlib
+from datetime import datetime
 from typing import Literal, TypedDict, cast, Any
 from typing import Optional
-from app.config import AP_CONTENT_TYPE, USER_AGENT
+from app.config import AP_CONTENT_TYPE, USER_AGENT, KEY_PATH, ID
 
 from loguru import logger
 
@@ -118,8 +121,8 @@ class HttpSignature:
             cls,
             method : str,
             path : str,
-            signed_headers : dict,
-            body_digest : str,
+            signed_headers : list,
+            body_digest : str | None,
             headers,
     ) -> str :
         signed_string = []
@@ -131,3 +134,47 @@ class HttpSignature:
             else:
                 signed_string.append(signed_header + ": " + headers[signed_header])
         return "\n".join(signed_string)
+
+
+class HTTPXSigAuth(httpx.Auth):
+    def __init__(self, key) -> None:
+        self.key = key
+
+    def auth_flow(
+        self, r: httpx.Request
+    ):
+        bodydigest = None
+        if r.content:
+            bh = hashlib.new("sha256")
+            bh.update(r.content)
+            bodydigest = "SHA-256=" + base64.b64encode(bh.digest()).decode("utf-8")
+
+        date = datetime.utcnow().strftime("%Y %m %d %H:%M:%S GMT")
+        r.headers["Date"] = date
+        sigheaders = {}
+        if bodydigest:
+            r.headers["digest"] = bodydigest
+            sigheaders = "(request-target) user-agent host date digest content-type"
+        else:
+            sigheaders = "(request-target) user-agent host date accept"
+
+        logger.warning(r.headers)
+        to_be_signed = HttpSignature.build_signature_string(
+            r.method, r.url.path, sigheaders.split(), bodydigest, r.headers
+        )
+        if not self.key:
+            raise ValueError("Should never happen")
+        signer = PKCS1_v1_5.new(self.key)
+        digest = SHA256.new()
+        digest.update(to_be_signed.encode("utf-8"))
+        sig = base64.b64encode(signer.sign(digest)).decode()
+
+        key_id = f"{ID}#main-key"
+        sig_value = f'keyId="{key_id}",algorithm="rsa-sha256",headers="{sigheaders}",signature="{sig}"'  # noqa: E501
+        logger.debug(f"signed request {sig_value=}")
+        r.headers["signature"] = sig_value
+        yield r
+
+k = KEY_PATH.read_text()
+k = RSA.importKey(k)
+auth = HTTPXSigAuth(k)