Add ACME certificate request gate mutation

functions/request.py

@@ -4,9 +4,63 @@ Let's Encrypt certificate request/create gate.
 
 from __future__ import annotations
 
+from functions.common import log
+from functions.common import replace_exactly_once
+
+
+REQUEST_FUNCTION_ANCHOR = '''\tcreate: async (access, data) => {
+\t\tawait access.can("certificates:create", data);
+'''
+
+REQUEST_GATE_FRAGMENT = '''\tcreate: async (access, data) => {
+\t\tawait access.can("certificates:create", data);
+
+\t\tif (data.provider === "letsencrypt") {
+\t\t\trequireAcmeAuthority();
+\t\t}
+'''
+
 
 def apply(source: str) -> str:
     """
-    Gate NPM create() for provider == letsencrypt before DB insertion.
+    Gate Let's Encrypt certificate creation before database insertion.
+
+    Custom certificate creation remains unaffected.
     """
-    raise NotImplementedError("request gate not implemented yet")
+
+    if REQUEST_GATE_FRAGMENT in source:
+        log("request_gate=already-present")
+        return source
+
+    source = replace_exactly_once(
+        source,
+        REQUEST_FUNCTION_ANCHOR,
+        REQUEST_GATE_FRAGMENT,
+        description="request gate",
+    )
+
+    log("request_gate=added")
+    return source
+
+
+def verify(source: str) -> None:
+    """
+    Verify that create() contains the Let's Encrypt authority gate.
+    """
+
+    if REQUEST_GATE_FRAGMENT not in source:
+        raise RuntimeError(
+            "request gate verification: authority check not found in create()"
+        )
+
+    gate_index = source.index(REQUEST_GATE_FRAGMENT)
+
+    db_anchor = "certificateModel.query().insertAndFetch(data)"
+    db_index = source.find(db_anchor, gate_index)
+
+    if db_index == -1:
+        raise RuntimeError(
+            "request gate verification: certificate DB insert not found after gate"
+        )
+
+    log("request_gate_verification=passed")