Expose the pre-constructed keypair functionality to the HTTP API

src/allmydata/client.py

@@ -32,6 +32,7 @@ from allmydata.storage.server import StorageServer, FoolscapStorageServer
 from allmydata import storage_client
 from allmydata.immutable.upload import Uploader
 from allmydata.immutable.offloaded import Helper
+from allmydata.mutable.filenode import MutableFileNode
 from allmydata.introducer.client import IntroducerClient
 from allmydata.util import (
     hashutil, base32, pollmixin, log, idlib,
@@ -1086,9 +1087,38 @@ class _Client(node.Node, pollmixin.PollMixin):
     def create_immutable_dirnode(self, children, convergence=None):
         return self.nodemaker.create_immutable_directory(children, convergence)
 
-    def create_mutable_file(self, contents=None, version=None):
+    def create_mutable_file(
+            self,
+            contents: bytes | None = None,
+            version: int | None = None,
+            *,
+            unique_keypair: tuple[rsa.PublicKey, rsa.PrivateKey] | None = None,
+    ) -> MutableFileNode:
+        """
+        Create *and upload* a new mutable object.
+
+        :param contents: If given, the initial contents for the new object.
+
+        :param version: If given, the mutable file format for the new object
+            (otherwise a format will be chosen automatically).
+
+        :param unique_keypair: **Warning** This valuely independently
+            determines the identity of the mutable object to create.  There
+            cannot be two different mutable objects that share a keypair.
+            They will merge into one object (with undefined contents).
+
+            It is not common to pass a non-None value for this parameter.  If
+            None is given then a new random keypair will be generated.
+
+            If non-None, the given public/private keypair will be used for the
+            new object.
+
+        :return: A Deferred which will fire with a representation of the new
+            mutable object after it has been uploaded.
+        """
         return self.nodemaker.create_mutable_file(contents,
-                                                  version=version)
+                                                  version=version,
+                                                  keypair=unique_keypair)
 
     def upload(self, uploadable, reactor=None):
         uploader = self.getServiceNamed("uploader")