Add @tx_out_cmd decorator (#17842)

This adds a new command decorator (unused for now but more PRs to come)
that automatically adds the functionality to export transactions rather
than automatically push them.

chia/_tests/cmds/wallet/test_tx_decorators.py

@@ -0,0 +1,27 @@
+from __future__ import annotations
+
+from typing import Any, List
+
+import click
+from click.testing import CliRunner
+
+from chia._tests.cmds.wallet.test_consts import STD_TX
+from chia.cmds.cmds_util import TransactionBundle, tx_out_cmd
+from chia.wallet.transaction_record import TransactionRecord
+
+
+def test_tx_out_cmd() -> None:
+    @click.command()
+    @tx_out_cmd
+    def test_cmd(**kwargs: Any) -> List[TransactionRecord]:
+        with open("./temp.push", "w") as file:
+            file.write(str(kwargs["push"]))
+        return [STD_TX, STD_TX]
+
+    runner: CliRunner = CliRunner()
+    with runner.isolated_filesystem():
+        runner.invoke(test_cmd, ["--transaction-file", "./temp.transaction"])
+        with open("./temp.transaction", "rb") as file:
+            assert TransactionBundle.from_bytes(file.read()) == TransactionBundle([STD_TX, STD_TX])
+        with open("./temp.push") as file2:
+            assert file2.read() == "True"

chia/cmds/cmds_util.py

@@ -327,6 +327,33 @@ def timelock_args(func: Callable[..., None]) -> Callable[..., None]:
     )
 
 
+@streamable
+@dataclasses.dataclass(frozen=True)
+class TransactionBundle(Streamable):
+    txs: List[TransactionRecord]
+
+
+def tx_out_cmd(func: Callable[..., List[TransactionRecord]]) -> Callable[..., None]:
+    def original_cmd(transaction_file: Optional[str] = None, **kwargs: Any) -> None:
+        txs: List[TransactionRecord] = func(**kwargs)
+        if transaction_file is not None:
+            print(f"Writing transactions to file {transaction_file}:")
+            with open(Path(transaction_file), "wb") as file:
+                file.write(bytes(TransactionBundle(txs)))
+
+    return click.option(
+        "--push/--no-push", help="Push the transaction to the network", type=bool, is_flag=True, default=True
+    )(
+        click.option(
+            "--transaction-file",
+            help="A file to write relevant transactions to",
+            type=str,
+            required=False,
+            default=None,
+        )(original_cmd)
+    )
+
+
 @streamable
 @dataclasses.dataclass(frozen=True)
 class CMDCoinSelectionConfigLoader(Streamable):