feat(tck): implement appendFile JSON-RPC method (#2631)

Signed-off-by: tannaya7 <234580934+tannaya7@users.noreply.github.com>
Signed-off-by: Ntege Daniel <danientege785@gmail.com>
Co-authored-by: tannaya7 <234580934+tannaya7@users.noreply.github.com>
Co-authored-by: Daniel Ntege <danientege785@gmail.com>

Author: tannaya7

tck/handlers/file.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+from hiero_sdk_python.file.file_append_transaction import FileAppendTransaction
 from hiero_sdk_python.file.file_contents_query import FileContentsQuery
 from hiero_sdk_python.file.file_create_transaction import FileCreateTransaction
 from hiero_sdk_python.file.file_delete_transaction import FileDeleteTransaction
@@ -9,9 +10,17 @@
 from hiero_sdk_python.hbar import Hbar
 from hiero_sdk_python.response_code import ResponseCode
 from hiero_sdk_python.timestamp import Timestamp
+from hiero_sdk_python.transaction.transaction_receipt import TransactionReceipt
 from tck.errors import JsonRpcError
 from tck.handlers.registry import rpc_method
-from tck.param.file import CreateFileParams, DeleteFileParams, GetFileContentsParams, GetFileInfoParams
+from tck.param.file import (
+    AppendFileParams,
+    CreateFileParams,
+    DeleteFileParams,
+    GetFileContentsParams,
+    GetFileInfoParams,
+)
+from tck.response.base import StatusOnlyResponse
 from tck.response.file import CreateFileResponse, DeleteFileResponse, GetFileContentsResponse, GetFileInfoResponse
 from tck.util.client_utils import get_client
 from tck.util.constants import DEFAULT_GRPC_TIMEOUT
@@ -60,6 +69,40 @@ def create_file(params: CreateFileParams) -> CreateFileResponse:
     return CreateFileResponse(file_id, ResponseCode(receipt.status).name)
 
 
+def _build_append_file_transaction(params: AppendFileParams) -> FileAppendTransaction:
+    transaction = FileAppendTransaction().set_grpc_deadline(DEFAULT_GRPC_TIMEOUT)
+
+    # Default to 0.0.0 so a missing fileId is rejected by the network with
+    # INVALID_FILE_ID rather than raising a client-side ValueError (TCK FileId #5).
+    transaction.set_file_id(FileId.from_string(params.fileId) if params.fileId is not None else FileId())
+
+    if params.contents is not None:
+        transaction.set_contents(params.contents)
+
+    if params.chunkSize is not None:
+        transaction.set_chunk_size(params.chunkSize)
+
+    if params.maxChunks is not None:
+        transaction.set_max_chunks(params.maxChunks)
+
+    return transaction
+
+
+@rpc_method("appendFile")
+def append_file(params: AppendFileParams) -> StatusOnlyResponse:
+    """Append contents to a file."""
+    client = get_client(params.sessionId)
+
+    transaction = _build_append_file_transaction(params)
+
+    if params.commonTransactionParams is not None:
+        params.commonTransactionParams.apply_common_params(transaction, client)
+
+    receipts: list[TransactionReceipt] = transaction.execute_all(client, wait_for_receipt=True, validate_status=True)
+
+    return StatusOnlyResponse(ResponseCode(receipts[-1].status).name)
+
+
 @rpc_method("getFileContents")
 def get_file_contents(params: GetFileContentsParams) -> GetFileContentsResponse:
     client = get_client(params.sessionId)

tck/param/file.py

@@ -3,7 +3,7 @@
 from dataclasses import dataclass
 
 from tck.param.base import BaseParams, BaseTransactionParams
-from tck.util.param_utils import parse_common_transaction_params, parse_session_id
+from tck.util.param_utils import parse_common_transaction_params, parse_session_id, to_int
 
 
 @dataclass
@@ -35,6 +35,31 @@ def parse_json_params(cls, params: dict) -> CreateFileParams:
         )
 
 
+@dataclass
+class AppendFileParams(BaseTransactionParams):
+    """Parameters for appending contents to a file. Extends BaseTransactionParams to include common transaction parameters."""
+
+    fileId: str | None = None
+    contents: str | None = None
+    maxChunks: int | None = None
+    chunkSize: int | None = None
+
+    @classmethod
+    def parse_json_params(cls, params: dict) -> AppendFileParams:
+        contents = params.get("contents")
+        if not isinstance(contents, str):
+            raise ValueError("contents is required and must be a string")
+
+        return cls(
+            fileId=params.get("fileId"),
+            contents=contents,
+            maxChunks=to_int(params.get("maxChunks")),
+            chunkSize=to_int(params.get("chunkSize")),
+            sessionId=parse_session_id(params),
+            commonTransactionParams=parse_common_transaction_params(params),
+        )
+
+
 @dataclass
 class GetFileContentsParams(BaseParams):
     """Parameters for getting a file's contents."""