feat: file append tx (#206)

* feat: file append tx

Signed-off-by: Ivaylo Nikolov <[email protected]>

* feat: file append example

Signed-off-by: Ivaylo Nikolov <[email protected]>

* test: file append tx

Signed-off-by: Ivaylo Nikolov <[email protected]>

* fix: import try catch

Signed-off-by: Ivaylo Nikolov <[email protected]>

* fix: remove chunk interval

Signed-off-by: Ivaylo Nikolov <[email protected]>

* fix: accept only fileid

Signed-off-by: Ivaylo Nikolov <[email protected]>

* chore: lint errors

Signed-off-by: Ivaylo Nikolov <[email protected]>

* test: remove mocked tests

Signed-off-by: Ivaylo Nikolov <[email protected]>

* fix: have to use protected member

Signed-off-by: Ivaylo Nikolov <[email protected]>

* test: check content test

Signed-off-by: Ivaylo Nikolov <[email protected]>

* chore: pr comments

Signed-off-by: Ivaylo Nikolov <[email protected]>

* fix: add check if file id is set

Signed-off-by: Ivaylo Nikolov <[email protected]>

* fix: file_id instead of fileId

Signed-off-by: Ivaylo Nikolov <[email protected]>

* test: add missing test

Signed-off-by: Ivaylo Nikolov <[email protected]>

* test: add missing unit test

Signed-off-by: Ivaylo Nikolov <[email protected]>

* fix: from_proto to _from_proto

Signed-off-by: Ivaylo Nikolov <[email protected]>

---------

Signed-off-by: Ivaylo Nikolov <[email protected]>
Signed-off-by: ivaylonikolov7 <[email protected]>

Author: ivaylonikolov7

examples/file_append.py

@@ -0,0 +1,107 @@
+#!/usr/bin/env python3
+
+"""
+File Append Example
+
+This example demonstrates how to append content to an existing file on the network.
+It shows both single-chunk and multi-chunk append operations.
+"""
+
+import sys
+import os
+from dotenv import load_dotenv
+
+# Load environment variables from .env file
+load_dotenv()
+
+from hiero_sdk_python import (
+    Client, Network, PrivateKey, FileCreateTransaction, AccountId,
+    FileAppendTransaction, ResponseCode
+)
+
+def setup_client():
+    """Initialize and set up the client with operator account"""
+    network = Network(network='testnet')
+    client = Client(network)
+
+    print(os.getenv('OPERATOR_ID'))
+    print(os.getenv('OPERATOR_KEY'))
+
+    operator_id = AccountId.from_string(os.getenv('OPERATOR_ID'))
+    operator_key = PrivateKey.from_string(os.getenv('OPERATOR_KEY'))
+    client.set_operator(operator_id, operator_key)
+    
+    
+    return client
+
+def file_append():
+    """
+    Demonstrates appending content to a file on the network by:
+    1. Setting up client with operator account
+    2. Creating a file with initial content
+    3. Appending additional content to the file
+    """
+    client = setup_client()
+    
+    file_private_key = PrivateKey.generate_ed25519()
+    
+    # Step 1: Create a file with initial content
+    print("Creating file with initial content...")
+    create_receipt = (
+        FileCreateTransaction()
+        .set_keys(file_private_key.public_key())
+        .set_contents(b"Initial file content")
+        .set_file_memo("File for append example")
+        .freeze_with(client)
+        .sign(file_private_key)
+        .execute(client)
+    )
+    
+    if create_receipt.status != ResponseCode.SUCCESS:
+        print(f"File creation failed with status: {ResponseCode(create_receipt.status).name}")
+        sys.exit(1)
+    
+    file_id = create_receipt.file_id
+    print(f"File created successfully with ID: {file_id}")
+    
+    # Step 2: Append content to the file (single chunk)
+    print("\nAppending content to file (single chunk)...")
+    append_receipt = (
+        FileAppendTransaction()
+        .set_file_id(file_id)
+        .set_contents(b"\nThis is appended content!")
+        .freeze_with(client)
+        .sign(file_private_key)
+        .execute(client)
+    )
+    
+    if append_receipt.status != ResponseCode.SUCCESS:
+        print(f"File append failed with status: {ResponseCode(append_receipt.status).name}")
+        sys.exit(1)
+    
+    print("Content appended successfully!")
+    
+    # Step 3: Append large content (multi-chunk)
+    print("\nAppending large content (multi-chunk)...")
+    large_content = b"Large content that will be split into multiple chunks. " * 100
+    
+    large_append_receipt = (
+        FileAppendTransaction()
+        .set_file_id(file_id)
+        .set_contents(large_content)
+        .set_chunk_size(1024)  # 1KB chunks
+        .set_max_chunks(50)    # Allow up to 50 chunks
+        .freeze_with(client)
+        .sign(file_private_key)
+        .execute(client)
+    )
+    
+    if large_append_receipt.status != ResponseCode.SUCCESS:
+        print(f"Large file append failed with status: {ResponseCode(large_append_receipt.status).name}")
+        sys.exit(1)
+    
+    print("Large content appended successfully!")
+    print(f"Total chunks used: {FileAppendTransaction().set_contents(large_content).get_required_chunks()}")
+
+if __name__ == "__main__":
+    file_append() 

src/hiero_sdk_python/__init__.py

@@ -81,6 +81,7 @@
 
 # File
 from .file.file_create_transaction import FileCreateTransaction
+from .file.file_append_transaction import FileAppendTransaction
 from .file.file_info_query import FileInfoQuery
 from .file.file_info import FileInfo
 from .file.file_contents_query import FileContentsQuery
@@ -166,6 +167,7 @@
 
     # File
     "FileCreateTransaction",
+    "FileAppendTransaction",
     "FileInfoQuery",
     "FileInfo",
     "FileContentsQuery",