Address comments

src/py/flwr/cli/build.py

@@ -146,7 +146,7 @@ def build(
                 write_to_zip(fab_file, str(archive_path), file_contents)
 
                 # Calculate file info
-                sha256_hash = get_sha256_hash(file_path)
+                sha256_hash = hashlib.sha256(file_contents).hexdigest()
                 file_size_bits = os.path.getsize(file_path) * 8  # size in bits
                 list_file_content += f"{archive_path},{sha256_hash},{file_size_bits}\n"
 

src/py/flwr/cli/install.py

@@ -160,34 +160,10 @@ def validate_and_install(
 
     version, fab_id = get_metadata_from_config(config)
     publisher, project_name = fab_id.split("/")
+    config_metadata = (publisher, project_name, version)
 
     if fab_name:
-        fab_publisher, fab_project_name, fab_version, fab_shorthash = (
-            get_metadata_from_fab_filename(fab_name)
-        )
-        if (
-            f"{fab_publisher}.{fab_project_name}.{fab_version}"
-            != f"{publisher}.{project_name}.{version}"
-            or len(fab_shorthash) != FAB_HASH_TRUNCATION  # Verify hash length
-        ):
-
-            typer.secho(
-                "❌ FAB file has incorrect name. The file name must follow the format "
-                "`<publisher>.<project_name>.<version>.<8hexchars>.fab`.",
-                fg=typer.colors.RED,
-                bold=True,
-            )
-            raise typer.Exit(code=1)
-
-        try:
-            _ = int(fab_shorthash, 16)  # Verify hash is a valid hexadecimal
-        except ValueError as e:
-            typer.secho(
-                f"❌ FAB file has an invalid hexadecimal string `{fab_shorthash}`.",
-                fg=typer.colors.RED,
-                bold=True,
-            )
-            raise typer.Exit(code=1) from e
+        _ = get_metadata_from_fab_filename(fab_name, config_metadata)
 
     install_dir: Path = (
         (get_flwr_dir() if not flwr_dir else flwr_dir)

src/py/flwr/cli/run/run.py

@@ -179,9 +179,9 @@ def _run_with_superexec(
     channel.subscribe(on_channel_state_change)
     stub = ExecStub(channel)
 
-    fab_path = Path(build(app)[0])
-    content = fab_path.read_bytes()
-    fab = Fab(hashlib.sha256(content).hexdigest(), content)
+    fab_path, fab_hash = build(app)
+    content = Path(fab_path).read_bytes()
+    fab = Fab(fab_hash, content)
 
     req = StartRunRequest(
         fab=fab_to_proto(fab),

src/py/flwr/common/config.py

@@ -14,6 +14,7 @@
 # ==============================================================================
 """Provide functions for managing global Flower config."""
 
+import sys
 import os
 import re
 from pathlib import Path
@@ -22,7 +23,12 @@
 import tomli
 
 from flwr.cli.config_utils import get_fab_config, validate_fields
-from flwr.common.constant import APP_DIR, FAB_CONFIG_FILE, FLWR_HOME
+from flwr.common.constant import (
+    APP_DIR,
+    FAB_CONFIG_FILE,
+    FAB_HASH_TRUNCATION,
+    FLWR_HOME,
+)
 from flwr.common.typing import Run, UserConfig, UserConfigValue
 
 
@@ -218,12 +224,42 @@ def get_metadata_from_config(config: dict[str, Any]) -> tuple[str, str]:
 
 
 def get_metadata_from_fab_filename(
-    fab_file: Union[Path, str]
-) -> tuple[str, str, str, str]:
+    fab_file: Union[Path, str], config_metadata: tuple[str, str, str]
+) -> Optional[tuple[str, str, str, str]]:
     """Extract metadata from the FAB filename."""
+
+    fab_file_name: str
+    publisher, project_name, version = config_metadata
+
     if isinstance(fab_file, Path):
         fab_file_name = fab_file.stem
     elif isinstance(fab_file, str):
         fab_file_name = fab_file.removesuffix(".fab")
-    publisher, project_name, version, shorthash = fab_file_name.split(".")
-    return publisher, project_name, version.replace("-", "."), shorthash
+
+    fab_publisher, fab_project_name, fab_version, fab_shorthash = fab_file_name.split(
+        "."
+    )
+
+    if (
+        f"{fab_publisher}.{fab_project_name}.{fab_version}"
+        != f"{publisher}.{project_name}.{version}"
+        or len(fab_shorthash) != FAB_HASH_TRUNCATION  # Verify hash length
+    ):
+        raise ValueError(
+            "❌ FAB file has incorrect name. The file name must follow the format "
+            "`<publisher>.<project_name>.<version>.<8hexchars>.fab`.",
+        )
+
+    try:
+        _ = int(fab_shorthash, 16)  # Verify hash is a valid hexadecimal
+    except Exception as e:
+        raise ValueError(
+            "❌ FAB file has an invalid hexadecimal string `{fab_shorthash}`."
+        ) from e
+
+    return (
+        fab_publisher,
+        fab_project_name,
+        fab_version.replace("-", "."),
+        fab_shorthash,
+    )