Separate generic functions from chunking functions

3 files changed, 35 insertions, 13 deletions

diff --git a/uploader/files/__init__.py b/uploader/files/__init__.py
index 4a62409..60d2f3b 100644
--- a/uploader/files/__init__.py
+++ b/uploader/files/__init__.py
@@ -1,4 +1,4 @@
+from .chunks import chunked_binary_read
 from .functions import (fullpath,
                         save_file,
-                        chunked_binary_read,
                         sha256_digest_over_file)
diff --git a/uploader/files/chunks.py b/uploader/files/chunks.py
new file mode 100644
index 0000000..c4360b5
--- /dev/null
+++ b/uploader/files/chunks.py
@@ -0,0 +1,32 @@
+"""Functions dealing with chunking of files."""
+from pathlib import Path
+from typing import Iterator
+
+from flask import current_app as app
+from werkzeug.utils import secure_filename
+
+
+def chunked_binary_read(filepath: Path, chunksize: int = 2048) -> Iterator:
+    """Read a file in binary mode in chunks."""
+    with open(filepath, "rb") as inputfile:
+        while True:
+            data = inputfile.read(chunksize)
+            if data != b"":
+                yield data
+                continue
+            break
+
+def chunk_name(uploadfilename: str, chunkno: int) -> str:
+    """Generate chunk name from original filename and chunk number"""
+    if uploadfilename == "":
+        raise ValueError("Name cannot be empty!")
+    if chunkno < 1:
+        raise ValueError("Chunk number must be greater than zero")
+    return f"{secure_filename(uploadfilename)}_part_{chunkno:05d}"
+
+
+def chunks_directory(uniqueidentifier: str) -> Path:
+    """Compute the directory where chunks are temporarily stored."""
+    if uniqueidentifier == "":
+        raise ValueError("Unique identifier cannot be empty!")
+    return Path(app.config["UPLOAD_FOLDER"], f"tempdir_{uniqueidentifier}")
diff --git a/uploader/files/functions.py b/uploader/files/functions.py
index d37a53e..5a3dece 100644
--- a/uploader/files/functions.py
+++ b/uploader/files/functions.py
@@ -1,7 +1,6 @@
 """Utilities to deal with uploaded files."""
 import hashlib
 from pathlib import Path
-from typing import Iterator
 from datetime import datetime
 
 from flask import current_app
@@ -9,6 +8,8 @@ from flask import current_app
 from werkzeug.utils import secure_filename
 from werkzeug.datastructures import FileStorage
 
+from .chunks import chunked_binary_read
+
 def save_file(fileobj: FileStorage, upload_dir: Path) -> Path:
     """Save the uploaded file and return the path."""
     assert bool(fileobj), "Invalid file object!"
@@ -29,17 +30,6 @@ def fullpath(filename: str):
     return Path(current_app.config["UPLOAD_FOLDER"], filename).absolute()
 
 
-def chunked_binary_read(filepath: Path, chunksize: int = 2048) -> Iterator:
-    """Read a file in binary mode in chunks."""
-    with open(filepath, "rb") as inputfile:
-        while True:
-            data = inputfile.read(chunksize)
-            if data != b"":
-                yield data
-                continue
-            break
-
-
 def sha256_digest_over_file(filepath: Path) -> str:
     """Compute the sha256 digest over a file's contents."""
     filehash = hashlib.sha256()