Separate generic functions from chunking functions

1 files changed, 32 insertions, 0 deletions

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}")