1 files changed, 91 insertions, 0 deletions

diff --git a/matweb/utils.py b/matweb/utils.py
new file mode 100644
index 0000000..8dfff45
--- /dev/null
+++ b/matweb/utils.py
@@ -0,0 +1,91 @@
+import hmac
+import os
+import hashlib
+import mimetypes as mtype
+
+from flask_restful import abort
+from libmat2 import parser_factory
+from werkzeug.utils import secure_filename
+
+
+def get_allow_origin_header_value():
+    return os.environ.get('MAT2_ALLOW_ORIGIN_WHITELIST', '*').split(" ")
+
+
+def hash_file(filepath: str) -> str:
+    sha256 = hashlib.sha256()
+    with open(filepath, 'rb') as f:
+        while True:
+            data = f.read(65536)  # read the file by chunk of 64k
+            if not data:
+                break
+            sha256.update(data)
+    return sha256.hexdigest()
+
+
+def check_upload_folder(upload_folder):
+    if not os.path.exists(upload_folder):
+        os.mkdir(upload_folder)
+
+
+def return_file_created_response(output_filename, mime, key, meta, meta_after, download_link):
+    return {
+        'output_filename': output_filename,
+        'mime': mime,
+        'key': key,
+        'meta': meta,
+        'meta_after': meta_after,
+        'download_link': download_link
+    }
+
+
+def get_supported_extensions():
+    extensions = set()
+    for parser in parser_factory._get_parsers():
+        for m in parser.mimetypes:
+            extensions |= set(mtype.guess_all_extensions(m, strict=False))
+    # since `guess_extension` might return `None`, we need to filter it out
+    return sorted(filter(None, extensions))
+
+
+def save_file(file, upload_folder):
+    filename = secure_filename(file.filename)
+    filepath = os.path.join(upload_folder, filename)
+    file.save(os.path.join(filepath))
+    return filename, filepath
+
+
+def get_file_parser(filepath: str):
+    parser, mime = parser_factory.get_parser(filepath)
+    return parser, mime
+
+
+def cleanup(parser, filepath, upload_folder):
+    output_filename = os.path.basename(parser.output_filename)
+    parser, _ = parser_factory.get_parser(parser.output_filename)
+    meta_after = parser.get_meta()
+    os.remove(filepath)
+
+    key = hash_file(os.path.join(upload_folder, output_filename))
+    return key, meta_after, output_filename
+
+
+def get_file_paths(filename, upload_folder):
+    filepath = secure_filename(filename)
+
+    complete_path = os.path.join(upload_folder, filepath)
+    return complete_path, filepath
+
+
+def is_valid_api_download_file(filename, key, upload_folder):
+    if filename != secure_filename(filename):
+        abort(400, message='Insecure filename')
+
+    complete_path, filepath = get_file_paths(filename, upload_folder)
+
+    if not os.path.exists(complete_path):
+        abort(404, message='File not found')
+
+    if hmac.compare_digest(hash_file(complete_path), key) is False:
+        abort(400, message='The file hash does not match')
+    return complete_path, filepath