feat: detect filetype with extension if libmagic is unavailable (#268)

* included the previous PR changes and verified black

* resolved the issues mentioned

* make tidy and add tests

---------

Co-authored-by: Matt Robinson <mrobinson@unstructured.io>
Co-authored-by: Matt Robinson <mrobinson@unstructuredai.io>

CHANGELOG.md

@@ -1,3 +1,9 @@
+## 0.4.16-dev0
+
+### Enhancements
+
+* Fallback to using file extensions for filetype detection if `libmagic` is not present
+
 ## 0.4.15
 
 ### Enhancements
@@ -199,3 +205,4 @@ of an email.
 ## 0.2.0
 
 * Initial release of unstructured
+

test_unstructured/file_utils/test_filetype.py

@@ -5,6 +5,7 @@ import zipfile
 
 import magic
 
+import unstructured.file_utils.filetype as filetype
 from unstructured.file_utils.filetype import (
     detect_filetype,
     FileType,
@@ -36,6 +37,27 @@ def test_detect_filetype_from_filename(file, expected):
     assert detect_filetype(filename) == expected
 
 
+@pytest.mark.parametrize(
+    "file, expected",
+    [
+        ("layout-parser-paper-fast.pdf", FileType.PDF),
+        ("fake.docx", FileType.DOCX),
+        ("example.jpg", FileType.JPG),
+        ("fake-text.txt", FileType.TXT),
+        ("fake-email.eml", FileType.EML),
+        ("factbook.xml", FileType.XML),
+        ("example-10k.html", FileType.HTML),
+        ("fake-html.html", FileType.HTML),
+        ("fake-excel.xlsx", FileType.XLSX),
+        ("fake-power-point.pptx", FileType.PPTX),
+    ],
+)
+def test_detect_filetype_from_filename_with_extension(monkeypatch, file, expected):
+    monkeypatch.setattr(filetype, "LIBMAGIC_AVAILABLE", False)
+    filename = os.path.join(EXAMPLE_DOCS_DIRECTORY, file)
+    assert detect_filetype(filename) == expected
+
+
 @pytest.mark.parametrize(
     "file, expected",
     [
@@ -60,6 +82,14 @@ def test_detect_filetype_from_file(file, expected):
         assert detect_filetype(file=f) in expected
 
 
+def test_detect_filetype_from_file_raises_without_libmagic(monkeypatch):
+    monkeypatch.setattr(filetype, "LIBMAGIC_AVAILABLE", False)
+    filename = os.path.join(EXAMPLE_DOCS_DIRECTORY, "fake-text.txt")
+    with open(filename, "rb") as f:
+        with pytest.raises(ImportError):
+            detect_filetype(file=f)
+
+
 def test_detect_xml_application_xml(monkeypatch):
     monkeypatch.setattr(magic, "from_file", lambda *args, **kwargs: "application/xml")
     filename = os.path.join(EXAMPLE_DOCS_DIRECTORY, "fake.xml")

unstructured/__version__.py

@@ -1 +1 @@
-__version__ = "0.4.15"  # pragma: no cover
+__version__ = "0.4.16-dev0"  # pragma: no cover

unstructured/file_utils/filetype.py

@@ -3,8 +3,14 @@ import os
 from typing import IO, Optional
 import zipfile
 
+try:
     import magic
 
+    LIBMAGIC_AVAILABLE = True
+except ImportError:  # pragma: nocover
+    LIBMAGIC_AVAILABLE = False  # pragma: nocover
+
+
 from unstructured.logger import logger
 from unstructured.nlp.patterns import EMAIL_HEAD_RE
 
@@ -91,7 +97,9 @@ EXT_TO_FILETYPE = {
     ".pdf": FileType.PDF,
     ".docx": FileType.DOCX,
     ".jpg": FileType.JPG,
+    ".jpeg": FileType.JPG,
     ".txt": FileType.TXT,
+    ".text": FileType.TXT,
     ".eml": FileType.EML,
     ".xml": FileType.XML,
     ".html": FileType.HTML,
@@ -117,13 +125,24 @@ def detect_filetype(
     if filename:
         _, extension = os.path.splitext(filename)
         extension = extension.lower()
+        if LIBMAGIC_AVAILABLE:
+            mime_type = None
             mime_type = magic.from_file(filename, mime=True)
+        else:
+            return EXT_TO_FILETYPE.get(extension.lower(), FileType.UNK)
     elif file is not None:
         extension = None
         # NOTE(robinson) - the python-magic docs recommend reading at least the first 2048 bytes
         # Increased to 4096 because otherwise .xlsx files get detected as a zip file
         # ref: https://github.com/ahupp/python-magic#usage
+        if LIBMAGIC_AVAILABLE:
             mime_type = magic.from_buffer(file.read(4096), mime=True)
+        else:
+            raise ImportError(
+                "libmagic is unavailable. "
+                "Filetype detection on file-like objects requires libmagic. "
+                "Please install libmagic and try again."
+            )
     else:
         raise ValueError("No filename nor file were specified.")