make libmagic optional (#201)

spirit/comment/forms.py

@@ -5,8 +5,6 @@ from __future__ import unicode_literals
 import os
 import logging
 
-import magic
-
 from django import forms
 from django.core.files.storage import default_storage
 from django.utils.translation import ugettext_lazy as _
@@ -22,6 +20,13 @@ from .models import Comment
 
 logger = logging.getLogger(__name__)
 
+# Mostly for Windows users who don't need file upload
+try:
+    import magic
+except ImportError as err:
+    logger.exceptioin(err)
+    magic = None
+
 
 class CommentForm(forms.ModelForm):
     comment = forms.CharField(
@@ -158,13 +163,7 @@ class CommentFileForm(forms.Form):
     def clean_file(self):
         file = self.cleaned_data['file']
 
-        try:
+        if not magic:
-            if isinstance(file, TemporaryUploadedFile):
-                file_mime = magic.from_file(file.temporary_file_path(), mime=True)
-            else:  # In-memory file
-                file_mime = magic.from_buffer(file.read(), mime=True)
-        except magic.MagicException as e:
-            logger.exception(e)
            raise forms.ValidationError(_("The file could not be validated"))
 
         # Won't ever raise. Has at most one '.' so lstrip is fine here
@@ -178,6 +177,15 @@ class CommentFileForm(forms.Form):
                     ", ".join(
                         sorted(settings.ST_ALLOWED_UPLOAD_FILE_MEDIA_TYPE.keys())))))
 
+        try:
+            if isinstance(file, TemporaryUploadedFile):
+                file_mime = magic.from_file(file.temporary_file_path(), mime=True)
+            else:  # In-memory file
+                file_mime = magic.from_buffer(file.read(), mime=True)
+        except magic.MagicException as e:
+            logger.exception(e)
+            raise forms.ValidationError(_("The file could not be validated"))
+
         if mime != file_mime:
             raise forms.ValidationError(
                 _("Unsupported file mime type %s. Supported types are %s." % (

spirit/comment/tests.py

@@ -16,10 +16,15 @@ from django.core.files.uploadedfile import SimpleUploadedFile
 from django.test.utils import override_settings
 from django.utils.six import BytesIO
 
+from . import forms as comment_forms
 from ..core.conf import settings
 from ..core.tests import utils
 from .models import Comment
-from .forms import CommentForm, CommentMoveForm, CommentImageForm
+from .forms import (
+    CommentForm,
+    CommentMoveForm,
+    CommentImageForm,
+    CommentFileForm)
 from .tags import render_comments_form
 from ..core.utils import markdown
 from .views import delete as comment_delete
@@ -794,6 +799,25 @@ class CommentFormTest(TestCase):
         form = CommentImageForm(data={}, files=files)
         self.assertFalse(form.is_valid())
 
+    def test_comment_file_upload_no_libmagic(self):
+        """
+        Magic lib should be optional
+        """
+        utils.login(self)
+        file = BytesIO(
+            b'%PDF-1.0\n1 0 obj<</Type/Catalog/Pages 2 0 R>>endobj 2 0 obj<</Type/Pages/Kids[3 0 R]/Count 1'
+            b'>>endobj 3 0 obj<</Type/Page/MediaBox[0 0 3 3]>>endobj\nxref\n0 4\n0000000000 65535 f\n000000'
+            b'0010 00000 n\n0000000053 00000 n\n0000000102 00000 n\ntrailer<</Size 4/Root 1 0 R>>\nstartxre'
+            b'f\n149\n%EOF\n')
+        files = {'file': SimpleUploadedFile('file.pdf', file.read(), content_type='application/pdf'),}
+        form = CommentFileForm(data={}, files=files)
+
+        comment_forms_magic_orig, comment_forms.magic = comment_forms.magic, None
+        try:
+            self.assertFalse(form.is_valid())
+        finally:
+            comment_forms.magic = comment_forms_magic_orig
+
     def test_comment_max_len(self):
         """
         Restrict comment len