[fix] handle the case when the image used for thumbnail generation does not have an extension

frappe/core/doctype/file/file.py

@@ -153,43 +153,10 @@ class File(NestedSet):
 	def make_thumbnail(self):
 		if self.file_url:
 			if self.file_url.startswith("/files"):
-				try:
-					image = Image.open(frappe.get_site_path("public", self.file_url.lstrip("/")))
-					filename, extn = self.file_url.rsplit(".", 1)
-				except IOError:
-					frappe.msgprint("Unable to read file format for {0}".format(self.file_url))
+				image, filename, extn = get_local_image(self.file_url)
 
 			else:
-				# downlaod
-				file_url = frappe.utils.get_url(self.file_url)
-				r = requests.get(file_url, stream=True)
-				try:
-					r.raise_for_status()
-				except requests.exceptions.HTTPError, e:
-					if "404" in e.args[0]:
-						frappe.throw(_("File '{0}' not found").format(self.file_url))
-					else:
-						raise
-
-				image = Image.open(StringIO.StringIO(r.content))
-
-				try:
-					filename, extn = self.file_url.rsplit("/", 1)[1].rsplit(".", 1)
-				except ValueError:
-					# the case when the file url doesn't have filename or extension
-					# but is fetched due to a query string. example: https://encrypted-tbn3.gstatic.com/images?q=something
-					filename = get_random_filename()
-					extn = ""
-
-				mimetype = None
-				if extn:
-					mimetype = mimetypes.guess_type(filename + "." + extn)[0]
-
-				if mimetype is None or not mimetype.startswith("image/"):
-					# detect file extension by reading image header properties
-					extn = imghdr.what(filename + "." + extn, h=r.content)
-
-				filename = "/files/" + strip(urllib.unquote(filename))
+				image, filename, extn = get_web_image(self.file_url)
 
 			thumbnail = ImageOps.fit(
 				image,
@@ -209,7 +176,6 @@ class File(NestedSet):
 
 			return thumbnail_url
 
-
 	def after_delete(self):
 		self.update_parent_folder_size()
 
@@ -300,3 +266,66 @@ def setup_folder_path(filename, new_parent):
 
 	if file.is_folder:
 		frappe.rename_doc("File", file.name, file.get_name_based_on_parent_folder(), ignore_permissions=True)
+
+def get_extension(filename, extn, content):
+	mimetype = None
+	if extn:
+		mimetype = mimetypes.guess_type(filename + "." + extn)[0]
+
+	if mimetype is None or not mimetype.startswith("image/") and content:
+		# detect file extension by reading image header properties
+		extn = imghdr.what(filename + "." + (extn or ""), h=content)
+
+	return extn
+
+def get_local_image(file_url):
+	file_path = frappe.get_site_path("public", file_url.lstrip("/"))
+
+	try:
+		image = Image.open(file_path)
+	except IOError:
+		frappe.msgprint("Unable to read file format for {0}".format(file_url))
+		return
+
+	content = None
+
+	try:
+		filename, extn = file_url.rsplit(".", 1)
+	except ValueError:
+		# no extn
+		with open(file_path, "r") as f:
+			content = f.read()
+
+		filename = file_url
+		extn = None
+
+	extn = get_extension(filename, extn, content)
+
+	return image, filename, extn
+
+def get_web_image(file_url):
+	# downlaod
+	file_url = frappe.utils.get_url(file_url)
+	r = requests.get(file_url, stream=True)
+	try:
+		r.raise_for_status()
+	except requests.exceptions.HTTPError, e:
+		if "404" in e.args[0]:
+			frappe.throw(_("File '{0}' not found").format(file_url))
+		else:
+			raise
+
+	image = Image.open(StringIO.StringIO(r.content))
+
+	try:
+		filename, extn = file_url.rsplit("/", 1)[1].rsplit(".", 1)
+	except ValueError:
+		# the case when the file url doesn't have filename or extension
+		# but is fetched due to a query string. example: https://encrypted-tbn3.gstatic.com/images?q=something
+		filename = get_random_filename()
+		extn = None
+
+	extn = get_extension(filename, extn, r.content)
+	filename = "/files/" + strip(urllib.unquote(filename))
+
+	return image, filename, extn