[IMP] core: support partial http response

An HTTP Partial Request is a regular GET request with a Range header
that indicate what chunk of the data the browser wishes to download. It
is useful to peek in a video stream or to resume an interrupted
download. The server can respond with a 206 - Partial Content response,
set the appropriate Content-Length and Content-Range headers and only
send a chunk of the data in the body.

Werkzeug's `send_file`, the library function we use to stream files over
http, is fully compliant with partial requests and responses. It
understands the Range request header and create the corresponding
response.

NGINX does also comply with the Range header even via X-Accel-Redirect.

closes odoo/odoo#97422

Signed-off-by: Julien Castiaux <juc@odoo.com>

odoo/addons/test_http/tests/test_static.py

@@ -25,9 +25,9 @@ class TestHttpStaticCommon(TestHttpBase):
             cls.placeholder_data = file.read()
 
     def assertDownload(
-        self, url, assert_status_code, assert_headers, assert_content=None
+        self, url, headers, assert_status_code, assert_headers, assert_content=None
     ):
-        res = self.db_url_open(url)
+        res = self.db_url_open(url, headers=headers)
         res.raise_for_status()
         self.assertEqual(res.status_code, assert_status_code)
         for header_name, header_value in assert_headers.items():
@@ -49,7 +49,7 @@ class TestHttpStaticCommon(TestHttpBase):
             headers['X-Accel-Redirect'] = f'/web/filestore/{self.cr.dbname}/{sha[:2]}/{sha}'
             headers['Content-Length'] = '0'
 
-        return self.assertDownload(url, 200, headers, b'' if x_sendfile else self.gizeh_data)
+        return self.assertDownload(url, {}, 200, headers, b'' if x_sendfile else self.gizeh_data)
 
     def assertDownloadPlaceholder(self, url):
         headers = {
@@ -57,7 +57,7 @@ class TestHttpStaticCommon(TestHttpBase):
             'Content-Type': 'image/png',
             'Content-Disposition': 'inline; filename=placeholder.png'
         }
-        return self.assertDownload(url, 200, headers, self.placeholder_data)
+        return self.assertDownload(url, {}, 200, headers, self.placeholder_data)
 
 
 @tagged('post_install', '-at_install')
@@ -248,6 +248,21 @@ class TestHttpStatic(TestHttpStaticCommon):
         res = self.url_open('/web/image/idontexist?download=True')
         self.assertEqual(res.status_code, 404)
 
+    def test_static15_range(self):
+        self.assertDownload(
+            url='/web/content/test_http.gizeh_png',
+            headers={'Range': 'bytes=100-199'},
+
+            assert_status_code=206,
+            assert_headers={
+                'Content-Length': '100',
+                'Content-Range': 'bytes 100-199/814',
+                'Content-Type': 'image/png',
+                'Content-Disposition': 'inline; filename=gizeh.png',
+            },
+            assert_content=self.gizeh_data[100:200]
+        )
+
 
 class TestHttpStaticCache(TestHttpStaticCommon):
     @freeze_time(datetime.utcnow())