Bridge files slack to zulip (#15)

* Fix a time zone sensitivity issue in the reformat test.

* Very basic support for mirroring files from slack to zulip.

- Only minimal error checking, and on any failure will revert to just
  saying there was a file there with no link.
- No tests.
- Does not do any clever caching -- editing without replacing the file
  just uploads another copy.

Author: robsiemb

__init__.py

@@ -249,7 +249,7 @@ async def receive_slack_msg(**payload):
                     needs_leading_newline = \
                         (len(msg) > 0 or len(formatted_attachments['markdown']) > 0)
                     formatted_files = slack_reformat.format_files_from_slack(
-                        files, needs_leading_newline)
+                        files, needs_leading_newline, SLACK_TOKEN, self.zulip_client)
 
                     zulip_message_text = \
                         msg + formatted_attachments['markdown'] + formatted_files['markdown']
@@ -327,6 +327,7 @@ async def receive_slack_msg(**payload):
 
     def send_from_zulip(self, msg):
         _LOGGER.debug('caught zulip message')
+        _LOGGER.debug('JSON: %s' % json.dumps(msg))
         try:
             if (msg['subject'] in PUBLIC_TWO_WAY and
                     msg['sender_short_name'] != ZULIP_BOT_NAME):

slack_reformat.py

@@ -5,8 +5,11 @@
 import logging
 import re
 import sys
+import requests
 import traceback
 
+from io import BytesIO
+
 _LOGGER = logging.getLogger(__name__)
 
 # These are module-private regular expressions used by the reformatter
@@ -151,10 +154,14 @@ async def replace_markdown_link(m):
                                replace_markdown_link)
 
 
-def format_files_from_slack(files, needs_leading_newline):
+def format_files_from_slack(files, needs_leading_newline,
+                            slack_bearer_token=None, zulip_client=None):
     '''Given a list of files from the slack API, return both a markdown and plaintext
        string representation of those files.
 
+       Assuming a bearer token and zulip client are provided, the files are mirrored to zulip
+       and those links are included in the markdown result.
+
        This method only uses the passed in message text to determine how to format its output
        caller must append as appropriate.'''
     if files == None:
@@ -174,7 +181,24 @@ def format_files_from_slack(files, needs_leading_newline):
             first_file = False
 
         if 'name' in file and file['name']:
-            output['markdown'] += f"*(Bridged Message included file: {file['name']}"
+            rendered_markdown_name = file['name']
+            if slack_bearer_token and zulip_client and 'url_private' in file and file['url_private']:
+                file_private_url = file['url_private']
+                r = requests.get(file_private_url,
+                                 headers={"Authorization": f"Bearer {slack_bearer_token}"})
+                if r.status_code == 200:
+                    uploadable_file = BytesIO(r.content)
+                    uploadable_file.name = file['name']
+
+                    response = zulip_client.upload_file(uploadable_file)
+                    if 'uri' in response and response['uri']:
+                        rendered_markdown_name = f"[{file['name']}]({response['uri']})"
+                    else:
+                        _LOGGER.info('Got bad response when uploading to zulip: {}'.format(response))
+                else:
+                    _LOGGER.info(f"Got code {r.status_code} when fetching {file_private_url} from slack.")
+
+            output['markdown'] += f"*(Bridged Message included file: {rendered_markdown_name}"
             output['plaintext'] += f"(Bridged Message included file: {file['name']}"
             if 'title' in file and file['title'] and file['name'] != file['title']:
                 output['markdown'] += f": '{file['title']}'"

slack_reformat_test.py

@@ -194,6 +194,9 @@ def test_markdown_links(self):
 
     def test_format_files_from_slack(self):
         # Note: This test is _not_ exhaustive!
+        #
+        # TODO: Figure out some way to mock out the pieces necessary to allow us to test the download/upload
+        # path for files.
 
         # None case
         output = slack_reformat.format_files_from_slack(None, False)
@@ -331,13 +334,17 @@ def test_format_attachments_from_slack(self):
         }
         output = do_await(slack_reformat.format_attachments_from_slack(
             'message', [github_app_attachment], False, _trivial_user_formatter))
+
+        # TODO This test (really, the formatting itself) is time zone sensitive to the TZ of the machine
+        # you are on!  Currently assumes Eastern time.
+
         self.assertEqual(
             output['markdown'],
-            '\n\n```quote\n**ABTech/zulip_slack_integration**\n**Stars**\n1\n**Language**\nPython\n*[ABTech/zulip_slack_integration](https://github.com/ABTech/zulip_slack_integration)* | *Thu May 23 14:35:12 2019*\n```'
+            '\n\n```quote\n**ABTech/zulip_slack_integration**\n**Stars**\n1\n**Language**\nPython\n*[ABTech/zulip_slack_integration](https://github.com/ABTech/zulip_slack_integration)* | *Thu May 23 17:35:12 2019*\n```'
         )
         self.assertEqual(
             output['plaintext'],
-            '\n\nABTech/zulip_slack_integration\nStars\n1\nLanguage\nPython\n[ABTech/zulip_slack_integration](https://github.com/ABTech/zulip_slack_integration) | Thu May 23 14:35:12 2019\n'
+            '\n\nABTech/zulip_slack_integration\nStars\n1\nLanguage\nPython\n[ABTech/zulip_slack_integration](https://github.com/ABTech/zulip_slack_integration) | Thu May 23 17:35:12 2019\n'
         )
 
 if __name__ == '__main__':