Add Slack webhook.

Adds a new webhook integration for Slack to receive messages
from one's Slack team's public channels.
Contains negative tests for broken, missing or invalid data.

Allows two different option for integration:
1. Receive notification on a single stream with different topics
for each of Slack's public channels.
2. Receive notification on different streams for each of Slack's
public channels.

Steps to choose between the two options is described in the documentation.

Fixes #3569.

tools/lib/capitalization.py

@@ -27,6 +27,7 @@ IGNORED_PHRASES = [
     r"MiB",
     r"Pivotal",
     r'REMOTE_USER',
+    r'Slack',
     r"SSO",
     r'Terms of Service',
     r"URL",

zerver/fixtures/slack/slack_message_info.txt

@@ -0,0 +1 @@
+token=aotJImaVOVEVWssawxmegDWt&team_id=T3W8CTX0F&team_domain=gsoc2017&service_id=133126759712&channel_id=C3W8CTZFZ&channel_name=general&timestamp=1485947263.000010&user_id=U3W8CTX2T&user_name=slack_user&text=test

zerver/fixtures/slack/slack_message_info_missing_channel_name.txt

@@ -0,0 +1 @@
+token=aotJImaVOVEVWssawxmegDWt&team_id=T3W8CTX0F&team_domain=gsoc2017&service_id=133126759712&channel_id=C3W8CTZFZ&timestamp=1485947263.000010&user_id=U3W8CTX2T&user_name=slack_user&text=test

zerver/fixtures/slack/slack_message_info_missing_text.txt

@@ -0,0 +1 @@
+token=aotJImaVOVEVWssawxmegDWt&team_id=T3W8CTX0F&team_domain=gsoc2017&service_id=133126759712&channel_id=C3W8CTZFZ&channel_name=general&timestamp=1485947263.000010&user_name=slack_user&user_id=U3W8CTX2T

zerver/fixtures/slack/slack_message_info_missing_user_name.txt

@@ -0,0 +1 @@
+token=aotJImaVOVEVWssawxmegDWt&team_id=T3W8CTX0F&team_domain=gsoc2017&service_id=133126759712&channel_id=C3W8CTZFZ&channel_name=general&timestamp=1485947263.000010&user_id=U3W8CTX2T&text=test

zerver/lib/integrations.py

@@ -151,6 +151,7 @@ WEBHOOK_INTEGRATIONS = [
     WebhookIntegration('pivotal', display_name='Pivotal Tracker'),
     WebhookIntegration('semaphore'),
     WebhookIntegration('sentry'),
+    WebhookIntegration('slack'),
     WebhookIntegration('solano', display_name='Solano Labs'),
     WebhookIntegration('splunk', display_name='Splunk'),
     WebhookIntegration('stash'),

zerver/webhooks/slack/doc.html

@@ -0,0 +1,41 @@
+<p>Get notifications from Slack for messages on your team's public channels</p>
+
+<p>
+    There are two ways in which you may want to receive a notification:
+    <ul type="disc">
+        <li>Slack Channel to a single Zulip stream with different topics</li>
+        <li>Multiple Zulip streams for multiple Slack channels</li>
+    </ul>
+</p>
+
+<p>
+    If you want a single Zulip stream to receive notifications from Slack then first create your desired stream.
+</p>
+
+
+<p>
+    Go to the following URL: <code>https://api.slack.com</code><br/>
+    Next, under the category of App features click on <b>Legacy custom integrations</b>.<br/>
+    <img class="screenshot" src="/static/images/integrations/slack/001.png"/><br/><br/>
+    Now, click on <b>Outgoing Webhooks</b> under <b>Custom Integrations</b>.<br/>
+    <img class="screenshot" src="/static/images/integrations/slack/002.png"/><br/><br/>
+    Then click the hyperlink <b>outgoing webhook integration</b> which can be found in the page.
+    <img class="screenshot" src="/static/images/integrations/slack/003.png"/><br/><br/>
+    Next, click the <b>Add Outgoing Webhook integration</b> button.
+    <img class="screenshot" src="/static/images/integrations/slack/004.png"/><br/><br/>
+</p><br/>
+<p>
+    Now, under <code> Integration Settings, </code> fill in the channel you'd like to get your notifications from.<br/><br/>
+    Then fill in <code>{{ external_api_uri_subdomain }}/v1/external/slack?api_key=abcdefgh&amp;stream=slack&amp;channels_map_topics=1</code> as your URL.<br/><br/>
+    <img class="screenshot" src="/static/images/integrations/slack/005.png"/><br/><br/>
+    Finally, save your settings.<br/><br/>
+</p>
+<p>
+    In case you want your Slack channels mapped to multiple Zulip streams, you have to
+    change the parameter <code>channels_map_to_topics=1</code> to <code>channels_map_to_topics=0</code> in your URL.
+    The resulting URL will be
+    <code>{{ external_api_uri_subdomain }}/v1/external/slack?api_key=abcdefgh&amp;stream=slack&amp;channels_map_topics=0</code>
+</p>
+<p><b>Congratulations, you're done!</b></p>
+<p><b>This integration is not created by, affiliated with, or supported by Slack Technologies, Inc.</b></p>
+

zerver/webhooks/slack/tests.py

@@ -0,0 +1,64 @@
+# -*- coding: utf-8 -*-
+from zerver.lib.test_classes import WebhookTestCase
+from six import text_type
+
+
+class SlackWebhookTests(WebhookTestCase):
+    STREAM_NAME = 'slack'
+    URL_TEMPLATE = "/api/v1/external/slack?stream={stream}&api_key={api_key}"
+    FIXTURE_DIR_NAME = 'slack'
+
+    def test_slack_channel_to_topic(self):
+        # type: () -> None
+
+        expected_subject = u"channel: general"
+        expected_message = u"**slack_user**: `test\n`"
+        self.send_and_test_stream_message('message_info', expected_subject, expected_message,
+                                          content_type="application/x-www-form-urlencoded")
+
+    def test_slack_channel_to_stream(self):
+        # type: () -> None
+
+        self.STREAM_NAME = 'general'
+        self.url = "{}{}".format(self.url, "&channels_map_to_topics=0")
+        expected_subject = u"Message from Slack"
+        expected_message = u"**slack_user**: `test\n`"
+        self.send_and_test_stream_message('message_info', expected_subject, expected_message,
+                                          content_type="application/x-www-form-urlencoded")
+
+    def test_missing_data_user_name(self):
+        # type: () -> None
+
+        payload = self.get_body('message_info_missing_user_name')
+        url = self.build_webhook_url()
+        result = self.client_post(url, payload, content_type="application/x-www-form-urlencoded")
+        self.assert_json_error(result, "Missing 'user_name' argument")
+
+    def test_missing_data_channel_name(self):
+        # type: () -> None
+
+        payload = self.get_body('message_info_missing_channel_name')
+        url = self.build_webhook_url()
+        result = self.client_post(url, payload, content_type="application/x-www-form-urlencoded")
+        self.assert_json_error(result, "Missing 'channel_name' argument")
+
+    def test_missing_data_text(self):
+        # type: () -> None
+
+        payload = self.get_body('message_info_missing_text')
+        url = self.build_webhook_url()
+        result = self.client_post(url, payload, content_type="application/x-www-form-urlencoded")
+        self.assert_json_error(result, "Missing 'text' argument")
+
+    def test_invalid_channels_map_to_topics(self):
+        # type: () -> None
+
+        payload = self.get_body('message_info')
+        url = "{}{}".format(self.url, "&channels_map_to_topics=abc")
+        result = self.client_post(url, payload, content_type="application/x-www-form-urlencoded")
+        self.assert_json_error(result, 'Error: channels_map_to_topics parameter other than 0 or 1')
+
+    def get_body(self, fixture_name):
+        # type: (text_type) -> text_type
+
+        return self.fixture_data("slack", fixture_name, file_type="txt")

zerver/webhooks/slack/view.py

@@ -0,0 +1,35 @@
+from __future__ import absolute_import
+from django.utils.translation import ugettext as _
+from django.http import HttpRequest, HttpResponse
+from django.utils.translation import ugettext as _
+from zerver.lib.actions import check_send_message, create_stream_if_needed
+from zerver.lib.response import json_success, json_error
+from zerver.lib.validator import check_string, check_int
+from zerver.decorator import REQ, has_request_variables, api_key_only_webhook_view
+from zerver.models import UserProfile, Client
+
+ZULIP_MESSAGE_TEMPLATE = "**{message_sender}**: `{text}`"
+VALID_OPTIONS = {'SHOULD_NOT_BE_MAPPED': '0', 'SHOULD_BE_MAPPED': '1'}
+
+@api_key_only_webhook_view('Slack')
+@has_request_variables
+def api_slack_webhook(request, user_profile, client,
+                      user_name=REQ(),
+                      text=REQ(),
+                      channel_name=REQ(),
+                      stream=REQ(default='slack'),
+                      channels_map_to_topics=REQ(default='1')):
+    # type: (HttpRequest, UserProfile, Client, str, str, str, str, str) -> HttpResponse
+
+    if channels_map_to_topics not in list(VALID_OPTIONS.values()):
+        return json_error(_('Error: channels_map_to_topics parameter other than 0 or 1'))
+
+    if channels_map_to_topics == VALID_OPTIONS['SHOULD_BE_MAPPED']:
+        subject = "channel: {}".format(channel_name)
+    else:
+        stream = channel_name
+        subject = _("Message from Slack")
+
+    content = ZULIP_MESSAGE_TEMPLATE.format(message_sender=user_name, text=text)
+    check_send_message(user_profile, client, "stream", [stream], subject, content)
+    return json_success()