Implement call to move to highest supported REST API version (#100)

Yaay hackathon!

This PR adds the ability to detect the highest supported version a given Tableau Server supports. In 10.1 and later this makes use of the `ServerInfo` endpoint, and in others it falls back to `auth.xml` which is guaranteed to be present on all versions of Server that we would care about.

If we can't determine the version for some reason, we default to 2.1, which is the last 'major' release of the API (with permissions semantics changes).
This currently doesn't have an auto-upgrade flag, that can come in another PR after more discussion

tableauserverclient/server/endpoint/__init__.py

@@ -1,7 +1,7 @@
 from .auth_endpoint import Auth
 from .datasources_endpoint import Datasources
 from .endpoint import Endpoint
-from .exceptions import ServerResponseError, MissingRequiredFieldError
+from .exceptions import ServerResponseError, MissingRequiredFieldError, ServerInfoEndpointNotFoundError
 from .groups_endpoint import Groups
 from .projects_endpoint import Projects
 from .schedules_endpoint import Schedules

tableauserverclient/server/endpoint/exceptions.py

@@ -24,3 +24,7 @@ def from_response(cls, resp):
 
 class MissingRequiredFieldError(Exception):
     pass
+
+
+class ServerInfoEndpointNotFoundError(Exception):
+    pass

tableauserverclient/server/endpoint/server_info_endpoint.py

@@ -1,4 +1,5 @@
 from .endpoint import Endpoint
+from .exceptions import ServerResponseError, ServerInfoEndpointNotFoundError
 from ...models import ServerInfoItem
 import logging
 
@@ -12,6 +13,11 @@ def baseurl(self):
 
     def get(self):
         """ Retrieve the server info for the server.  This is an unauthenticated call """
-        server_response = self.get_unauthenticated_request(self.baseurl)
+        try:
+            server_response = self.get_unauthenticated_request(self.baseurl)
+        except ServerResponseError as e:
+            if e.code == "404003":
+                raise ServerInfoEndpointNotFoundError
+
         server_info = ServerInfoItem.from_response(server_response.content)
         return server_info

tableauserverclient/server/server.py

@@ -1,8 +1,19 @@
+import xml.etree.ElementTree as ET
+
 from .exceptions import NotSignedInError
-from .endpoint import Sites, Views, Users, Groups, Workbooks, Datasources, Projects, Auth, Schedules, ServerInfo
+from .endpoint import Sites, Views, Users, Groups, Workbooks, Datasources, Projects, Auth, \
+    Schedules, ServerInfo, ServerInfoEndpointNotFoundError
 
 import requests
 
+_PRODUCT_TO_REST_VERSION = {
+    '10.0': '2.3',
+    '9.3': '2.2',
+    '9.2': '2.1',
+    '9.1': '2.0',
+    '9.0': '2.0'
+}
+
 
 class Server(object):
     class PublishMode:
@@ -47,6 +58,29 @@ def _set_auth(self, site_id, user_id, auth_token):
         self._user_id = user_id
         self._auth_token = auth_token
 
+    def _get_legacy_version(self):
+        response = self._session.get(self.server_address + "/auth?format=xml")
+        info_xml = ET.fromstring(response.content)
+        prod_version = info_xml.find('.//product_version').text
+        version = _PRODUCT_TO_REST_VERSION.get(prod_version, '2.1')  # 2.1
+        return version
+
+    def _determine_highest_version(self):
+        try:
+            old_version = self.version
+            self.version = "2.4"
+            version = self.server_info.get().rest_api_version
+        except ServerInfoEndpointNotFoundError:
+            version = self._get_legacy_version()
+
+        finally:
+            self.version = old_version
+
+        return version
+
+    def use_highest_version(self):
+        self.version = self._determine_highest_version()
+
     @property
     def baseurl(self):
         return "{0}/api/{1}".format(self._server_address, str(self.version))

test/assets/server_info_404.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<tsResponse xmlns="http://tableau.com/api" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://tableau.com/api http://tableau.com/api/ts-api-2.3.xsd">
+  <error code="404003">
+    <summary>Resource Not Found</summary>
+    <detail>Unknown resource '/2.4/serverInfo' specified in URI.</detail>
+  </error>
+</tsResponse>

test/assets/server_info_auth_info.xml

@@ -0,0 +1,12 @@
+<authinfo>
+<version version="0.31">
+<api_version>0.31</api_version>
+<server_api_version>0.31</server_api_version>
+<document_version>9.2</document_version>
+<product_version>9.3</product_version>
+<external_version>9.3.4</external_version>
+<build>hello.16.1106.2025</build>
+<publishing_method>unrestricted</publishing_method>
+<mobile_api_version>2.6</mobile_api_version>
+</version>
+</authinfo>

test/test_server_info.py

@@ -6,21 +6,48 @@
 TEST_ASSET_DIR = os.path.join(os.path.dirname(__file__), 'assets')
 
 SERVER_INFO_GET_XML = os.path.join(TEST_ASSET_DIR, 'server_info_get.xml')
+SERVER_INFO_404 = os.path.join(TEST_ASSET_DIR, 'server_info_404.xml')
+SERVER_INFO_AUTH_INFO_XML = os.path.join(TEST_ASSET_DIR, 'server_info_auth_info.xml')
 
 
 class ServerInfoTests(unittest.TestCase):
     def setUp(self):
         self.server = TSC.Server('http://test')
-        self.server.version = '2.4'
         self.baseurl = self.server.server_info.baseurl
 
     def test_server_info_get(self):
         with open(SERVER_INFO_GET_XML, 'rb') as f:
             response_xml = f.read().decode('utf-8')
         with requests_mock.mock() as m:
-            m.get(self.baseurl, text=response_xml)
+            self.server.version = '2.4'
+            m.get(self.server.server_info.baseurl, text=response_xml)
             actual = self.server.server_info.get()
 
             self.assertEqual('10.1.0', actual.product_version)
             self.assertEqual('10100.16.1024.2100', actual.build_number)
             self.assertEqual('2.4', actual.rest_api_version)
+
+    def test_server_info_use_highest_version_downgrades(self):
+        with open(SERVER_INFO_AUTH_INFO_XML, 'rb') as f:
+            # This is the auth.xml endpoint present back to 9.0 Servers
+            auth_response_xml = f.read().decode('utf-8')
+        with open(SERVER_INFO_404, 'rb') as f:
+            # 10.1 serverInfo response
+            si_response_xml = f.read().decode('utf-8')
+        with requests_mock.mock() as m:
+            # Return a 404 for serverInfo so we can pretend this is an old Server
+            m.get(self.server.server_address + "/api/2.4/serverInfo", text=si_response_xml, status_code=404)
+            m.get(self.server.server_address + "/auth?format=xml", text=auth_response_xml)
+            self.server.use_highest_version()
+            self.assertEqual(self.server.version, '2.2')
+
+    def test_server_info_use_highest_version_upgrades(self):
+        with open(SERVER_INFO_GET_XML, 'rb') as f:
+            si_response_xml = f.read().decode('utf-8')
+        with requests_mock.mock() as m:
+            m.get(self.server.server_address + "/api/2.4/serverInfo", text=si_response_xml)
+            # Pretend we're old
+            self.server.version = '2.0'
+            self.server.use_highest_version()
+            # Did we upgrade to 2.4?
+            self.assertEqual(self.server.version, '2.4')