Add weblate_utils.py to work with Weblate REST API

Rewrites existing ZanataUtils.py to work with Weblate as part of migration work.

Key summary:
- IniConfig class name is the same
- ZanataRestService class name is renamed as WeblateRestService class
  with the same functionality
- ProjectConfig class is not implemented since Weblate does not
  have project configuration file like zanata.xml.

Implements: blueprint weblate-tools
Change-Id: Ie4cf861cc6ca59456c5d563d7673fbf54b3bb42f

tools/weblate/weblate_utils.py

@@ -0,0 +1,100 @@
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+import json
+from urllib import parse
+
+import requests
+
+import wlc
+from wlc import config as cfg
+
+
+class IniConfig(object):
+    """Object that stores weblate.ini configuration.
+
+    Read url and key from weblate.ini and make its values available.
+    Attributes:
+    url: The URL of the Weblate server.
+    key: The API key to use for authentication.
+    _inifile: The path to the ini file to load values from (not public).
+    """
+
+    def __init__(self, inifile):
+        self._inifile = inifile
+        self._find_config()
+
+    def _find_config(self):
+        config = cfg.WeblateConfig()
+        config.load(self._inifile)
+        self.url, self.key = config.get_url_key()
+
+
+class WeblateRestService(object):
+    """Object that communicates with the Weblate REST API.
+
+    Attributes:
+    url: The URL of the Weblate server.
+    key: The API key to use for authentication.
+    headers: The HTTP headers to use for requests. Must contain the key.
+    verify: Whether to verify SSL certificates.
+    """
+
+    def __init__(
+        self,
+        wconfig,
+        accept="application/json, text/javascript",
+        content_type="application/json",
+        verify=True,
+    ):
+        self.url, self.key = wconfig.url, wconfig.key
+        self.weblate_obj = wlc.Weblate()
+        self.headers = {
+            "Accept": accept,
+            "Content-Type": content_type,
+            "Authorization": "Token " + self.key,
+        }
+        self.verify = verify
+
+    def _construct_url(self, url_fragment):
+        return parse.urljoin(self.url, url_fragment)
+
+    def query(self, url_fragment, raise_errors=True):
+        request_url = self._construct_url(url_fragment)
+        try:
+            r = requests.get(
+                request_url,
+                verify=self.verify,
+                headers=self.headers
+                )
+        except requests.exceptions.ConnectionError:
+            raise ValueError("Connection Error")
+        if raise_errors and r.status_code != 200:
+            raise ValueError(
+                "Got status code %s for %s" % (r.status_code, request_url)
+                )
+        if raise_errors and not r.content:
+            raise ValueError(
+                "Did not receive any data from %s" % request_url
+                )
+        return r
+
+    def push(self, url_fragment, data):
+        request_url = self._construct_url(url_fragment)
+        try:
+            return requests.put(
+                request_url,
+                verify=self.verify,
+                headers=self.headers,
+                data=json.dumps(data),
+            )
+        except requests.exceptions.ConnectionError:
+            raise ValueError("Connection error")