From 95772acbd2676873d1b1c7b2c4a4df0a44c01293 Mon Sep 17 00:00:00 2001
From: Egor Tensin <Egor.Tensin@gmail.com>
Date: Thu, 16 Jun 2016 15:12:59 +0300
Subject: add CSV database reader

---
 vk/utils/tracking/db/reader/__init__.py |  5 +++
 vk/utils/tracking/db/reader/csv.py      | 22 +++++++++++
 vk/utils/tracking/db/record.py          | 68 +++++++++++++++++++++++++--------
 vk/utils/tracking/db/writer/csv.py      | 21 +++++-----
 4 files changed, 92 insertions(+), 24 deletions(-)
 create mode 100644 vk/utils/tracking/db/reader/__init__.py
 create mode 100644 vk/utils/tracking/db/reader/csv.py

(limited to 'vk/utils')

diff --git a/vk/utils/tracking/db/reader/__init__.py b/vk/utils/tracking/db/reader/__init__.py
new file mode 100644
index 0000000..330d5a8
--- /dev/null
+++ b/vk/utils/tracking/db/reader/__init__.py
@@ -0,0 +1,5 @@
+# Copyright 2016 Egor Tensin <Egor.Tensin@gmail.com>
+# This file is licensed under the terms of the MIT License.
+# See LICENSE.txt for details.
+
+__all__ = 'csv',
diff --git a/vk/utils/tracking/db/reader/csv.py b/vk/utils/tracking/db/reader/csv.py
new file mode 100644
index 0000000..b66e397
--- /dev/null
+++ b/vk/utils/tracking/db/reader/csv.py
@@ -0,0 +1,22 @@
+# Copyright 2016 Egor Tensin <Egor.Tensin@gmail.com>
+# This file is licensed under the terms of the MIT License.
+# See LICENSE.txt for details.
+
+import csv
+
+from ..record import Record
+
+class Reader:
+    def __init__(self, path):
+        self._fd = open(path)
+        self._reader = csv.reader(self._fd)
+
+    def __enter__(self):
+        self._fd.__enter__()
+        return self
+
+    def __exit__(self, *args):
+        self._fd.__exit__(*args)
+
+    def __iter__(self):
+        return map(Record.from_row, self._reader)
diff --git a/vk/utils/tracking/db/record.py b/vk/utils/tracking/db/record.py
index 0a1a687..e126442 100644
--- a/vk/utils/tracking/db/record.py
+++ b/vk/utils/tracking/db/record.py
@@ -5,23 +5,61 @@
 from collections import OrderedDict
 from datetime import datetime
 
-from vk.user import Field
+from vk.user import Field as UserField
+
+def _gen_timestamp():
+    return datetime.utcnow().replace(microsecond=0)
 
 class Record:
-    _FIELDS = (
-        Field.UID,
-        Field.FIRST_NAME,
-        Field.LAST_NAME,
-        Field.SCREEN_NAME,
-        Field.ONLINE,
-        Field.LAST_SEEN,
+    _USER_FIELDS = (
+        UserField.UID,
+        UserField.FIRST_NAME,
+        UserField.LAST_NAME,
+        UserField.SCREEN_NAME,
+        UserField.ONLINE,
+        UserField.LAST_SEEN,
     )
 
-    def __init__(self, user):
-        self._fields = OrderedDict()
-        for field in self._FIELDS:
-            self._fields[field] = user[field]
-        self._timestamp = datetime.utcnow().replace(microsecond=0)
+    def __init__(self, fields, timestamp=None):
+        self._fields = fields
+        self._timestamp = timestamp if timestamp is not None else _gen_timestamp()
+
+    def __iter__(self):
+        return iter(self._fields)
+
+    def __contains__(self, field):
+        return field in self._fields
+
+    def __getitem__(self, field):
+        return self._fields[field]
+
+    def __setitem__(self, field, value):
+        self._fields[field] = value
+
+    def get_timestamp(self):
+        return self._timestamp
+
+    @staticmethod
+    def _timestamp_from_string(s):
+        return datetime.fromtimestamp(s)
+
+    def timestamp_to_string(self):
+        return self.get_timestamp().isoformat()
+
+    @staticmethod
+    def from_user(user):
+        fields = OrderedDict()
+        for field in Record._USER_FIELDS:
+            fields[field] = user[field]
+        return Record(fields)
+
+    @staticmethod
+    def from_row(row):
+        timestamp = Record._timestamp_from_string(row[0])
+        fields = OrderedDict()
+        for i in range(len(Record._USER_FIELDS)):
+            fields[Record._USER_FIELDS[i]] = row[i + 1]
+        return Record(fields, timestamp)
 
-    def to_list(self):
-        return [self._timestamp.isoformat()] + list(self._fields.values())
+    def to_row(self):
+        return [self.timestamp_to_string()] + [self[field] for field in self]
diff --git a/vk/utils/tracking/db/writer/csv.py b/vk/utils/tracking/db/writer/csv.py
index 4594e09..8dc2299 100644
--- a/vk/utils/tracking/db/writer/csv.py
+++ b/vk/utils/tracking/db/writer/csv.py
@@ -3,7 +3,6 @@
 # See LICENSE.txt for details.
 
 import csv
-from datetime import datetime
 
 from ..record import Record
 
@@ -15,25 +14,29 @@ class Writer:
             self._fd = open(path, mode)
             self._writer = csv.writer(self._fd, lineterminator='\n')
 
-    def _is_valid(self):
+    def __bool__(self):
         return self._fd is not None
 
     def __enter__(self):
-        if not self._is_valid():
-            return None
+        if not self:
+            return self
         self._fd.__enter__()
         return self
 
     def __exit__(self, *args):
-        if self._is_valid():
-            self._fd.__exit__(*args)
+        if not self:
+            return
+        self._fd.__exit__(*args)
 
     def flush(self):
-        if self._is_valid():
-            self._fd.flush()
+        if not self:
+            return
+        self._fd.flush()
 
     def write_record(self, user):
-        self._write_row(Record(user).to_list())
+        if not self:
+            return
+        self._write_row(Record.from_user(user).to_row())
         self.flush()
 
     def _write_row(self, row):
-- 
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