Histories: xml import/export — untested

To be tested when history generation is available

histories/models.py

@@ -6,6 +6,8 @@ interests, keywords...
 import random
 from math import floor
 from queue import Queue
+from xml.etree import ElementTree as ET
+from datetime import datetime
 from django.db import models
 import profiles.models as profiles
 from crawl import crawl
@@ -13,6 +15,15 @@ from pinocchio.settings import HISTORY_MIN
 from .tor_runner import TorInstance
 
 
+class InvalidXml(Exception):
+    def __init__(self, what='unexpected XML data.'):
+        super().__init__()
+        self.what = what
+
+    def __str__(self):
+        return "Invalid XML: " + self.what
+
+
 class HistoryEntry(models.Model):
     """ A history entry, aka a url, and a timestamp.
     """
@@ -28,14 +39,48 @@ class HistoryEntry(models.Model):
         """
         return "{} : {}".format(self.timestamp, self.search)
 
+    def to_xml(self, xml_root):
+        entry = ET.Element('history')
+        entry_url = ET.Element('url')
+        entry_url.text = self.search
+        entry_ts = ET.Element('timestamp')
+        entry_ts.text = self.timestamp.timestamp()
+        entry.append(entry_url)
+        entry.append(entry_ts)
+        xml_root.append(entry)
+
+    @staticmethod
+    def from_xml(xml_root, in_history):
+        if xml_root.tag != 'history':
+            raise InvalidXml("expected <history> tag here.")
+        url, timestamp = None, None
+
+        for child in xml_root:
+            if child.tag == 'url':
+                url = child.text
+            elif child.tag == 'timestamp':
+                try:
+                    timestamp = datetime.fromtimestamp(child.text)
+                except TypeError:
+                    raise InvalidXml("invalid timestamp {}".format(child.text))
+            else:
+                raise InvalidXml("unknown tag {} as child of <history>".format(
+                    child.tag))
+        output = HistoryEntry()
+        output.search = url
+        output.timestamp = timestamp
+        output.history = in_history
+
+        return output
+
 
 class History(models.Model):
     """ A history for a user, containing some web connections (http, https).
     Each history is timed, in a human-behaviour manner. """
 
     start_ts = models.DateTimeField(
-        help_text='The starting timestamp of the history. Useful for cron-like '
-                  'structure.'
+        help_text=('The starting timestamp of the history. Useful for '
+                   'cron-like structure.')
 
     )
     played = models.BooleanField(default=False)
@@ -58,7 +103,6 @@ class History(models.Model):
         header = "[History]:\n"
         return header + "\n".join(history_set)
 
-
     def play_histories(self):
         """ Actually plays the history.
         """
@@ -66,6 +110,48 @@ class History(models.Model):
         runner = TorInstance(self.history)
         self.save()
 
+    def to_xml(self, xml_root):
+        ''' Exports the current history to xml '''
+        hist_node = ET.Element("history", attrib={
+            'start-ts': self.start_ts,
+            'played': 1 if self.played else 0,
+            'user': self.user.pk,
+        })
+        xml_root.append(hist_node)
+        for entry in self.history_set:
+            entry.to_xml(hist_node)
+
+    @staticmethod
+    def from_xml(xml_root):
+        ''' Loads an history from an XML file '''
+
+        REQUIRED_ATTR = ['start-ts', 'played', 'user']
+
+        if xml_root.tag != 'history':
+            raise InvalidXml('unexpected node {} as root of an history'.format(
+                xml_root.tag))
+        for attr in REQUIRED_ATTR:
+            if attr not in xml_root.attrib:
+                raise InvalidXml(('missing attribute "{}" for tag of type '
+                                  'history').format(attr))
+        start_ts = xml_root.attrib['start-ts']
+        played = xml_root.attrib['played']
+        user_pk = xml_root.attrib['user']
+        users = History.objects.filter(pk=1)
+        if len(users) != 1:
+            raise InvalidXml('primary key for History {} is invalid'.format(
+                user_pk))
+
+        output = History()
+        output.start_ts = start_ts
+        output.played = played > 0
+        output.user = users[0]
+
+        for child in xml_root:
+            HistoryEntry.from_xml(child, output)
+
+        return output
+
 
 def generate_partial_history(user, t_start):
     """ Generate the part of the history resulting from the crawl starting at
@@ -75,32 +161,30 @@ def generate_partial_history(user, t_start):
     result = []
     basis = generate_first_url(user)
     result.append((basis, timestamp))
-    timestamp += 5* random.weibullvariate(1, 1.5)
+    t_start += 5 * random.weibullvariate(1, 1.5)
     queue = Queue()
     crawler = crawl.CrawlingThread(user, basis, queue)
     crawler.start()
     crawler.join()
     urls = queue.get()
     for url in urls:
-        timestamp += 5* random.weibullvariate(1, 1.5)
+        t_start += 5 * random.weibullvariate(1, 1.5)
         result.append((url, timestamp))
     return result
 
+
 def generate_first_url(user):
     """ Generate the first url of a partial history, based on the user
     information. """
-    interest = random.choice(
-        [user.interests.keywords.all(), user.interests.places.all(),
+    interest = random.choice([
+        user.interests.keywords.all(), user.interests.places.all(),
         user.interests.websites.all(), user.interests.events.all()
-        ]
-    )
+    ])
     search_term = random.choice(interest)
     url = search_term.generate_url(user)
     return url
 
 
-
-
 def generate_history(user, ts_start):
     """ Generate a new history for the user `user`, starting from timestamp
     `ts_start`.