Helpviewer/UserAgent/UserAgentManager.py

# -*- coding: utf-8 -*-

# Copyright (c) 2012 - 2013 Detlev Offenbach <detlev@die-offenbachs.de>
#

"""
Module implementing a user agent manager.
"""

import os

from PyQt4.QtCore import pyqtSignal, QObject, QXmlStreamReader

from E5Gui import E5MessageBox

from .UserAgentWriter import UserAgentWriter
from .UserAgentReader import UserAgentReader

from Utilities.AutoSaver import AutoSaver
import Utilities


class UserAgentManager(QObject):
    """
    Class implementing a user agent manager.
    
    @signal changed() emitted to indicate a change
    @signal userAgentSettingsSaved() emitted after the user agent settings were saved
    """
    changed = pyqtSignal()
    userAgentSettingsSaved = pyqtSignal()
    
    def __init__(self, parent=None):
        """
        Constructor
        
        @param parent reference to the parent object (QObject)
        """
        super().__init__(parent)
        
        self.__agents = {}      # dictionary with agent strings indexed by host name
        self.__loaded = False
        self.__saveTimer = AutoSaver(self, self.save)
        
        self.changed.connect(self.__saveTimer.changeOccurred)
    
    def getFileName(self):
        """
        Public method to get the file name of the user agents file.
        
        @return name of the user agents file (string)
        """
        return os.path.join(Utilities.getConfigDir(), "browser", "userAgentSettings.xml")
    
    def save(self):
        """
        Public slot to save the user agent entries to disk.
        """
        if not self.__loaded:
            return
        
        agentFile = self.getFileName()
        writer = UserAgentWriter()
        if not writer.write(agentFile, self.__agents):
            E5MessageBox.critical(None,
                self.trUtf8("Saving user agent data"),
                self.trUtf8("""<p>User agent data could not be saved to <b>{0}</b></p>"""
                            ).format(agentFile))
        else:
            self.userAgentSettingsSaved.emit()
    
    def __load(self):
        """
        Private method to load the saved user agent settings.
        """
        agentFile = self.getFileName()
        if not os.path.exists(agentFile):
            self.__loadNonXml(os.path.splitext(agentFile)[0])
        else:
            reader = UserAgentReader()
            self.__agents = reader.read(agentFile)
            if reader.error() != QXmlStreamReader.NoError:
                E5MessageBox.warning(None,
                    self.trUtf8("Loading user agent data"),
                    self.trUtf8("""Error when loading user agent data on"""
                                """ line {0}, column {1}:\n{2}""")\
                        .format(reader.lineNumber(),
                                reader.columnNumber(),
                                reader.errorString()))
        
        self.__loaded = True
    
    def __loadNonXml(self, agentFile):
        """
        Private method to load non-XML user agent files.
        
        This method is to convert from the old, non-XML format to the new
        XML based format.
        
        @param agentFile name of the non-XML user agent file (string)
        """
        if os.path.exists(agentFile):
            try:
                f = open(agentFile, "r", encoding="utf-8")
                lines = f.read()
                f.close()
            except IOError as err:
                E5MessageBox.critical(None,
                    self.trUtf8("Loading user agent data"),
                    self.trUtf8("""<p>User agent data could not be loaded """
                                """from <b>{0}</b></p>"""
                                """<p>Reason: {1}</p>""")\
                        .format(agentFile, str(err)))
                return
            
            for line in lines.splitlines():
                if not line or \
                   line.startswith("#") or \
                   "@@" not in line:
                    continue
                
                host, agent = line.split("@@", 1)
                self.__agents[host] = agent
            
            os.remove(agentFile)
        
        self.__loaded = True
        
        # this does the conversion
        self.save()
    
    def reload(self):
        """
        Public method to reload the user agent settings.
        """
        if not self.__loaded:
            return
        
        self.__agents = {}
        self.__load()
    
    def close(self):
        """
        Public method to close the user agents manager.
        """
        self.__saveTimer.saveIfNeccessary()
    
    def removeUserAgent(self, host):
        """
        Public method to remove a user agent entry.
        
        @param host host name (string)
        """
        if host in self.__agents:
            del self.__agents[host]
            self.changed.emit()
    
    def allHostNames(self):
        """
        Public method to get a list of all host names we a user agent setting for.
        
        @return sorted list of all host names (list of strings)
        """
        if not self.__loaded:
            self.__load()
        
        return sorted(self.__agents.keys())
    
    def hostsCount(self):
        """
        Public method to get the number of available user agent settings.
        
        @return number of user agent settings (integer)
        """
        if not self.__loaded:
            self.__load()
        
        return len(self.__agents)
    
    def userAgent(self, host):
        """
        Public method to get the user agent setting for a host.
        
        @param host host name (string)
        @return user agent string (string)
        """
        if not self.__loaded:
            self.__load()
        
        if host not in self.__agents:
            return ""
        
        return self.__agents[host]
    
    def setUserAgent(self, host, agent):
        """
        Public method to set the user agent string for a host.
        
        @param host host name (string)
        @param agent user agent string (string)
        """
        if host != "" and agent != "":
            self.__agents[host] = agent
            self.changed.emit()
    
    def userAgentForUrl(self, url):
        """
        Publci method to determine the user agent for the given URL.
        
        @param url URL to determine user agent for (QUrl)
        @return user agent string (string)
        """
        if url.isValid():
            host = url.host()
            return self.userAgent(host)
        
        return ""
    
    def setUserAgentForUrl(self, url, agent):
        """
        Public method to set the user agent string for an URL.
        
        @param url URL to register user agent setting for (QUrl)
        @param agent new current user agent string (string)
        """
        if url.isValid():
            host = url.host()
            self.setUserAgent(host, agent)