schema.py

#!/usr/bin/env python


#############################################################################
##
## Copyright (C) 2013 Riverbank Computing Limited.
## Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
## All rights reserved.
##
## This file is part of the examples of PyQt.
##
## $QT_BEGIN_LICENSE:BSD$
## You may use this file under the terms of the BSD license as follows:
##
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## modification, are permitted provided that the following conditions are
## met:
##   * Redistributions of source code must retain the above copyright
##     notice, this list of conditions and the following disclaimer.
##   * Redistributions in binary form must reproduce the above copyright
##     notice, this list of conditions and the following disclaimer in
##     the documentation and/or other materials provided with the
##     distribution.
##   * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
##     the names of its contributors may be used to endorse or promote
##     products derived from this software without specific prior written
##     permission.
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## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
## "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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## A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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## (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
## OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
## $QT_END_LICENSE$
##
#############################################################################


from PyQt5.QtCore import QByteArray, QFile, QRegExp, Qt
from PyQt5.QtGui import (QColor, QFont, QSyntaxHighlighter, QTextCharFormat,
        QTextCursor, QTextFormat)
from PyQt5.QtWidgets import QApplication, QMainWindow, QTextEdit
from PyQt5.QtXmlPatterns import (QAbstractMessageHandler, QSourceLocation,
        QXmlSchema, QXmlSchemaValidator)

import schema_rc
from ui_schema import Ui_SchemaMainWindow


def encode_utf8(ba):
    try:
        return unicode(ba, encoding='utf8')
    except NameError:
        return str(ba, encoding='utf8')


def decode_utf8(qs):
    try:
        return QByteArray(qs.decode(encoding='utf8'))
    except AttributeError:
        return QByteArray(bytes(qs, encoding='utf8'))


class XmlSyntaxHighlighter(QSyntaxHighlighter):

    def __init__(self, parent=None):
        super(XmlSyntaxHighlighter, self).__init__(parent)

        self.highlightingRules = []

        # Tag format.
        format = QTextCharFormat()
        format.setForeground(Qt.darkBlue)
        format.setFontWeight(QFont.Bold)
        pattern = QRegExp("(<[a-zA-Z:]+\\b|<\\?[a-zA-Z:]+\\b|\\?>|>|/>|</[a-zA-Z:]+>)")
        self.highlightingRules.append((pattern, format))

        # Attribute format.
        format = QTextCharFormat()
        format.setForeground(Qt.darkGreen)
        pattern = QRegExp("[a-zA-Z:]+=")
        self.highlightingRules.append((pattern, format))

        # Attribute content format.
        format = QTextCharFormat()
        format.setForeground(Qt.red)
        pattern = QRegExp("(\"[^\"]*\"|'[^']*')")
        self.highlightingRules.append((pattern, format))

        # Comment format.
        self.commentFormat = QTextCharFormat()
        self.commentFormat.setForeground(Qt.lightGray)
        self.commentFormat.setFontItalic(True)

        self.commentStartExpression = QRegExp("<!--")
        self.commentEndExpression = QRegExp("-->")

    def highlightBlock(self, text):
        for pattern, format in self.highlightingRules:
            expression = QRegExp(pattern)
            index = expression.indexIn(text)
            while index >= 0:
                length = expression.matchedLength()
                self.setFormat(index, length, format)
                index = expression.indexIn(text, index + length)

        self.setCurrentBlockState(0)

        startIndex = 0
        if self.previousBlockState() != 1:
            startIndex = self.commentStartExpression.indexIn(text)

        while startIndex >= 0:
            endIndex = self.commentEndExpression.indexIn(text, startIndex)
            if endIndex == -1:
                self.setCurrentBlockState(1)
                commentLength = text.length() - startIndex
            else:
                commentLength = endIndex - startIndex + self.commentEndExpression.matchedLength()

            self.setFormat(startIndex, commentLength, self.commentFormat)
            startIndex = self.commentStartExpression.indexIn(text,
                    startIndex + commentLength)


class MessageHandler(QAbstractMessageHandler):

    def __init__(self):
        super(MessageHandler, self).__init__()

        self.m_description = ""
        self.m_sourceLocation = QSourceLocation()

    def statusMessage(self):
        return self.m_description

    def line(self):
        return self.m_sourceLocation.line()

    def column(self):
        return self.m_sourceLocation.column()

    def handleMessage(self, type, description, identifier, sourceLocation):
        self.m_description = description
        self.m_sourceLocation = sourceLocation


class MainWindow(QMainWindow, Ui_SchemaMainWindow):

    def __init__(self):
        super(MainWindow, self).__init__()

        self.setupUi(self)

        XmlSyntaxHighlighter(self.schemaView.document())
        XmlSyntaxHighlighter(self.instanceEdit.document())

        self.schemaSelection.addItem("Contact Schema")
        self.schemaSelection.addItem("Recipe Schema")
        self.schemaSelection.addItem("Order Schema")

        self.instanceSelection.addItem("Valid Contact Instance")
        self.instanceSelection.addItem("Invalid Contact Instance")

        self.schemaSelection.currentIndexChanged.connect(self.schemaSelected)
        self.instanceSelection.currentIndexChanged.connect(self.instanceSelected)
        self.validateButton.clicked.connect(self.validate)
        self.instanceEdit.textChanged.connect(self.textChanged)

        self.validationStatus.setAlignment(Qt.AlignCenter | Qt.AlignVCenter)

        self.schemaSelected(0)
        self.instanceSelected(0)

    def schemaSelected(self, index):
        self.instanceSelection.clear()

        if index == 0:
            self.instanceSelection.addItem("Valid Contact Instance")
            self.instanceSelection.addItem("Invalid Contact Instance")
        elif index == 1:
            self.instanceSelection.addItem("Valid Recipe Instance")
            self.instanceSelection.addItem("Invalid Recipe Instance")
        elif index == 2:
            self.instanceSelection.addItem("Valid Order Instance")
            self.instanceSelection.addItem("Invalid Order Instance")

        self.textChanged()

        schemaFile = QFile(':/schema_%d.xsd' % index)
        schemaFile.open(QFile.ReadOnly)
        schemaData = schemaFile.readAll()
        self.schemaView.setPlainText(encode_utf8(schemaData))

        self.validate()

    def instanceSelected(self, index):
        index += 2 * self.schemaSelection.currentIndex()
        instanceFile = QFile(':/instance_%d.xml' % index)
        instanceFile.open(QFile.ReadOnly)
        instanceData = instanceFile.readAll()
        self.instanceEdit.setPlainText(encode_utf8(instanceData))

        self.validate()

    def validate(self):
        schemaData = decode_utf8(self.schemaView.toPlainText())
        instanceData = decode_utf8(self.instanceEdit.toPlainText())

        messageHandler = MessageHandler()

        schema = QXmlSchema()
        schema.setMessageHandler(messageHandler)
        schema.load(schemaData)

        errorOccurred = False
        if not schema.isValid():
            errorOccurred = True
        else:
            validator = QXmlSchemaValidator(schema)
            if not validator.validate(instanceData):
                errorOccurred = True

        if errorOccurred:
            self.validationStatus.setText(messageHandler.statusMessage())
            self.moveCursor(messageHandler.line(), messageHandler.column())
            background = Qt.red
        else:
            self.validationStatus.setText("validation successful")
            background = Qt.green

        styleSheet = 'QLabel {background: %s; padding: 3px}' % QColor(background).lighter(160).name()
        self.validationStatus.setStyleSheet(styleSheet)

    def textChanged(self):
        self.instanceEdit.setExtraSelections([])

    def moveCursor(self, line, column):
        self.instanceEdit.moveCursor(QTextCursor.Start)

        for i in range(1, line):
            self.instanceEdit.moveCursor(QTextCursor.Down)

        for i in range(1, column):
            self.instanceEdit.moveCursor(QTextCursor.Right)

        extraSelections = []
        selection = QTextEdit.ExtraSelection()

        lineColor = QColor(Qt.red).lighter(160)
        selection.format.setBackground(lineColor)
        selection.format.setProperty(QTextFormat.FullWidthSelection, True)
        selection.cursor = self.instanceEdit.textCursor()
        selection.cursor.clearSelection()
        extraSelections.append(selection)

        self.instanceEdit.setExtraSelections(extraSelections)

        self.instanceEdit.setFocus()


if __name__ == '__main__':

    import sys

    app = QApplication(sys.argv)
    window = MainWindow()
    window.show()
    sys.exit(app.exec_())