generatefile method of the SitemapGenerator class for a tutorial on the SSaurel's Blog

generatefile.py

def generatefile(self):
    urlsbylevel = {}
    maxlevel = 0

    for key, value in self.urls.items():
        if value > maxlevel :
            maxlevel = value

        listurls = None

        if value not in urlsbylevel:
            listurls = []
        else :
            listurls = urlsbylevel[value]

        if listurls != None :
            listurls.append(key)
            urlsbylevel[value] = listurls

    # priority between 0 and 1
    # calculate the step between each level
    step = 1 / (maxlevel * 2)

    rootstr = '<urlset></urlset>'
    root = ET.fromstring(rootstr)
    root.attrib = {'xmlns' : 'http://www.sitemaps.org/schemas/sitemap/0.9'}

    for key, value in urlsbylevel.items():
        priority = round(1 - step * key, 2)

        if priority < 0:
            print("Step = " + str(step) + " Key = " + str(key))

        for item in value:
            url = ET.SubElement(root, "url")
            ET.SubElement(url, "loc").text = item
            ET.SubElement(url, "priority").text = str(priority)


    tree = ET.ElementTree(root)     
    ET.indent(tree, '  ')
    # writing xml
    tree.write(self.filename, encoding="utf-8", xml_declaration=True)