如何使用 lxml 验证多个 xsd 模式？

Question

我正在编写一个单元测试来验证我通过获取其 xsd 架构并使用 python 的 lxml 库验证生成的站点地图 xml：

这是我的根元素的一些元数据：

xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"
xmlns:image="http://www.google.com/schemas/sitemap-image/1.1"
xsi:schemaLocation="http://www.sitemaps.org/schemas/sitemap/0.9 
http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd 
http://www.google.com/schemas/sitemap-image/1.1 
http://www.google.com/schemas/sitemap-image/1.1/sitemap-image.xsd"

还有这个测试代码：

_xsd_validators = {}
def get_xsd_validator(url):
    if url not in _xsd_validators:
        _xsd_validators[url] = etree.XMLSchema(etree.parse(StringIO(requests.get(url).content)))
    return _xsd_validators[url]


# this util function is later on in a TestCase
def validate_xml(self, content):
    content.seek(0)
    doc = etree.parse(content)
    schema_loc = doc.getroot().attrib.get('{http://www.w3.org/2001/XMLSchema-instance}schemaLocation').split(' ')
    # lxml doesn't like multiple namespaces
    for i, loc in enumerate(schema_loc):
        if i % 2 == 1:
            get_xsd_validator(schema_loc[i]).assertValid(doc)
    return doc

验证失败的示例 XML：

<?xml version="1.0" encoding="UTF-8"?>
<urlset
  xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"
  xmlns:image="http://www.google.com/schemas/sitemap-image/1.1"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="
    http://www.sitemaps.org/schemas/sitemap/0.9
    http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd
    http://www.google.com/schemas/sitemap-image/1.1
    http://www.google.com/schemas/sitemap-image/1.1/sitemap-image.xsd"
>
  <url>
    <loc>https://www.example.com/press</loc>
    <lastmod>2016-08-11</lastmod>

    <changefreq>weekly</changefreq>
  </url>

  <url>
    <loc>https://www.example.com/about-faq</loc>
    <lastmod>2016-08-11</lastmod>

    <changefreq>weekly</changefreq>
  </url>


</urlset>

当我刚刚拥有一个常规站点地图时，一切都很好，但是当我添加图像站点地图标记时，assertValid 开始失败：

E   DocumentInvalid: Element '{http://www.google.com/schemas/sitemap-image/1.1}image': No matching global element declaration available, but demanded by the strict wildcard., line 12

或者：

E   DocumentInvalid: Element '{http://www.sitemaps.org/schemas/sitemap/0.9}urlset': No matching global declaration available for the validation root., line 6

Answer 1

您可以尝试定义一个包装器模式 wrapper-schema.xsd，它会导入所有需要的模式，并将此模式与 lxml 一起使用，而不是其他每个模式。

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:import
    namespace="http://www.sitemaps.org/schemas/sitemap/0.9"
    schemaLocation="http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd"/>
  <xs:import
    namespace="http://www.google.com/schemas/sitemap-image/1.1"
    schemaLocation="http://www.google.com/schemas/sitemap-image/1.1/sitemap-image.xsd"/>
</xs:schema>

我没有 python，但这在 oXygen 中成功验证：

<?xml version="1.0" encoding="UTF-8"?>
<urlset  xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"
    xmlns:image="http://www.google.com/schemas/sitemap-image/1.1"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:noNamespaceSchemaLocation="wrapper-schema.xsd"
    >
    <image:image>
        <image:loc>http://www.example.com/image</image:loc>
    </image:image>
    <url>
        <loc>https://www.example.com/press</loc>
        <lastmod>2016-08-11</lastmod>
        <changefreq>weekly</changefreq>
    </url>
    <url>
        <loc>https://www.example.com/about-faq</loc>
        <lastmod>2016-08-11</lastmod>
        <changefreq>weekly</changefreq>
    </url>
</urlset>