Django Piston：定义返回元素的优先级

Question

让我们看这个示例：

url(r'^test[/]$', test_handler, { 'emitter_format': 'xml' }),

使用以下处理程序：

class testHandler(BaseHandler):
    allowed_methods = ('GET',)
    def read(self, request):
        return {'element': 'I want to be first', 'test': 'No way', }

调用 API 时的结果将是：

Content-Type: text/xml; charset=utf-8
<?xml version="1.0" encoding="utf-8"?>
<response><test>No way</test><element>I want to be first</element></response>

我不想首先得到“不行”，那么如何定义返回元素的顺序优先级？

Answer 1

我通过创建自己的发射器找到了答案：

class CustomXmlEmitter(Emitter):
    def _to_xml(self, xml, data):
        if isinstance(data, (list, tuple)):            
            for item in data:
                self._to_xml(xml, item)
        elif isinstance(data, dict):
            for key, value in data.iteritems():
                xml.startElement(key, {})
                self._to_xml(xml, value)
                xml.endElement(key)
        else:
            xml.characters(smart_unicode(data))

    def render(self, request):
        stream = StringIO.StringIO()
        xml = SimplerXMLGenerator(stream, "utf-8")
        xml.startDocument()
        xml.startElement("response", {})
        self._to_xml(xml, self.construct())
        xml.endElement("response")
        xml.endDocument()
        return stream.getvalue()
Emitter.register('custom_xml', CustomXmlEmitter, 'text/xml; charset=utf-8')
Mimer.register(lambda *a: None, ('text/xml',))

并返回以这种方式嵌套的元素：

return [{'element': 'I want to be first'}, {'test': 'No way', }]