`xml.dom.minidom` --- 最小的 DOM 實作¶

原始碼：Lib/xml/dom/minidom.py

xml.dom.minidom is a minimal implementation of the Document Object Model interface, with an API similar to that in other languages. It is intended to be simpler than the full DOM and also significantly smaller. Users who are not already proficient with the DOM should consider using the xml.etree.ElementTree module for their XML processing instead.

備註

如果你需要剖析不受信任或未經驗證的資料，請參閱 XML 安全性。

DOM applications typically start by parsing some XML into a DOM. With xml.dom.minidom, this is done through the parse functions:

from xml.dom.minidom import parse, parseString

dom1 = parse('c:\\temp\\mydata.xml')  # 以檔名來剖析 XML 檔案

datasource = open('c:\\temp\\mydata.xml')
dom2 = parse(datasource)  # 剖析開啟的檔案

dom3 = parseString('<myxml>Some data<empty/> some more data</myxml>')

parse() 函式可以接受一個檔案名稱或開啟的檔案物件。

xml.dom.minidom.parse(filename_or_file, parser=None, bufsize=None)¶: Return a Document from the given input. filename_or_file may be either a file name, or a file-like object. parser, if given, must be a SAX2 parser object. This function will change the document handler of the parser and activate namespace support; other parser configuration (like setting an entity resolver) must have been done in advance.

如果你有一個字串中的 XML，你可以使用 parseString() 函式來代替：

xml.dom.minidom.parseString(string, parser=None)¶: Return a Document that represents the string. This method creates an io.StringIO object for the string and passes that on to parse().

這兩個函式都會回傳一個 Document 物件，表示文件的內容。

What the parse() and parseString() functions do is connect an XML parser with a "DOM builder" that can accept parse events from any SAX parser and convert them into a DOM tree. The names of the functions are perhaps misleading, but are easy to grasp when learning the interfaces. The parsing of the document will be completed before these functions return; it's simply that these functions do not provide a parser implementation themselves.

You can also create a Document by calling a method on a "DOM Implementation" object. You can get this object either by calling the getDOMImplementation() function in the xml.dom package or the xml.dom.minidom module. Once you have a Document, you can add child nodes to it to populate the DOM:

from xml.dom.minidom import getDOMImplementation

impl = getDOMImplementation()

newdoc = impl.createDocument(None, "some_tag", None)
top_element = newdoc.documentElement
text = newdoc.createTextNode('Some textual content.')
top_element.appendChild(text)

Once you have a DOM document object, you can access the parts of your XML document through its properties and methods. These properties are defined in the DOM specification. The main property of the document object is the documentElement property. It gives you the main element in the XML document: the one that holds all others. Here is an example program:

dom3 = parseString("<myxml>Some data</myxml>")
assert dom3.documentElement.tagName == "myxml"

When you are finished with a DOM tree, you may optionally call the unlink() method to encourage early cleanup of the now-unneeded objects. unlink() is an xml.dom.minidom-specific extension to the DOM API that renders the node and its descendants essentially useless. Otherwise, Python's garbage collector will eventually take care of the objects in the tree.

也參考

Document Object Model (DOM) Level 1 Specification: W3C 對 xml.dom.minidom DOM 支援的建議。

DOM 物件¶

The definition of the DOM API for Python is given as part of the xml.dom module documentation. This section lists the differences between the API and xml.dom.minidom.

Node.unlink()¶

Break internal references within the DOM so that it will be garbage collected on versions of Python without cyclic GC. Even when cyclic GC is available, using this can make large amounts of memory available sooner, so calling this on DOM objects as soon as they are no longer needed is good practice. This only needs to be called on the Document object, but may be called on child nodes to discard children of that node.

You can avoid calling this method explicitly by using the with statement. The following code will automatically unlink dom when the with block is exited:

with xml.dom.minidom.parse(datasource) as dom:
    ... # 使用 dom。

Node.writexml(writer, indent='', addindent='', newl='', encoding=None, standalone=None)¶

Write XML to the writer object. The writer receives texts but not bytes as input, it should have a write() method which matches that of the file object interface. The indent parameter is the indentation of the current node. The addindent parameter is the incremental indentation to use for subnodes of the current one. The newl parameter specifies the string to use to terminate newlines.

For the Document node, an additional keyword argument encoding can be used to specify the encoding field of the XML header.

Similarly, explicitly stating the standalone argument causes the standalone document declarations to be added to the prologue of the XML document. If the value is set to True, standalone="yes" is added, otherwise it is set to "no". Not stating the argument will omit the declaration from the document.

在 3.8 版的變更: The writexml() method now preserves the attribute order specified by the user.

在 3.9 版的變更: 新增 standalone 參數。

Node.toxml(encoding=None, standalone=None)¶

Return a string or byte string containing the XML represented by the DOM node.

With an explicit encoding [1] argument, the result is a byte string in the specified encoding. With no encoding argument, the result is a Unicode string, and the XML declaration in the resulting string does not specify an encoding. Encoding this string in an encoding other than UTF-8 is likely incorrect, since UTF-8 is the default encoding of XML.

The standalone argument behaves exactly as in writexml().

在 3.8 版的變更: 現在 toxml() 方法會保留使用者指定的屬性順序。

在 3.9 版的變更: 新增 standalone 參數。

Node.toprettyxml(indent='\t', newl='\n', encoding=None, standalone=None)¶

Return a pretty-printed version of the document. indent specifies the indentation string and defaults to a tabulator; newl specifies the string emitted at the end of each line and defaults to \n.

The encoding argument behaves like the corresponding argument of toxml().

The standalone argument behaves exactly as in writexml().

在 3.8 版的變更: The toprettyxml() method now preserves the attribute order specified by the user.

在 3.9 版的變更: 新增 standalone 參數。

DOM 範例¶

This example program is a fairly realistic example of a simple program. In this particular case, we do not take much advantage of the flexibility of the DOM.

import xml.dom.minidom

document = """\
<slideshow>
<title>Demo slideshow</title>
<slide><title>Slide title</title>
<point>This is a demo</point>
<point>Of a program for processing slides</point>
</slide>

<slide><title>Another demo slide</title>
<point>It is important</point>
<point>To have more than</point>
<point>one slide</point>
</slide>
</slideshow>
"""

dom = xml.dom.minidom.parseString(document)

def getText(nodelist):
    rc = []
    for node in nodelist:
        if node.nodeType == node.TEXT_NODE:
            rc.append(node.data)
    return ''.join(rc)

def handleSlideshow(slideshow):
    print("<html>")
    handleSlideshowTitle(slideshow.getElementsByTagName("title")[0])
    slides = slideshow.getElementsByTagName("slide")
    handleToc(slides)
    handleSlides(slides)
    print("</html>")

def handleSlides(slides):
    for slide in slides:
        handleSlide(slide)

def handleSlide(slide):
    handleSlideTitle(slide.getElementsByTagName("title")[0])
    handlePoints(slide.getElementsByTagName("point"))

def handleSlideshowTitle(title):
    print(f"<title>{getText(title.childNodes)}</title>")

def handleSlideTitle(title):
    print(f"<h2>{getText(title.childNodes)}</h2>")

xml.dom.minidom --- 最小的 DOM 實作¶

DOM 物件¶

DOM 範例¶

`xml.dom.minidom` --- 最小的 DOM 實作¶