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需求:
在實(shí)際應(yīng)用中,需要對xml配置文件進(jìn)行實(shí)時(shí)修改,
1.增加、刪除 某些節(jié)點(diǎn)
2.增加,刪除,修改某個(gè)節(jié)點(diǎn)下的某些屬性
3.增加,刪除,修改某些節(jié)點(diǎn)的文本
xml源文件格式[例]
- <?xml version="1.0" encoding="UTF-8"?>
- <framework>
- <processers>
- <processer name="AProcesser" file="lib64/A.so"
- path="/tmp">
- </processer>
- <processer name="BProcesser" file="lib64/B.so" value="fordelete">
- </processer>
- <processer name="BProcesser" file="lib64/B.so2222222"/>
-
- <services>
- <service name="search" prefix="/bin/search?"
- output_formatter="OutPutFormatter:service_inc">
-
- <chain sequency="chain1"/>
- <chain sequency="chain2"></chain>
- </service>
- <service name="update" prefix="/bin/update?">
- <chain sequency="chain3" value="fordelete"/>
- </service>
- </services>
- </processers>
- </framework>
使用庫:
xml.etree.ElementTree
官方文檔地址:http://docs./library/xml.etree.elementtree.html
實(shí)現(xiàn)思想:
使用ElementTree,先將文件讀入,解析成樹,之后,根據(jù)路徑,可以定位到樹的每個(gè)節(jié)點(diǎn),再對節(jié)點(diǎn)進(jìn)行修改,最后直接將其輸出
代碼附文檔:
- #!/usr/bin/python
- # -*- coding=utf-8 -*-
- # author : wklken@yeah.net
- # date: 2012-05-25
- # version: 0.1
-
- from xml.etree.ElementTree import ElementTree,Element
-
- def read_xml(in_path):
- '''''讀取并解析xml文件
- in_path: xml路徑
- return: ElementTree'''
- tree = ElementTree()
- tree.parse(in_path)
- return tree
-
- def write_xml(tree, out_path):
- '''''將xml文件寫出
- tree: xml樹
- out_path: 寫出路徑'''
- tree.write(out_path, encoding="utf-8",xml_declaration=True)
-
- def if_match(node, kv_map):
- '''''判斷某個(gè)節(jié)點(diǎn)是否包含所有傳入?yún)?shù)屬性
- node: 節(jié)點(diǎn)
- kv_map: 屬性及屬性值組成的map'''
- for key in kv_map:
- if node.get(key) != kv_map.get(key):
- return False
- return True
-
- #---------------search -----
-
- def find_nodes(tree, path):
- '''''查找某個(gè)路徑匹配的所有節(jié)點(diǎn)
- tree: xml樹
- path: 節(jié)點(diǎn)路徑'''
- return tree.findall(path)
-
-
- def get_node_by_keyvalue(nodelist, kv_map):
- '''''根據(jù)屬性及屬性值定位符合的節(jié)點(diǎn),返回節(jié)點(diǎn)
- nodelist: 節(jié)點(diǎn)列表
- kv_map: 匹配屬性及屬性值map'''
- result_nodes = []
- for node in nodelist:
- if if_match(node, kv_map):
- result_nodes.append(node)
- return result_nodes
-
- #---------------change -----
-
- def change_node_properties(nodelist, kv_map, is_delete=False):
- '''''修改/增加 /刪除 節(jié)點(diǎn)的屬性及屬性值
- nodelist: 節(jié)點(diǎn)列表
- kv_map:屬性及屬性值map'''
- for node in nodelist:
- for key in kv_map:
- if is_delete:
- if key in node.attrib:
- del node.attrib[key]
- else:
- node.set(key, kv_map.get(key))
-
- def change_node_text(nodelist, text, is_add=False, is_delete=False):
- '''''改變/增加/刪除一個(gè)節(jié)點(diǎn)的文本
- nodelist:節(jié)點(diǎn)列表
- text : 更新后的文本'''
- for node in nodelist:
- if is_add:
- node.text += text
- elif is_delete:
- node.text = ""
- else:
- node.text = text
-
- def create_node(tag, property_map, content):
- '''''新造一個(gè)節(jié)點(diǎn)
- tag:節(jié)點(diǎn)標(biāo)簽
- property_map:屬性及屬性值map
- content: 節(jié)點(diǎn)閉合標(biāo)簽里的文本內(nèi)容
- return 新節(jié)點(diǎn)'''
- element = Element(tag, property_map)
- element.text = content
- return element
-
- def add_child_node(nodelist, element):
- '''''給一個(gè)節(jié)點(diǎn)添加子節(jié)點(diǎn)
- nodelist: 節(jié)點(diǎn)列表
- element: 子節(jié)點(diǎn)'''
- for node in nodelist:
- node.append(element)
-
- def del_node_by_tagkeyvalue(nodelist, tag, kv_map):
- '''''同過屬性及屬性值定位一個(gè)節(jié)點(diǎn),并刪除之
- nodelist: 父節(jié)點(diǎn)列表
- tag:子節(jié)點(diǎn)標(biāo)簽
- kv_map: 屬性及屬性值列表'''
- for parent_node in nodelist:
- children = parent_node.getchildren()
- for child in children:
- if child.tag == tag and if_match(child, kv_map):
- parent_node.remove(child)
-
-
-
- if __name__ == "__main__":
-
- #1. 讀取xml文件
- tree = read_xml("./test.xml")
-
- #2. 屬性修改
- #A. 找到父節(jié)點(diǎn)
- nodes = find_nodes(tree, "processers/processer")
- #B. 通過屬性準(zhǔn)確定位子節(jié)點(diǎn)
- result_nodes = get_node_by_keyvalue(nodes, {"name":"BProcesser"})
- #C. 修改節(jié)點(diǎn)屬性
- change_node_properties(result_nodes, {"age": "1"})
- #D. 刪除節(jié)點(diǎn)屬性
- change_node_properties(result_nodes, {"value":""}, True)
-
- #3. 節(jié)點(diǎn)修改
- #A.新建節(jié)點(diǎn)
- a = create_node("person", {"age":"15","money":"200000"}, "this is the firest content")
- #B.插入到父節(jié)點(diǎn)之下
- add_child_node(result_nodes, a)
-
- #4. 刪除節(jié)點(diǎn)
- #定位父節(jié)點(diǎn)
- del_parent_nodes = find_nodes(tree, "processers/services/service")
- #準(zhǔn)確定位子節(jié)點(diǎn)并刪除之
- target_del_node = del_node_by_tagkeyvalue(del_parent_nodes, "chain", {"sequency" : "chain1"})
-
- #5. 修改節(jié)點(diǎn)文本
- #定位節(jié)點(diǎn)
- text_nodes = get_node_by_keyvalue(find_nodes(tree, "processers/services/service/chain"), {"sequency":"chain3"})
- change_node_text(text_nodes, "new text")
-
- #6. 輸出到結(jié)果文件
- write_xml(tree, "./out.xml")
-
-
通過main處理后的結(jié)果文件:
- <?xml version='1.0' encoding='utf-8'?>
- <framework>
- <processers>
- <processer file="lib64/A.so" name="AProcesser" path="/tmp">
- </processer>
- <processer age="1" file="lib64/B.so" name="BProcesser">
- <person age="15" money="200000">this is the firest content</person>
- </processer>
- <processer age="1" file="lib64/B.so2222222" name="BProcesser">
- <person age="15" money="200000">this is the firest content</person>
- </processer>
-
- <services>
- <service name="search" output_formatter="OutPutFormatter:service_inc"
- prefix="/bin/search?">
-
- <chain sequency="chain2" />
- </service>
- <service name="update" prefix="/bin/update?">
- <chain sequency="chain3" value="fordelete">new text</chain>
- </service>
- </services>
- </processers>
- </framework>
The end!
wklken
2012-05-25
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