我使用Lua 5.1.我想要解析以下模式的XML文件.我该怎么做呢

Question

我尝试使用LuaXml库。但它的功能是有限的，因为它只返回特定属性的第一个子表，而且不会超出这个范围。然后我尝试了字符串模式匹配，这很有效，但我走到了死胡同，无法完全完成任务。LuaExpat库存在于我的lua的lib文件夹中，还有一个名为lom.lua的文件。但通常它不起作用，或者给我"找不到模块"的错误

我的XML文件如下所示：

<Service>
<NewInstance ref="5A">
<Std>DiscoveredElement</Std>
<Key>5A</Key>
<Attributes>
<Attribute name="TARGET_TYPE" value="weblogic_cluster" />
<Attribute name="DISCOVERED_NAME" value="/Farm_soa4_sys20_soa4_domain/soa4_domain/WSM4_Cluster" />
<Attribute name="BROKEN_REASON" value="0" />
<Attribute name="TARGET_NAME" value="/Farm_soa4_sys20_soa4_domain/soa4_domain/WSM4_Cluster" />
<Attribute name="EMD_URL" value="https://uxsys460.schneider.com:3872/emd/main/" />
</Attributes>
</NewInstance>
<NewInstance ref="6C">
<Std>DiscoveredElement</Std>
<Key>6C</Key>
<Attributes>
<Attribute name="TARGET_TYPE" value="oracle_weblogic_nodemanager" />
<Attribute name="SERVICE_TYPE" value=" " />
<Attribute name="ORG_ID" value="0" />
<Attribute name="TARGET_NAME" value="Oracle WebLogic NodeManager-uxlab090" />
</Attributes>
</NewInstance>
<NewInstance ref="98">
<Std>DiscoveredElement</Std>
<Key>98</Key>
<Attributes>
<Attribute name="TARGET_TYPE" value="composite" />
<Attribute name="SERVICE_TYPE" value=" " />
<Attribute name="TARGET_NAME" value="SYS-IMG-Grp" />
<Attribute name="EMD_URL" value="" />
</Attributes>
</NewInstance>
<NewRelationship>
<Parent>
<Instance ref="98" />
</Parent>
<GenericRelations>
<Relations type="contains">
<Instance ref="5A" />
</Relations>
</GenericRelations>
</NewRelationship>
<NewRelationship>
<Parent>
<Instance ref="5A" />
</Parent>
<GenericRelations>
<Relations type="contains">
<Instance ref="6C" />
</Relations>
</GenericRelations>
</NewRelationship>
<NewRelationship>
<Parent>
<Instance ref="5A" />
</Parent>
<GenericRelations>
<Relations type="contains">
<Instance ref="98" />
</Relations>
</GenericRelations>
</NewRelationship>
</Service>

我的议程是显示NewInstance ID及其相应的目标类型和目标名称，以及它与的关系类型和与其相关的实例引用的ID，以及它的目标类型与目标名称例如：

NewInstance ID - 5A
Target Type - weblogic_cluster 
Target Name - /Farm_soa4_sys20_soa4_domain/soa4_domain/WSM4_Cluster
Relation Type - contains
Instance ref - 6C
Target Type - oracle_weblogic_nodemanager
Target Name - Oracle WebLogic NodeManager-uxlab090
Instance ref - 98
Target Type - composite
Target Name - SYS-IMG-Grp

现在不能使用LuaXml来实现这一点。字符串模式匹配的代码我将在下面列出，它帮助我完成任务，直到关系类型，但不准确的

代码为：

a={}
b={}
c={}
d={}
p=0
i=0
q=0
local file = io.open("oem_topology_output.xml", "rb")   -- Open file   for    reading (binary data)
  for instance in file:read("*a"):gmatch("<NewInstance ref="(.-)">") do
     a[i] = instance
     i = i+1
  end
file:close()
local files = io.open("oem_topology_output.xml", "rb")   -- Open file for  reading (binary data)
  for instances in files:read("*a"):gmatch("<NewInstance ref=".-">(.-)</NewInstance>") do
     TARGET_TYPE = instances:match('TARGET_TYPE.-value="(.-)"')
     TARGET_NAME = instances:match('TARGET_NAME.-value="(.-)"')
     b[p] = TARGET_TYPE
     c[p] = TARGET_NAME
     p =p+1
  end
local file = io.open("oem_topology_output.xml", "rb")   -- Open file   for   reading (binary data)
  for type in file:read("*a"):gmatch("<Relations type="(.-)">") do
    d[q] = type
    q = q+1
  end
files:close()
for j=0,i-1 do
print("INSTANCE ID : ", a[j])
print("TARGET TYPE : ", b[j])
print("TARGET NAME : ", c[j])
print("RELATION TYPE : ",d[j])
end

请建议我应该遵循什么方法才能以所需的方式解析XMl文件。其中内置库将提供apt功能。如果你建议，LuaExpat让我知道它不适合我的可能原因。

Answer 1

您不需要任何特殊的库来解析lua中的xml，有很多内置功能可以编写自己的解析器。

例如，为了检索节点的属性，可以编写这样的内容。

local file = "oem_topology_output.xml"
local node = "<(%a-)%s* "
local attributes = {
    "ref",
    "name",
    "value",
    "type"
}

for line in io.lines(file) do
    for a in line:gmatch(node) do
        for x = 1, #attributes do
            n = line:match(attributes[x]..'="(.-)"')
            if n then
                print(a, attributes[x], n)
            end
        end
    end
end

产生类似的输出

NewInstance ref 5A
Attribute   name    TARGET_TYPE
Attribute   value   weblogic_cluster
Attribute   name    DISCOVERED_NAME
Attribute   value   /Farm_soa4_sys20_soa4_domain/soa4_domain/WSM4_Cluster
Attribute   name    BROKEN_REASON
Attribute   value   0
Attribute   name    TARGET_NAME
Attribute   value   /Farm_soa4_sys20_soa4_domain/soa4_domain/WSM4_Cluster
Attribute   name    EMD_URL
Attribute   value   https://uxsys460.schneider.com:3872/emd/main/
NewInstance ref 6C
Attribute   name    TARGET_TYPE
Attribute   value   oracle_weblogic_nodemanager
Attribute   name    SERVICE_TYPE
Attribute   value    
Attribute   name    ORG_ID
Attribute   value   0
Attribute   name    TARGET_NAME
Attribute   value   Oracle WebLogic NodeManager-uxlab090
NewInstance ref 98
Attribute   name    TARGET_TYPE
Attribute   value   composite
Attribute   name    SERVICE_TYPE
Attribute   value    
Attribute   name    TARGET_NAME
Attribute   value   SYS-IMG-Grp
Attribute   name    EMD_URL
Attribute   value   
Instance    ref 98
Relations   type    contains
Instance    ref 5A
Instance    ref 5A
Relations   type    contains
Instance    ref 6C
Instance    ref 5A
Relations   type    contains
Instance    ref 98

无需打开或关闭文件，因为没有写入文件的意图。

Answer 2

local a, b, c, d = {}, {}, {}, {}
local h = io.open("oem_topology_output.xml", "rb")   
if not h then return end
local txt = h:read("*a")
h:close()
for ref, instances in txt:gmatch('<NewInstance ref="(%w+)">(.-)</NewInstance>') do
    a[#a+1] = ref   
    TARGET_TYPE = instances:match('name="TARGET_TYPE"%s+value="(.-)"')
    if TARGET_TYPE then b[#b+1] = TARGET_TYPE end
    TARGET_NAME = instances:match('name="TARGET_NAME"%s+value="(.-)"')
    if TARGET_NAME then  c[#c+1] = TARGET_NAME end
end
for relationship in txt:gmatch('<NewRelationship>(.-)</NewRelationship>') do
    parent = relationship:match('<Parent>.-ref="(%w+)".-</Parent>')
    node = relationship:match('<Relations type="contains">.-ref="(%w+)".-</Relations>')
    if parent and node then    d[#d+1] = {  [parent] = node } end
end
for j=1,#a do
   local id = a[j]
    print("INSTANCE ID : ", id)
    print("TARGET TYPE : ", b[j])
    print("TARGET NAME : ", c[j])
    for k,v in  pairs(d) do
        if type(v)=='table' and v[id] then
            print("tRELATION: ",v[id])
        end
    end
end

输出：

INSTANCE ID :   5A
TARGET TYPE :   weblogic_cluster
TARGET NAME :   /Farm_soa4_sys20_soa4_domain/soa4_domain/WSM4_Cluster
    RELATION:   6C
    RELATION:   98
INSTANCE ID :   6C
TARGET TYPE :   oracle_weblogic_nodemanager
TARGET NAME :   Oracle WebLogic NodeManager-uxlab090
INSTANCE ID :   98
TARGET TYPE :   composite
TARGET NAME :   SYS-IMG-Grp
    RELATION:   5A