如何使用Nokogiri和XPath向XML添加元素

Question

我有以下XML：

    ?xml version="1.0" encoding="utf-8"?>
    <configuration>
  <!--
       The .NET 2.0 build of the console runner only 
    runs under .NET 2.0 or higher. The setting
    useLegacyV2RuntimeActivationPolicy only applies 
    under .NET 4.0 and permits use of mixed mode 
    assemblies, which would otherwise not load 
    correctly.
    -->
  <startup useLegacyV2RuntimeActivationPolicy="true">
    <!-- Comment out the next line to force use of .NET 4.0 -->
  </startup>
  <runtime>
    <!-- Ensure that test exceptions don't crash NUnit -->
    <legacyUnhandledExceptionPolicy enabled="1"/>
    <!-- Run partial trust V2 assemblies in full trust under .NET 4.0 -->
    <loadFromRemoteSources enabled="true"/>
    <!-- Look for addins in the addins directory for now -->
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <probing privatePath="lib;addins"/>
    </assemblyBinding>
  </runtime>
</configuration>

使用Rakefile，我想在<startup>部分添加一个元素说：

<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.7.2" />

成为：

<startup>
   <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.7.2" />
</startup>

目前我有这个：

task :update_test_runner_supported_runtime do
    test_runner_path   = 'Packages\NUnit.Runners.2.6.4\tools\nunit-console-x86.exe.config'
    test_runner_config = Nokogiri::XML(open(functional_connection_path))
  functional_connection_config.xpath("//startup/")  #to find the start up element
  File.open(test_runner_path, 'w+') { |f| f.write(test_runner_config) } #to write the changes
end

在支持的运行时添加此详细信息的实际语法是什么？

Answer 1

我想知道您是否可以通过简单的sub!调用来实现？

test_runner_config.sub!('<startup useLegacyV2RuntimeActivationPolicy="true">', '<startup>\n    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.7.2" />')
File.open(test_runner_path, 'w+') { |f| f.write(test_runner_config) }

Answer 2

尝试一下。

require 'nokogiri'

doc = Nokogiri::XML(<<EOT)
<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <startup useLegacyV2RuntimeActivationPolicy="true">
  </startup>
  <runtime>
    <legacyUnhandledExceptionPolicy enabled="1"/>
    <loadFromRemoteSources enabled="true"/>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <probing privatePath="lib;addins"/>
    </assemblyBinding>
  </runtime>
</configuration>

EOT

startup_node = doc.at('startup')
startup_node.delete('useLegacyV2RuntimeActivationPolicy')
startup_node.add_child('<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.7.2" />')

将导致：

doc.to_xml
# => "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n" +
#    "<configuration>\n" +
#    "  <startup>\n" +
#    "  <supportedRuntime version=\"v4.0\" sku=\".NETFramework,Version=v4.7.2\"/></startup>\n" +
#    "  <runtime>\n" +
#    "    <legacyUnhandledExceptionPolicy enabled=\"1\"/>\n" +
#    "    <loadFromRemoteSources enabled=\"true\"/>\n" +
#    "    <assemblyBinding xmlns=\"urn:schemas-microsoft-com:asm.v1\">\n" +
#    "      <probing privatePath=\"lib;addins\"/>\n" +
#    "    </assemblyBinding>\n" +
#    "  </runtime>\n" +
#    "</configuration>\n"