PHP XML Parser能够定义期望多个值(PHP XML Parser with ability to define expect multiple values)

编程入门行业动态更新时间:2024-10-24 16:23:39

我们必须编写读者来定期输入xml数据，我们得到的常见错误是，如果你有一个可以有多个子节点的节点，并且在特定实例中只有一个子节点，那么生成的数组或对象将返回单个孩子而不是孩子阵列。

例如，解析：

将返回一个对象或数组，如：

[child] => array( [0] => array( [name] => "Bill" ) [1] => array( [name] => "John" ) )

而解析：

将返回：

[child] => array( [name] => "John" )

我知道，根据具体情况，我们可以手动检查这些事情：

if（isset（$ parent ['child'] ['name']））$ parent ['child'] = array（$ parent ['child']）;

但这是你必须记住要做的事情，它经常出现在bug报告中。许多这些xml源已经有WSDL规范或DTD，它们确定了一个元素可能有多次出现，如下所示，所以我们需要的信息已经存在，但我们使用的解析器似乎都没有足够的智能来使用这些信息时构造结果。

<s:complexType name="parent"> <s:sequence> <s:element minOccurs="0" maxOccurs="unbounded" name="child" nillable="true" type="tns:child"/> </s:sequence> </s:complexType> <s:complexType name="child"> <s:complexContent mixed="false"> <s:sequence> <s:element minOccurs="1" maxOccurs="1" name="name" type="s:string"/> </s:sequence> </s:extension> </s:complexContent> </s:complexType>

是否有一个更聪明的xml解析器，其解释数据，知道一组元素何时是基于DTD，XSD，WSDL的列表，并始终返回值数组而不是使用最佳猜测来折叠单个值，或者是否可以将解析器设置为始终使每个子节点成为一个数组，虽然编码时有点笨重，但意味着无论元素数量多少，结构至少始终保持一致。

We have to write readers to input xml data on a regular basis, and a common bug we get is where, if you have a node that can have multiple children, and in a particular instance there's only 1 child, then the resulting array or object will return the single child rather than array of children.

For example, parsing:

Will return an object or array like:

[child] => array( [0] => array( [name] => "Bill" ) [1] => array( [name] => "John" ) )

Whereas parsing:

Will return:

[child] => array( [name] => "John" )

I know that, on a case by case basis, we can check these things manually like:

if( isset( $parent[ 'child' ][ 'name' ] ) ) $parent[ 'child' ] = array( $parent[ 'child' ] );

But it's something you have to remember to do all the time and it pops up often in bug reports. Many of these xml sources already have WSDL specifications or DTD's which do specify that an element may have multiple occurrences, as below, so the information we need is already there but none of the parsers we use seem to be smart enough to use that information when structuring the result.

Is there an xml parser available that is smarter with its interpretation of data that knows when a set of elements is a list based on the DTD, XSD, WSDL, and always returns an array of values instead of using best guesses to collapse single values, or is it possible to set the parser to always make every child node into an array which, while a bit unwieldy when coding, means the structure is at least always consistent regardless of the number of elements.