simplexml failed to parse xml like this?

Question

Is there a stronger reference?

<?xml version="1.0" encoding="UTF-8"?>
<rss xmlns:nutch="http://www.nutch.org/opensearchrss/1.0/" xmlns
:opensearch="http://a9.com/-/spec/opensearchrss/1.0/" version="2.0">

    <channel>

        <title>Nutch: "php Developers" notdirectory:1 </title>

        <description>Nutch search results for query: "php Developers" notdirectory:1 </description>

        <opensearch:totalResults>2</opensearch:totalResults>
        <opensearch:startIndex>0</opensearch:startIndex>
        <opensearch:results>2</opensearch:results>
        <opensearch:itemsPerPage>10</opensearch:itemsPerPage>
        <item>
            <title/>
        </item>
        <item>
            <title/>
        </item>
    </channel>
</rss>

Answer 1

That is not a valid XML file.

Empty prefix is not allowed according to XML Namespace specification.

Namespace prefix ':' is not defined.

Once I cleaned up the opensearch namespace definition (removed the excess quotation marks and line breaks) all looked good:

xmlns:opensearch="http://a9.com/-/spec/opensearchrss/1.0/"

Answer 2

If that is your exact code, it might have something to do with the linebreak on the first line

change it so that xmlns is right beside :opensearch

<rss
    xmlns:nutch="http://www.nutch.org/opensearchrss/1.0/"
    xmlns:opensearch="http://a9.com/-/spec/opensearchrss/1.0/"
    version="2.0"
>