Content-as-stream

Select-Xml -Content does not support input as stream

Select-Xml supports several kinds of input: file paths, XML nodes, strings. Strings are specified by the parameter Content:

help Select-Xml -Full

SYNTAX
    ...
    Select-Xml [-XPath] <String> [-Namespace [<Hashtable>]] -Content <String[]>

PARAMETERS
    -Content <String[]>
        Specifies a string that contains the XML to search. You can also pipe strings to Select-Xml.

        Accept pipeline input?       true (ByValue)

The parameter Content accepts an array of strings or strings may be piped. The help does not tell that each input string should be a well-formed XML.

For example this command which pipes XML content by lines does not work well:

pandoc.exe README.md --standalone | Select-Xml //x:a -Namespace @{x="http://www.w3.org/1999/xhtml"}

Out-String converts input lines to a single string and solves the issue:

pandoc.exe README.md --standalone | Out-String | Select-Xml //x:a -Namespace @{x="http://www.w3.org/1999/xhtml"}

In PowerShell v2 Select-Xml -Content works differently, it ignores not-well formed XML strings. In newer versions it writes non-terminating errors.

Scripts

• Test-1.as.stream.ps1 shows issues on using lines as input
• Test-2.as.string.ps1 shows a workaround with Out-String