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WebCmdlets parse XML declaration to get encoding value, if present. #18748

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Merged
iSazonov merged 10 commits into from
Jan 21, 2023
Merged

WebCmdlets parse XML declaration to get encoding value, if present. #18748

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64b238c
get { return to ->
CarloToso Dec 8, 2022
13c0ad9
#endregion
CarloToso Dec 8, 2022
a81c1c8
add regex to detect encoding from xml declaration
CarloToso Dec 8, 2022
6db83db
remove useless do-while
CarloToso Dec 8, 2022
42f4f2b
fix typo
CarloToso Dec 8, 2022
282c328
add comment
CarloToso Dec 8, 2022
ce00870
remove useless ()
CarloToso Dec 8, 2022
93c9b12
reuse the same substring
CarloToso Dec 8, 2022
41d524f
Updated with suggestions
CarloToso Dec 9, 2022
3f84029
Merge branch 'master' into xmlregex-streamhelper
CarloToso Jan 21, 2023
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53 changes: 31 additions & 22 deletions src/Microsoft.PowerShell.Commands.Utility/commands/utility/WebCmdlet/StreamHelper.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -28,7 +28,7 @@ internal class WebResponseContentMemoryStream : MemoryStream
private bool _isInitialized = false;
private readonly Cmdlet _ownerCmdlet;

#endregion
#endregion Data

#region Constructors
/// <summary>
Expand All @@ -44,7 +44,7 @@ internal WebResponseContentMemoryStream(Stream stream, int initialCapacity, Cmdl
_originalStreamToProxy = stream;
_ownerCmdlet = cmdlet;
}
#endregion
#endregion Constructors

/// <summary>
/// </summary>
Expand Down Expand Up @@ -411,10 +411,15 @@ internal static bool TryGetEncoding(string characterSet, out Encoding encoding)
return result;
}

private static readonly Regex s_metaexp = new(
private static readonly Regex s_metaRegex = new(
@"<meta\s.*[^.><]*charset\s*=\s*[""'\n]?(?<charset>[A-Za-z].[^\s""'\n<>]*)[\s""'\n>]",
RegexOptions.Compiled | RegexOptions.Singleline | RegexOptions.ExplicitCapture | RegexOptions.CultureInvariant | RegexOptions.IgnoreCase
RegexOptions.Compiled | RegexOptions.Singleline | RegexOptions.ExplicitCapture | RegexOptions.CultureInvariant | RegexOptions.IgnoreCase | RegexOptions.NonBacktracking
);

private static readonly Regex s_xmlRegex = new(
@"<\?xml\s.*[^.><]*encoding\s*=\s*[""'\n]?(?<charset>[A-Za-z].[^\s""'\n<>]*)[\s""'\n>]",
RegexOptions.Compiled | RegexOptions.Singleline | RegexOptions.ExplicitCapture | RegexOptions.CultureInvariant | RegexOptions.IgnoreCase | RegexOptions.NonBacktracking
);

internal static string DecodeStream(Stream stream, ref Encoding encoding)
{
Expand All @@ -429,27 +434,31 @@ internal static string DecodeStream(Stream stream, ref Encoding encoding)
string content = StreamToString(stream, encoding);
if (isDefaultEncoding)
{
do
// We only look within the first 1k characters as the meta element and
// the xml declaration are at the start of the document
string substring = content.Substring(0, Math.Min(content.Length, 1024));

// Check for a charset attribute on the meta element to override the default
Match match = s_metaRegex.Match(substring);

// Check for a encoding attribute on the xml declaration to override the default
if (!match.Success)
{
// Check for a charset attribute on the meta element to override the default
// we only look within the first 1k characters as the meta tag is in the head
// tag which is at the start of the document
Match match = s_metaexp.Match(content.Substring(0, Math.Min(content.Length, 1024)));
if (match.Success)
{
Encoding localEncoding = null;
string characterSet = match.Groups["charset"].Value;

if (TryGetEncoding(characterSet, out localEncoding))
{
stream.Seek(0, SeekOrigin.Begin);
content = StreamToString(stream, localEncoding);
match = s_xmlRegex.Match(substring);
}

if (match.Success)
{
Encoding localEncoding = null;
string characterSet = match.Groups["charset"].Value;

// Report the encoding used.
encoding = localEncoding;
}
if (TryGetEncoding(characterSet, out localEncoding))
{
stream.Seek(0, SeekOrigin.Begin);
content = StreamToString(stream, localEncoding);
encoding = localEncoding;
}
} while (false);
}
}

return content;
Expand Down