Invoke-RestMethod -FollowRelLink does not work when links contain commas #17528
Description
Prerequisites
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- Make sure you are able to repro it on the latest released version
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- Refer to Differences between Windows PowerShell 5.1 and PowerShell.
Steps to reproduce
Here is a basic sample with PowerShell based on what the current code seems to do:
[string[]]$Links = "<https://some.api.com/api/item?fields=id,description,name&offset=0&limit=1000>;rel=`"first`",<https://some.api.com/api/item?fields=id,short_description,name&offset=1000&limit=1000>;rel=`"next`",<https://some.api.com/api/item?fields=id,short_description,name&offset=4000&limit=1000>;rel=`"last`""
$Links[0].Split(',')Result
<https://some.api.com/api/item?fields=id
description
name&offset=0&limit=1000>;rel="first"
<https://some.api.com/api/item?fields=id
short_description
name&offset=1000&limit=1000>;rel="next"
<https://some.api.com/api/item?fields=id
short_description
name&offset=4000&limit=1000>;rel="last"
Expected behavior
Invoke-RestMethod can follow RelLink when a comma does appear within a header url. Although I feel the REST API provider (I discovered this with ServiceNow) should provide urlencoded links, I believe this cannot be relied upon and is an easy fix by using a MatchCollection instead.
Current - ParseLinkHeader
Suggested
internal void ParseLinkHeader(HttpResponseMessage response, System.Uri requestUri)
{
if (_relationLink == null)
{
// Must ignore the case of relation links. See RFC 8288 (https://tools.ietf.org/html/rfc8288)
_relationLink = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
}
else
{
_relationLink.Clear();
}
// we only support the URL in angle brackets and `rel`, other attributes are ignored
// user can still parse it themselves via the Headers property
const string pattern = "<(?<url>.*?)>;\\s*rel=(?<quoted>\")?(?<rel>(?(quoted).*?|[^,;]*))(?(quoted)\")";
IEnumerable<string> links;
if (response.Headers.TryGetValues("Link", out links))
{
foreach (string linkHeader in links)
{
MatchCollection matchCollection = Regex.Matches(link, pattern)
foreach (Match match in matchCollection)
{
if (match.Success)
{
string url = match.Groups["url"].Value;
string rel = match.Groups["rel"].Value;
if (url != string.Empty && rel != string.Empty && !_relationLink.ContainsKey(rel))
{
Uri absoluteUri = new(requestUri, url);
_relationLink.Add(rel, absoluteUri.AbsoluteUri);
}
}
}
}
}
}Actual behavior
See Steps To Reproduce. Splitting the links returned by a comma breaks the links before they can be parsed by the regex.
Error details
N/A
Environment data
7+
Visuals
No response