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Consider adding more headers to HeaderNames #31374
Description
Follow up to #31311 (comment)
With #31311 there are advantages to having items in the header list (single instance string).
This is most useful for request headers as they are always constructed strings; whereas response headers set in code are usually and interned string.
Non-exhaustive list of headers not currently included but are interesting:
Commonly used request headers:
public static readonly string XCorrelationId = "X-Correlation-ID";
public static readonly string XRequestId = "X-Request-ID";
public static readonly string XForwardedFor = "X-Forwarded-For";
public static readonly string XForwardedHost = "X-Forwarded-Host";
public static readonly string XForwardedProto = "X-Forwarded-Proto";However if the server is also reverse-proxying/forwarding/routing between other servers; then response headers also become constructed strings (as they are parsed from the network). So that would then potentially include:
// Security header
public static readonly string ReferrerPolicy = "Referrer-Policy";
// Allow the browser to read cross origin timing values for the Resource Timing API
public static readonly string TimingAllowOrigin = "Timing-Allow-Origin";
// Ye olde "ASP.NET" header
public static readonly string XPoweredBy = "X-Powered-By";Location is used for redirect; but sometimes Refresh is also used as a non-JS delay timed redirect (with interstitial)
public static readonly string Refresh = "Refresh";Never seen; but rfc7240
public static readonly string Prefer = "Prefer";
public static readonly string PreferenceApplied = "Preference-Applied";
Activity
kimsey0 commentedon Feb 8, 2023
Accept-CH(client hints, per RFC 8942) would be nice to add too.MaRokas2005 commentedon Jun 30, 2025
Couldn't someone else write the code, and you would just need to confirm it? Because that would speed up the emergence of new header names. @martincostello
MaRokas2005 commentedon Jul 1, 2025
Also you do not need 'X-' as prefix of custom header names. Link: don't need prefix '-'