Get header values in ASP.NET MVC

Question

I have a requirement to capture the HTTP User Agent header coming in from a device, take the value and remove a 'uuid' This UUID can then be used to direct the device to the correct location to give it the files relevant to the device.

In webforms I was able to get it using

Request.ServerVariables["HTTP_USER_AGENT"]; //inside of Page_Load method

How would I go about this in MVC?

score 30 · Answer 1 · answered Dec 29 '14 at 07:10

30

if in controller, you can easily get the header by this:

Request.Headers.GetValues("XXX");

if the name does not exist, it will throw an exception.

answered Dec 29 '14 at 07:10

Sheldon Wei

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what type of exception? – Zapnologica Jun 26 '17 at 07:51
@Zapnologica InvalidOperationException – Jansen Feb 02 '20 at 05:45
For .Net Core 6, use `TryGetValue` instead. – eggsloveoats Sep 07 '22 at 07:39

score 15 · Answer 2 · edited May 23 '17 at 11:59

15

You do it the same way, in the controller:

Request.ServerVariables.Get("HTTP_USER_AGENT");

The Request object is part of ASP.NET, MVC or not.

See this for example.

edited May 23 '17 at 11:59

Community

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answered Oct 01 '10 at 21:32

Oded

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score 6 · Answer 3 · answered Oct 01 '10 at 21:34

6

It should be in the Request.Headers dictionary.

answered Oct 01 '10 at 21:34

Nick Larsen

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Jeremy Thompson · Answer 4 · 2022-09-08T05:58:52.203

.Net 6 and above, this is how it works:

Request.Headers.TryGetValue("Auth-Token", out StringValues headerValues);
string jsonWebToken = headerValues.FirstOrDefault();

I prefer the new syntax which is more concise:

[HttpGet]
public async Task<IActionResult> GetAuth(FromHeader(Name = "Auth-Token")] string jwt) {

Headers without hypens -'s don't need the Name, they map automagically:

[HttpGet]
public async Task<IActionResult> GetAuth([FromHeader]string host) {

score 0 · Answer 5 · answered Jul 08 '19 at 21:57

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If there is anyone like me, who Googled to see how to get the Content-Type HTTP request header specifically, it's fairly easy:

Request.ContentType

answered Jul 08 '19 at 21:57

Robert Dundon

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score 0 · Answer 6 · answered Oct 12 '22 at 15:49

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With Core 3.1 and Microsoft.AspNetCore.Mvc.Razor 3.1, you can:

string sid = Request.Headers["SID"];

For whatever header variable you are looking for. Returns NULL if not found.

answered Oct 12 '22 at 15:49

Ben

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Mahi · Answer 7 · 2023-05-10T12:19:04.227

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To be on the safe side in terms of exception throws while the key doesn't exist in the header.

const string HeaderKeyName = "HeaderKey";
bool isValueExist = Request.Headers.TryGetValues(HeaderKeyName, out var values);

if isValueExist true then you should get arrays of values

edited May 10 '23 at 12:19

answered May 10 '23 at 12:10

Mahi

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Get header values in ASP.NET MVC

7 Answers7