Azure Maps API ignoring 'If-None-Match' header?

Wiesmüller, Benjamin 1

Hello,

I am using the https://atlas.microsoft.com/map/tile?api-version=2.0 endpoint to get map tiles via a Node.js server (acting as a proxy to prevent exposing the subscription key on a website).

I noticed the Azure Maps API returns an ETag in the response header.

I tested caching by requesting a tile with Header "If-None-Match" set to the ETag returned by a request sent immediately beforehand.
I noticed the server still responds with HTTP status 200 instead of the expected 304 (Not Modified).

Does the server support the "If-None-Match" header?
Is there something wrong with my HTTP request?

Wiesmüller, Benjamin 1 Reputation point

2020-08-18T11:54:55.19+00:00

Attached is a Node.js example demonstrating the problem.

1 answer

rbrundritt 18,061 Reputation points Microsoft Employee

2020-08-18T15:52:23.55+00:00
I'm not sure about your questions but a couple of things to be aware of:

Server side caching as a way to reduce calls and serve multiple users is against the terms of use.

Instead of trying to hide a subscription key, consider using Azure Active Directory with Azure Maps. It provides a lot more security and specifically added to Azure Maps for this reason. Here are a bunch of code samples and resources on this:

https://video2.skills-academy.com/en-us/azure/azure-maps/how-to-manage-authentication

https://github.com/Azure-Samples/Azure-Maps-AzureAD-Samples
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Wiesmüller, Benjamin 1 Reputation point

2020-08-18T16:53:16.56+00:00

Thank you for your answer:

Server side caching as a way to reduce calls and serve multiple users is against the terms of use.

Our server is not caching the tiles. I am trying to correctly use the caching mechanism provided by the Azure API.

The returned tiles have the 'cache-control' header set to 'max-age=86400' and also include a header 'etag'.
As far as I know the browser should cache the tile for 86400 seconds and after that send a request to the server including the header 'if-none-match' set to the ETag of the original response.
If the tile has not changed (its ETag still is the same) the server should return status 304, but what I see is status 200, meaning the tile is transferred again unnecessarily.

Wiesmüller, Benjamin 1 Reputation point

2020-08-18T16:53:26.29+00:00

Instead of trying to hide a subscription key, consider using Azure Active Directory with Azure Maps.

We are using Leaflet to show the map, similar to this sample:
https://github.com/Azure-Samples/AzureMapsCodeSamples/blob/master/AzureMapsCodeSamples/Third%20Party%20Map%20Controls/Raster%20Tiles%20in%20Leaflet%20JS.html

I think the AD authentication requires access tokens to be passed in the authorization header, but I cannot modify the headers sent by leaflet.

QuantumCache 20,266 Reputation points

2020-08-21T16:46:50.867+00:00

Hello @Wiesmüller, Benjamin , Just checking back, could you please let us know if you need further help in this matter.

Please accept helpful responses as 'Answer', which will be helpful to others as well with similar question.

Wiesmüller, Benjamin 1 Reputation point

2020-08-25T07:42:29.747+00:00

Hello,
my question about how/if the maps/tile API is supposed to work with the "If-None-Match" header for caching is still open.

QuantumCache 20,266 Reputation points

2020-10-13T14:39:05.147+00:00

Hello @Wiesmüller, Benjamin , Apologies in delay responding.

Just checking back, could you please let us know if you need further help in this matter, we will reopen the case to further help you.

Cc: @rbrundritt , @António Sérgio Azevedo , @AshokPeddakotla-MSFT

QuantumCache 20,266 Reputation points

2020-10-17T18:05:16.357+00:00

Hello @Wiesmüller, Benjamin , Thanks for posting this great question on this forum!

Below is the response from Microsoft's Azure Maps product team, I hope this helps with your query.

Question: my question about how/if the maps/tile API is supposed to work with the "If-None-Match" header for caching is still open.

PG Response:

Azure Maps don't support that header.
You might be already aware of (or) may be interested in Azure Active Directory which provides a lot more security options.

Please let me know if you need further help in this matter.

Please accept helpful responses as 'Answer', which will be helpful to others as well with similar question, so that we can close this thread.

QuantumCache 20,266 Reputation points

2020-10-21T01:50:36.293+00:00

Hello @Wiesmüller, Benjamin Just checking back, could you please let us know if you need further help in this matter.
Please accept the helpful response as 'Answer', which will be helpful to others as well with similar question, so that we can close this thread.
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Azure Maps API ignoring 'If-None-Match' header?

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