Fix ion asset caching #6353
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Fix ion asset caching #6353
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ion asset caching was essentially broken because sending the access token in the query string would bust the cache. The initial fix was to allow the token in the Authorization header, which fixed caching but triggered a preflight request for every tile request (due to CORS), this adds unnecessary overhead. To work around this CORS limitation, the ion servers also support including the token in the `Accept` header, which is non-standard but perfectly legal and does not trigger a pre-flight. Unfortunately, including token in the Accept header means we can no longer vary the accept header to handle terrain extensions. Cesium ion supports passing extensions via query parameters, so `CesiumTerrainProvider` now detects an ion resource and uses query parameters for them. Also turned the private and static function `Resource._makeRequest` into a prototype function so that I could override it `IonResource`
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@tfili bump |
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Looks good. |
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ion asset caching was essentially broken because sending the access token in the query string would bust the cache. The initial fix was to allow the token in the Authorization header, which fixed caching but triggered a preflight request for every tile request (due to CORS), this adds unnecessary overhead. To work around this CORS limitation, the ion servers also support including the token in the
Acceptheader, which is non-standard but perfectly legal and does not trigger a pre-flight.Unfortunately, including token in the Accept header means we can no longer vary the accept header to handle terrain extensions. Cesium ion supports passing extensions via query parameters, so
CesiumTerrainProvidernow detects an ion resource and uses query parameters for them.Also turned the private and static function
Resource._makeRequestinto a prototype function so that I could override itIonResource. This actually opens the way for some future simplification ofIonResource, but that's definitely a separate PR.CC @shunter @tfili