Same ETag is used for two different versions of the resource #2101
Description
Environment
- Server version: 7.1.7
- Node.js version: 22.21.1
- npm version: 10.9.4
Description
The ETag sent by the CSS uses a UNIX timestamp to distinguish between different versions of a single resource. The timestamp is in seconds, which causes issues when two modification requests are done within one second. In this case, the client that made the request first receives a 302 Not Modified response for subsequent GET requests, even though the resource contains different data.
I took a look to the code and the behavior is caused by the updateModifiedDate function which removes milliseconds from the metadata.
CommunitySolidServer/src/util/ResourceUtil.ts
Lines 34 to 39 in 5ff9424
I think that the comment about issues with milliseconds refers to the fact that the HTTP headers If-Modified-Since and If-Unmodified-Since do not include milliseconds. The values of these two headers are used to check BasicConditions.
CommunitySolidServer/src/storage/conditions/BasicConditions.ts
Lines 56 to 65 in 5ff9424
I have not found any other place where the presence of milliseconds in the dcterms:modified value could cause problems.