HTTP cache
Etag MD5 expire time has a bug cache-control max-age=600
Expire is different from cache-control because the expire time can be set locally and the expiration time can be set artificially, whereas cache-control is set within a specified time
Difference between Etag and cache-control Etag has a request, while cache-control has no request
Get is used to get data. Post is used to submit data.