您托管的文件上的浏览器缓存

Question

I understand how to use version numbers and force the download of updated files on my own website but what can be done under this circumstance.....

I have some small scripts i've written for public use , and i have about 200 different websites who link my js file on their website. When i make an update to the file , i have to get them all to manually change the version number of the file so they and their users are re downloading the latest update.

Is there anything i can do on my server , the host , that can force the other sites to redownload latest version without anything manual on their end of things ?

Answer 1

There are 2 persistent problems in computing: Cache invalidation, naming things, and off-by-one errors.

If you want clients to get new versions of a file without changing the name of the file then you simply have to lower the max-age you set in the caching headers so that they check more frequently and get the new version in a reasonable period of time.

That's it. End of list.

You can somewhat mitigate the effects of the increased request load by also implementing an ETag header that the client will send back on subsequent requests and can be used to detect if the resource is unchanged and optionally serve a 304 Not modified response.

However, depending on the cost of implementing and running ETag checks you might just want to re-serve the existing resource and be done with it.

Or use a CDN which should handle all the ETag nonsense for you.