# Image\_tag adding request parameter **URL:** \ **Category:** Rails\ **Created:** [April 10, 2006, 6:12pm UTC](https://www.ruby-forum.com/t/image-tag-adding-request-parameter/57406 "2006-04-10T18:12:30Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![thiagoalessio](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/d6d6ee/32.png) [@thiagoalessio](https://www.ruby-forum.com/u/thiagoalessio)\ **Post date:** [April 10, 2006, 6:12pm UTC](https://www.ruby-forum.com/t/image-tag-adding-request-parameter/57406/1 "2006-04-10T18:12:30Z")
I have noticed that the image\_tag helper method now appends a request parameter to the generated src attribute. With Rails 1.0/actionpack-1.11.2 I had ![](https://test.ruby-forum.com/images/rss.gif) Now (1.1/1.12.1) I get ![Rss](https://test.ruby-forum.com/images/rss.gif?1142366545) Is there any use for that number? Where does it come from? This is very far from critical and is in no way a breaking change (at least for me), but I am curious to know why things changed. Cheers, Thiago A. ---
**Author:** ![thiagoalessio](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/d6d6ee/32.png) [@thiagoalessio](https://www.ruby-forum.com/u/thiagoalessio)\ **Post date:** [April 10, 2006, 6:24pm UTC](https://www.ruby-forum.com/t/image-tag-adding-request-parameter/57406/2 "2006-04-10T18:24:43Z")
Changelog: Added automated timestamping to AssetTagHelper methods for stylesheets, javascripts, and images when Action Controller is run under Rails [DHH]. Example: image\_tag(“rails.png”) # =\> ‘ ![Rails](https://www.ruby-forum.com/images/rails.png?1143664135)’ ?to avoid frequent stats (not a problem for most people), you can set RAILS\_ASSET\_ID in the ENV to avoid stats: ENV[“RAILS\_ASSET\_ID”] = “2345” image\_tag(“rails.png”) # =\> ‘ ![Rails](https://www.ruby-forum.com/images/rails.png?2345)’ This can be used by deployment managers to set the asset id by application revision ---
**Author:** ![thiagoalessio](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/d6d6ee/32.png) [@thiagoalessio](https://www.ruby-forum.com/u/thiagoalessio)\ **Post date:** [April 10, 2006, 6:52pm UTC](https://www.ruby-forum.com/t/image-tag-adding-request-parameter/57406/3 "2006-04-10T18:52:29Z")
Edward F. \ writes: > Added automated timestamping to AssetTagHelper methods for > stylesheets, javascripts, and images when Action Controller is run > under Rails [DHH]. Example: That’s quit extreme, screwing up caches _by default_ to please a few corner cases that can’t handle dynamic content properly. The example below is specially bad: > image\_tag(“rails.png”) # =\> ‘ ![Rails](https://www.ruby-forum.com/images/rails.png?1143664135)’ “/images” will usually live under public, so it is _static_. Why add timestamping to a static resource? At worse, these tags should add timestamping only in the rare case where the image path is actually mapped _to_ an action controller (not _from_ a controller). That, or I’m really missing something… – Pazu ---
**Author:** ![thiagoalessio](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/d6d6ee/32.png) [@thiagoalessio](https://www.ruby-forum.com/u/thiagoalessio)\ **Post date:** [April 10, 2006, 7:01pm UTC](https://www.ruby-forum.com/t/image-tag-adding-request-parameter/57406/4 "2006-04-10T19:01:34Z")
I thought the purpose of this is the browser cache. If a ressource file gets changed, it’s changed at the browser with the next request. Especially important for IE (in case there are pople still using it…). ---
**Author:** ![thiagoalessio](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/d6d6ee/32.png) [@thiagoalessio](https://www.ruby-forum.com/u/thiagoalessio)\ **Post date:** [April 11, 2006, 3:20pm UTC](https://www.ruby-forum.com/t/image-tag-adding-request-parameter/57406/5 "2006-04-11T15:20:13Z")
> Browser cache is a Good Thing ™. It avoids repeated requests for resources > that don’t change (hence the name ‘static resources’), saving network traffic, > reducing the load in your application, loading pages faster and generally making > the user happier. > > Of course, you need to understand how the browser cache (and http caches in > general) works, and play well with it. The rules are actually quite simple, and > it doesn’t take much to make sure browsers will cache what they can, and refetch > what they should. Do you think timestamping that was added breaks caching in any way? From what I see it helps, not breaks. Timestamp is not some random value, but time of the file modification, so it in fact helps in cases when “If-modified-since” and “If-none-match” don’t play nice. ## Regards, Rimantas [http://rimantas.com/](http://rimantas.com/) ---
**Author:** ![thiagoalessio](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/d6d6ee/32.png) [@thiagoalessio](https://www.ruby-forum.com/u/thiagoalessio)\ **Post date:** [April 11, 2006, 2:52pm UTC](https://www.ruby-forum.com/t/image-tag-adding-request-parameter/57406/6 "2006-04-11T14:52:37Z")
Roberto S. \ writes: > I thought the purpose of this is the browser cache. If a ressource file gets > changed, it’s changed at the browser with the next request. Especially > important for IE (in case there are pople still using it…). Browser cache is a Good Thing ™. It avoids repeated requests for resources that don’t change (hence the name ‘static resources’), saving network traffic, reducing the load in your application, loading pages faster and generally making the user happier. Of course, you need to understand how the browser cache (and http caches in general) works, and play well with it. The rules are actually quite simple, and it doesn’t take much to make sure browsers will cache what they can, and refetch what they should. – Pazu ---
**Author:** ![thiagoalessio](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/d6d6ee/32.png) [@thiagoalessio](https://www.ruby-forum.com/u/thiagoalessio)\ **Post date:** [April 11, 2006, 10:44pm UTC](https://www.ruby-forum.com/t/image-tag-adding-request-parameter/57406/7 "2006-04-11T22:44:44Z")
Rimantas L. \ writes: > Timestamp is not some random value, but time of the > file modification I knew I was missing something 😉 From the messages above, I had the impression that ‘timestamp’ was referring to some value generated at request time, and not the actual file timestamp. You’re right, done this way, timestamping will only help caching instead of hurting it. – Pazu