# What's the "update" equivalent to the "build" method? **URL:** \ **Category:** Rails\ **Created:** [December 19, 2009, 9:22pm UTC](https://www.ruby-forum.com/t/whats-the-update-equivalent-to-the-build-method/180482 "2009-12-19T21:22:12Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![AlwaysCharging](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/ee7513/32.png) [@AlwaysCharging](https://www.ruby-forum.com/u/AlwaysCharging)\ **Post date:** [December 19, 2009, 9:22pm UTC](https://www.ruby-forum.com/t/whats-the-update-equivalent-to-the-build-method/180482/1 "2009-12-19T21:22:12Z")
Currently I’m using .build in my Create action so that I have a little more control before it gets saved. For instance, I have: @comment = current\_user.comments.build(params[:comment]) @comment.blog\_comment = @comment.blog\_comment[0…140] to chop the blog\_comment off at 140 characters. Well, that works great, but if a user goes to edit that comment, they can then make the comment longer than 140 characters since I’m using the following in the update action: ``` @comment = Comment.find(params[:id]) if @comment.update_attributes(params[:comment]) ``` So, how do I interject and chop off the comment at 140 characters when a user decides to update their comment? – You received this message because you are subscribed to the Google Groups “Ruby on Rails: Talk” group. To post to this group, send email to removed\_email\_address@domain.invalid. To unsubscribe from this group, send email to removed\_email\_address@domain.invalid. For more options, visit this group at [http://groups.google.com/group/rubyonrails-talk?hl=en](http://groups.google.com/group/rubyonrails-talk?hl=en). ---
**Author:** ![AlwaysCharging](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/ee7513/32.png) [@AlwaysCharging](https://www.ruby-forum.com/u/AlwaysCharging)\ **Post date:** [December 19, 2009, 9:36pm UTC](https://www.ruby-forum.com/t/whats-the-update-equivalent-to-the-build-method/180482/2 "2009-12-19T21:36:51Z")
On Sat, Dec 19, 2009 at 3:20 PM, AlwaysCharging [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > @comment = Comment.find(params[:id]) > if @comment.update\_attributes(params[:comment]) > > So, how do I interject and chop off the comment at 140 characters when > a user decides to update their comment? One way might be to alter the value first with something like: @comment = Comment.find(params[:id] comment\_attributes = params[:comment] comment\_attributes[‘blog\_comment’] &&= comment\_attributes[‘blog\_comment’][0…140] if @comment.update\_attributes(comment\_attributes) Something similar could also be done in the create case, in which case I’d factor out the two lines calculating comment\_attributes into a controller method. – Rick DeNatale Blog: [http://talklikeaduck.denhaven2.com/](http://talklikeaduck.denhaven2.com/) Twitter: [http://twitter.com/RickDeNatale](http://twitter.com/RickDeNatale) WWR: [http://www.workingwithrails.com/person/9021-rick-denatale](http://www.workingwithrails.com/person/9021-rick-denatale) LinkedIn: [Rick DeNatale - Developer - IBM | LinkedIn](http://www.linkedin.com/in/rickdenatale) – You received this message because you are subscribed to the Google Groups “Ruby on Rails: Talk” group. To post to this group, send email to removed\_email\_address@domain.invalid. To unsubscribe from this group, send email to removed\_email\_address@domain.invalid. For more options, visit this group at [http://groups.google.com/group/rubyonrails-talk?hl=en](http://groups.google.com/group/rubyonrails-talk?hl=en). ---
**Author:** ![AlwaysCharging](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/ee7513/32.png) [@AlwaysCharging](https://www.ruby-forum.com/u/AlwaysCharging)\ **Post date:** [December 19, 2009, 9:59pm UTC](https://www.ruby-forum.com/t/whats-the-update-equivalent-to-the-build-method/180482/3 "2009-12-19T21:59:41Z")
Seems like the perfect place for a call back if you’re doing this without discriminating. class Comment \< ActiveRecord::Base … before\_validation :trim\_blog\_comment protected def block\_comment self.blog\_comment = blog\_comment[0…140] if blog\_comment.length \> 140 end end Now it’s being trimmed at the model level on all creates/saves/ updates, no matter where the call to save comes from. On Dec 19, 3:20 pm, AlwaysCharging [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > ``` > @comment = Comment.find(params[:id]) > if @comment.update_attributes(params[:comment]) > > ``` > > So, how do I interject and chop off the comment at 140 characters when > a user decides to update their comment? – You received this message because you are subscribed to the Google Groups “Ruby on Rails: Talk” group. To post to this group, send email to removed\_email\_address@domain.invalid. To unsubscribe from this group, send email to removed\_email\_address@domain.invalid. For more options, visit this group at [http://groups.google.com/group/rubyonrails-talk?hl=en](http://groups.google.com/group/rubyonrails-talk?hl=en). ---
**Author:** ![AlwaysCharging](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/ee7513/32.png) [@AlwaysCharging](https://www.ruby-forum.com/u/AlwaysCharging)\ **Post date:** [December 20, 2009, 3:24am UTC](https://www.ruby-forum.com/t/whats-the-update-equivalent-to-the-build-method/180482/4 "2009-12-20T03:24:38Z")
This is perfect! Thank you Emery. I was thinking the same thing, but was trying before\_save filters and couldn’t get it to work for the Update action. Honestly, I didn’t even know about the before\_validation helper, guess I got some more learnin’ to do. Thanks again. And @Rick, thank you for the suggestion as well. On Dec 19, 3:58 pm, Emery F. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > 140 > > > ``` > > @comment.blog_comment = @comment.blog_comment[0...140] > > > > ``` > > > > a user decides to update their comment? > > – You received this message because you are subscribed to the Google Groups “Ruby on Rails: Talk” group. To post to this group, send email to removed\_email\_address@domain.invalid. To unsubscribe from this group, send email to removed\_email\_address@domain.invalid. For more options, visit this group at [http://groups.google.com/group/rubyonrails-talk?hl=en](http://groups.google.com/group/rubyonrails-talk?hl=en).