Hello,
to implement some some kind of optimistic locking, I want to build a
view, where an object is displayed together with a link containing the
data of the displayed object. My first try looked something like
<%= object.object_discription %>
<%= link_to "action", :action => "take_action", :data
=> object %>
this won''t work because object is of a class derived from ActiveRecord
and thus only the object.id will be transmitted. Next I''ve tried some
approaches to stringinize or urlizie the contents of object and read and
searching the documentation. The closed I came up with was:
<%= link_to "action", {:action =>
"take_action"}.merge(object.attributes_before_type_cast) %>
This way I can see the data of the object in the @params Hash but
instead of the needed values "data" => {"attr1" =>
"value1", "attr2" =>
"value2"} I get a more flattened Hash: {"attr1" =>
"value1", "attr2" =>
"value2"}. I think I might solve the problem by appending a
"[data]" to
every key of the object.attributes_before_type_cast hash.
Is there already a solution for my problem in Rails? Thanks for reading
this longish text ;-)
best regards
Torsten
On May 17, 2006, at 11:57 AM, Torsten Robitzki wrote:> Hello, > to implement some some kind of optimistic locking, I want to build > a view, where an object is displayed together with a link > containing the data of the displayed object. My first try looked > something likeHi Torsten - have you tried the bundled optimistic locking? http://api.rubyonrails.com/classes/ActiveRecord/Locking.html It uses a lock_version column rather than comparing existing fields. You pass the lock_version along with your form data, query params, or even as a session var if you don''t want to muddy your URLs. jeremy
Hi Jeremy, Jeremy Kemper wrote:> On May 17, 2006, at 11:57 AM, Torsten Robitzki wrote: > >> Hello, >> to implement some some kind of optimistic locking, I want to build a >> view, where an object is displayed together with a link containing >> the data of the displayed object. My first try looked something like > > > Hi Torsten - have you tried the bundled optimistic locking? > http://api.rubyonrails.com/classes/ActiveRecord/Locking.htmlno. :-(> It uses a lock_version column rather than comparing existing fields. > You pass the lock_version along with your form data, query params, or > even as a session var if you don''t want to muddy your URLs.This would solve my problem much better, thank you for this hint. Meanwhile I''ve tried my suggested solution and find that it will work (except that the field names have to be between []). But I''m going to use the solution with the update counter. best regards Torsten
I''ve never tried this, but it sounds like you want to marshal the data prior to linking it. This may not be practical in a GET request because of the length of the URL. Look into Marshal.dump and Marshal.load. For a bit of extra security, you might use code like: my_obj = Marshal.load(Base64.encode64(@the_obj.dup) unless @the_obj.nil? rescue '''' <% link_to "action", :action => "take_action", :data => my_obj %> See if that works... On Wednesday, May 17, 2006, at 8:57 PM, Torsten Robitzki wrote:>Hello, >to implement some some kind of optimistic locking, I want to build a >view, where an object is displayed together with a link containing the >data of the displayed object. My first try looked something like > ><%= object.object_discription %> ><%= link_to "action", :action => "take_action", :data => object %> > >this won''t work because object is of a class derived from ActiveRecord >and thus only the object.id will be transmitted. Next I''ve tried some >approaches to stringinize or urlizie the contents of object and read and >searching the documentation. The closed I came up with was: > ><%= link_to "action", {:action => >"take_action"}.merge(object.attributes_before_type_cast) %> > >This way I can see the data of the object in the @params Hash but >instead of the needed values "data" => {"attr1" => "value1", "attr2" => >"value2"} I get a more flattened Hash: {"attr1" => "value1", "attr2" => >"value2"}. I think I might solve the problem by appending a "[data]" to >every key of the object.attributes_before_type_cast hash. > >Is there already a solution for my problem in Rails? Thanks for reading >this longish text ;-) > >best regards >Torsten > > >_______________________________________________ >Rails mailing list >Rails@lists.rubyonrails.org >http://lists.rubyonrails.org/mailman/listinfo/rails-- Posted with http://DevLists.com. Sign up and save your mailbox.
Hi Steve, steve ross wrote:> I''ve never tried this, but it sounds like you want to marshal the data > prior to linking it.yes, that is what I''ve tried. I just had the idea to use the same protocol that rails is using for marshalling data. > This may not be practical in a GET request because> of the length of the URL.I have quit small objects here, but who knows, there are good chances that they will grow. > Look into Marshal.dump and Marshal.load. For a> bit of extra security, you might use code like:Interesting, thanks. best regards, Torsten
On Friday, May 19, 2006, at 8:40 PM, Torsten Robitzki wrote:>Hi Steve, > >steve ross wrote: >> I''ve never tried this, but it sounds like you want to marshal the data >> prior to linking it. > >yes, that is what I''ve tried. I just had the idea to use the same >protocol that rails is using for marshalling data. > > > This may not be practical in a GET request because >> of the length of the URL. > >I have quit small objects here, but who knows, there are good chances >that they will grow. > > > Look into Marshal.dump and Marshal.load. For a >> bit of extra security, you might use code like: > >Interesting, thanks. > >best regards, >Torsten > > >_______________________________________________ >Rails mailing list >Rails@lists.rubyonrails.org >http://lists.rubyonrails.org/mailman/listinfo/railsPersonally, I would use the lock_version column, but if you really want another option you could try this. key = Digest::MD5(object.to_yaml) this will generate a MD5 digest that is unique to the contents of the object at the time you call it. You can check it again before you save, if it''s different, someone has changed the record. The length of this key will always be the same, so you can use it for any object. If you want to ignore certain fields, you can use your own method instead of to_yaml. _Kevin -- Posted with http://DevLists.com. Sign up and save your mailbox.
Hi Kevin,> Personally, I would use the lock_version column, but if you really want > another option you could try this. > > key = Digest::MD5(object.to_yaml)I will go the lock_version column way, but I will keep your idea in mind. This approach could be quit useful if it''s not possible to change the used data base. best regards Torsten