Very nice!

Maybe make available as a plugin instead?

Also - why "has_finder" - why not just an explicit "finder"?

Awesome. I wrote something to enable the same call syntax the other day, but this is much better. I second the vote for a plugin!

Josh/Ryan -- thanks for the feedback. I'll package this as a plugin soon. As for calling the method "finder" vs. "has_finder" -- I'm OK with both. Let's have a vote!

Really sweet!

But isn't with_scope going to be a protected method? Implications on this?

Trying something like Page.published.find(params[:id])) in edge and it fails, something like @page.published.children.find(:all) works fine though..

Joel -- I just updated the gem to use send :with_scope. I can't seem to get rake to run on a freshly generated edge rails app, so I'm unsure whether this will fix the defect or not. Let me know!

That seems to do it. Much obliged =)

(Did you try gem update --system; gem update rake; for edge rails?)

Hi,

For some reason there is a bug when using with scope. For example

User.scoped_by_site(1) { User.superusers }

and

User.scoped_by_site(1) { User.superusers.find(:all) }

for the first example, it doesn't respect the scope, for the second it does.

Any thoughts?

Cyx: That kind of usage is impossible to support, unfortunately. It's difficult to explain why that doesn't work, but let me try:

User.superusers returns a proxy object, not an array. What you're doing:

<code>User.scoped_by_site(1) { User.superusers }
</code>

is more or less equivalent to just

<code>User.superusers
</code>

Since the more complex expression just returns the proxy object. The withscope only "lasts" as long as the block being passed to it; it's destroyed as soon as the block returns. In your first example, you'll only effect the find after scopedbysite returns (e.g., by calling #each or #find), at which point the withscope is long gone.

This fact is, by far, the most complex part of how hasfinder works. If you want an object to encapsulate a scope (which is more or less what hasfinder does), composition is only possible if the objects no how to chain themselves together, such that method invocation leads to nested with_scopes. Look at the source code for details. In any case, I recommend you do the following:

<code>class User
  has_finder :scoped_by_site lambda{|site_id| {...} }
end
</code>

and then you should be OK.

great idea! vote for plugin too :).

for STI it doesn't work. for now i put has_finder's definition in a module and included it in tables-children. other way i've got that:

The error occurred while evaluating nil.call from .../gems/has_finder-0.1.2/lib/has_finder/has_finder.rb:59:in 'published'

One problem I'm having with nested scopes:

Article.published.popular executes two queries, one to get published and another to get published AND popular AND published.

SELECT * FROM articles WHERE (published = 1)

SELECT * FROM articles WHERE (( ( published = 1 ) AND ( popular = 1 ) ) AND ( published = 1 ))

I was hacking around earlier and ended up implementing a half-baked version of this that doesn't involve the use of AssociationProxies:

http://pastie.caboo.se/95207

It's definitely under-powered (I'm using has_finder instead), but folks might find the approach interesting.

I was hacking around earlier and ended up implementing a half-baked version of this that doesn't involve the use of AssociationProxies:

http://pastie.caboo.se/95207

It's definitely under-powered (I'm using has_finder instead), but folks might find the approach interesting.

macovsky - i'll fix this bug and release a new version in the next couple of days. grant - i'll see if I can reproduce this behavior.

Great! Since I was playing around with scopeout and scopedproxy, I always wanted to somehow combine the advantages of both plugins. I didn't try hasfinder yet, but it looks like it does exactly what I am searching for, so +1 for a hasfinder plugin :-)

macovsky/grant - both issues should be fixed and are now available as has_finder 0.1.3.

Hi, thanks again for a excellent piece of software..

Have you thought about calculations? eg. Order.completed.sum(:amount) ect. (That maybe out of scope for has_finder though)

Just checking if you are implementing it before I try a stab at it myself..

On another note, it's busted in edge again =) I'm getting

vendor/rails/activerecord/lib/activerecord/base.rb:1277:in method_missing_without_paginate': undefined methodhasfinder' for # (NoMethodError)

lots of stuff going on in edge now apparantly.

I think it has to do with how you include the HasManyAssociations, changing from just using include to doing a class_eval seems to do it.

like so:

ActiveRecord::Base.send :include, HasFinder::ActiveRecord module ActiveRecord::Associations [HasManyAssociation, HasManyThroughAssociation].each do |klass| klass.class_eval do include HasFinder::HasManyAssociation aliasmethodchain :methodmissing, :hasfinder end end end

whoops, busted rendering but you get the idea =)

Joel -- I'll make those fixes later tonight... As for #sum, in theory they should be working (I thought they were already) since I thought with_scope affected calculations as well... I'll double check that stuff.

Joel -- I fixed the issue with sum (was being delegated to the array rather than ActiveRecord). I could not reproduce your issue in edge (just tried with latest version right now), sorry!

Try 0.1.5 and let me know if it's any better.

two things. one, i'm unable to get hasfinder working. I get an error from ActiveRecord::Base: "in'method_missing':ArgumentError: no id given" on the line that calls "super" at the end. not sure what's going on there.

also...Is there any way to include has_finder finders directly on an association? so for instance: User - has_finder :active, :conditions = {:deactivated = false}

Group has_many :memberships has_many :members, :through = :memberships, :with_finder = :active

that would seem easier than having to always access @group.members.active

Hi oliver:

1. There's not yet planned support for things like: hasmany ... :withfinder => :active Good idea though, so I'll consider adding it.

2. I cannot reproduce the error you have with has_finder. I need more detail. Send me a full stack trace (nick @ pivotallabs.com), and any source code that you can... Something to do might be generate a new rails app, require the gem in your environment and write a few lines of code that fail... you can zip it up and send it all to me.

Oliver, PS:

<code>class Group
  has_many :memberships ...
  def active_memberships
    memberships.active
  end
</code>

end

Not super-concise, but it gives you almost all that you want.

Nick,

HasFinder is quite a gem (in many ways), but do you have it available in an svn repo so it can be installed as a plugin?

brandon: source code is in rubyforge in the pivotalrb project. thanks for your interest!

I want to install as script/plugin is it posible?

I want to install as script/plugin is it posible?

can you use associations in the conditional:

<code>class Song &lt; ActiveRecord::Base
has_many :reviews
has_finder :u2, {:conditions =&gt; {"songs.artist" =&gt; "U2", "reviews.rating" =&gt; 8 }, :include =&gt; :reviews }
</code>

can you use associations in the conditional:

<code>class Song &lt; ActiveRecord::Base
has_many :reviews
has_finder :u2, {:conditions =&gt; {"songs.artist" =&gt; "U2", "reviews.rating" =&gt; 8 }, :include =&gt; :reviews }
</code>

can you use associations in the conditional:

<code>class Song &lt; ActiveRecord::Base
has_many :reviews
has_finder :u2, {:conditions =&gt; {"songs.artist" =&gt; "U2", "reviews.rating" =&gt; 8 }, :include =&gt; :reviews }
</code>

@ those that were asking about using this as a plugin:

Install it as a gem, then copy the 'has_finder-0.1.5' from the 'ruby/lib/ruby/gems/1.8/gems' directory into 'vendor/plugins', and put:

require 'has_finder'

into a new file named init.rb, inside that folder, then you dont need the two lines in your environment.rb file either.

I think you can also safely delete the config and test folders, and the 'setup.rb' file, as they are then redundant. Oh and don't forget to restart the server (as I always do!)

A lot of gems can be 'converted' this way as they share the same basic structure as rails plugins.

And thanks nick, this is just what i've been looking for :)

This plugin (gem) seems to have the same problem with :group option of AR.find method that scope_out suffers. Namely it does not seem to support it.

ex...

hasfinder :nonactive, :group => 'login'

fails with...

ActionView::TemplateError (Unknown key(s): group) on line #10 of app/views/users/_index.rhtml:

/var/lib/gems/1.8/gems/activesupport-1.4.4/lib/activesupport/coreext/hash/keys.rb:48:in assert_valid_keys' /var/lib/gems/1.8/gems/activerecord-1.15.5/lib/active_record/base.rb:913:inwith_scope'

FYI, a work around for the lack of :group support

ex...

hasfinder :nonactive, :select => 'distinct ...'

seems to work for me, but the :group option would be nice - as it's a standard part of find method

Mark -- your technique should work.

Andy -- unfortunately, I rely on with_scope (as does scope_out) and it does not support group by. I can give you source code to make with_scope support group_by, (it's fairly straightforward), but I wouldn't want to include it in has_finder because of its potentially undesirable effect on the rest of the Rails app.

It would be good to get an access to SVN repo. I want to install this plugin using Piston (http://piston.rubyforge.org/). It is much better than copying Gem

DEkart -- http://pivotalrb.rubyforge.org/svn/hasfinder/trunk/hasfinder/

I am currently using custom finders like this

class Barcode < ActiveRecord::Base def self.findallbyclient(clientid) self.findallbyclientid(clientid, :include => {:item => :itemtype}, :order => "item_types.name, items.name") end end

I would like to replace it with this but how can I pass the session variable session[:client] to the has_finder method?

hasfinder :all, :conditions => {:clientid => session[:client]}, :include => {:item => :itemtype}, :order => "itemtypes.name, items.name"

My underscores got stripped out of that post but you can still get the point.

Chris -- only the controller (and view) have access to the session (for better or worse). The easiest thing to do is pass in the client_id as a parameter to the finder, as you did in your self.find_all_by...

<code>class Barcode
  has_finder :all, lambda {|client_id| { :conditions =&gt; {:client_id =&gt; client_id} } }
end

class BarcodesController
  ...
    Barcode.all(session[:client_id])
</code>

In the example you gave above, it doesn't seem like you need your model to know about the session... But,

If you want the session available in your model layer, this is an obstacle totally unrelated to has_finder. Use an around_filter to set (and unset) a class variable on AR::Base or a thread-local variable that AR::Base has access to. Better yet, alias_method_chain perform_actionto do the same thing (this will ensure your session is available in your models in the after_filters that happen after your around_filter).

Don't let anyone give you a hard time about MVC. Dogma does not lead to good software design.

Thanks, that works great for finding a collection of objects but when I try to find a single item for my show action, I get an method missing error. I think this is because has_finder is returning an array and my show action is treating it like an object.

hasfinder :one, lambda {|id, clientid| { :conditions => {:id => id, :clientid => clientid} } }

How can I write this to return a single object instead of an array of 1, or should I just use a custom method for finding one object instead of using has_finder?

chris -- has finder is not really designed for the "one" case. A simple, but clumsy, implementation might be something like the following:

<code>has_finder :ones, lambda {|id, client_id| {...} }

def self.one
  ones.first
end
</code>

Thanks Nick, you've been so helpful. One more question. I have the following defined.

<code>
has_finder :active, lambda {|client_id| { :conditions => {:client_id => client_id, :active => true}, :include => [:tiers, :sale_contracts], :order => "plans.monthly_fee" } }
has_finder :business, lambda {|client_id| { :conditions => {:client_id => client_id, :is_business_plan => true}, :include => [:tiers, :sale_contracts], :order => "plans.monthly_fee" } } </code>

When I call Plan.active.business(session[:client]) I get nothing in the result list because the conditions are merged and the has finder for active is supplying the condition client_id = null because I didn't pass it in the controller. To make it work I have to call Plan.active(session[:client]).business(session[:client]) and that works fine, I was just wondering if there was a prettier way to write it.

By the time I got to the end of writing this post, I have decided to myself that its better this way but still let me know what you think. I'm still considering using the around filter that you mentioned before because the way my app is designed, every query in every model requires the client_id.

This is perfect, just in the nick of time.

Thanks!

gem 'has_finder' = true require 'has_finder' NoMethodError: undefined method 'delegate' for HasFinder::FinderProxy:Class

Eek, what's going on?

delegate is a method from activesupport. You must be requring 'hasfinder' too early in your environment file--assuming you're using Rails. If you're not using Rails, make sure to require has_finder after active record

YOU ROCK. This works great!

Daniel:

<code>class Writing
  has_many :pages
end

class Page
  has_finder :beginnings, :conditions =&gt; { :position =&gt; 1 }
end
</code>

And voila:

<code>my_writing.pages.openings
</code>

Haha, thanks! I ended up doing this before the reply:

<code>first_scoped_page = self.writing.pages.find(:all, :conditions =&gt; ["position = 1"] )
</code>

Now I can refactor!

Thanks!

Absolutely Great thing, thanks a lot, man!

I've noticed a bug when was using models in modules.

<code>class Foo::Bar &lt; ActiveRecord::Base
  belongs_to :x
  belongs_to :y
#...

  has_finder from_x, lambda {|x| {:conditions =&gt; {:from_id =&gt; x}}}
  has_finder in_y,  lambda {|y| {:conditions =&gt; {:y_id =&gt; y}}}
end

class Foo::Z &lt; ActiveRecord::Base
  belongs_to :x
  belongs_to :y
#...

  def outgoing_bars
     Bar.from_x(x_id).in_y(y_id)
  end
end
</code>

results in a 'X is not missing constant Bar' error.

The workaround for this is to use absolute name - ::Foo::Bar, instead of just Bar.

But it is possible that I did something wrong...

Okay, we really need to package this as a plugin...

Vlad -- if you give me a full stack trace I will look into it in more detail. I know that using AR's in modules in general can cause problems with associations like belongsto (at least it did with Rails 1.2.3), so it's possible hasfinder is unrelated, not sure. But I'll fix it if I can.

Sure, here it is:

<code>/var/lib/gems/1.8/gems/activesupport-1.4.4/lib/active_support/dependencies.rb:240:in `load_missing_constant'
/var/lib/gems/1.8/gems/activesupport-1.4.4/lib/active_support/dependencies.rb:468:in `const_missing'
/var/lib/gems/1.8/gems/activesupport-1.4.4/lib/active_support/dependencies.rb:470:in `send'
/var/lib/gems/1.8/gems/activesupport-1.4.4/lib/active_support/dependencies.rb:470:in `const_missing'
/app/models/foo/z.rb:15:in `outgoing_bars'
/var/lib/gems/1.8/gems/activerecord-1.15.5/lib/active_record/associations/association_proxy.rb:123:in `send'
/var/lib/gems/1.8/gems/activerecord-1.15.5/lib/active_record/associations/association_proxy.rb:123:in `method_missing'
/app/views/shared/_document_bars.rhtml:5:in 
...
</code>

The call is like

<code>document.z.outgoing_bars
</code>

To get the point what I'm trying to do: navigating kind of a graph, with multiple paths on the same vertices :)

I thought I posted this already but I didn't see the comment appear. I have realized that in rails, when you do a find(:all) statement inside of an association (has_many :somethings, :thought => :other_things do; def completed; find(:all, :conditions => {:completed => 1}); end;) it breaks the :uniq => true statement in the association. I'm able to fix this in my models when i define finders to narrow a search down by just adding a .uniq to the end of the statement (find(:all).uniq) .. is there any way to add this functionality to has_finders? I'd love to use this gem and make my finders much easier to use and read, but i NEED the uniq fix and can't figure out how to do it myself with this gem. Any help?

After playing around in the source, I added .uniq to the find(:all) statement in the load_found private method and it now only returns unique results. This'll do until an official fix is released.

Those looking for a plugin version can try this checkout into their plugins directory..

svn checkout http://pivotalrb.rubyforge.org/svn/has_finder/trunk/has_finder

Hi!, I tried to use has_finder and has_many_polymorphs (tagging_extensions), but I get a strange behavior... I have two taggable models, in one of them I've added a finder (using has_finder)... and in that model I can't access the dynamic method added by tagging_extensions (tags for example). In the model where I haven't added any finder I can access these methods without any problem.

For some reason, when I ask for the Tag model... this problem doesn't happen anymore.... ----- environment.rb require 'tagging_extensions' require 'has_finder' Tag The last line makes all work fine. This model Tag, adds to my two models a lot of methods via :extend options in has_many_polymorphs... I think that is the reason why the problem doesn't happen anymore.. but I think that is not the correct way for solving it..

Any ideas? Thanks

Finally found a scoping plugin that works with acts_as_tree out of the box. Thank you :)

It seems that HasFinder overrides the model translating aspect of Globalize (an il8n plugin for Rails), at least in the case where one is using the default translation storage.

It's a very nice system, otherwise!

This is so great. One "problem" I found though, was that I've started using rails new partial renderthingie:

controller: @posts = Post.a_has_finder_finder

view: render :partial => @posts

This doesn't work anymore.. probably since the objects in @posts aren't pure Post-classes anymore, but some has_finder proxy thingie.

The workaround isn't that big of a deal though, just go back to using the "old way":

view: render :partial "posts/post", :locals => bla bla ...

.. Maybe something could be done so it works with the first way though?

Oups, sorry for the dups.. didn't see my comments comming.

And one correction, the way one has to do with has_finder in the view is:

render :partial => "posts/post", :collection => @posts ... which isn't such a big deal.

I'm trying to dynamically add has_finder methods to model classes. As my first exploration I tried the following in a model class:

content_columns.select {|c| c.type == :string}.each do |column|
    has_finder column.name.to_sym, 
                     lambda {|param| { :conditions => {column.name.to_sym => param} } }
end

Unfortunately this isn't working. I'm seeing the following error many times when I true to use one of these finders:

/path/to/my/mode_model.rb:42: warning: multiple values for a block parameter (0 for 1) from /path/to/my/rails_root/vendor/plugins/has_finder/lib/has_finder/has_finder.rb:55

Any idea how I might be able to pull this off?

Thanks.

Hello there,

has anyone used has_finder successfully with has_many_polymorphs associations?

Basically I have an user model which has many items (which can be of type :a, :b and :c) and for example I want to get all UserItems which have been created yesterday (finding within the hmp user.items associations). I am kinda confused atm because it isn't working as expected :-/

_j

Markdown obviously messes with the _'es ;)

Anyway - what I forgot to add was the setup: I have one User model, one UserItem model and several other models A, B and C. UserItem is the join model for the hmp associations. I placed e.g. this finder in there:

has_finder :created_today, :conditions => ['created_at > ?', Date.yesterday]

Now when I fetch an User u and do a u.items.created_today, I get a big, bad exception:

ActiveRecord::StatementInvalid: Mysql::Error: Column 'created_at' in where clause is ambiguous: .... :-/

A, B and C have all the typical 2 rails timestamp columns and so do the useritems.

Any Idea what's wrong here?

Jorg,

HMP scares me - I've used it before and with no good effect. It looks like a simple workaround to your problem would be:

has_finder :created_today, :conditions => ['users.created_at > ?', Date.yesterday]

Note the prefix on the created_at column. Also, bear in mind that doing Date.yesterday is really dangerous as the statement gets evalled at class-eval time, meaning if your code is long-running, yesterday may be 5 days ago, etc.

Two workarounds for that are: 1) use the lambda form, 2) put the date in the sql clause, not using bind (the question-mark).

Hi Nick,

I found a bug with finders that only do an "order by". For example:

hasfinder :popular, :order => 'hits desc' hasfinder :alphabetical, :order => 'name asc'

Topic.popular.alphabetical would only do "order by hits desc" and not "order by hits desc, name asc".

You've created a wonderful gem. Any update on if and when it will be available as a plugin or can we hope to see this in the official Rails release soon?

Regards, Jason

Hi again! First, I have to say I am really digging this gem, man! This is exactly what Rails needed.

I found another small bug - when I do something like this: forum.topics.popular

The generated SQL checks forum_id twice: SELECT * FROM topics WHERE (topics.forum_id = 13) AND (topics.forum_id = 13) ORDER BY posts_count desc

My finder is the following: has_finder :popular, :order => 'posts_count desc'

I think that rails core team should consider has_finder as part of AR. It's useful thing like associations. I hope that some day it becomes part of AR.

Thank you for releasing has_finder. It's a pleasure to use.

I want to use it in conjunction Geokit. Geokit adds :origin and :within options to finders. In a has_finder, it does not recognise these options.

Can anyone help at all?

I encountered a "superclass mismatch for class Annotation" when trying to use with rails 2.0.2.

How to fix that?

My solution is ugly -but it works. You have to remove the spec directory from plugin's source.

And there is second way.

Just install it as a gem. (instructions here: http://pivotalrb.rubyforge.org/svn/has_finder/trunk/has_finder/README.txt)

In such way it has no problems with rake.

I had the same problem jochen. I also removed the spec directory!

I want to chain a number of has_finders together. Some of these finders might have nil as parameter, in which case I'd like it to be ignored. Is there any way of doing this?

i.e. Shoes.of_size(10).of_colour(nil).under(40)

I tried messing with the lamda but didn't get very far.

How does this plugin play along with paginating_find?

I'm trying to do something like:

has_finder :paged, :page => {:size => 100, :auto => true}, :order => :id

Which should potentially allow:

User.active.paged

Am I correct in assuming has_finder will not work with HABTM associations? I've tried it and it doesn't produce the correct results. Just wondering if I'm doing something wrong or its just not supported.

Other than that, been loving the plugin, thanks!

Hi,

nice gem!

I wanted to point another use which was very helpful for me.

I needed to compose several OPTIONAL queries... Say your Person#controller accepts params[:search] and params[:ver] (with a boolean field), and you can call it with either or both of params. In the controller I would like just to call:

Person.search(params[:search]).verification(params[:ver])

and I wanted it to work with no (eg. give me all Person), one or the above two params options.

I managed to do this by defining the has_finder like:

has_finder :search, lambda {|name| {:conditions => name.nil? ? nil : ["name LIKE ?", name+"%"] } } has_finder :ver, lambda {|v| {:conditions => v.nil? ? nil : :conditions => {:verification = v} } }

Bye, Z

Hi nick,

great job!

but i found that has_finder does not work with polymorphic :has_many.

here is the test code.

class Membership < ActiveRecord::Base belongs_to :joinable, :polymorphic => true

class Group < ActiveRecord::Base has_many :memberships, :as => :joinable end

the snippet Group.find(:first).memberships produces the sql SELECT * FROM memberships WHERE (memberships.joinable_id = 1 AND memberships.joinable_type = 'Group')

while Group.find(:first).memberships.accepted only produces the sql SELECT * FROM memberships WHERE (accepted_at is not NULL)

am i missing something?

Hi nick,

great job!

but i found that has_finder does not work with polymorphic :has_many.

here is the test code.

<code>
class Membership < ActiveRecord::Base

  belongs_to :joinable, :polymorphic => true

  has_finder :accepted, :conditions => { :accepted => true }

end

class Group < ActiveRecord::Base

  has_many :memberships,    :as => :joinable

end
</code>

the snippet

produces the sql

<code>

SELECT * FROM `memberships` WHERE (memberships.joinable_id = 1 AND memberships.joinable_type = 'Group')

</code>

while

only produces the sql

<code>
SELECT * FROM `memberships` WHERE (accepted_at is not NULL)
</code>

am i missing something?

Hi there,

Does has_finder cache the result of searches like usual AssociationProxies do?

class Task < AR has_finder :resolved, :condititions => { :resolved => true } end

Task.resolved Task.resolved

produces two SQL quiries!!!

UVSoft:

It does cache results. x = Task.resolved has not yet hit the database. x.collect will hit the db one time. x.collect again will not hit the database. You do not want to cache Task.resolved as it's effectively a global variable that will persist across http requests.