I am working on an app in rails 3.
I have several records that i want to save to my database. I am trying to make sure that all the objects in an array (the records are stored in an array) are valid before saving. The Owner model validates the presence of name and email. In the rails console, I have tried the following:
#owner = Array.new
=> []
#owner[0] = Owner.new (name:"peter", email:"peter#gmail.com")
=> returns object
#owner[1] = Owner.new (name:"fred", email:"fred#gmail.com")
=> returns object
#owner[2] = Owner.new (name:"", email:"")
=> returns object
#owner[0].valid?
=> true
#owner[1].valid?
=> true
#owner[2].valid?
=> false
#owner.each { |t| t.valid? }
=> returns an array like this: [object1, object2, object3]. I would expect something like this instead: [true,true,false]
I dont understand why the .valid? method works fine if I individually check the elements of the array using #owner[i], but doesnt work correctly if I'm using .each to iterate through the array. Anybody know what might be the problem?
What I am trying to do is achieve something like this:
(#owner.each { |t| t.valid? }).all?
To make sure that each record is valid, then I can proceed to save them.
Thanks
Each does not return an array of valid? values. You probably want either:
(#owner.collect { |t| t.valid? }).all?
or
(#owner.all? { |t| t.valid? })
The examples can also be written as:
#owner.collect(&:valid?).all?
or
#owner.all?(&:valid?)
Related
I have a user, a micropost and a response model.
The user has many microposts and has many responses.
Microposts have tags using the acts as taggable gem.
I need to find the number of responses a user has, to microposts that are tagged with a specific tag. To be clear, for example, how many responses has user 1 given to microposts on "exercise"
There is some basic ruby syntax and relationship logic I am missing. This is what I haev in my user model.
def user_responses_on_topic tag
microposts = self.microposts.tagged_with(tag, :on => :tags)
responses_count = 0
microposts.each do |micropost|
count = micropost.responses.where("user_id = :user_id", user_id: self.id).size
responses_count = responses_count + count
end
end
Its giving me a value but I know its wrong because when I add responses on a particular topic the users value doesn't increase.
I am sure there is a simple "ruby" way to get at this using
responses = user.microposts.responses
But I need to know how to get the tagged logic on microposts into this code
I have tightened it up a bit but still not luck. The individual components of this code work but I can't get the whole thing to work together
def user_responses_on_topic(interest)
microposts = Micropost.tagged_with(interest, :on => :tags, :any => true)
responses ||= 0
microposts.each do |micropost|
responses += micropost.responses.where("user_id = :user_id", user_id: self.id).size
end
end
EDIT:
This works
def user_responses_on_topic(interest)
microposts = Micropost.tagged_with(interest, :on => :tags, :any => true)
count = 0
microposts.each do |micropost|
responses = micropost.responses.size
count = count + responses
end
count
end
But there's got to be a better Rails way (this smells of PHP)
Any ideas?
If all of the components are working independently, it might be as simple as adding a line to the end of your method: responses. After the .each loop executes, it returns the original array (not the value you modified within the loop). Since you want to return the number stored in responses, you want that variable to be the last line of your method.
You should be able to do the count in a single query like this:
microposts.tagged_with(tag, on: :tags).joins(:responses).where(responses: {user_id: id}).count
I have a Ruby hash converted from JSON data, it looks like this:
{ :query => {
:pages => {
:"743958" => {
:pageid => 743958,
:ns => 0,
:title => "Asterix the Gaul",
:revisions => [ {
:contentformat => "text/x-wiki",
:contentmodel => "wikitext",
:* => "{{Cleanup|date=April 2010}}\n{{Infobox graphic novel\n<!--Wikipedia:WikiProject Comics-->...
All the good stuff is inside the revisions array and then the Infobox hash.
The problem I have is getting to the Infobox hash. I can't seem to get to it. The pages and pageid hashes might not exist for other entries and of course the ID would be different.
I've tried all sorts of methods I could think of like .map, .select, .find, .include?, etc to no avail because they are not recursive and will not go into each key and array.
And all the answers I've seen in StackOverflow are to get the value by name inside a one-dimensional array which doesn't help.
How can I get the Infobox data from this?
Is this what you're looking for?
pp data
=> {:query=> {:pages=>
{:"743958"=>
{:pageid=>743958,
:ns=>0,
:title=>"Asterix the Gaul",
:revisions=>
[{:contentformat=>"text/x-wiki",
:contentmodel=>"wikitext",
:*=>"{{Cleanup..."}]}}}}
# just return data from the first revisionb
data[:query][:pages].map{|page_id,page_hash| page_hash[:revisions].first[:"*"]}
=> ["{{Cleanup..."]
# get data from all revisions
data[:query][:pages].map{|page_id,page_hash| page_hash[:revisions].map{|revision| revision[:"*"] }}.flatten
=> ["{{Cleanup..."]
Let's say we have a MongoDB collection called "images", and a MongoMapper-powered application with a corresponding "Image" model. If we set up a MongoMapper query using this model, we see that it is of type Plucky::Query and returns results of type Image:
>> Image.where(:file_type => 'image/jpeg').class
=> Plucky::Query
>> Image.where(:file_type => 'image/jpeg').first.class
=> Image
We can run the corresponding query directly on the Mongo adapter, mostly bypassing MongoMapper, by accessing the MongoMapper.connection. If we do it this way, the query is of type Mongo::Cursor and returns raw data results of type BSON::OrderedHash:
>> MongoMapper.connection.db(dbname).collection('images').find({ :file_type => 'image/jpeg' }).class
=> Mongo::Cursor
>> MongoMapper.connection.db(dbname).collection('images').find({ :file_type => 'image/jpeg' }).first.class
=> BSON::OrderedHash
The question is, is there a way to take a Plucky::Query like above and convert it to (or retrieve from it) a basic, non-extended Mongo::Cursor object?
At first I thought I found a solution with find_each, which does actually take a Plucky::Query and return a Mongo::Cursor:
>> Image.where(:file_type => 'image/jpeg').find_each.class
=> Mongo::Cursor
But it turns out this Mongo::Cursor is somehow extended or otherwise different from the above one because it still returns Image objects instead of BSON::OrderHash objects:
>> Image.where(:file_type => 'image/jpeg').find_each.first.class
=> Image
Update: I can't simply bypass MongoMapper query magic altogether like I did in the second case because I need to access features of MongoMapper (specifically named scopes) to build up the query, so what I end up with is a Plucky::Query. But then I want the results to be plain data objects, not models, because all I need is data and I don't want the overhead of model instantiation.
If you drop to the driver, the transformer is nil by default:
1.9.3p194 :003 > Image.collection.find({ :file_type => 'image/jpeg' }, { :limit => 1 }).first.class
=> BSON::OrderedHash
MongoMapper achieves the conversion by setting a "transformer" lambda on the plucky query. You can see this in the MongoMapper source code:
def query(options={})
query = Plucky::Query.new(collection, :transformer => transformer)
...
end
...
def transformer
#transformer ||= lambda { |doc| load(doc) }
end
So after each mongo document retrieval, this Plucky::Query runs the transformation that loads the model. Looking at the Plucky source code we see that there is a simple setter method [] we can use to disable this. So this is the solution:
plucky_query = Image.where(:file_type => 'image/jpeg')
plucky_query.first.class
# => Image
plucky_query[:transformer] = nil
plucky_query.first.class
# => BSON::OrderedHash
If you don't mind monkey-patching you can encapsulate like so:
module Plucky
class Query
def raw_data
self[:transformer] = nil
self
end
end
end
Then you could simply write:
Image.where(:file_type => 'image/jpeg').raw_data.first.class
# => BSON::OrderedHash
I want to try Mongo with Ruby. I connected, selected collection and I can query data from MongoDB.
irb(main):049:0> coll.find_one({:x=>4})
=> #<BSON::OrderedHash:0x3fdb33fdd59c {"_id"=>BSON::ObjectId('4f8ae4d7c0111ba6383cbe1b'), "x"=>4.0, "j"=>1.0}>
irb(main):048:0> coll.find_one({:x=>4}).to_a
=> [["_id", BSON::ObjectId('4f8ae4d7c0111ba6383cbe1b')], ["x", 4.0], ["j", 1.0]]
But how to access propeties, when I retrieve BSON hash? I need something like this:
data.x
=> 4
to_hash method gives me the same BSON::OrderedHash... :(
When you say coll.find_one({:x=>4}), you get a BSON::OrderedHash back that you access like a normal Hash:
h = coll.find_one(:x => 4)
puts h['x']
# 4 comes out unless you didn't find anything.
If you use a full find instead of find_one, you get a MongoDB::Cursor which is an Enumerable so you can iterate it like any other collection; the cursor will return BSON::OrderedHash instances as you iterate so you can do things like this:
cursor = coll.find(:thing => /stuff/)
cursor.each { |h| puts h['thing'] }
things = cursor.map { |h| h['thing'] }
If you wanted objects instead of Hashes then you'd have to wrap the MongoDB::Cursor and BSON::OrderedHash instances with object yourself (possibly via Struct).
Mongodb find_one method returns hash object, find method returns cursor object.
Cursor object can be iterated and then is possible to extract the answer in a normal hash.
require 'rubygems'
require 'mongo'
include Mongo
client = MongoClient.new('localhost', 27017)
db = client.db("mydb")
coll = db.collection("testCollection")
coll.insert({"name"=>"John","lastname"=>"Smith","phone"=>"12345678"})
coll.insert({"name"=>"Jane","lastname"=>"Fonda","phone"=>"87654321"})
cursor = coll.find({"phone"=>"87654321"})
answer = {}
cursor.map { |h| answer = h }
puts answer["name"]
Using Mongoid, is it possible to use "update_all" to push a value onto an array field for all entries matching a certain criteria?
Example:
class Foo
field :username
field :bar, :type => Array
def update_all_bars
array_of_names = ['foo','bar','baz']
Foo.any_in(username: foo).each do |f|
f.push(:bar,'my_new_val')
end
end
end
I'm wondering if there's a way to update all the users at once (to push the value 'my_new_val' onto the "foo" field for each matching entry) using "update_all" (or something similar) instead of looping through them to update them one at a time. I've tried everything I can think of and so far no luck.
Thanks
You need call that from the Mongo DB Driver. You can do :
Foo.collection.update(
Foo.any_in(username:foo).selector,
{'$push' => {bar: 'my_new_val'}},
{:multi => true}
)
Or
Foo.collection.update(
{'$in' => {username: foo}},
{'$push' => {bar: 'my_new_val'}},
{:multi => true}
)
You can do a pull_request or a feature request if you want that in Mongoid builtin.