Well, I've finally decided that I'm not crazy. So, that leaves DataMapper.
Here's what I'm doing. I have a model Msrun which has 1 Metric.
tmp = Msrun.first_or_create # I'll skip the boring details
tmp.metric = Metric.first_or_create( {msrun_id: tmp.id}, {metric_input_file: #metricsfile} )
p tmp.metric # => #<Metric #metric_input_file=nil #msrun_id=1>
tmp.metric.metric_input_file = #metricsfile
p tmp.metric # => #<Metric #metric_input_file=#<Pathname:/home/ryanmt/Dropbox/coding/rails/metrics_site/spec/tfiles/single_metric.txt> #msrun_id=1>
So, why doesn't this work? I'm reading http://datamapper.org/docs/create_and_destroy and doing what it shows working. This has been terribly arduous. Thanks for any help.
Update:
I still can't figure out what is going on, but to prove I'm not insane...
puts Metric.all # => []
tmp.metric = Metric.first_or_create( {msrun_id: tmp.id}, {metric_input_file: #metricsfile} )
puts Metric.all # => [] #??????????????
tmp.metric.metric_input_file = #metricsfile
p tmp.metric # => #<Metric #metric_input_file=#<Pathname:/home/ryanmt/Dropbox/coding/rails/metrics_site/spec/tfiles/single_metric.txt> #msrun_id=1>
tmp.metric.save
puts Metric.all # => [#<Metric #metric_input_file=#<Pathname:/home/ryanmt/Dropbox/coding/rails/metrics_site/spec/tfiles/single_metric.txt> #msrun_id=1>]
So, not only is first_or_create not delivering on the behavior I expect by reading the source
def first_or_create(conditions = {}, attributes = {})
first(conditions) || create(conditions.merge(attributes))
end
but it is also not even creating.
I'm probably missing something here (more of those boring details might help) but if the metric exists, it's metric_input_file shouldn't be updated, i.e., it's only set when new. If you're after updating then you can do
.first_or_create(msrun_id: tmp.id).update(metric_input_file: #metricsfile)
Or if not hitting the database twice is relevant, then
m = Metric.first_or_new(msrun_id: tmp.id)
[set..save..assign]
But if it's not being set on new models, I don't see what would cause that from the code posted so far, more..?
[UPDATED]
Based on your new code, I'd say this is "a classic case" of a false DM save. I usually add the following line to an initialization section, e.g., application.rb in Rails.
DataMapper::Model.raise_on_save_failure = true
Unfortunately, the exception raised never tells you why (there's a special place in hell for that choice, right next to people who talk in theaters.) But it's typically one of:
a slightly incorrect association definition
a has/belongs_to that isn't "required: false" and isn't set
putting the wrong datatype into a field, e.g., a string into a decimal
a validation failing
If you want to post your model definitions, the problem may be spottable there.
In addition to the answer above, I've seen this call die (like, literally halt all execution) with no error when I was doing a find_or_create that would have created an object that violated the primary key constraint. This is because the datamapper model was not in sync with the actual database schema.
Related
I'm trying to complete this Codewars Challenge and I'm confused as to where I'm going wrong. Could someone please give me a hand?
The question provides a "database" of translations for Welcome, and the instructions say:
Think of a way to store the languages as a database (eg an object). The languages are listed below so you can copy and paste!
Write a 'welcome' function that takes a parameter 'language' (always a string), and returns a greeting - if you have it in your database. It should default to English if the language is not in the database, or in the event of an invalid input.
My attempt:
def greet(language)
greeting = { 'english'=>'Welcome',
'czech'=>'Vitejte',
'danish'=>'Velkomst',
'dutch'=>'Welkom',
'estonian'=>'Tere tulemast',
'finnish'=>'Tervetuloa',
'flemish'=>'Welgekomen',
'french'=>'Bienvenue',
'german'=>'Willkommen',
'irish'=>'Failte',
'italian'=>'Benvenuto',
'latvian'=>'Gaidits',
'lithuanian'=>'Laukiamas',
'polish'=>'Witamy',
'spanish'=>'Bienvenido',
'swedish'=>'Valkommen',
'welsh'=>'Croeso'
}
greeting.key?(language) ? greeting.each { |k, v| return v if language == k } : 'IP_ADDRESS_INVALID'
end
To my eyes when I run my code through the IDE it seems to be working as per request but I guess I must be wrong somehow.
It's telling me it :
Expected: "Laukiamas", instead got: "Welcome"
But when I type:
p greet("lithuanian")
I get Laukiamas.
You can provide you greeting hash with a default value. It is as simple as
greeting.default = "Welcome"
This enhanced hash does all the work for you. Just look up the key; when it is not there you'll get "Welcome".
Preface
First of all, please don't post links to exercises or homework questions. Quote them in your original question to avoid link rot or additional create work for people trying to help you out.
Understanding the Problem Defined by the Linked Question
Secondly, you're misunderstanding the core question. The requirement is basically to return the Hash value for a given language key if the key exists in the Hash. If it doesn't, then return the value of the 'english' key instead. Implicit in the exercise is to understand the various types of improper inputs that would fail to find a matching key; the solution below addresses most of them, and will work even if your Ruby has frozen strings enabled.
A Working Solution
There are lots of ways to do this, but here's a simple example that will handle invalid keys, nil as a language argument, and abstract away capitalization as a potential issue.
DEFAULT_LANG = 'english'
TRANSLATIONS = {
'english' => 'Welcome',
'czech' => 'Vitejte',
'danish' => 'Velkomst',
'dutch' => 'Welkom',
'estonian' => 'Tere tulemast',
'finnish' => 'Tervetuloa',
'flemish' => 'Welgekomen',
'french' => 'Bienvenue',
'german' => 'Willkommen',
'irish' => 'Failte',
'italian' => 'Benvenuto',
'latvian' => 'Gaidits',
'lithuanian' => 'Laukiamas',
'polish' => 'Witamy',
'spanish' => 'Bienvenido',
'swedish' => 'Valkommen',
'welsh' => 'Croeso'
}
# Return a translation of "Welcome" into the language
# passed as an argument.
#
# #param language [String, #to_s] any object that can
# be coerced into a String, and therefore to
# String#downcase
# #return [String] a translation of "Welcome" or the
# string-literal +Welcome+ if no translation found
def greet language
language = language.to_s.downcase
TRANSLATIONS.fetch language, TRANSLATIONS[DEFAULT_LANG]
end
# Everything in the following Array of examples except
# +Spanish+ should return the Hash value for +english+.
['Spanish', 'Español', 123, nil].map { greet(_1) }
This will correctly return:
#=> ["Bienvenido", "Welcome", "Welcome", "Welcome"]
because only Spanish (when lower-cased) will match any of the keys currently defined in the TRANSLATIONS Hash. All the rest will use the default value defined for the exercise.
Test Results
Since there are some RSpec tests included with the linked question:
describe "Welcome! Translation" do
it "should translate input" do
Test.assert_equals(greet('english'), 'Welcome', "It didn't work out this time, keep trying!");
Test.assert_equals(greet('dutch'), 'Welkom', "It didn't work out this time, keep trying!");
Test.assert_equals(greet('IP_ADDRESS_INVALID'), 'Welcome', "It didn't work out this time, keep trying!")
end
end
The code provided not only passes the provided tests, but it also passes a number of other edge cases not defined in the unit tests. When run against the defined tests, the code above passes cleanly:
If this is homework, then you might want to create additional tests to cover all the various edge cases. You might also choose to refactor to less idiomatic code if you want more explanatory variables, more explicit intermediate conversions, or more explicit key handling. The point of good code is to be readable, so be as explicit in your code and as thorough in your tests as you need to be in order to make debugging easier.
I'm trying to create a validation for a predetermined list of valid brands as part of an ETL pipeline. My validation requires case insensitivity, as some brands are compound words or abbreviations that are insignificant.
I created a custom predicate, but I cannot figure out how to generate the appropriate error message.
I read the error messages doc, but am having a hard time interpreting:
How to build the syntax for my custom predicate?
Can I apply the messages in my schema class directly, without referencing an external .yml file? I looked here and it seems like it's not as straightforward as I'd hoped.
Below I've given code that represents what I have tried using both built-in predicates, and a custom one, each with their own issues. If there is a better way to compose a rule that achieves the same goal, I'd love to learn it.
require 'dry/validation'
CaseSensitiveSchema = Dry::Validation.Schema do
BRANDS = %w(several hundred valid brands)
# :included_in? from https://dry-rb.org/gems/dry-validation/basics/built-in-predicates/
required(:brand).value(included_in?: BRANDS)
end
CaseInsensitiveSchema = Dry::Validation.Schema do
BRANDS = %w(several hundred valid brands)
configure do
def in_brand_list?(value)
BRANDS.include? value.downcase
end
end
required(:brand).value(:in_brand_list?)
end
# A valid string if case insensitive
valid_product = {brand: 'Valid'}
CaseSensitiveSchema.call(valid_product).errors
# => {:brand=>["must be one of: here, are, some, valid, brands"]} # This message will be ridiculous when the full brand list is applied
CaseInsensitiveSchema.call(valid_product).errors
# => {} # Good!
invalid_product = {brand: 'Junk'}
CaseSensitiveSchema.call(invalid_product).errors
# => {:brand=>["must be one of: several, hundred, valid, brands"]} # Good... (Except this error message will contain the entire brand list!!!)
CaseInsensitiveSchema.call(invalid_product).errors
# => Dry::Validation::MissingMessageError: message for in_brand_list? was not found
# => from .. /gems/2.5.0/gems/dry-validation-0.12.2/lib/dry/validation/message_compiler.rb:116:in `visit_predicate'
The correct way to reference my error message was to reference the predicate method. No need to worry about arg, value, etc.
en:
errors:
in_brand_list?: "must be in the master brands list"
Additionally, I was able to load this error message without a separate .yml by doing this:
CaseInsensitiveSchema = Dry::Validation.Schema do
BRANDS = %w(several hundred valid brands)
configure do
def in_brand_list?(value)
BRANDS.include? value.downcase
end
def self.messages
super.merge({en: {errors: {in_brand_list?: "must be in the master brand list"}}})
end
end
required(:brand).value(:in_brand_list?)
end
I'd still love to see other implementations, specifically for a generic case-insensitive predicate. Many people say dry-rb is fantastically organized, but I find it hard to follow.
I'm having trouble getting typed results out of the pg gem.
require 'pg'
require_relative 'spec/fixtures/database'
client = PG.connect( DB[:pg] )
client.type_map_for_queries = PG::BasicTypeMapForQueries.new(client)
client.type_map_for_results = PG::BasicTypeMapForResults.new(client)
client.exec( %|select * from testme;| ) do |query|
query.each {|r| puts r.inspect }
end
This program gives the output:
Warning: no type cast defined for type "money" with oid 790. Please cast this type explicitly to TEXT to be safe for future changes.
Warning: no type cast defined for type "numeric" with oid 1700. Please cast this type explicitly to TEXT to be safe for future changes.
{"string"=>"thing", "logical"=>true, "cash"=>"£1.23", "reel"=>"2.34", "day"=>#<Date: 2015-12-31 ((2457388j,0s,0n),+0s,2299161j)>, "float"=>3.45}
So: booleans and floats and dates (and integers) get converted, but not numerics or the money type.
Can anyone tell me how to "cast the type explicitly", assuming that I don't want to hard-code a solution for each table?
Hijacking this thread, as after some digging I finally found a way to add a custom decoder/encoder, so posting an example below:
require 'ipaddr'
require 'pg'
class InetDecoder < PG::SimpleDecoder
def decode(string, tuple=nil, field=nil)
IPAddr.new(string)
end
end
class InetEncoder < PG::SimpleEncoder
def encode(ip_addr)
ip_addr.to_s
end
end
# 0 if for text format, can also be 1 for binary
PG::BasicTypeRegistry.register_type(0, 'inet', InetEncoder, InetDecoder)
Here's a catch all for those seeking to cast strings by default:
client = PG.connect( DB[:pg] )
map = PG::BasicTypeMapForResults.new(conn)
map.default_type_map = PG::TypeMapAllStrings.new
client.type_map_for_results = map
Got the same problem with a text-ish field. Solved by duplicating a coder and editing its OID.
text_coder = client.type_map_for_results.coders.find { |c| c.name == 'text' }
new_coder = text_coder.dup.tap { |c| c.oid = 19 } # oid from the warning
conn.type_map_for_results.add_coder(new_coder)
How I got there: it might interest the next guy, if the problem is similar but not identical.
I read other people online talking about type_map_for_results, but how they didn't know how to define a coder. Since it was a text field in my case, I decided to try cloning an existing one. I knew I could find a textual pre-set in a Rails app, so I opened a rails console and searched:
adapter = ActiveRecord::Base.connection
connection = adapter.instance_variable_get("#connection")
mapping = connection.type_map_for_results
cd mapping # my console of choice is `pry`
ls # spotted a likely getter named `coders`
cd coders # again
ls # spotted getter `name` and setter `oid=`
So I put together the code in the solution. Gave it a try, and it worked.
It had not been straightforward to find, so I decided to exit lurker mode and share it on SO. Thereby: thanks #Andreyy for bringing me in :)
[pry cd and ls]
Google the error message: "Warning: no type cast defined for type"
You can find it's source github.
Reding the class, I would guess lines from 150 to 214 could be consiredered
examples:
register_type 0, 'text', PG::TextEncoder::String
alias_type 0, 'varchar', 'text'
Since register_type and alias_type are class methods of PG::BasicTypeRegistry::CoderMap I would play with them just and see if anything changes:
PG::BasicTypeRegistry::CoderMap.alias_type 0, 'money', 'text'
PG::BasicTypeRegistry::CoderMap.alias_type 0, 'numeric', 'text'
Reading the comments in the class it seems that the coding/decoding of those and some other fields is not implemented.
You might consider using a higher level ORM library like AvtiveRecord which implements more types (money).
I'm having some issues deleting my document using Mongoid...
The code actually does delete the gallery, but I get a browser error which looks like:
Mongoid::Errors::DocumentNotFound at /admin/galleries/delete/4e897ce07df6d15a5e000001
The suspect code is below:
def self.removeGalleryFor(user_session_id, gallery_id)
person = Person.any_in(session_ids: [user_session_id])
return false if person.count != 1
return false if person[0].userContent.nil?
return false if person[0].userContent.galleries.empty?
gallery = person[0].userContent.galleries.find(gallery_id) #ERROR is on this line
gallery.delete if !gallery.nil?
end
My Person class embeds one userContent which embeds many galleries.
Strangely enough I've got a couple of tests around this which work fine...
I'm really not sure what's happening - my gallery seems to be found fine, and is even deleted from Mongo.
Any ideas?
find throws an error if it can't find a document with the given id. Instead of checking presence of given gallery and returning nil if it doesn't exist, you directly ask mongodb while querying to remove any such gallery.
def self.remove_gallery_for(user_session_id, gallery_id)
user_session_id = BSON::ObjectId.from_string(user_session_id) if user_session_id.is_a?(String)
gallery_id = BSON::ObjectId.from_string(gallery_id) if gallery_id.is_a?(String)
# dropping to mongo collection object wrapped by mongoid,
# as I don't know how to do it using mongoid's convenience methods
last_error = Person.collection.update(
# only remove gallery for user matching user_session_id
{"session_ids" => user_session_id},
# remove gallery if there exists any
{"$pull" => {:userContent.galleries => {:gallery_id => gallery_id}}},
# [optional] check if successfully removed the gallery
:safe => true
)
return last_error["err"].nil?
end
This way you do not load the Person, you don't even get the data from monogdb to application server. Just get the gallery removed if it exists.
But you should prefer #fl00r's answer if you need to fire callbacks and switch to destroy instead of delete
def self.removeGalleryFor(user_session_id, gallery_id)
# person = Person.where(session_ids: user_session_id).first
person = Person.any_in(session_ids: [user_session_id])
if person && person.userContent && person.userContent.galleries.any?
gallery = person.userContent.galleries.where(id: gallery_id).first
gallery.delete if gallery
end
end
ps:
In Ruby usually under_score naming rather then CamelCase is used
Kudos to Rubish for pointing me to a solution that at least passes my tests - for some reason fl00r's code didn't work - it looks like it should, but doesn't for some reason...
Person.collection.update(
{"session_ids" => user_session_id},
{"$pull" => {'userContent.galleries' => {:_id => gallery_id}}},
:safe => true
)
=> this code will pass my tests, but then once it's running in sinatra it doesn't work.... so frustrating!
have posted this code with tests on github https://github.com/LouisSayers/bugFixes/tree/master/mongoDelete
I have a collection of objects. There are 3 properties in each object
'id', 'name', 'is_primary'
The collection of objects will usually have anywhere from 1 to 5 objects.
What I want to do is check the collection to see if is_primary is true. If so output the name, or at least return it.
I want to do this in 1 line of code if possible. I am trying to slim up this one line for erb output in rails. Later in the page i'll output them all. I thought I had it, but if I return nil it adds extra space which shifts all the html oddly.
Thanks.
Hmm, this doesn't quite work if no element is_primary...I'm still thinking...
c.detect(&:is_primary).name
Ok, how about:
((a = c.detect(&:is_primary)) && a.name).to_s
As it happens, it is OK in an erb template for the <%= expression to return nil, that just results in an empty string, so for that case you can use:
(a = c.detect(&:is_primary)) && a.name
Update: Responding to the first comment, I do have a test case that I didn't post...
class A; attr_accessor :is_primary, :name, :id; end
t = [A.new, A.new, A.new, (a = A.new; a.name = 'xyz'; a.is_primary = true; a)]
puts (a = t.detect(&:is_primary)) && a.name
puts ((a = [].detect(&:is_primary)) && a.name).to_s
Complementing #DigitalRoss, you can also write:
collection.detect(&:is_primary).try(:name) || "default_if_no_element_or_name"
(well, to be honest I prefer Ick's maybe over Rails' try: c.detect(&:is_primary).maybe.name)
Side note: IMHO a flag that can only be active for a row it's not such a good idea. You may have inconsistent states with more than one being active and you'll have worry about it when updating (transactions, and so on). Try to store the PK reference somewhere else (a parent model? a state model?).
I want to do this in 1 line of code if possible. I am trying to slim up this one line for erb output in rails. Later in the page i'll output them all.
No need for one-liners (funny since I just wrote one): move the code to yous models or helpers as appropriate and keep your views pristine.