I'm trying to create a small Phoenix application, and having troubles finding the best way to process user input that came to the model from a controller.
I have 2 models and 1 controller:
defmodule MyApp.Post do
use MyApp.Web, :model
schema "posts" do
field :title, :string
field :text, :string
field :comments_count, :integer
has_many :comments, MyApp.Comment
timestamps()
end
end
defmodule MyApp.Comment do
use MyApp.Web, :model
schema "comments" do
field :text, :string
field :parent_path, :string # I want to store comments in a tree, using "Materialized Path" method
belongs_to :post, MyApp.Post
timestamps()
end
defmodule Ops do
# I keep all operations that are related to comments in this module
alias MyApp.{Repo, Comment}
def create_by_user(params) do
# params came straight from the controller. Expected fields are:
# 1. text - text of the comment, required
# 2. post_id - id of the post, required
# 3. parent_id - id of the parent comment, optional
# This function must:
# 1. Validate presence of the text (this is simple)
# 2. Check that post with given "post_id" exists
# 3. If "parent_id" is given:
# 3.1. Check that parent comment exists and belongs to the same post
# 3.2. Based on fields of parent comment, calculate the "parent_path" value of the new comment
# 4. If input is valid, insert a new comment to database and update post's "comments_count" field
end
end
end
defmodule MyApp.CommentController do
use MyApp.Web, :controller
alias MyApp.{Post, Comment}
def create(conn, params) do
case Comment.Ops.create_by_user(params) do
{:ok, comment} -> conn |> put_status(200) |> json("not implemented yet")
{:error, changeset} -> conn |> put_status(422) |> json("not implemented yet")
# Also, in case of error, it would be nice to look into changeset.errors and if post wasn't found, return 404
end
end
end
What is the most elegant implementation of Comment.Ops.create_by_user function?
Related
I'm trying to create a contact form in a phoenix 1.3 app. I used mix phx.gen.html to create the relevant files. However, I'm getting a compilation error when trying to start the server:
== Compilation error on file lib/iotc/web/controllers/email_controller.ex ==
** (CompileError) lib/iotc/web/controllers/email_controller.ex:7: Email.__struct__/1 is undefined, cannot expand struct Email
(stdlib) lists.erl:1354: :lists.mapfoldl/3
lib/iotc/web/controllers/email_controller.ex:6: (module)
(stdlib) erl_eval.erl:670: :erl_eval.do_apply/6
Looking at some other posts with a similar issue, it could be related to the alias, but I have alias Itoc.Contact in the controller, and I don't think alias Iotc.Contact.Email would be right here.
email_controller.ex
defmodule Iotc.Web.EmailController do
use Iotc.Web, :controller
alias Iotc.Contact
def index(conn, _params) do
changeset = Email.changeset(%Email{})
emails = Contact.list_emails()
render(conn, "index.html", emails: emails, changeset: changeset)
end
...
email.ex
defmodule Iotc.Contact.Email do
use Ecto.Schema
import Ecto.Changeset
alias Iotc.Contact.Email
schema "contact_emails" do
field :email, :string
field :event, :string
field :message, :string
field :name, :string
timestamps()
end
#doc false
def changeset(%Email{} = email, attrs) do
email
|> cast(attrs, [:name, :email, :message, :event])
|> validate_required([:name, :email, :message, :event])
end
end
With respect to this
OK makes sense. I've updated it to the controller to : changeset =
Contact.Email.changeset(%Contact.Email{}) But I now get: warning:
function Iotc.Contact.Email.changeset/1 is undefined or private. Did
you mean one of: * changeset/2
You only have one function changeset/2 defined in the Email module.
But you're doing Contact.Email.changeset(%Contact.Email{}) passing only one argument. Do ``Contact.Email.changeset(%Contact.Email{})` and it should work.
The /2 part of the signature tells you the arity of the function, namely how many arguments takes.
I'm trying to determine the right way to validate a many-to-many relationship in Ecto 2. I have a Conversation model that needs to have many members, and Users can be part of many conversations, so I've established the models like so:
# User Model
defmodule MyApp.User do
...
schema "users" do
....
many_to_many :conversations, Conversation, join_through: "conversations_users"
...
end
...
end
# Conversation Model
defmodule MyApp.Conversation do
...
schema "conversations" do
has_many :messages, Message
many_to_many :members, User, join_through: "conversations_users"
timestamps()
end
def changeset(struct, _params) do
struct
|> validate_member_count
end
defp validate_member_count(changeset) do
members = Repo.all(assoc(changeset, :members))
valid? = length(members) == 2
if valid? do
add_error(changeset, :members, "foo")
else
changeset
end
end
end
However, I just can't get this to work. I've written a simple test to verify that the validations run correctly, but I keep getting the following error:
# Test
test "fails to validate a conversation with less than two members" do
changeset = Conversation.changeset(%Conversation{}, %{})
{message, []} = changeset.errors[:members]
assert message === "must have at least two members"
end
** (FunctionClauseError) no function clause matching in Ecto.Changeset.add_error/4
I'm having a hard time understanding what I'm doing wrong. It seems like it can't find the function, but I've checked the documentation and it seems like Ecto.Changeset.add_error/4 is definitely right, and the arguments to it seem correct as well.
My best guess is that I need to do something in the validation before calling my custom validator, but I just don't know what I should do.
There are 2 mistakes:
You're passing a MyApp.Conversation to validate_member_count, not an Ecto.Changeset. You can convert an Ecto Schema defining Struct into an Ecto.Changeset using Ecto.Changeset.change/1:
def changeset(struct, _params) do
struct
|> change
|> validate_member_count
end
Ecto.assoc/2 accepts an Ecto Schema Struct, not an Ecto.Changeset. You can access the underlying struct from an Ecto.Changeset using .data:
members = Repo.all(assoc(changeset.data, :members))
Final code:
def changeset(struct, _params) do
struct
|> change
|> validate_member_count
end
defp validate_member_count(changeset) do
members = Repo.all(assoc(changeset.data, :members))
valid? = length(members) == 2
if valid? do
add_error(changeset, :members, "foo")
else
changeset
end
end
I am running Ruby 2.1 and Mongoid 5.0 (no Rails).
I want to track on a before_save callback whether or not an embedded field has changed.
I can use the document.attribute_changed? or document.changed methods to check normal fields, but somehow these don't work on relations (embed_one, has_one, etc).
Is there a way of detecting these changes before saving the document?
My model is something like this
class Company
include Mongoid::Document
include Mongoid::Attributes::Dynamic
field :name, type: String
#...
embeds_one :address, class_name: 'Address', inverse_of: :address
#...
before_save :activate_flags
def activate_flags
if self.changes.include? 'address'
#self.changes never includes "address"
end
if self.address_changed?
#This throws an exception
end
end
One example of how I save my document is:
#...
company.address = AddressUtilities.parse address
company.save
#After this, the callback is triggered, but self.changes is empty...
#...
I have read the documentation and Google the hell out of it, but I can't find a solution?
I have found this gem, but it's old and doesn't work with the newer versions of Mongoid. I want to check if there is another way of doing it before considering on trying to fix/pull request the gem...
Adding these two methods to your Model and calling get_embedded_document_changes should provide you an hash with the changes to all its embedded documents:
def get_embedded_document_changes
data = {}
relations.each do |name, relation|
next unless [:embeds_one, :embeds_many].include? relation.macro.to_sym
# only if changes are present
child = send(name.to_sym)
next unless child
next if child.previous_changes.empty?
child_data = get_previous_changes_for_model(child)
data[name] = child_data
end
data
end
def get_previous_changes_for_model(model)
data = {}
model.previous_changes.each do |key, change|
data[key] = {:from => change[0], :to => change[1]}
end
data
end
[ source: https://gist.github.com/derickbailey/1049304 ]
In rails 4.0.2, I am trying to use a search plugin called dusen. Using this, I can search same model's values but I am not able to search other(associated) model values. How can I achieve this for single association(has_one / belongs_to) & multi association(has_many) model values?
Reference link:
https://github.com/makandra/dusen
Gem which I am using is dusen (0.4.10)
In controller,
#query = params[:query] || ""
Contact.search(#query)
In model,
belongs_to :city, :class_name=>"City"
search_syntax do
search_by :text do |scope, phrases|
columns = [:name, :contact_number, :email]
scope.where_like(columns => phrases)
end
end
Here, It will search only :name, :contact_number, :email fields, if i try to add below piece of code then it will show an error like undefined method 'search_text' for #<Dusen::Description:0xb438a248>
search_text do
[city.name]
end
Please suggest a solution for this issue.
Assuming your model name is 'User', you'd set it up as follows:
# User.rb
belongs_to :city, :class_name=>"City"
search_syntax do
search_by :text do |scope, phrases|
# namespaced fields to search by.
columns = ["users.name", "users.contact_number", "users.email", "cities.name"]
# specify association to City in scope.
scope.joins(:city).where_like(columns => phrases)
end
end
I hope this helps!
I have a model, Domain, which has a text field, names.
> rails g model Domain names:text
invoke active_record
create db/migrate/20111117233221_create_domains.rb
create app/models/domain.rb
> rake db:migrate
== CreateDomains: migrating ==================================================
-- create_table(:domains)
-> 0.0015s
== CreateDomains: migrated (0.0066s) =========================================
I set this field as serialized into an array in the model.
# app/models/domain.rb
class Domain < ActiveRecord::Base
serialize :names, Array
end
Create the ActiveAdmin resource for this model
> rails g active_admin:resource Domain
create app/admin/domains.rb
then, in the app/admin/domains.rb, I setup the various blocks to handle the serialized field as such
# app/admin/domains.rb
ActiveAdmin.register Domain do
index do
id_column
column :names do |domain|
"#{domain.names.join( ", " ) unless domain.names.nil?}"
end
default_actions
end
show do |domain|
attributes_table do
row :names do
"#{domain.names.join( ", " ) unless domain.names.nil?}"
end
end
end
form do |f|
f.inputs "Domain" do
f.input :names
end
f.buttons
end
# before we save, take the param[:domain][:name] parameter,
# split and save it to our array
before_save do |domain|
domain.names = params[:domain][:names].split(",") unless params[:domain].nil? or params[:domain][:names].nil?
end
end
Nearly everything works great -- my names are displayed as comma separated in the index and show views. When I update a record with my names field set to "a,b,c", the before_save works to turn that into an array that is then saved via the ActiveRecord serialize.
What I can not solve is how to make the edit form put in a comma-separated list into the text field. I tried using a partial and using formtastic syntax directly as well as trying to make it work via the active_admin DLS syntax. Does anyone know how to make this work?
Specifically, if I have the following array saved in my domain.names field:
# array of names saved in the domain active_record
domain.names = ["a", "b", "c"]
how to change:
form do |f|
f.inputs "Domain" do
f.input :names
end
f.buttons
end
so that when the edit form is loaded, in the text field instead of seeing abc, you see a,b,c.
Here is a summary of how I handled this situation. I added an accessor to the model which can turn the Array into a string joined by a linefeed and split it back to an Array.
# app/models/domain.rb
class Domain < ActiveRecord::Base
serialize :names, Array
attr_accessor :names_raw
def names_raw
self.names.join("\n") unless self.names.nil?
end
def names_raw=(values)
self.names = []
self.names=values.split("\n")
end
end
then, in my admin resource for domain, instead of using the :names field, I used the :names_raw field. setting this value would save the names Array with the new values.
# app/admin/domains.rb
form do |f|
f.inputs "Domain" do
f.input :names_raw, :as => :text
end
f.buttons
end
Stumbled on this question looking for something to have access to a serialized Hash's YAML. I used this solution on Rails 3.2:
def target_raw
#attributes['target'].serialized_value
end
def target_raw=(new_value)
#attributes['target'].state = :serialized
#attributes['target'].value = new_value
end