关于 ruby??:Rails ActiveRecord save error undefined method `[]’ for nil:NilClass

Rails ActiveRecord save error undefined method `[]' for nil:NilClass

尝试将我的模型对象保存在 Rails 中时出现错误。让我说我没有使用数据库迁移，而是使用带有 Rails 的预先存在的数据库。
这是我的模型类：

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require 'bcrypt'
require 'securerandom'
class Profile < ActiveRecord::Base
include BCrypt

self.table_name = 'profiles'
self.primary_key = 'id'

attr_accessor :id, :username, :password_hash, :salt, :first_name, :last_name, :location, :status, :game_status

def initialize(attributes = {}, options = {})
@username = attributes[:username]
@salt=SecureRandom.hex
@password_hash = Password.create(attributes[:password] + @salt).to_s
@first_name = attributes[first_name]
@last_name = attributes[last_name]
@location = attributes[location]
@status ="Hi"
@game_status ="Playing some game..."
end

def hash_rep
hash = {}
hash['id'] = @id
hash['username'] = @username
hash['password_hash'] = @password_hash
hash['salt'] = @salt
hash['location'] = @location
hash['status'] = @status
hash['game_status'] = @game_status
return hash
end

end

这是我的数据库架构：

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id int Unsigned NOT NULL AUTO_INCREMENT
username varchar(16) NOT NULL
password_hash tinytext NOT NULL
salt varchar(64) NOT NULL
first_name varchar(16) NOT NULL
last_name varchar(16) NOT NULL
location tinytext NOT NULL
status tinytext NULL
game_status tinytext NULL

这是我的控制器代码：

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def register
profile = Profile.new(:id => params[:id],
:username => params[:username],
:password => params[:password],
:first_name => params[:first_name],
:last_name => params[:last_name],
:location => params[:location])
profile.save
render_profile(profile)
end

错误发生在 \\'profile.save\\' 方法上。这是相关的堆栈跟踪：

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activerecord (4.2.0) lib/active_record/transactions.rb:375:in `clear_transaction_record_state'
activerecord (4.2.0) lib/active_record/transactions.rb:306:in `ensure in rollback_active_record_state!'
activerecord (4.2.0) lib/active_record/transactions.rb:306:in `rollback_active_record_state!'
activerecord (4.2.0) lib/active_record/transactions.rb:285:in `save'
app/controllers/profile_controller.rb:52:in `register'
actionpack (4.2.0) lib/action_controller/metal/implicit_render.rb:4:in `send_action'
actionpack (4.2.0) lib/abstract_controller/base.rb:198:in `process_action'

错误提示："undefined method `[]\\' for nil:NilClass"

相关讨论

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require 'bcrypt'
require 'securerandom'
class Profile < ActiveRecord::Base
include BCrypt

self.table_name = 'profiles'
self.primary_key = 'id'

def hash_rep
hash = {}
hash['id'] = id
hash['username'] = username
hash['password_hash'] = password_hash
hash['salt'] = salt
hash['location'] = location
hash['status'] = status
hash['game_status'] = game_status
hash
end

def self.build(args)
new_profile = Profile.new
new_profile.username = args[:username]
salt=SecureRandom.hex
new_profile.password_hash = Password.create(args[:password] + salt).to_s
new_profile.first_name = args[:first_name]
new_profile.last_name = args[:last_name]
new_profile.location = args[:location]
new_profile.status ="Hi"
new_profile.game_status ="Playing some game..."
new_profile
end
end

现在你可以像这样使用它：

1	Profile.build({ username: 'foo' })

顺便说一句，你的 hash_rep 方法没那么有用，试试：

1 2	profile = Profile.build({ username: 'foo' }) profile.attributes

旁注：

由于你遵循约定，你不需要添加这些行，你可以删除它们：self.table_name = 'profiles', self.primary_key = 'id'
小心散列，似乎你不关心字符串或符号键，但它们不一样
有更优雅的方法来编写你的方法，但我保持简单，因为在这个阶段没有必要详细说明

在 Rails 中设置默认属性的更好方法是通过回调：

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require 'bcrypt'
require 'securerandom'
class Profile < ActiveRecord::Base
include BCrypt

attr_accessor :password # is a virtual attribute

after_initialize do
if new_record?
# values will be available for new record forms.
self.status = status ||"Hi"
self.game_status = game_status ||"Playing some game..."
end
end

before_validation(on: :create) do
self.salt=SecureRandom.hex
self.password_hash = Password.create(password + salt).to_s
end

# Yuck. use http://apidock.com/rails/ActiveModel/Serialization/serializable_hash
def hash_rep
serializable_hash( only: [:id, :username, :password_hash, :salt, :location, :status, :game_status] )
end

end

您不需要为 ActiveRecord 列创建访问器。您不需要指定 table 和 primary_key。 Rails 为您解决了这个问题。此外，您真的不想重新定义 initialize 因为活动记录有很多在那里进行。

您的控制器也缺少标记。 Rails 通常在资源名称下嵌套参数。如果您使用的是 Rails 4 - 您将通过以下方式将参数列入白名单并分配：

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class ProfileController < ApplicationController

def new
@profile = Profile.new
end

def register
@profile = Profile.new(create_params)
if @profile.save
redirect_to @profile
else
render action: :new
end
end

private
def create_params
params.require(:profile).allow(:username, :password, : first_name :last_name :location)
end
end