使用Devise Gem时登录认证失败，无法正常登录问题排查

问题现象 #

登录页面显示正常，但使用seeds.rb中已存在的用户信息登录时，始终触发else分支返回登录页，无法跳转首页。曾尝试将user.authenticate(params[:password])修改为page.authenticate(params[:password])，问题未解决。

相关代码 #

def sign_in
    page = User.find_by(email: params[:email])
    if page.present? && page.authenticate(params[:password])
        session[:user_id] = page.id
        redirect_to root_path, notice: "You have successfully logged in"
    else
        flash[:alert] = "Invalid info"
        redirect_to login_path
    end
end

请求日志 #

Started POST "/login" for ::1 at 2022-11-15 19:30:14 -0600
Processing by PagesController#sign_in as TURBO_STREAM
Parameters: {"authenticity_token"=>"[FILTERED]", "session"=>{"email"=>"hi@email.com", "password"=>"[FILTERED]"}, "commit"=>"Login"}
User Load (0.4ms) SELECT "users".* FROM "users" WHERE "users"."email" IS NULL LIMIT $1 [["LIMIT", 1]]
↳ app/controllers/pages_controller.rb:14:in `sign_in'
Redirected to http://localhost:3000/login
Completed 302 Found in 188ms (ActiveRecord: 2.1ms | Allocations: 8011)

Started GET "/login" for ::1 at 2022-11-15 19:30:14 -0600
Processing by PagesController#login as TURBO_STREAM
Rendering layout layouts/application.html.erb
Rendering pages/login.html.erb within layouts/application
Rendered pages/login.html.erb within layouts/application (Duration: 1.2ms | Allocations: 817)
Rendered shared/_flash.html.erb (Duration: 0.1ms | Allocations: 31)
Rendered layout layouts/application.html.erb (Duration: 80.3ms | Allocations: 6806)
Completed 200 OK in 102ms (Views: 82.3ms | ActiveRecord: 0.0ms | Allocations: 7152)

问题分析与修复方案 #

从日志的SQL查询语句能直接定位问题：查询条件是WHERE "users"."email" IS NULL，说明params[:email]取值为nil。结合请求参数结构，邮箱和密码是嵌套在session参数里的，所以正确的取值方式应该是params[:session][:email]和params[:session][:password]，而非直接读取params[:email]。

修复后的代码：

def sign_in
    page = User.find_by(email: params[:session][:email])
    if page.present? && page.authenticate(params[:session][:password])
        session[:user_id] = page.id
        redirect_to root_path, notice: "登录成功"
    else
        flash[:alert] = "账号或密码错误"
        redirect_to login_path
    end
end

内容的提问来源于stack exchange，提问作者Sync Vinyu