“使用Clojure进行Web开发”：无此类变量：db / get-user

我正在使用“使用Clojure进行Web开发”这本书来制作教程留言簿应用程序，但遇到了麻烦。自从本书发行以来，似乎某些库及其功能已经更新，这对我的Web开发造成了一些坎bump的介绍。我可以通过在可能的情况下更新依赖关系或在不可以的情况下使用旧版本的库来解决大多数问题，但是这种策略已达到极限，我遇到了一个棘手的问题。当我尝试在本地主机服务器上运行我的应用程序时，得到了此堆栈跟踪：

Exception in thread "main" java.lang.RuntimeException: No such var: db/get-user, compiling:(guestbook/routes/auth.clj:38:14)
    at clojure.lang.Compiler.analyze(Compiler.java:6380)
    at clojure.lang.Compiler.analyze(Compiler.java:6322)
    at clojure.lang.Compiler$InvokeExpr.parse(Compiler.java:3573)
    at clojure.lang.Compiler.analyzeSeq(Compiler.java:6562)
    at clojure.lang.Compiler.analyze(Compiler.java:6361)
    at clojure.lang.Compiler.access$100(Compiler.java:37)
    at clojure.lang.Compiler$LetExpr$Parser.parse(Compiler.java:5973)
    at clojure.lang.Compiler.analyzeSeq(Compiler.java:6560)
    at clojure.lang.Compiler.analyze(Compiler.java:6361)
    at clojure.lang.Compiler.analyzeSeq(Compiler.java:6548)
    at clojure.lang.Compiler.analyze(Compiler.java:6361)
    at clojure.lang.Compiler.analyze(Compiler.java:6322)
    at clojure.lang.Compiler$BodyExpr$Parser.parse(Compiler.java:5708)
    at clojure.lang.Compiler$FnMethod.parse(Compiler.java:5139)
    at clojure.lang.Compiler$FnExpr.parse(Compiler.java:3751)
    at clojure.lang.Compiler.analyzeSeq(Compiler.java:6558)
    at clojure.lang.Compiler.analyze(Compiler.java:6361)
    at clojure.lang.Compiler.analyzeSeq(Compiler.java:6548)
    at clojure.lang.Compiler.analyze(Compiler.java:6361)
    at clojure.lang.Compiler.access$100(Compiler.java:37)
    at clojure.lang.Compiler$DefExpr$Parser.parse(Compiler.java:529)
    at clojure.lang.Compiler.analyzeSeq(Compiler.java:6560)
    at clojure.lang.Compiler.analyze(Compiler.java:6361)
    at clojure.lang.Compiler.analyze(Compiler.java:6322)
    at clojure.lang.Compiler.compile1(Compiler.java:7148)
    at clojure.lang.Compiler.compile(Compiler.java:7219)
    at clojure.lang.RT.compile(RT.java:398)
    at clojure.lang.RT.load(RT.java:438)
    at clojure.lang.RT.load(RT.java:411)
    at clojure.core$load$fn__5018.invoke(core.clj:5530)
    at clojure.core$load.doInvoke(core.clj:5529)
    at clojure.lang.RestFn.invoke(RestFn.java:408)
    at clojure.core$load_one.invoke(core.clj:5336)
    at clojure.core$load_lib$fn__4967.invoke(core.clj:5375)
    at clojure.core$load_lib.doInvoke(core.clj:5374)
    at clojure.lang.RestFn.applyTo(RestFn.java:142)
    at clojure.core$apply.invoke(core.clj:619)
    at clojure.core$load_libs.doInvoke(core.clj:5413)
    at clojure.lang.RestFn.applyTo(RestFn.java:137)
    at clojure.core$apply.invoke(core.clj:619)
    at clojure.core$require.doInvoke(core.clj:5496)
    at clojure.lang.RestFn.invoke(RestFn.java:457)
    at guestbook.handler$loading__4910__auto__.invoke(handler.clj:1)
    at clojure.lang.AFn.applyToHelper(AFn.java:159)
    at clojure.lang.AFn.applyTo(AFn.java:151)
    at clojure.lang.Compiler$InvokeExpr.eval(Compiler.java:3458)
    at clojure.lang.Compiler.compile1(Compiler.java:7153)
    at clojure.lang.Compiler.compile1(Compiler.java:7143)
    at clojure.lang.Compiler.compile(Compiler.java:7219)
    at clojure.lang.RT.compile(RT.java:398)
    at clojure.lang.RT.load(RT.java:438)
    at clojure.lang.RT.load(RT.java:411)
    at clojure.core$load$fn__5018.invoke(core.clj:5530)
    at clojure.core$load.doInvoke(core.clj:5529)
    at clojure.lang.RestFn.invoke(RestFn.java:408)
    at clojure.core$load_one.invoke(core.clj:5336)
    at clojure.core$compile$fn__5023.invoke(core.clj:5541)
    at clojure.core$compile.invoke(core.clj:5540)
    at user$eval19.invoke(form-init6949279956252999274.clj:1)
    at clojure.lang.Compiler.eval(Compiler.java:6619)
    at clojure.lang.Compiler.eval(Compiler.java:6609)
    at clojure.lang.Compiler.load(Compiler.java:7064)
    at clojure.lang.Compiler.loadFile(Compiler.java:7020)
    at clojure.main$load_script.invoke(main.clj:294)
    at clojure.main$init_opt.invoke(main.clj:299)
    at clojure.main$initialize.invoke(main.clj:327)
    at clojure.main$null_opt.invoke(main.clj:362)
    at clojure.main$main.doInvoke(main.clj:440)
    at clojure.lang.RestFn.invoke(RestFn.java:421)
    at clojure.lang.Var.invoke(Var.java:419)
    at clojure.lang.AFn.applyToHelper(AFn.java:163)
    at clojure.lang.Var.applyTo(Var.java:532)
    at clojure.main.main(main.java:37)
Caused by: java.lang.RuntimeException: No such var: db/get-user
    at clojure.lang.Util.runtimeException(Util.java:219)
    at clojure.lang.Compiler.resolveIn(Compiler.java:6848)
    at clojure.lang.Compiler.resolve(Compiler.java:6818)
    at clojure.lang.Compiler.analyzeSymbol(Compiler.java:6779)
    at clojure.lang.Compiler.analyze(Compiler.java:6343)
    ... 72 more
Compilation failed: Subprocess failed

我想我可能在这里装载了一些不需要的东西，但是我的project.clj文件看起来像这样：

(defproject guestbook "0.1.0-SNAPSHOT"
  :description "FIXME: write description"
  :url "http://example.com/FIXME"
  :dependencies [[org.clojure/clojure "1.5.1"]
                 [compojure "1.1.6"]
                 [hiccup "1.0.5"]
                 [ring-server "0.3.1"]
                 [lein-light-nrepl "0.0.15"]
                 [org.clojure/clojurescript "0.0-2156"]
                 [org.clojure/java.jdbc "0.2.3"]
                 [org.xerial/sqlite-jdbc"3.7.2"]
                 [lib-noir "0.8.0"]]
  :repl-options {:nrepl-middleware [lighttable.nrepl.handler/lighttable-ops]}
  :plugins [[lein-ring "0.8.7"]
            [lein-ancient "0.5.4"]]
  :ring {:handler guestbook.handler/app
         :init guestbook.handler/init
         :destroy guestbook.handler/destroy}
  :aot :all
  :profiles
  {:production
   {:ring
    {:open-browser? false, :stacktraces? false, :auto-reload? false}}
   :dev
   {:dependencies [[ring-mock "0.1.5"] [ring/ring-devel "1.2.1"]]}})

主文件：

(ns guestbook.routes.home
  (:require [compojure.core :refer :all]
            [guestbook.views.layout :as layout]
            [hiccup.form :refer :all]
            [guestbook.models.db :as db]
            [noir.session :as session]))


(defn format-time [timestamp]
  (-> "dd/MM/yyyy"
      (java.text.SimpleDateFormat.)
      (.format timestamp)))


(defn home []
  (layout/common [:h1 "Guestbook"]
                 [:p "Welcome to my guestbook"]
                 [:hr]
                 [:form]
                 [:p "name"]
                 [:input]
                 [:p "Message"]
                 [:textarea {:rows 10 :cols 40}]))


(defn show-guests []
 [:ul.guests
   (for [{:keys [message name timestamp]} (db/read-guests)]
    [:li
       [:blockquote message]
       [:p "-" [:cite name]]
       [:time (format-time timestamp)]])])

(defn home [& [name message error]]
  (layout/common
    [:h1 "Guestbook " (session/get :user)]
    [:p "Welcome to my guestbook"]
    [:p error]

    (show-guests)

    [:hr]

    (form-to [:post "/"]
             [:p "Name:" (text-field "name" name)]
             [:p "Message:" (text-area {:rows 10 :cols 40} "message" message)]
             (submit-button "comment"))))


(defn save-message [name message]
 (cond
   (empty? name)
   (home name message "You forgot to leave a name, dumbass.")
   (empty? message)
   (home name message "Don't you have something to say?")
   :else
   (do
     (db/save-message name message)
     (home))))



(defroutes home-routes
  (GET "/" [] (home))
  (POST "/" [name message] (save-message name message)))

处理程序：

(ns guestbook.handler
  (:use compojure.core
        ring.middleware.resource
        ring.middleware.file-info
        hiccup.middleware
        guestbook.routes.home)
  (:require [compojure.handler :as handler]
            [compojure.route :as route]
            [guestbook.models.db :as db]
            [guestbook.routes.auth :refer [auth-routes]]))

(defn init []
  (println "guestbook is starting")
  (if-not (.exists (java.io.File. "./db.sq3"))
    (db/create-guestbook-table)))

(defn destroy []
  (println "guestbook is shutting down"))

(defroutes app-routes
  (route/resources "/")
  (route/not-found "Not Found"))

(def app
  (-> (routes auth-routes home-routes app-routes)
      (handler/site)
      (wrap-base-url)))

数据库：

(ns guestbook.models.db
  (:require [clojure.java.jdbc :as sql])
  (:import java.sql.DriverManager))

(def db {:classname  "org.sqlite.JDBC",
         :subprotocol   "sqlite",
         :subname       "db.sq3"})

(defn create-guestbook-table []
  (sql/with-connection
    db
    (sql/create-table
      :guestbook
      [:id "INTEGER PRIMARY KEY AUTOINCREMENT"]
      [:timestamp "TIMESTAMP DEFAULT CURRENT_TIMESTAMP"]
      [:name "TEXT"]
      [:message "TEXT"])
    (sql/do-commands "CREATE INDEX timestamp_index ON guestbook (timestamp)")))

(defn read-guests []
  (sql/with-connection
    db
    (sql/with-query-results res
      ["SELECT * FROM guestbook ORDER BY timestamp DESC"]
      (doall res))))

(defn save-message [name message]
  (sql/with-connection
    db
    (sql/insert-values
      :guestbook
      [:name :message :timestamp]
      [name message (new java.util.Date)])))

授权：

(ns guestbook.routes.auth
  (:require [compojure.core :refer [defroutes GET POST]]
            [guestbook.views.layout :as layout]
            [hiccup.form :refer
             [form-to label text-field password-field submit-button]]
            [noir.response :refer [redirect]]
            [noir.session :as session]
            [noir.validation
             :refer [rule errors? has-value? on-error]]
            [noir.util.crypt :as crypt]
            [guestbook.models.db :as db]))

(defn format-error [[error]]
  [:p.error error])

(defn control [field name text]
  (list (on-error name format-error)
        (label name text)
        (field name)
        [:br]))

(defn registration-page []
  (layout/common
    (form-to [:post "/register"]
      (control text-field :id "screen name")
      (control password-field :pass "Password")
      (control password-field :pass1 "Retype Password")
      (submit-button "Create Account"))))

(defn login-page []
  (layout/common
    (form-to [:post "/login"]
      (control text-field :id "screen name")
      (control password-field :pass "Password")
      (submit-button "login"))))

(defn handle-login [id pass]
  (let [user (db/get-user id)]
    (rule (has-value? id)
          [:id "screen name is required"])
    (rule (has-value? pass)
          [:pass "password is required"])
    (rule (and user (crypt/compare pass (:pass user)))
          [:pass "invalid password"])
    (if (errors? :id :pass)
    (login-page)
    (do
      (session/put! :user id)
      (redirect "/")))))

(defn handle-registration [id pass pass1]
  (rule (= pass pass1)
        [:pass "password was not retyped correctly"])
  (if (errors? :pass)
    (registration-page)
    (do
      (db/add-user-record {:id id :pass (crypt/encrypt pass)})
      (redirect "/login"))))

(defroutes auth-routes
  (GET "/register" [] (registration-page))
  (POST "/register" [id pass pass1]
        (handle-registration id pass pass1))

  (GET "/login" [] (login-page))
  (POST "/login" [id pass]
    (handle-login id pass))

  (GET "/logout" []
        (layout/common
          (form-to [:post "/logout"]
            (submit-button "logout"))))
  (POST "/logout" []
        (session/clear!)
        (redirect "/")))

有人可以帮我放松一下，让我重新开始学习本教程吗？同样，有关如何基于不赞成使用的库有效更新代码的任何技巧也将有所帮助。我为冗长的代码表示歉意，但我仍然是菜鸟，也不完全知道问题出在哪里。我怀疑它与数据库依赖项有关系，因为在我的Google搜索[org.clojure / java.jdbc“ 0.2.3”]依赖项中，特别是sql / with-connection已弃用现在版本0.3.3。