Add CRU for the about content.

src/main/blog/db.cljs

@@ -1,6 +1,6 @@
 (ns blog.db
   (:require ["pg" :refer [Client]]
-            [cljs.core.async :refer [go, take!, put!, >!, chan]]
+            [cljs.core.async :refer [go, take!, put!, <!, >!, chan]]
             [cljs.core.async.interop :refer-macros [<p!]]
             [cljs.core :refer [clj->js js->clj]]
             [blog.env :as env]))
@@ -17,10 +17,6 @@
   [client]
   (. client connect))
 
-(defn create-tables
-  [client]
-  (. client query "CREATE TABLE IF NOT EXISTS articles (id SERIAL PRIMARY KEY, title VARCHAR(255) NOT NULL, content TEXT NOT NULL, created TIMESTAMP DEFAULT CURRENT_TIMESTAMP);"))
-
 (defn get-articles
   "Reads all articles and returns via channel. It gets and returns the same channel."
   [client channel]
@@ -142,3 +138,69 @@
       (catch js/Error err (js/console.log (ex-cause err)))))
   channel)
 
+(defn get-about
+  "Reads the about article. It gets and returns the same channel. Empty collection if not found."
+  [client channel]
+  (go
+    (try
+      (let [res (<p! (.query client
+                             "select id, content, created from about where id=1"))
+            about (-> (.-rows res)
+                      (js->clj :keywordize-keys true)
+                      (first))]
+        (>! channel (or about [])))
+      (catch js/Error err
+        (do
+          (>! channel nil)
+          (js/console.log (ex-cause err))))))
+  channel)
+
+(defn insert-about
+  "Insert the about article and return the id via channel. It gets and returns the same channel."
+  [client channel]
+  (go
+    (try
+      (let [res (<! (.query client
+                             "insert into about(id, content) values(1, 'Please, Change ME!!!') returning id;"))]
+        (>! channel (-> (.-rows res)
+                        (js->clj :keywordize-keys true)
+                        (first)
+                        (:id))))
+      (catch js/Error err (js/console.log (ex-cause err)))))
+  channel)
+
+(defn insert-about-if-not-exist
+  "Insert the about article if not exist and return the id via channel. It gets and returns the same channel."
+  [client]
+  (go
+    (let [channel (chan)]
+      (try
+        (let [about (<! (get-about client channel))]
+          (if (= about [])
+            (insert-about client channel))
+          false)
+          (catch js/Error err
+            (do (js/console.log (ex-cause err))
+                                true))))))
+
+(defn update-about
+  "Update the about article and return the id via channel. The timestamp for created will be updated to current timestamp. It gets and returns the same channel."
+  [client content channel]
+  (go
+    (try
+      (let [res (<! (.query client
+                             (str "update about "
+                                  "set content = $1,"
+                                      "created = CURRENT_TIMESTAMP "
+                                  "where id = 1;")
+                             (clj->js [content])))]
+        (>! channel (-> 1)))
+      (catch js/Error err (js/console.log (ex-cause err)))))
+  channel)
+
+(defn create-tables
+  [client]
+  (. client query "CREATE TABLE IF NOT EXISTS articles (id SERIAL PRIMARY KEY, title VARCHAR(255) NOT NULL, content TEXT NOT NULL, created TIMESTAMP DEFAULT CURRENT_TIMESTAMP);")
+  (. client query "CREATE TABLE IF NOT EXISTS about (id SERIAL PRIMARY KEY, content TEXT NOT NULL, created TIMESTAMP DEFAULT CURRENT_TIMESTAMP);")
+  (insert-about-if-not-exist client))
+