From 2e58bd108cc0065a653d9af695ea07acedd12a8c Mon Sep 17 00:00:00 2001
From: Johan Nordberg <its@johan-nordberg.com>
Date: Thu, 4 Apr 2013 14:29:17 +0200
Subject: [PATCH] Levelup db model

---
 scraper/model.coffee | 56 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)
 create mode 100644 scraper/model.coffee

diff --git a/scraper/model.coffee b/scraper/model.coffee
new file mode 100644
index 0000000..082797a
--- /dev/null
+++ b/scraper/model.coffee
@@ -0,0 +1,56 @@
+
+levelup = require 'levelup'
+path = require 'path'
+
+throwop = (error) -> throw error if error?
+
+safeGet = (db, key, callback) ->
+  db.get key, (error, result) ->
+    if error? and error.name isnt 'NotFoundError'
+      callback error
+    else
+      callback null, result or null
+
+class Model
+
+  constructor: (@id) ->
+
+  serialize: -> {@id}
+
+  save: (callback) ->
+    db = @constructor.db()
+    db.put @id, @serialize(), callback
+
+Model.dblocation = path.join __dirname, './data'
+
+Model.db = ->
+  if not @_db?
+    dbpath = path.join this.dblocation, this.name.toLowerCase()
+    console.log "Opening database at #{ dbpath }"
+    @_db = levelup dbpath,
+      keyEncoding: 'utf8'
+      valueEncoding: 'json'
+    process.on 'exit', => @_db.close()
+  return @_db
+
+Model.load = (id, ignoreCache, callback) ->
+  if arguments.length isnt 3
+    callback = arguments[1] or throwop
+    ignoreCache = false
+
+  safeGet @db(), id, (error, result) =>
+    return callback error if error?
+    if not result? or ignoreCache
+      this.new id, (error, result) ->
+        return callback error, result if error? or not result?
+        result.save (error) -> callback error, result
+    else
+      this.deserialize id, result, callback
+
+Model.deserialize = (id, data, callback) ->
+  throw new Error 'Not implemented'
+
+Model.new = (id, callback) ->
+  throw new Error 'Not implemented'
+
+module.exports = {Model}