database/sql: add WebSQL wrapping

opal · Feb 3, 2014 · 0dcfc89 · 0dcfc89
1 parent 93aec20
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diff --git a/opal/browser/database/sql.rb b/opal/browser/database/sql.rb
@@ -0,0 +1,194 @@
+require 'promise'
+require 'ostruct'
+
+module Browser; module Database
+
+class SQL
+  # Check if the browser supports WebSQL.
+  def self.supported?
+    Browser.supports? 'WebSQL'
+  end
+
+  class Error < StandardError
+    def self.new(error)
+      return super if self != Error
+
+      [Unknown, Database, Version, TooLarge, Quota, Syntax, Constraint, Timeout] \
+        [`error.code`].new(`error.message`)
+    end
+
+    Unknown    = Class.new(self)
+    Database   = Class.new(self)
+    Version    = Class.new(self)
+    TooLarge   = Class.new(self)
+    Quota      = Class.new(self)
+    Syntax     = Class.new(self)
+    Constraint = Class.new(self)
+    Timeout    = Class.new(self)
+  end
+
+  include Native
+
+  # @return [String] the name of the database
+  attr_reader :name
+
+  # @return [String] the description for the database
+  attr_reader :description
+
+  # @return [Integer] the size constraint in bytes
+  attr_reader :size
+
+  # Open a database with the given name and options.
+  #
+  # @param name [String] the name for the database
+  # @param options [Hash] options to open the database
+  #
+  # @option options [String] :description the description for the database
+  # @option options [String] :version ('') the expected version of the database
+  # @option options [Integer] :size (5 * 1024 * 1024) the size constraint in bytes
+  def initialize(name, options = {})
+    @name        = name
+    @description = options[:description] || name
+    @version     = options[:version]     || ''
+    @size        = options[:size]        || 5 * 1024 * 1024
+
+    super(`window.openDatabase(#{name}, #{@version}, #{@description}, #{@size})`)
+  end
+
+  # @overload version()
+  #
+  #   Get the version of the database.
+  #
+  #   @return [String]
+  #
+  # @overload version(from, to, &block)
+  #
+  #   Migrate the database to a new version.
+  #
+  #   @param from [String] the version you're migrating from
+  #   @param to [String] the version you're migrating to
+  #
+  #   @yieldparam transaction [Transaction] the transaction to work with
+  def version(from = nil, to = nil, &block)
+    return `#@native.version` unless block
+
+    `#@native.changeVersion(#{from}, #{to},
+      #{-> t { block.call(Transaction.new(self, t)) }})`
+  end
+
+  # Start a transaction on the database.
+  #
+  # @yieldparam transaction [Transaction] the transaction to work on
+  def transaction(&block)
+    raise ArgumentError, 'no block given' unless block
+
+    `#@native.transaction(#{-> t { block.call(Transaction.new(self, t)) }})`
+  end
+
+  # Allows you to make changes to the database or read data from it.
+  class Transaction
+    include Native
+
+    # @return [Database] the database the transaction has been created from
+    attr_reader :database
+
+    # @private
+    def initialize(database, transaction)
+      @database = database
+
+      super(transaction)
+    end
+
+    # Query the database.
+    #
+    # @param query [String] the SQL query to send
+    # @param parameters [Array] optional bind parameters for the query
+    #
+    # @return [Promise]
+    def query(query, *parameters)
+      promise = Promise.new
+
+      `#@native.executeSql(#{query}, #{parameters},
+        #{-> _, r { promise.resolve(Result.new(self, r)) }},
+        #{-> _, e { promise.reject(Error.new(e)) }})`
+
+      promise
+    end
+  end
+
+  # Represents a row.
+  class Row < OpenStruct
+    # @private
+    def initialize(row)
+      super(Hash.new(row))
+    end
+
+    def inspect
+      "#<SQL::Row: #{Hash.new(@native).inspect}>"
+    end
+  end
+
+  class Result
+    include Native
+
+    # @return [Transaction] the transaction the result came from
+    attr_reader :transaction
+
+    # @return [SQL] the database the result came from
+    attr_reader :database
+
+    # @private
+    def initialize(transaction, result)
+      @transaction = transaction
+      @database    = transaction.database
+
+      super(result)
+    end
+
+    include Enumerable
+
+    # Get a row from the result.
+    #
+    # @param index [Integer] the index for the row
+    #
+    # @return [Row]
+    def [](index)
+      if index < 0
+        index += length
+      end
+
+      unless index < 0 || index >= length
+        Row.new(`#@native.rows.item(index)`)
+      end
+    end
+
+    # Enumerate over the rows.
+    #
+    # @yieldparam row [Row]
+    #
+    # @return [self]
+    def each(&block)
+      return enum_for :each unless block
+
+      %x{
+        for (var i = 0, length = #@native.rows.length; i < length; i++) {
+          #{block.call(self[`i`])};
+        }
+      }
+
+      self
+    end
+
+    # @!attribute [r] length
+    # @return [Integer] number of rows in the result
+    def length
+      `#@native.rows.length`
+    end
+
+    # @!attribute [r] affected
+    # @return [Integer] number of affected rows
+    alias_native :affected, :rowsAffected
+  end
+end
+
+end; end
diff --git a/spec/database/sql_spec.rb b/spec/database/sql_spec.rb
@@ -0,0 +1,130 @@
+require 'spec_helper'
+require 'browser/database/sql'
+
+describe Browser::Database::SQL do
+  SQL = Browser::Database::SQL
+
+  describe '#new' do
+    it 'sets the attributes properly' do
+      sql = SQL.new('test', description: 'trains', size: 1024)
+
+      expect(sql.name).to eq('test')
+      expect(sql.description).to eq('trains')
+      expect(sql.size).to eq(1024)
+    end
+
+    it 'sets the version properly' do
+      sql = SQL.new('test2', version: '1.0')
+      expect(sql.version).to eq('1.0')
+
+      sql = SQL.new('test')
+      expect(sql.version).to eq('')
+    end
+  end
+
+  describe '#transaction' do
+    async 'calls the block with the transaction' do
+      sql = SQL.new('test')
+
+      sql.transaction {|t|
+        async {
+          expect(t).to be_a(SQL::Transaction)
+        }
+      }
+    end
+
+    async 'the transaction database is the right one' do
+      sql = SQL.new('test')
+
+      sql.transaction {|t|
+        async {
+          expect(t.database).to eq(sql)
+        }
+      }
+    end
+  end
+
+  describe SQL::Transaction do
+    describe '#query' do
+      async 'returns a promise' do
+        sql = SQL.new('test')
+
+        sql.transaction {|t|
+          async {
+            expect(t.query('hue')).to be_a(Promise)
+          }
+        }
+      end
+
+      async 'resolves on success' do
+        sql = SQL.new('test')
+
+        sql.transaction {|t|
+          t.query('CREATE TABLE IF NOT EXISTS test(ID INTEGER PRIMARY KEY ASC, a TEXT)').then {|r|
+            async {
+              expect(r).to be_a(SQL::Result)
+            }
+          }
+        }
+      end
+
+      async 'rejects on failure' do
+        sql = SQL.new('test')
+
+        sql.transaction {|t|
+          t.query('huehue').rescue {|e|
+            async {
+              expect(e).to be_a(SQL::Error::Syntax)
+            }
+          }
+        }
+      end
+    end
+  end
+
+  describe SQL::Result do
+    describe '#length' do
+      async 'has the proper length' do
+        sql = SQL.new('test')
+
+        sql.transaction {|t|
+          t.query('SELECT 1').then {|r|
+            async {
+              expect(r.length).to eq(1)
+            }
+          }
+        }
+      end
+    end
+
+    describe '#[]' do
+      async 'returns a row' do
+        sql = SQL.new('test')
+
+        sql.transaction {|t|
+          t.query('SELECT 1, 2, 3').then {|r|
+            async {
+              expect(r[0]).to be_a(SQL::Row)
+              expect(r[-1]).to be_a(SQL::Row)
+
+              expect(r[0]).to eq(r[-1])
+            }
+          }
+        }
+      end
+
+      async 'returns nil on missing row' do
+        sql = SQL.new('test')
+
+        sql.transaction {|t|
+          t.query('SELECT 1, 2, 3').then {|r|
+            async {
+              expect(r[5]).to be_nil
+              expect(r[-5]).to be_nil
+            }
+          }
+        }
+      end
+    end
+  end
+end if Browser::Database::SQL.supported?