feat(migrations): add support for making db actions

this.db will allow to execute database actions using the database provider

Closes #53

src/Migrations/Mixins/Migrate.js

@@ -12,6 +12,7 @@
 const _ = require('lodash')
 const CatLog = require('cat-log')
 const cf = require('co-functional')
+const co = require('co')
 const CE = require('../../Exceptions')
 const logger = new CatLog('adonis:lucid')
 
@@ -55,7 +56,24 @@ Migrate._translateActions = function (schemaInstance, direction) {
  */
 Migrate._callSchemaActions = function (defination, connection) {
   const builder = this.database.connection(connection).schema
-  return builder[defination.action](defination.key, this._wrapSchemaCallback(defination.callback))
+  /**
+   * Custom check to allow access the database provider and
+   * do custom stuff with support for co-routines.
+   */
+  if (defination.action === 'db') {
+    return co.wrap(function * () {
+      return yield defination.callback(this.database)
+    }.bind(this))
+  }
+
+  /**
+   * co.wrap returns a function which returns a promise, so we
+   * need to wrap schema method inside a function to keep
+   * the API stable.
+   */
+  return (function () {
+    return builder[defination.action](defination.key, this._wrapSchemaCallback(defination.callback))
+  }.bind(this))
 }
 
 /**
@@ -160,7 +178,7 @@ Migrate._executeMigrations = function * (migrations, direction, batchNumber) {
  */
 Migrate._executeActions = function * (actions, file, direction, batchNumber) {
   yield cf.forEachSerial(function * (action) {
-    return yield action
+    return yield action()
   }, _.flatten(actions))
 
   /**

src/Schema/proxyHandler.js

@@ -51,6 +51,26 @@ proxyHandler.get = function (target, name) {
     if (Object.keys(aliases).indexOf(name) > -1) {
       name = aliases[name]
     }
+
+    /**
+     * Trying to be more explicit here by adding the if clause
+     * on the name instead of checking the existence on
+     * callback and when key is a function but that will not
+     * be clear that this custom behaviour is required for
+     * this.db only.
+     *
+     * @example
+     * this.db(function () {})
+     *
+     * @alternate-check
+     * if (!callback && typeof (key) === 'function') {
+     *   // not explicit
+     * }
+     */
+    if (name === 'db') {
+      callback = key
+      key = null
+    }
     target.actions.push({key, callback, action: name})
   }
 }

test/unit/migrations.spec.js

@@ -10,12 +10,13 @@
 */
 
 /* global describe, it, before,after */
-const Migrations = require('../../src/Migrations')
-const Database = require('../../src/Database')
-const Schema = require('../../src/Schema')
 const _ = require('lodash')
 const Ioc = require('adonis-fold').Ioc
 const chai = require('chai')
+const cf = require('co-functional')
+const Migrations = require('../../src/Migrations')
+const Database = require('../../src/Database')
+const Schema = require('../../src/Schema')
 const filesFixtures = require('./fixtures/files')
 const config = require('./helpers/config')
 const expect = chai.expect
@@ -731,6 +732,7 @@ describe('Migrations', function () {
     const migrationsCompleted = yield runner.database.table('adonis_migrations')
     expect(migrationsCompleted).to.be.an('array')
     expect(migrationsCompleted).to.have.length(0)
+    yield runner.database.schema.dropTable('adonis_migrations')
   })
 
   it('should return the sql output for rollback', function * () {
@@ -755,5 +757,67 @@ describe('Migrations', function () {
     expect(response).to.have.length(1)
     expect(response[0].file).to.equal('2015-01-20')
     expect(response[0].queries).to.be.an('array')
+    yield runner.database.schema.dropTable('users')
+    yield runner.database.schema.dropTable('adonis_migrations')
+  })
+
+  it('should be able to access the database provider using this.db', function * () {
+    const Runner = new Migrations(Database, Config)
+    const runner = new Runner()
+    let db = null
+    class Users extends Schema {
+      up () {
+        this.db(function * (database) {
+          db = database
+        })
+      }
+    }
+    const migrations = {'2016-04-20': Users}
+    yield runner.up(migrations)
+    expect(db.table).to.be.a('function')
+    yield runner.database.schema.dropTable('adonis_migrations')
+  })
+
+  it('should be able to migrate a table data to a different column @fun', function * () {
+    const Runner = new Migrations(Database, Config)
+    const runner = new Runner()
+    class Users extends Schema {
+      up () {
+        this.create('users', (table) => {
+          table.increments()
+          table.string('username')
+        })
+
+        this.db(function * (database) {
+          yield database.table('users').insert([{username: 'foo'}, {username: 'bar'}])
+        })
+      }
+    }
+
+    class UsersMigrate extends Schema {
+      up () {
+        this.table('users', (table) => {
+          table.string('uname')
+        })
+
+        this.db(function * (database) {
+          const usernames = yield database.table('users').pluck('username')
+          yield cf.forEach(function * (username) {
+            yield database.table('users').where('username', username).update('uname', username)
+          }, usernames)
+        })
+
+        this.table('users', (table) => {
+          table.dropColumn('username')
+        })
+      }
+    }
+
+    const migrations = {'2016-04-20': Users, '2016-10-30': UsersMigrate}
+    yield runner.up(migrations)
+    const users = yield Database.table('users').pluck('uname')
+    expect(users).deep.equal(['foo', 'bar'])
+    yield runner.database.schema.dropTable('users')
+    yield runner.database.schema.dropTable('adonis_migrations')
   })
 })