Automatically generate loopback models from existing MySQL schema (all at once)

automatically_generate_loopback_models_from_MySQL_README.md

Prerequisites

When using this script I'm assuming the following things are true:

1. You have a working LoopBack application created.
2. You have loopback-connector-mysql installed.
3. You have a datasources.json file created inside the LoopBack application root folder server and have set up connection to your MySQL database. Basic example:

   "mydb": {
     "name": "mydb",
     "connector": "mysql",
     "host": "localhost",
     "port": 3306,
     "username": "username",
     "password": "password",
     "database": "database"
   }

4. You have a model-config.json file created inside the LoopBack application root folder server with default content, like:

   {
     "_meta": {
       "sources": [
         "loopback/common/models",
         "loopback/server/models",
         "../common/models",
         "./models"
       ],
       "mixins": [
         "loopback/common/mixins",
         "loopback/server/mixins",
         "../common/mixins",
         "./mixins"
       ]
     }
   }

Usage

1. Put the file in the folders server/bin inside your LoopBack application root folder.
2. Run the script in the command line as node server/bin/script (omitting the .js extension name, but you can use it with it too, if you like).
3. Enjoy (hopefully) / provide feedback!

Credits (based on)

https://stackoverflow.com/a/30179478/2037924 https://gist.github.com/serkanserttop/64fc2d4465fb154066db#file-discover-js

script.js

var fs = require('fs');
var path = require('path');
var app = require(path.resolve(__dirname, '../server'));
var appDir = './';
var baseFileName = 'model-config.json';
var fileName = path.resolve(__dirname, '../' + baseFileName);
var file = require(fileName);

var dataSource = app.dataSources.mydb;
var db = dataSource.settings.database;

function capitaliseFirstLetter(string){
  return string.charAt(0).toUpperCase() + string.slice(1);
}

function jsFileString(model_name){
  return '' +
    'module.exports = function(' + capitaliseFirstLetter(model_name) + ') {\n' +
      '\t\n' +
    '};';
}

dataSource.discoverModelDefinitions({schema:db}, function (err, models) {
  models.forEach(function (model) {
    dataSource.discoverSchema(model.name, {associations: true}, function (err, schema) {
      if( schema.options.mysql.schema !== db ){
        console.log('options.mysql.schema !== db', schema);
      }
      fs.writeFile( appDir + 'common/models/' + model.name + '.json', JSON.stringify(schema, null, '  '), function (err) {
        if (err) throw err;
        console.log('Created ' + model.name + '.json file');
      });
      fs.writeFile( appDir + 'common/models/' + model.name + '.js', jsFileString(model.name), function (err) {
        if (err) throw err;
        console.log('Created ' + model.name + '.js file');
      });
      file[schema.name] = {
        "dataSource": dataSource.settings.name,
        "public": false
      };
      fs.writeFile(fileName, JSON.stringify(file, null, 2), function (err) {
        if (err) throw err;
        console.log('Updated ' + baseFileName + ' with an entry of ' + model.name);
      });
    });
  });
});

This is just what I need - if only I can get it to work ;-) I'm getting this error:-

C:\dev\api> node server/bin/script
C:\dev\api\node_modules\mysql\lib\protocol\Parser.js:79
throw err; // Rethrow non-MySQL errors
^

TypeError: Cannot read property 'options' of undefined
at C:\dev\api\server\bin\script.js:26:17
at C:\dev\api\node_modules\loopback-datasource-juggler\lib\datasource.js:1412:13
at C:\dev\api\node_modules\loopback-datasource-juggler\node_modules\async\dist\async.js:359:16
at iteratorCallback (C:\dev\api\node_modules\loopback-datasource-juggler\node_modules\async\dist\async.js:933:13)
at C:\dev\api\node_modules\loopback-datasource-juggler\node_modules\async\dist\async.js:843:16
at C:\dev\api\node_modules\loopback-datasource-juggler\node_modules\async\dist\async.js:3691:13
at apply (C:\dev\api\node_modules\loopback-datasource-juggler\node_modules\async\dist\async.js:21:25)
at C:\dev\api\node_modules\loopback-datasource-juggler\node_modules\async\dist\async.js:56:12
at callback (C:\dev\api\node_modules\loopback-connector\lib\sql.js:1896:7)
at cbForWork (C:\dev\api\node_modules\loopback-datasource-juggler\lib\observer.js:234:34)
at C:\dev\api\node_modules\loopback-connector\lib\sql.js:642:7
at handleResponse (C:\dev\api\node_modules\loopback-connector-mysql\lib\mysql.js:193:17)
at Query._callback (C:\dev\api\node_modules\loopback-connector-mysql\lib\mysql.js:204:7)
at Query.Sequence.end (C:\dev\api\node_modules\mysql\lib\protocol\sequences\Sequence.js:86:24)