Grails for You

Merging place names

Michael Astreiko — Thu, 06 Sep 2012 14:37:08 +0000

Problem If you are working on service which need to aggregate place names from different sources, like Google Places, Foursquare and local db for example, then you always have a problem not to display same place more then one time. Imagine you have Paolo Pizza at Backer Street 43 and all three data sources return [...]

Load City list for Country

Michael Astreiko — Wed, 05 Sep 2012 18:24:02 +0000

Task Need to show two selectboxes to User: Country City City select box should change its data based on Country Possible solutions Online Webservice That was me fist idea: just find needed (possibly free!) API Service and use it from grails project. But after googling a lot I did not find any solution which allow [...]

Grails, MySQL and java.io.EOFException: Can not read response from server.

Michael Astreiko — Wed, 11 Apr 2012 18:59:36 +0000

After migration to new PROD server start getting error from some inactivity period: 2012-04-11 14:27:29,415 [TP-Processor3] ERROR (org.hibernate.util.JDBCExceptionReporter) - Communications link failure due to underlying exception: ** BEGIN NESTED EXCEPTION ** java.io.EOFException MESSAGE: Can not read response from server. Expected to read 4 bytes, read 0 bytes before connection was unexpectedly lost. STACKTRACE: java.io.EOFException: Can [...]

RESTful API for grails Domains

Michael Astreiko — Sun, 08 Apr 2012 19:58:41 +0000

Problem Ofter we need to create RESTful API to READ data for existed domain objects with easy manipulation of fields in it. For example, we do not need to see in API result fields like ‘id’, ‘lastUpdated’, ‘createdBy’, collections, references and any other fields. Also we want to have easy way to change field name. [...]

QR Code and Bar Code rendering in Grails

Michael Astreiko — Mon, 27 Feb 2012 18:35:14 +0000

Problem Need to generate QRCode and as many as possible BarCodes based on specific code. Solution After looking to several plugins like qrcode and barcode4j and after unsuccessful usage of them I’ve decided to do it myself and found out that it is easy enough. Step 1 – Add necessary libs After looking to several [...]

Distinct paging in grails app with Criteria Builder

Michael Astreiko — Mon, 13 Feb 2012 21:59:24 +0000

Have multiple domain which connected with each other. Need to provide deep search functionality, so that need to search in Master domain’s 3-d and 4-th level children. For example we have structure like 1 2 3 4 5 6 7 8 9 10 11 12 13 14 class Person { static hasMany = [clothes:Cloth] ... [...]

Ajax file uploading in grails

Michael Astreiko — Sun, 12 Feb 2012 23:22:09 +0000

For Ajax file uploading I’m using Andrew Valums AJAX file uploader. On UI I added jQuery script like: jQuery(function() { var uploader = new qq.FileUploaderBasic({ button: document.getElementById('addButton'), action: "${createLink(controller: 'upload', action: 'uploadImage')}", multiple: true, allowedExtensions:['PNG', 'JPG', 'JPEG', 'GIF'], sizeLimit:4194304, // max 4GB file onSubmit:function(){jQuery('#spinner').show()}, onComplete:function(id, fileName, responseJSON){ reloadImage("urlHolder", responseJSON[0]) } }); }); Where reloadImage is [...]

Grails database migration on existing project in PROD

Michael Astreiko — Sun, 12 Feb 2012 20:50:27 +0000

Problem We have grails project which is already running in PROD without using database migration/liquibase plugins. Need to do changes in database structure without destroying of existing data. Solution Let’s call database states: state A is current state of database state B new state of database, which we want to get in result First of [...]