Programmer blog

Found a new pattern to use recently that is called Promise. I really like the way ES6/7 brings new thinking patterns into life nowdays. Here is Promise used instead of old pattern. It was to give JS method a callback function. This splitting code and making a lot of possibilities for error to come out in this place. One would write old times according to MDN : function greeting ( name ) { alert ( 'Hello ' + name ); } function processUserInput ( callback ) { var name = prompt ( 'Please enter your name.' ); callback ( name ); } processUserInput ( greeting ); And now it is made with Promise pattern like so: let promise = new Promise (( resolve , reject ) => { resolve ( prompt ( 'Please enter your name.' )); }); promise . then (( name ) => { alert ( 'Hello ' + name ); }); In general and briefly this now helps to avoid 'callback hell' with functions passed as arguments and write as...

It often gets that you need it because you invent something that is meant to be displayed for admin. E.g. some nasty form field or something. Here is my recipe to add some additional Django static to your admin. Rather than writing a widget , that is more proper way here... I was using a widget already (from another package). So I could not use it properly, at least without a ton of overrides and complexity it leads to. SO I've decided to add the JS functionality to override a lack of backend. First of all we should add the javascript/css like so: # admin.py class MyModelAdmin (admin.ModelAdmin): # admin additions class Media : css = { "all" : ( "css/my_style.css" ,) } js = ( "js/my_script.js" ,) This add should list your files, loaded in the admin . So you can access them and see in the Django admin frontend itself. Like so: Now that your script and style are loaded you could jus...

You may often require serialization of a form in JS and parsing of it's data. Here is a nice recipe to validate date with browser default methods. I like it because of relative simplicity. It works on a principle of parsing date's components. We will create a JavaScript Date object from it and check if it is the same as a parsed date string. Date components that are wrong will go out of rage. SO we will have them different from the existing strings. This method is based on that hack. I use this only to validate the string itself. I am specifying a placeholder of an input field to minimise user possibility to make a mistake. And I usually force user to enter date in my format with this tool. Anyway it's a good idea to put any datepicker component also. function validate_date ( value ) { /**********************************************     * Validating date in format dd/mm/yyyy     ************************************...

Being studying Meteor myself I'd like to help beginners like me. I have searched for certain decisions that became wired to me after python development. So I'll just leave them here for your consideration. Imagine a situation when you need to bind your plugins to a newly rendered template. If you are diving into asynchronous JS dev, like I did and have developed AJAX websites... You will, one word, be quite confused because main concepts are different from the one's you used to know. Anyhow I'd try to explain on this simple task. Assume we have a template: < template name = "site-part" > < p > {{my-text}} </ p > </ template > And I render it's content like so: Template . site - part . content = function ( ) { return Session . get ( " my_data " ) ; } So I have this template piece rendered when "my_data" variable appears in session. And I have events binded to newly rendered webpage:...

As a novice I'd like to describe a situation when you may need to make calls to a different domain. In my case it was a requirement to access external API. Anyway I'd like to describe here my perspective of usage this in meteor. You would need to get those data and parse them. First thought is to use client. Wrong. You would need to add CORS support to your application. It means you need to have header  Access-Control-Allow-Origin: * added to all of your response objects. This will enable Meteor usage of external domain responses. And requires you to hack Meteor code. But there is more "proper" way to work with server. Code on a server is executed synchronously and so you can be sure it will be executed and result returned. So. First we need to make sure we have a Meteor.http package installed. You can install it by executing "meteor add http" in your project root directory. Meteor.http can work in both synchronous and asynchronous modes. It is d...

Our project will have a new architecture changes in future. We've chosen from different tech. But now we 're experimenting with CouchDB a bit. It may become a part of our new architectural Changes. I'll try to cover most of newbies observations with CouchDB for Python(Django) programmer, planning to use it in your project. First article will be, unsurprisingly, installing CouchDB under Mac OS X. It, sure, has some inches that you need to scratch. So let's roll... CouchDB is not a simple SQL database like you used to install before. It has own server to accept connections. And, in fact, you can work with database from your browser GUI (without other server proxy, like Django or ...). Anyway it will not be our target. Building JS UI is quite easier with CouchDB and changes your logic dramatically. To build UI with Python we need some proxy parts. Anyway, again, CouchDB is a standalone server, that runs on your server's port and talks to your APP/Browser/wha...

There are 2 main usual tasks with web project's deployment and about .css and .js files. First one - size minimization. But there are lot's of utilities helping you to compress CSS files. Delete unused spaces, comments and so on... Second one - Version control. For e. g. When you've updated the script on your deployment server, but user's browser uses old one until user manually hits 'Refresh'. That's where Static files compressor comes in to mind. Upon selecting among available one's found top "google" results: - django-compress - django-compressor - webassets Project uses 'django.contrib.staticfiles', so django-compress was not compatible... It does not support Django's static files gently. Webassets s a good lib. but project has a huge amount of different static. Maybe it's ok for e small project, but when you need to specify/change a 100's javascript in python module for certain templates... Nothing good comes ...

jQuery Sometimes you need to disable/enable the form element like input or textarea. Jquery helps you to easily make this with setting disabled attribute to "disabled". For e.g.: //To disable  $( '.someElement' ).attr( 'disabled' , 'disabled' ); To enable disabled element you need to remove "disabled" attribute from this element or empty it's string. For e.g: //To enable  $( '.someElement' ).removeAttr( 'disabled' ); // OR you can set attr to ""  $( '.someElement' ).attr( 'disabled' , '' ); Javascript My case was a bit different. I had to disable simple control element used without a form. < a   class = "rotator"   href = ""   onclick = "return rotate(this, parameter, url)"   > I made a javascript like this: /** script */ var  disabled =  false ; function  rotate(button, parameter, url) {      if  (disabled)          return   false ;     d...

In most common cases of programming Django with Eclipse are that Django is installed in system, like Python. I dislike this method, because it makes confusions for beginners. What Django version I'm in. Why did I download an app "X" and added an Eclipse project. Everything seems to be fine, but I cant install proper dependencies... So it's not a secret. Managing Django distributions is a hard work for junior developer. Let's try to make their work simpler, by this article. I'll try to show you the right way to install Django environment on Eclipse. 1. First of all let's install Eclipse from official site . I chose "Eclipse IDE for JavaScript Web Developers". Mac 32bit version, because I'm using this OS type. Any other distributive will work just fine, I think. 2. Unpack downloaded archive into some dir. It will be installation directory of the eclipse. Usually it doesn't mater where it is stored. So I used "/Users/garmoncheg/De...