SEARCH KEYWORD -- LOG AGGREGATION


  Name resolution order in JavaScript

To understand what value a variable has in JavaScript, we need to understand some concepts such as scope and name resolution order. JavaScript has two scopes; one is program level and the other one is function level. Unlike in C,C++ or Java, JavaScript has no block level scope. So a variable defined in a if block will still be available outside. For example, the below example: var foo = 1; function bar() { if (true) { var foo = 10; } alert(foo); } bar(); The alert will display 10 since the ...

   JavaScript,Scope,Name resolution     2013-07-10 01:29:28

  9 reasons to use Zsh

Like majority *nix users, I have been using bash for many years. Sometimes I feel uncomfortable with bash. I tried use some other shells as well such as ksh, tcsh and zsh which I am going to talk about. A few days ago, I found an open source project ranking in the 6th named oh-my-zsh on Github, I downloaded it and had a try with it. It's amazing. We should use zsh to replace bash now. Why do we need to use zsh? Here is a 4 minutes YouTube video which shows many reasons why we should switch from ...

   zsh, advantage, command     2012-09-28 12:46:39

  Start to work with rollup.js to pack JS files

rollup.js is a module bundler for JavaScript. It compiles small piece of JavaScript modules spreading in different files into a single larger standardized ES code file. This post will show some entry level usage for this library. Introduction Normally a bundler tool would compile a few small JavaScript files into a single JavaScript so that web browser can read, parse and render it properly. A bundler tool may be needed because of a few reasons: Some early stage browsers don't understand module...

   ROLLUP.JS,COMMONJS,ES MODULE,BUNDLE,WEBPACK     2022-06-12 00:00:14

  Android socket programming example

Socket is a kind of interface for different sides t communicate, it usually identified by an IP and a port. There are many server side software on a server and they would provide different service. Each server many create some sockets and bind them to some ports so that clients can listen to. Software on the Internet will exchange data though a bidirectional connection established. Each end of the connection has a socket created. In Java, Socket and ServerSocket are in java.net package, ServerSo...

   Android,Socket,Java     2013-05-11 22:17:16

  HeartBleed: OpenBSD now starts to clean up OpenSSL

Since the disclosure of HeartBleed bug in OpenSSL, some arguments emerge around the safety of OpenSSL, the largest open source SSL/TLS library used by large number of servers, applications. Some people are even starting to create their own version of SSL library. This includes OpenBSD, a famous Unix like open source operating system. Just a few days after the HeartBleed bug, OpenBSD forked a new branch of OpenSSL and started to clean up the forked branch and plans to merge it to its own cod...

   HeartBleed,OpenBSD     2014-04-15 04:21:26

  Resolve stylesheet_link_tag fails to work in Ruby on Rails

When developing Ruby On Rails application, developers sometimes will see an unexpected behavior where the application cannot be loaded due to "TypeError: Object doesn't support this property or method" when invoking stylesheet_link_tag. The symptom looks like  And the Rails log will show something similar to below The error occurs because there is some problem finding the correct assets which are located in app/assets. To resolve the issue, you can following below steps. Add gem 'coffee-...

   RUBY ON RAILS,STYLESHEET_LINK_TAG,JAVASCRIPT_INCLUDE_TAG,TYPEERROR     2016-10-14 03:59:11

  File upload once again

File upload is one of the oldest operation of web design. After 20 years, it's still has no big change, difficult to handle, lack of interaction and poor user experience. Web developers have thought many methods to improve the experience of uploading file in web apps, they developed various plugins based on different JavaScript libraries. However, because of the difference among different web browsers, there is no common interface which makes these plugins work properly or easily on all web brow...

   Web design, File upload, Asynchronous,HTML5     2012-09-02 11:52:21

  Mozilla releases a web identity system : Persona

Now almost every website requires the user to register, there are many benefits of registration for a website, such as retaining users, accommodating discussions, providing customized content and so on.But there is too much trouble if each site requires registration, right?Of course, users can also have their own way, for those less important sites, for example, using a unified user name, password and email so that you only need to remember one account. Then, we also see some advanced methods em...

   Mozilla,Persona,Security,ID     2012-09-28 12:02:25

  Error handling in GoLang

Error handling is one of the must talked topics for any programming language. The program would be more reliable and stable if errors are handled properly and timely. Each programming language has its own way to handle error, this applies to GoLang as well. This post will discuss more about GoLang's error handling mechanism. Error handling Before talking more about GoLang's error handling, we can see how different programming languages are handling errors. C's error check The most direct way of ...

   GOLANG,ERROR HANDLING,FLUENT INTERFACE     2021-03-06 21:36:08

  One Way to Quickly Locate SQL with High CPU Usage in MySQL

When the CPU usage of a MySQL database rises abnormally, it's necessary to quickly identify the problematic SQL statements. In this post, we try to provide one way to achieve this.  Below are the actual steps. 1. Use the top command to find the threads with the highest CPU usage in the MySQL process. # Find the MySQL process ID ps -ef | grep mysql # Use the process ID to find the thread IDs with the highest CPU usage: top -H -p In top, press P to sort by CPU usage. Note the thread ID, fo...

   MYSQL,DEBUG,HIGH CPU,SLOW QUERY     2024-08-01 21:25:48

RECENT