SEARCH KEYWORD -- New data

  An Object is not a Hash

Following my article A String is not an Error, I want to bring attention to an issue that similarly applies to JavaScript in general, but has special relevance in the Node.JS environment. The problem boils down to the usage of {} as a data-structure where the keys are supplied by untrusted user input, and the mechanisms that are normally used to assert whether a key exists. Consider the example of a simple blog created with Express. We decide to store blog posts in memory in a {}, indexed ...

   Object,Hash,Node.js,JavaScript     2012-01-19 10:16:10

  Get vs Post in HTML form

In HTML, one can specify two different submission methods for a form. The method is specified inside a FORM element, using the METHOD attribute. The difference between METHOD="GET" (the default) and METHOD="POST" is primarily defined in terms of form data encoding. The official recommendations say that "GET" should be used if and only if the form processing is idempotent, which typically means a pure query form. Generally it is advisabl...

   Get,Post,HTML,form,data submission     2011-05-10 11:12:04

  Are college students learning?

In his State of the Union address last Tuesday, President Obama proposed several measures to lower college tuition. University leaders responded cautiously, warning that cost-cutting reforms might also cut into instructional quality. But here's the big open secret in American higher education: Most institutions have no meaningful way to measure the quality...

   College students,Learning,Survey     2012-02-02 07:10:02

  Why does LinkedIn migrate to NodeJS from Ruby?

Node.js, the server-side JavaScript-based software platform used to build scalable network applications, has been all the rage among many developers for the past couple of years. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, perfect for data-intensive real-time applications that run across distributed devices. Because of these advantages, there are many websites are migrating to Node.js.One of them is LinkedIn. LinkedIn was initially built on Ruby...

   LinkedIn,NodeJS,Ruby     2014-03-21 23:39:25

  Build route graph of Hurricane Sandy

Hurricane Sandy swept US east side and landed in New York, it killed 113 persons and incurred 50 billion US dollars economic loss. Sandy is also considered as the most expensive hurricane. We will now use matplotlib and basemap libraries in Python to build a route graph of Sandy. Below is the animated GIF. Shadow is added in the graph to show the time at night, we can see from the graph that Sandy stayed a while in Panama after emerging, then it went through Cuba and became Hurricane-2. Late...

   Hurricane Sandy,Route graph,Python     2012-11-17 07:58:13

  Data as code

What is a good command line parser API? A good command line parser should consider below 5 aspects: Support convenient help information generation Support sub commands, for example, git has push,pull,commit sub commands. Support single character option, word option, flag option and option with parameter. Support default option, for example, if no -port is set, set it as 5037 Support usage model, for example, tar's -c and -x is mutually exclusive, they belong to different usage models. Here are...

   Command line,API     2013-08-08 22:40:36

  Using public key authentication in SSH

SSH is a popular cryptographic network protocol for secure network service operation. It is frequently used in remote server login. For a system administrator or software developer, SSH is frequently used to access remote servers or development servers or testing servers etc.  To login with SSH, there are different authentication mechanisms : password, public key and interactive etc. If a remote server needs to be accessed frequently, password authentication may be too troublesome as p...

   LINUX,DEBUG,SSH,PUBLIC KEY     2016-09-10 05:55:46

  It makes nothing but sense...Mobile Payment...

Chinese New Year is around the corner, every place in China and lots of places in the work have been in the CNY mode. People are rushing out to get all the stuff ready to welcome the New Year Eveand the Spring Festival. I also packed my stuff and flew back to my howntown in China to enjoy the great moment to stay with families and hang out with friends whom I have't been seeing for almost one year. I am exited... However, the first thing stunned me is not my friends but the mobile payment s...

   CHINA,WECHAT PAY,ALIPAY,MOBILE PAYMENT     2018-02-12 00:07:46

  Building the new AJAX mail UI part 2: Better than templates, building highly dynamic web pages

This is part 2 of a series of technical posts documenting some of the interesting work and technologies we’ve used to power the new interface (see also part 1, Instant notifications of new emails via eventsource/server-sent events). Regular users can skip these posts, but we hope technical users find them interesting. As dynamic websites constructed entirely on the client side become de rigueur, there are a number of templating languages battling it out to become the One True Wayâ„...

   Web design,Dynamic,Ajax,UI     2012-02-21 05:32:29

  Select top 3 values from each group in a table with SQL

Yesterday, my friend Liu Bing asked me a question about how to select top 3 values for each person in a database table using SQL. I think this question is interesting and it deserves some thoughts. Here I record down how to solve this issue. Assume we have a table which has two columns, one column contains the names of some people and the other column contains some values related to each person. One person can have more than one value. Each value has a numeric type. The question is we want to se...

   SQL,Correlated query,top 3     2013-05-23 03:21:25

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