问题 英文：svn: OPTIONS of 'https://server.domain.local/svn/repo': SSL handshake failed: SSL error: Key usage violation in certificate has been detected. (https://server.domain.local) 中文：SSL handshake failed: SSL 错误：在证书中检测到违规的密钥用法。 解决方案 Symptoms Subversion clients receive the following error message when attempting to connect to VisualSVN Server: svn: OPTIONS of 'https://server.domain.local/svn/repo': SSL handshake failed: SSL error: Key usage viol...

本文基于Python后台搭建了一个视频服务器，集视频的上传，视频的格式转化，视频的播放于一体，后台基于Django框架和Amazon S3的存储，视频格式的转换基于Encoding.com的在线服务，消息队列基于RabbitMQ，视频上传和转换处理完毕后，采用浏览器的Html5播放，采用了Video.js。 Stickyworld's consultation web app has supported video for a long time but it's been hosted via a YouTube embed. When we started building the new version of the web app we wanted to take control of the video content and al...

一篇优秀的NODE.JS入门文章，介绍了安装，运行简单的程序，IO程序，NPM安装依赖包，Module开发。 There's no shortage of Node.js tutorials out there, but most of them cover specific use cases or topics that only apply when you've already got Node up and running. I see comments every once and awhile that sound something like, "I've downloaded Node, now what?" This tutorial answers that question and explains how to get started from the very beginning. What is Node.js? A lot of the ...

AOP通俗来讲，就是在不改变既有代码的基础上增加新功能，比如常用的地方有日志记录，可能我们已经上线了产品，代码也已经进行了发布，如何在此种情况下，增加log记录，打印出后台函数的调用记录，参数传递情况等等。在面向对象的设计过程中，已经有其他的方式可以利用，比如继承，组合，代理等，但是相对于AOP来说，都没有后者灵活。本文基于JavaScript语言进行介绍。 Aspect Oriented Programming (AOP) is a technique for augmenting the behavior of objects, methods, and functions non-invasively. AOP all...

上一篇文章《libiec61850在OpenSCADA系统中的使用》介绍了libiec61850和OpenSCADA系统的混合编译，编译是没有问题，但是做成模块的话运行起来还是会出现问题，其中最主要的问题就是库的链接，导致运行时函数找不到，原因出在C和C++函数相互调用的关系，libiec61850是C库，OpenSCADA是C++。 本文采用将libiec61850编译成动态库的方式供OpenSCADA系统调用，步骤如下： 动态库的编译安装 1. 修改libiec61850的 "lib61850\make\target_system.mk" 文件，编译选项添加fPIC CFLAGS += -g CFLAGS += -fPIC 2. 修改libiec...

在开发Java的过程中，怎么样合理的利用Object，资源的申请与释放，每种类型的Object占用的内存大小是多少，有没有可以替换的lib可以使用。鉴于效率的考量和内存占用的考量，我们应该选择什么样的数据结构，那么如下的文章将会找到答案。 This article will give you the general advices on memory consumption optimization in Java. Memory usage optimization is the most important type of optimization in Java. Current systems are limited by memory access times rather than by CPU frequency (otherwi...

libiec61850 是一套开源的C库，它实现了大多数的61850的协议转换，原理同样是基于MMS协议的映射。本文要将libiec61850用在OpenSCADA系统中，使OpenSCADA系统可以提供智能变电站61850协议的接入。 简介 libiec61850 is an open-source (GPLv3) implementation of an IEC 61850 client and server library. It is implemented in C to provide maximum portability. It can be used to implement IEC 61850 compliant client and server applications on embedded systems and PCs running Linux and Windows. Inclu...

前言 OpenSCADA作为一个开源的Scada系统，本文基于此系统来添加一个子模块，例子中准备添加一个支持61850协议的模块（名称为SP61850）。 OpenScada内置支持如下的子系统 "Data Bases" "Communication Interfaces, Transports" "Protocols of the communication interfaces" "Data Sources and Data Acquisition" "Archives(Histories) (of messages and values)" "User Interfaces (GUI, TUI, WebGUI, speach, signal ...)" "Additional modules" 我们所要添加的子模块隶属于如上的"Additional modules"，即"spe...