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  How to do pprof for gRPC service

gRPC is a RPC framework based on HTTP and is frequently used for communications among micro service inside the same organization network. However,  the service functions cannot be accessed via normal HTTP URL as it's not a WEB framework. In this case, how to do pprof on a gRPC service? The trick is starting a HTTP server asynchronously while starting the gRPC service. This HTTP server can be accessed to run prrof debug. go func(){ http.ListenAndServe(":10001", nil) }() Since it uses the de...

   GOLANG,PPROF,GRPC     2021-01-29 23:11:33

  What can .htaccess file do?

A .htaccess file is a directory-level configuration file supported by several web servers, that allows for decentralized management of web server configuration. What can a .htaccess file do? We summarized some of them here.  Hope it may help you. 1. Timezone settingSometimes when you use date() or mktime() functions in PHP, , it may display some weird information because of the timezone difference. For example, one possible warning is :Warning: date(): It is not safe to rely on the syste...

   .htaccess,setting,tip     2012-06-15 06:39:39

  Some tricks and tips for using for range in GoLang

GoLang provides two major ways to loop through elements of array, slice and map. They are for and for range. Many people find that for range is very convenient when don't care about the index of the element. In this post, some tricks and tips would be talked about regarding for range. 1. Loop and get pointer of each element Assume there is a code snippet like below which is to get the pointer of each element in an array and create a new array with the corresponding pointer. arr := [2]int{1, 2} r...

   POINTER,FOR LOOP,GOLANG,FOR RANGE     2020-03-08 01:07:00

  Samsung announces Galaxy S III mini

Samsung announces Galaxy S III mini today, compared to Galaxy S III, the mini version has some changes in screen size and configurations. Below are the detail configurations of Galaxy S III mini: 4-inch screen 800 × 480 resolution 5-megapixel primary camera, VGA front camera 1GHz dual-core processor Android 4.1 operating system Support the Samsung S Voice Personal Assistant, NFC and S Beam transmission function 1GB RAM, two versions with 8GB and 16GB memory, expandable to 32GB with microS...

   Galaxy S III mini,Configuration     2012-10-11 19:27:53

  Why accessing Java HashMap may cause infinite loop in concurrent environment

HashMap in Java is frequently used to handle key/value pairs. But it is not a good candidate to be used in concurrent environment where ConcurrentHashMap should be used instead. If used in concurrent environment, it may cause lots of unexpected behavior even including make the program getting into an infinite loop situation. To understand how this can happen, let's first discuss how HaspMap works internally. In this post we will use implementation of HashMap before Java 8 as example, Java 8 prov...

   JAVA,HASHMAP,INFINITE LOOP     2020-03-29 01:47:00

  Understanding an interesting JavaScript map function question

With the evolvement of JavaScript, lots of new features have been added this old but robust language.  Among them are lots of functional programming language related functions like map, filter, each etc. In this post, we will cover one function map and its interesting behavior. Before dive into the details, let first take an example, do you know the output of below function call? ['1', '7', '11'].map(parseInt) You may think that it's easy and the output would be [1, 7, 11] Can you try to ru...

   JAVASCRIPT,MAP,FUNCTIONAL PROGRAMMING     2019-06-14 08:34:46

  Find the kth smallest number in an array

This is an classical question, the general solution to this question is first using sorting algorithm to sort the array, then get the kth number in the array, the complexity is O(nlogn), we can also use selective sort or head sort to, the complexity of selective sort is O(kn) and heap sort is O(nlogk). The better solution is to use quick sort to find the kth smallest number, the complexity is O(n), the worst case cost is O(n^2). But today we introduce one more solution which has the worst case c...

   Sort, Quick sort, Search,Smallest     2013-01-09 06:20:54

  Severe SSL 3.0 vulnerability to be released

According to The Register, another severe security vulnerability has been found in the widely used SSL v3 protocol. Until now, it's still in patch phase and the details of this vulnerability is expected to be released today. There are a few widely impacted security vulnerabilities revealed this year and they bring people's attention to the long existing security concerns. Previously, we have seen the HeartBleed issue and also the recently ShellShock issue. Both of them occur in popular libraries...

   SSL,Security vulnerability, The Register     2014-10-14 22:22:39

  Use cases of Java enumeration

JDK 1.5 introduces a new type -- enumeration. In Java, it's just a small feature, but it can bring us much convenience.Here we summarize some use cases of Java enumeration. 1. Constant Prior to JDK 1.5, we can define constant as public static final..., now we can use enumeration to group all constants in one enum variable and it also provides some useful functions. public enum Color {     RED, GREEN, BLANK, YELLOW   }  2.In Swit...

   Java, Enum,enumeration     2013-01-05 09:15:30

  CSS DIV position analysis

When using CSS to set the position of DIV, we may often get confused with the 4 position properties : static, relative, absolute and fixed. If we don't understand them correctly, we may often get unexpected result. Here we make some analysis to them.The definitions of these 4 properties:static : The default position property. It has no position actually. The element will appear where it should be (top, bottom, left, right or z-index has no use here)relative : This one will position relati...

   CSS, DIV,position,relative,absolute     2013-01-29 03:23:57

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