In a GoLang web server, every request coming in will be handled by a goroutine. In the request handler, the logic may also need to create new goroutine to handle other tasks like RPC call. When the request is processed and response is returned, these goroutines created need to be exited so that no goroutine leak should happen.package mainimport ( "fmt" "log" "net/http")func main() { http.HandleFunc("/echo", func(w http.ResponseWriter, r *http.Request) { fmt.Println(&r) w.Write([]byte("hello")) }) log.Fatal(http.ListenAndServe(":8080", nil))}go run main.go0xc0000060100xc0000760480xc000076...

Normally the executable file built with go is a bit large, it is always desired that a smaller executable file should be generated though. In this post, a couple of ways to reduce the size of the executable will be introduced. The end effect is that the executable file size would be much less than the normal generated one.The file which is built normally has below size.Mode LastWriteTime Length Name---- ------------- ------ -----a---- 12/14/2019 9:47 AM 1974272 main-ori.exeAdd build flags Two ld parameters can be added when usin...

In a development environment, there might be multiple projects going on at the same time and they may require different development environments with different versions of build tool. In many programming languages, it is possible to have multiple versions of different build tool or development tool on a single environment. For example, there can be multiple JDKs, multiple versions of Ruby using RVM. For GoLang, there is a similar tool called GVM which can also be used to maintain multiple versions of Go in one single environment.In this post, we provide a mini guide on how to setup multiple ve...

In almost all mainstream programming languages, there is either built-in or third-party library to support parse JSON data because it is so popular for organizing and transferring data among different services. In GoLang, the built in json package also provides functions for marshalling and unmarshalling JSON data. Marshalling GoLang struct to a JSON string is relatively simple, just need to call json.Marshal(), it's a bit complicated to unmarshal an arbitrary JSON string into a GoLang struct object though. This post will try to walk through some scenarios of unmarshalling JSON string to GoLan...

IntroductionA set of user-defined functions (UDF) or utility functions are helpful to simplify our code and avoid repeating the same typing for daily analysis work. Previously, I saved all my R functions to a single R file. Whenever I want to use them, I can simply source the R file to import all functions. This is a simple but not perfect approach, especially when I want to check the documentation of certain functions. It was quite annoying that you can’t just type ?func to navigate to the help file. So, this is the main reason for me to write my own util package to ...

Fastjson just fixed a bug which might cause service down a few days ago. This bug is caused by some mishandling of special character \x which is an escaped character to indicate hexdecimal number. The impact of this bug would be big if the attacker constructs a malicious data which would cause the service down. The code which causes the issue is in com.alibaba.fastjson.parser.JSONLexerBase#scanString, when a JSON string is passed in, fastjson would parse the string character by character, when it finds the \x, it would try to process the following two characters automatically an...

In cases where a new Eclipse is installed or the location of the Java virtual machine binaries has been changed, you may face issue when launching Eclipse. The error would look like.And if you go to the location specified in the error message, there is no such path indeed. And when clicks OK, the program just exits. The issue here is that it tries to find the java.exe binary and launch the program but it failed to locate it and hence exits.To fix this, you first need to ensure you have Java installed on your system no matter it's a JRE or JDK. Then navigate to the Eclipse installation pat...

By default, GoLang doesn't provide the ECB mode cipher for DESede though there is CBC mode provided. In cases we need to encrypt/decrypt data with ECB mode, we need to implement those by ourselves. This mode is frequently used when encrypting/decrypting PIN block which is small block data less than 16 bytes.In this post, we will introduce how to implement the DESede/ECB/NoPadding algorithm in GoLang by using the existing cipher support. Here we will not cover how DESede works in detail, instead we will just cover the logic to make it work.Below is the sample code which can be used to encrypt/d...