Go

Intro Hi Folks. This is a follow up on my previous post about Google Sign-In. In this post we will discover what to do with the information retrieved in the first encounter, which you can find here: Google Sign-In Part 1. Forewords The Project Everything I did in the first post, and that I’m going to do in this example, can be found in this project: Google-OAuth-Go-Sample. Just to recap, we left off previously on the point where we successfully obtained information about the user, with a secure token and a session initiated with them. Google nicely enough provided us with some details which we can use. This information was in JSON format and looked something like this: ...

Update: This post ignored the fact that this works for utf-8 characters only. Characters which are stored on more than 1 byte will cause trouble. Look at this Effective Go Example. for pos, char := range "日本\x80語" { // \x80 is an illegal UTF-8 encoding fmt.Printf("character %#U starts at byte position %d\n", char, pos) } Prints: character U+65E5 '日' starts at byte position 0 character U+672C '本' starts at byte position 3 character U+FFFD '�' starts at byte position 6 character U+8A9E '語' starts at byte position 7 Keep this in mind when working with strings. ...

Quick reminder. If you have a never changing regex in Go, do NOT put it into a frequently called function. ALWAYS put it into a global variable. I’ll show you why. Benchmark for code with a variable in a frequently called function: BenchmarkNumber-8 30000 41633 ns/op BenchmarkAreaCode-8 50000 27736 ns/op BenchmarkFormat-8 50000 29263 ns/op PASS ok _/phone-number 5.110s Benchmark for code with the same variable outside in a global scope: BenchmarkNumber-8 300000 5618 ns/op BenchmarkAreaCode-8 500000 3884 ns/op BenchmarkFormat-8 300000 4696 ns/op PASS ok _/phone-number 5.197s Notice the magnitude change in ns/op! That’s something to keep an eye out for. ...

Hi folks. Today, I would like to write up a step - by - step guide with a sample web app on how to do Google Sign-In and authorization. ...

Hi Folks. So Wercker was not working. After a minor modification it seems to be okay now. The config file needed for it to work looks like this: box: golang build: steps: - arjen/hugo-build: theme: redlounge deploy: steps: - install-packages: packages: git - leipert/git-push: gh_oauth: $GIT_TOKEN repo: skarlso/skarlso.github.io branch: master basedir: public The modification is the box type to golang and removed ssh-client from packages. ...

Basics This is a wercker Test.

Basics This is a wercker Test.

Basics Hello folks. This will be a quick post about how to do CORS with jQuery, Gin in Go with a very simple ajax GET and Json. I’m choosing JSON here because basically I don’t really like JSONP. And actually, it’s not very complicated to do CORS, it’s just hidden enough so that it doesn’t become transparent. First, what is CORS? It’s Cross-Platform Resource Sharing. It has been invented so that without your explicit authorization in the header of a request, Javascript can’t reach outside of your domain and be potentially harmful to your visitors. ...

Hello folks. I wanted to share with you my tale of working through the problems with Advent Of Code. It is a nice tale and there are a few things I learned from it, especially in Go, since I used that solve all of the problems. So, let’s get started. Solving the problems The most important lesson I learned while doing these exercises was, how to solve these problems. A couple of them were simple enough to not have to over think it, but most of them got very tricky. I could have gone with a brute force attempt, but as we see later, that wasn’t always a very good solution. And people who used that, actually just got lucky finding their solutions. ...

Hello Folks. Today I would like to share with you my little tale of refactoring my solution to Advent Of Code Day 13. It’s a lovely tale of action, adventure, drama, and comedy. Let’s being with my first iteration of the problem. package main import ( "bufio" "fmt" "math" "os" "strconv" "strings" "github.com/skarlso/goutils/arrayutils" ) var seatingCombinations = make([][]string, 0) var table = make(map[string][]map[string]int) var keys = make([]string, 0) //Person a person type Person struct { // neighbour *Person name string like int } func main() { file, _ := os.Open("input.txt") defer file.Close() scanner := bufio.NewScanner(file) for scanner.Scan() { line := scanner.Text() split := strings.Split(line, " ") like, _ := strconv.Atoi(split[3]) //If lose -> * -1 if split[2] == "lose" { like *= -1 } table[split[0]] = append(table[split[0]], map[string]int{strings.Trim(split[10], "."): like}) if !arrayutils.ContainsString(keys, split[0]) { keys = append(keys, split[0]) } } generatePermutation(keys, len(keys)) fmt.Println("Best seating efficiency:", calculateSeatingEfficiancy()) } func generatePermutation(s []string, n int) { if n == 1 { news := make([]string, len(s)) copy(news, s) seatingCombinations = append(seatingCombinations, news) } for i := 0; i < n; i++ { s[i], s[n-1] = s[n-1], s[i] generatePermutation(s, n-1) s[i], s[n-1] = s[n-1], s[i] } } func calculateSeatingEfficiancy() int { bestSeating := math.MinInt64 for _, v := range seatingCombinations { calculatedOrder := 0 for i := range v { left := (i - 1) % len(v) //This is to work around the fact that in Go //modulo of a negative number will not return a positive number. //So -1 % 4 will not return 3 but -1. In that case we add length. if left < 0 { left += len(v) } right := (i + 1) % len(v) // fmt.Printf("Left: %d; Right: %d\n", left, right) leftLike := getLikeForTargetConnect(v[i], v[left]) rightLike := getLikeForTargetConnect(v[i], v[right]) // fmt.Printf("Name: %s; Left:%d; Right:%d\n", v[i], leftLike, rightLike) calculatedOrder += leftLike + rightLike } // fmt.Printf("Order for: %v; Calc:%d\n", v, calculatedOrder) if calculatedOrder > bestSeating { bestSeating = calculatedOrder } } return bestSeating } func getLikeForTargetConnect(name string, neighbour string) int { neighbours := table[name] for _, t := range neighbours { if v, ok := t[neighbour]; ok { return v } } return 0 } This is quiet large. And takes a bit of explaining. So what is happening here? We are putting the names which correspond with numbers and neighbours into a map which has a map as a value. The map contains seating information for a person. For example, next to Alice, a bunch of people can sit, and they have a certain relationship to Alice, represented by a number. ...