# Static blog template engine implementation in Go *2017-12-26* Some days ago, I decided to start this blog, to put there all the thoughts and ideas that goes through my mind. After some research, I've found some interesting projects, but with a lot of features that I don't need to use. So I decided to write my own minimalistic static blog template engine with Go lang. This is how I made [blogo](https://github.com/arnaucube/blogo) the blog static template engine to do this blog. ### Static blog template engine? The main idea is to be able to write the blog posts in Markdown files, and with the template engine, output the HTML files ready to upload in the web hosting server. ## Structure What we wan to have in the input is: ``` /blogo /input /css mycss.css /img post01_image.png index.html postThumbTemplate.html post01.md post01thumb.md post02.md post02thumb.md ``` #### blogo.json This is the file that have the configuration that will be read by the Go script. ```json { "title": "my blog", "indexTemplate": "index.html", "postThumbTemplate": "postThumbTemplate.html", "posts": [ { "thumb": "post01thumb.md", "md": "post01.md" }, { "thumb": "post02thumb.md", "md": "post02.md" } ], "copyRaw": [ "css", "js" ] } ``` The *copyRaw* element, will be all the directories to copy raw to the output. #### index.html This is the file that will be used as the template for the main page and also for the posts pages. ```html [blogo-title]
[blogo-content]
``` As we can see, we just need to define the html file, and in the title define the *[blogo-title]*, and in the content place the *[blogo-content]*. #### postThumbTemplate.html This is the file where is placed the html box for each post that will be displayed in the main page. ```html
[blogo-index-post-template]
``` #### post01thumb.md ```markdown # Post 01 thumb This is the description of the Post 01 ``` #### post01.md ```markdown # Title of the Post 01 Hi, this is the content of the post '''js console.log("hello world"); ''' ``` ## Let's start to code As we have exposed, we want to develop a Go lang script that from some HTML template and the Markdown text files, generates the complete blog with the main page and all the posts. #### readConfig.go This is the file that reads the *blogo.json* file to get the blog configuration. ```go package main import ( "encoding/json" "io/ioutil" ) //Post is the struct for each post of the blog type Post struct { Thumb string `json:"thumb"` Md string `json:"md"` } //Config gets the config.json file into struct type Config struct { Title string `json:"title"` IndexTemplate string `json:"indexTemplate"` PostThumbTemplate string `json:"postThumbTemplate"` Posts []Post `json:"posts"` CopyRaw []string `json:"copyRaw"` } var config Config func readConfig(path string) { file, err := ioutil.ReadFile(path) check(err) content := string(file) json.Unmarshal([]byte(content), &config) } ``` #### files.go, the operations with files We will need some file operation functions, so we have placed all in this file. ```go package main import ( "io/ioutil" "os/exec" "strings" "github.com/fatih/color" ) func readFile(path string) string { dat, err := ioutil.ReadFile(path) if err != nil { color.Red(path) } check(err) return string(dat) } func writeFile(path string, newContent string) { err := ioutil.WriteFile(path, []byte(newContent), 0644) check(err) color.Green(path) } func getLines(text string) []string { lines := strings.Split(text, "\n") return lines } func concatStringsWithJumps(lines []string) string { var r string for _, l := range lines { r = r + l + "\n" } return r } func copyRaw(original string, destination string) { color.Green(original + " --> to --> " + destination) _, err := exec.Command("cp", "-rf", original, destination).Output() check(err) } ``` #### main.go To convert the HTML content to Markdown content, we will use https://github.com/russross/blackfriday ```go package main import ( "fmt" "strings" blackfriday "gopkg.in/russross/blackfriday.v2" ) const directory = "blogo-input" func main() { readConfig(directory + "/blogo.json") fmt.Println(config) // generate index page indexTemplate := readFile(directory + "/" + config.IndexTemplate) indexPostTemplate := readFile(directory + "/" + config.PostThumbTemplate) var blogoIndex string blogoIndex = "" for _, post := range config.Posts { mdpostthumb := readFile(directory + "/" + post.Thumb) htmlpostthumb := string(blackfriday.Run([]byte(mdpostthumb))) //put the htmlpostthumb in the blogo-index-post-template m := make(map[string]string) m["[blogo-index-post-template]"] = htmlpostthumb r := putHTMLToTemplate(indexPostTemplate, m) filename := strings.Split(post.Md, ".")[0] r = "" + r + "" blogoIndex = blogoIndex + r } //put the blogoIndex in the index.html m := make(map[string]string) m["[blogo-title]"] = config.Title m["[blogo-content]"] = blogoIndex r := putHTMLToTemplate(indexTemplate, m) writeFile("index.html", r) // generate posts pages for _, post := range config.Posts { mdcontent := readFile(directory + "/" + post.Md) htmlcontent := string(blackfriday.Run([]byte(mdcontent))) m := make(map[string]string) m["[blogo-title]"] = config.Title m["[blogo-content]"] = htmlcontent r := putHTMLToTemplate(indexTemplate, m) //fmt.Println(r) filename := strings.Split(post.Md, ".")[0] writeFile(filename+".html", r) } //copy raw fmt.Println("copying raw:") for _, dir := range config.CopyRaw { copyRaw(directory+"/"+dir, ".") } } func putHTMLToTemplate(template string, m map[string]string) string { lines := getLines(template) var resultL []string for _, line := range lines { inserted := false for k, v := range m { if strings.Contains(line, k) { //in the line, change [tag] with the content lineReplaced := strings.Replace(line, k, v, -1) resultL = append(resultL, lineReplaced) inserted = true } } if inserted == false { resultL = append(resultL, line) } } result := concatStringsWithJumps(resultL) return result } ``` ## Try it To try it, we need to compile the Go code: ``` > go build ``` And run it: ``` > ./blogo ``` Or we can just build and run to test: ``` > go run *.go ``` As the output, we will obtain the html pages with the content: - index.html ```html my blog

Post 01 thumb

This is the description of the Post 01

Post 02 thumb
``` - post01.html ```html my blog

Title of the Post 01

Hi, this is the content of the post

                console.log("hello world");
``` ## Conclusion In this post, we have seen how to develop a very minimalistic static blog template engine with Go. In fact, is the blog engine that I'm using for this blog. There are lots of blog template engines nowadays, but maybe we don't need sophisticated engine, and we just need a minimalistic one. In that case, we have seen how to develop one. The complete project code is able in https://github.com/arnaucube/blogo