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|
package main
import (
_ "embed"
"encoding/gob"
"html/template"
"io"
"log"
"net/http"
"os"
"os/signal"
"runtime/debug"
)
// File for persistent storage
var DataFilename = "ideas.data"
// Version number used for debugging compatibility with the .data file
var Version string
// layout for how the date should be output in html
var DateLayout string = "02/01/2006 on 15:04"
// template for listing out the ideas, should be bundled inside the executable
//
//go:embed ideas.html
var ideas_html string
var data Store
// ToDo's
// - [ ] Add a post
// - [ ] Remove a post
// - [ ] work with funcmaps in templates
// - [ ] Put a reaction on a post
// - [x] Store ideas to a file (encoder/gob)
// - [x] Change the date format printing
// Represents an idea
// CreatedAt is a formatted date string
// out of 5 rating of the idea
// formatted time string with DateLayout
type Idea struct {
Title string
Description string
Author string
CreatedAt string
}
// Data needed through the programm, this data is written to DataFilename for persistent storage
// Is also the format for the Data file
type Store struct {
Version string
Ideas []Idea
}
func GetVersion() string {
buildinfo, ok := debug.ReadBuildInfo()
if !ok {
log.Fatalln("Could not read buildinfo to know package version.")
}
return buildinfo.Main.Version
}
func main() {
Version = GetVersion()
// Create a .data file in the cache directory and decode eventual ideas from it
{
p := os.Getenv("XDG_CACHE_HOME")
// TODO: remove for testing
p = ""
if p == "" {
p = "."
}
DataFilename = p + "/" + DataFilename
f, err := os.OpenFile(DataFilename, os.O_RDONLY|os.O_CREATE, 0666)
if err != nil {
log.Fatalln("Error while opening data file:", err)
}
dec := gob.NewDecoder(f)
if err := dec.Decode(&data); err != io.EOF && err != nil {
log.Fatalln("Error while decoding ideas:", err)
}
log.Println(data)
if data.Version != Version {
log.Fatalf("Version mismatch for datafile@%s != package@%s\n", data.Version, Version)
}
log.Printf("Imported @%s: %d ideas\n", data.Version, len(data.Ideas))
if err := f.Close(); err != nil {
log.Fatalln("Error while closing file:", err)
}
}
// Handle SIGINT
// On program exit it should write all its data to the datafile
// TODO: Instead of recreating the file the new ideas should be appended, a way to achieve this would be that every time a new idea is added it is appended to the file, this way there is no need to ensure this.
go func() {
c := make(chan os.Signal, 1)
signal.Notify(c, os.Interrupt)
<-c
f, err := os.Create(DataFilename)
if err != nil {
log.Fatalln(err)
}
defer f.Close()
enc := gob.NewEncoder(f)
if err := enc.Encode(data); err != nil {
log.Fatalln(err)
}
log.Println("data saved.")
os.Exit(0)
}()
tmpl, err := template.New("ideas_html").Parse(ideas_html)
if err != nil {
log.Fatalln(err)
}
http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
tmpl.Execute(w, data)
})
log.Println("Listening on http://localhost:8080")
err = http.ListenAndServe(":8080", nil)
if err != nil {
log.Fatalln(err)
}
}
|
