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Golang Flash demo using cookies - recreate the Flask Flash library using Golang and HTMX and make life easier.
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| <html> | |
| <head> | |
| <script src="https://unpkg.com/[email protected]"></script> | |
| <script src="https://cdn.tailwindcss.com"></script> | |
| <title>Template Fragment Example</title> | |
| </head> | |
| <body> | |
| <div hx-get="/notifications" hx-trigger="load" hx-swap="outerHTML"><!-- I GET REPLACED --></div> | |
| <h1>Template Fragment Example</h1> | |
| <p> | |
| This page demonstrates how to create and serve | |
| <a href="https://htmx.org/essays/template-fragments/" | |
| >template fragments</a | |
| > | |
| using the | |
| <a href="https://pkg.go.dev/text/template">built-in template package</a> | |
| in Go. | |
| </p> | |
| <p> | |
| This is accomplished by using the "block" action in the template, which | |
| lets you define and execute a sub-template in a single step. | |
| </p> | |
| <!-- Here's the fragment. We can target it by executing the "buttonOnly" template. --> | |
| {{block "buttonOnly" .}} | |
| <button | |
| hx-get="/?counter={{.next}}&template=buttonOnly" | |
| hx-swap="outerHTML" | |
| > | |
| This Button Has Been Clicked {{.counter}} Times | |
| </button> | |
| {{end}} | |
| </body> | |
| </html> |
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| package main | |
| import ( | |
| "bytes" | |
| "encoding/base64" | |
| "encoding/gob" | |
| "log" | |
| "net/http" | |
| "time" | |
| ) | |
| type Flash struct { | |
| Type string // Warning | Success | Info | |
| Title string | |
| Content string | |
| } | |
| func init() { | |
| gob.Register(&Flash{}) | |
| } | |
| func SetFlash(w http.ResponseWriter, flashType string, title string, content string) { | |
| // Initialize a buffer to hold the gob data. | |
| var buf bytes.Buffer | |
| f := Flash{ | |
| Type: flashType, | |
| Title: title, | |
| Content: content, | |
| } | |
| err := gob.NewEncoder(&buf).Encode(&f) | |
| if err != nil { | |
| log.Println(err) | |
| http.Error(w, "Internal Server Error", http.StatusInternalServerError) | |
| return | |
| } | |
| enc := base64.URLEncoding.EncodeToString(buf.Bytes()) | |
| c := &http.Cookie{Name: "flash", Value: enc} | |
| http.SetCookie(w, c) | |
| } | |
| func GetFlash(w http.ResponseWriter, r *http.Request) (Flash, error) { | |
| var f Flash | |
| c, err := r.Cookie("flash") | |
| if err != nil { | |
| switch err { | |
| case http.ErrNoCookie: | |
| return f, nil | |
| default: | |
| return f, err | |
| } | |
| } | |
| // No point worrying about bad data. Just move on past. | |
| uDec, _ := base64.URLEncoding.DecodeString(c.Value) | |
| if err := gob.NewDecoder(bytes.NewReader(uDec)).Decode(&f); err != nil { | |
| log.Println(err) | |
| http.Error(w, "Internal Server Error", http.StatusInternalServerError) | |
| return Flash{}, err | |
| } | |
| // "Delete" by setting expired cookie | |
| http.SetCookie(w, &http.Cookie{Name: "flash", MaxAge: -1, Expires: time.Unix(1, 0)}) | |
| return f, nil | |
| } |
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| <div | |
| class="fixed top-0 z-10 flex w-full flex-col items-center justify-center space-y-2" | |
| > | |
| {{ if eq .Type "Warning" }} | |
| <div | |
| class="border-l-8 border-orange-500 bg-orange-100 p-4 text-sm text-orange-700 shadow-lg" | |
| role="alert" | |
| style="cursor: pointer" | |
| onclick="this.remove()" | |
| > | |
| <p class="font-bold">{{ .Title }}</p> | |
| <p>{{ .Content }}</p> | |
| </div> | |
| {{end}} {{ if eq .Type "Success" }} | |
| <div | |
| class="border-l-8 border-green-500 bg-green-100 p-4 text-sm text-green-600 shadow-lg" | |
| role="alert" | |
| style="cursor: pointer" | |
| onclick="this.remove()" | |
| > | |
| <p class="font-bold">{{ .Title }}</p> | |
| <p>{{ .Content }}</p> | |
| </div> | |
| {{end}} {{ if eq .Type "Info" }} | |
| <div | |
| class="border-l-8 border-blue-500 bg-blue-100 p-4 text-sm text-blue-600 shadow-lg" | |
| role="alert" | |
| style="cursor: pointer" | |
| onclick="this.remove()" | |
| > | |
| <p class="font-bold">{{ .Title }}</p> | |
| <p>{{ .Content }}</p> | |
| </div> | |
| {{end}} | |
| </div> |
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| ... | |
| // Flash demo | |
| unprotectedRouter.HandleFunc("/notifications", func(w http.ResponseWriter, r *http.Request) { | |
| var tpl = template.Must(template.ParseFiles("templates/flash.tmpl.html")) | |
| f, err := GetFlash(w, r) | |
| if err != nil { | |
| log.Println("Error received", err) | |
| } | |
| tpl.Execute(w, f) | |
| }) | |
| unprotectedRouter.HandleFunc("/test", func(w http.ResponseWriter, r *http.Request) { | |
| var tpl = template.Must(template.ParseFiles("templates/login.tmpl.html")) | |
| SetFlash(w, "Warning", "This is a warning", "This is the contents - i was set via Flash()") | |
| tpl.Execute(w, nil) | |
| }) | |
| unprotectedRouter.HandleFunc("/test1", func(w http.ResponseWriter, r *http.Request) { | |
| var tpl = template.Must(template.ParseFiles("templates/demo.tmpl.html")) | |
| tpl.Execute(w, nil) | |
| }) | |
| ... |
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https://gist.github.com/17twenty/60f501a4556a6ed006283a4d0e7ca890#file-main-go-L15 this could either be a simple template setting the flash OR you set the flash and redirect to another and have the flash show on that page.