Server side sessions

cmd/ratchetd/main.go

@@ -6,10 +6,14 @@ import (
 	"log/slog"
 	"net/http"
 	"os"
+	"time"
 
 	rdb "git.runcible.io/learning/ratchet/internal/database"
 	"git.runcible.io/learning/ratchet/internal/logging"
 	"git.runcible.io/learning/ratchet/internal/server"
+	"github.com/alexedwards/scs/sqlite3store"
+	"github.com/alexedwards/scs/v2"
+	_ "github.com/mattn/go-sqlite3"
 	// "git.runcible.io/learning/ratchet"
 	// ratchethttp "git.runcible.io/learning/ratchet/internal"
 )
@@ -43,11 +47,19 @@ func main() {
 	defer db.Close()
 
 	tc, err := server.InitTemplateCache()
+	if err != nil {
+		slog.Error(err.Error())
+		os.Exit(1)
+	}
 
+	// SessionManager
+	sm := scs.New()
+	sm.Store = sqlite3store.New(db)
+	sm.Lifetime = 12 * time.Hour
 	// Propagate build information to root package to share globally
 	// ratchet.Version = strings.TrimPrefix(version, "")
 	// ratchet.Commit = commit
-	server := server.NewRatchetServer(logger, tc, db)
+	server := server.NewRatchetServer(logger, tc, db, sm)
 
 	// START SERVING REQUESTS
 	slog.Debug("Herp dirp!")

go.mod

@@ -5,6 +5,7 @@ go 1.23.3
 require github.com/mattn/go-sqlite3 v1.14.24
 
 require (
+	github.com/alexedwards/scs/sqlite3store v0.0.0-20240316134038-7e11d57e8885 // indirect
 	github.com/alexedwards/scs/v2 v2.8.0 // indirect
 	github.com/go-playground/form/v4 v4.2.1 // indirect
 )

go.sum

@@ -1,7 +1,10 @@
+github.com/alexedwards/scs/sqlite3store v0.0.0-20240316134038-7e11d57e8885 h1:+DCxWg/ojncqS+TGAuRUoV7OfG/S4doh0pcpAwEcow0=
+github.com/alexedwards/scs/sqlite3store v0.0.0-20240316134038-7e11d57e8885/go.mod h1:Iyk7S76cxGaiEX/mSYmTZzYehp4KfyylcLaV3OnToss=
 github.com/alexedwards/scs/v2 v2.8.0 h1:h31yUYoycPuL0zt14c0gd+oqxfRwIj6SOjHdKRZxhEw=
 github.com/alexedwards/scs/v2 v2.8.0/go.mod h1:ToaROZxyKukJKT/xLcVQAChi5k6+Pn1Gvmdl7h3RRj8=
 github.com/go-playground/assert/v2 v2.0.1/go.mod h1:VDjEfimB/XKnb+ZQfWdccd7VUvScMdVu0Titje2rxJ4=
 github.com/go-playground/form/v4 v4.2.1 h1:HjdRDKO0fftVMU5epjPW2SOREcZ6/wLUzEobqUGJuPw=
 github.com/go-playground/form/v4 v4.2.1/go.mod h1:q1a2BY+AQUUzhl6xA/6hBetay6dEIhMHjgvJiGo6K7U=
+github.com/mattn/go-sqlite3 v1.14.6/go.mod h1:NyWgC/yNuGj7Q9rpYnZvas74GogHl5/Z4A/KQRfk6bU=
 github.com/mattn/go-sqlite3 v1.14.24 h1:tpSp2G2KyMnnQu99ngJ47EIkWVmliIizyZBfPrBWDRM=
 github.com/mattn/go-sqlite3 v1.14.24/go.mod h1:Uh1q+B4BYcTPb+yiD3kU8Ct7aC0hY9fxUwlHK0RXw+Y=

internal/server/handlers.go

@@ -10,11 +10,12 @@ import (
 
 	"git.runcible.io/learning/ratchet/internal/model"
 	"git.runcible.io/learning/ratchet/internal/validator"
+	"github.com/alexedwards/scs/v2"
 	"github.com/go-playground/form/v4"
 )
 
 // TODO function should accept and a pointer to an interface allowing for mocking in tests.
-func handleHome(logger *slog.Logger, tc *TemplateCache, snippetService *model.SnippetService) http.Handler {
+func handleHome(logger *slog.Logger, tc *TemplateCache, sm *scs.SessionManager, snippetService *model.SnippetService) http.Handler {
 	return http.HandlerFunc(
 		func(w http.ResponseWriter, r *http.Request) {
 			// Retrieve Snippets from DB
@@ -30,7 +31,7 @@ func handleHome(logger *slog.Logger, tc *TemplateCache, snippetService *model.Sn
 			// data := templateData{
 			// 	Snippets: snippets,
 			// }
-			data := newTemplateData()
+			data := newTemplateData(r, sm)
 			data.Snippets = snippets
 
 			renderTemplate(w, r, tc, http.StatusOK, "home.go.tmpl", data)
@@ -62,7 +63,7 @@ func handleHome(logger *slog.Logger, tc *TemplateCache, snippetService *model.Sn
 		})
 }
 
-func handleSnippetView(logger *slog.Logger, tc *TemplateCache, snippetService *model.SnippetService) http.Handler {
+func handleSnippetView(logger *slog.Logger, tc *TemplateCache, sm *scs.SessionManager, snippetService *model.SnippetService) http.Handler {
 	return http.HandlerFunc(
 		func(w http.ResponseWriter, r *http.Request) {
 			id, err := strconv.Atoi(r.PathValue("id"))
@@ -85,6 +86,15 @@ func handleSnippetView(logger *slog.Logger, tc *TemplateCache, snippetService *m
 				return
 			}
 
+			// Use the PopString() method to retrieve the value for the "flash" key.
+			// PopString() also deletes the key and value from the session data, so it
+			// acts like a one-time fetch. If there is no matching key in the session
+			// data this will return the empty string.
+
+			// See also GetInt, GetBool, GetBytes, GetTime etc.
+			// NOW DONE IN TEMPLATE DATA FUNC
+			// flash := sm.PopString(r.Context(), "flash")
+
 			// files := []string{
 			// 	"./ui/html/base.go.tmpl",
 			// 	"./ui/html/partials/nav.go.tmpl",
@@ -117,15 +127,16 @@ func handleSnippetView(logger *slog.Logger, tc *TemplateCache, snippetService *m
 			// data := templateData{
 			// 	Snippet: snippet,
 			// }
-			data := newTemplateData()
+			data := newTemplateData(r, sm)
 			data.Snippet = snippet
+			data.Flash = flash
 			renderTemplate(w, r, tc, http.StatusOK, "view.go.tmpl", data)
 		})
 }
 
-func handleSnippetCreateGet(tc *TemplateCache) http.Handler {
+func handleSnippetCreateGet(tc *TemplateCache, sm *scs.SessionManager) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		data := newTemplateData()
+		data := newTemplateData(r, sm)
 		// Initialize a new snippetCreateForm instance and pass it to the template.
 		// Notice how this is also a great opportunity to set any default or
 		// 'initial' values for the form --- here we set the initial value for the
@@ -140,7 +151,7 @@ func handleSnippetCreateGet(tc *TemplateCache) http.Handler {
 // snippetCreate handles display of the form used to create snippets
 //
 // curl -iL -d "" http://localhost:5001/snippet/create
-func handleSnippetCreatePost(logger *slog.Logger, tc *TemplateCache, formDecoder *form.Decoder, snippetService *model.SnippetService) http.Handler {
+func handleSnippetCreatePost(logger *slog.Logger, tc *TemplateCache, formDecoder *form.Decoder, sm *scs.SessionManager, snippetService *model.SnippetService) http.Handler {
 	return http.HandlerFunc(
 		func(w http.ResponseWriter, r *http.Request) {
 			// example of a custom header. Must be done before calling WriteHeader
@@ -242,7 +253,7 @@ func handleSnippetCreatePost(logger *slog.Logger, tc *TemplateCache, formDecoder
 			form.CheckField(validator.PermittedValue(form.Expires, 1, 7, 365), "expires", "this field cannot be blank")
 
 			if !form.Valid() {
-				data := newTemplateData()
+				data := newTemplateData(r, sm)
 				data.Form = form
 				renderTemplate(w, r, tc, http.StatusUnprocessableEntity, "create.go.tmpl", data)
 				return
@@ -264,6 +275,10 @@ func handleSnippetCreatePost(logger *slog.Logger, tc *TemplateCache, formDecoder
 			}
 			logger.Info(fmt.Sprintf("Inserted record. id: %d", id))
 
+			// Use the Put() method to add a string value ("Snippet successfully
+			// created!") and the corresponding key ("flash") to the session data.
+			sm.Put(r.Context(), "flash", "Snippet successfully created!")
+
 			http.Redirect(w, r, fmt.Sprintf("/snippet/view/%d", id), http.StatusSeeOther)
 		})
 }

internal/server/routes.go

@@ -6,6 +6,7 @@ import (
 	"net/http"
 
 	"git.runcible.io/learning/ratchet/internal/model"
+	"github.com/alexedwards/scs/v2"
 	"github.com/go-playground/form/v4"
 )
 
@@ -14,16 +15,17 @@ func addRoutes(mux *http.ServeMux,
 	tc *TemplateCache,
 	db *sql.DB,
 	fd *form.Decoder,
+	sm *scs.SessionManager,
 	snippetService *model.SnippetService) http.Handler {
 
 	// /{$} is used to prevent subtree path patterns from acting like a wildcard
 	// resulting in this route requiring an exact match on "/" only
 	// You can only include one HTTP method in a route pattern if you choose
 	// GET will match GET & HEAD http request methods
-	mux.Handle("GET /{$}", handleHome(logger, tc, snippetService))
-	mux.Handle("GET /snippet/view/{id}", handleSnippetView(logger, tc, snippetService))
-	mux.Handle("GET /snippet/create", handleSnippetCreateGet(tc))
-	mux.Handle("POST /snippet/create", handleSnippetCreatePost(logger, tc, fd, snippetService))
+	mux.Handle("GET /{$}", sm.LoadAndSave(handleHome(logger, tc, sm, snippetService))) // might be time to swith to github.com/justinas/alice dynamic chain
+	mux.Handle("GET /snippet/view/{id}", sm.LoadAndSave(handleSnippetView(logger, tc, sm, snippetService)))
+	mux.Handle("GET /snippet/create", sm.LoadAndSave(handleSnippetCreateGet(tc, sm)))
+	mux.Handle("POST /snippet/create", sm.LoadAndSave(handleSnippetCreatePost(logger, tc, fd, sm, snippetService)))
 	// mux.Handle("/something", handleSomething(logger, config))
 	// mux.Handle("/healthz", handleHealthzPlease(logger))
 	// mux.Handle("/", http.NotFoundHandler())

internal/server/server.go

@@ -6,6 +6,7 @@ import (
 	"net/http"
 
 	"git.runcible.io/learning/ratchet/internal/model"
+	"github.com/alexedwards/scs/v2"
 	"github.com/go-playground/form/v4"
 )
 
@@ -18,14 +19,16 @@ type RatchetServer struct {
 	snippetService *model.SnippetService
 	UserService    model.UserService
 	formDecoder    *form.Decoder
+	sessionManager *scs.SessionManager
 }
 
-func NewRatchetServer(logger *slog.Logger, tc *TemplateCache, db *sql.DB) *RatchetServer {
+func NewRatchetServer(logger *slog.Logger, tc *TemplateCache, db *sql.DB, sm *scs.SessionManager) *RatchetServer {
 	rs := new(RatchetServer)
 	rs.logger = logger
 	rs.snippetService = &model.SnippetService{DB: db}
 	rs.formDecoder = form.NewDecoder()
 	rs.templateCache = tc
+	rs.sessionManager = sm
 	// TODO implement middleware that disables directory listings
 	fileServer := http.FileServer(http.Dir("./ui/static/"))
 	router := http.NewServeMux()
@@ -35,7 +38,7 @@ func NewRatchetServer(logger *slog.Logger, tc *TemplateCache, db *sql.DB) *Ratch
 
 	// Mux Router implements the Handler interface. AKA it has a ServeHTTP receiver.
 	// SEE we can really clean things up by moving this into routes.go and handlers.go
-	wrappedMux := addRoutes(router, rs.logger, rs.templateCache, db, rs.formDecoder, rs.snippetService)
+	wrappedMux := addRoutes(router, rs.logger, rs.templateCache, db, rs.formDecoder, sm, rs.snippetService)
 	rs.Handler = CommonHeaderMiddleware(wrappedMux)
 	rs.Handler = RequestLoggingMiddleware(rs.Handler, logger)
 	rs.Handler = RecoveryMiddleware(rs.Handler)

internal/server/templates.go

@@ -10,6 +10,7 @@ import (
 	"time"
 
 	"git.runcible.io/learning/ratchet/internal/model"
+	"github.com/alexedwards/scs/v2"
 )
 
 // Define a templateData type to act as the holding structure for
@@ -21,11 +22,12 @@ type templateData struct {
 	Snippet     model.Snippet
 	Snippets    []model.Snippet
 	Form        any
+	Flash       string
 }
 
 // newTemplateData is useful to inject default values. Example CSRF tokens for forms.
-func newTemplateData() templateData {
-	return templateData{CurrentYear: time.Now().Year()}
+func newTemplateData(r *http.Request, sm *scs.SessionManager) templateData {
+	return templateData{CurrentYear: time.Now().Year(), Flash: sm.PopString(r.Context(), "flash")}
 }
 
 // TEMPLATE FUNCTIONS

ui/html/base.go.tmpl

@@ -15,6 +15,9 @@
         </header>
         {{template "nav" .}}
         <main>
+            {{with .Flash}}
+                <div class='flash'>{{.}}</div>
+            {{end}}
             {{template "main" .}}
         </main>
         <footer>Powered by <a href='https://golang.org/'>Go</a> in {{ .CurrentYear }}</footer>