feat(examples): add simple userbook realm

examples/gno.land/r/demo/pagination/gno.mod

@@ -0,0 +1,8 @@
+module gno.land/r/demo/pagination
+
+require (
+	gno.land/p/demo/avl v0.0.0-latest
+	gno.land/p/demo/mux v0.0.0-latest
+	gno.land/p/demo/testutils v0.0.0-latest
+	gno.land/p/demo/ufmt v0.0.0-latest
+)

examples/gno.land/r/demo/pagination/pagination.gno

@@ -0,0 +1,137 @@
+// This realm demonstrates a pagination system working with gnoweb
+// It keeps a slice of signed up addresses for efficient pagination
+package pagination
+
+import (
+	"std"
+	"strconv"
+
+	"gno.land/p/demo/avl"
+	"gno.land/p/demo/mux"
+	"gno.land/p/demo/ufmt"
+)
+
+type Signup struct {
+	account string
+	height  int64
+}
+
+// signups - keep a slice of signed up addresses efficient pagination
+var signups []Signup
+
+// tracker - keep track of who signed up
+var tracker *avl.Tree
+
+const pageSize = 20
+
+func init() {
+	tracker = avl.NewTree()
+	SignUp()
+}
+
+func SignUp() string {
+	caller := std.GetOrigCaller().String()
+	height := std.GetHeight()
+
+	_, exists := tracker.Get(caller)
+	if exists {
+		panic(caller + " is already signed up!")
+	}
+
+	tracker.Set(caller, struct{}{})
+	signup := Signup{
+		caller,
+		height,
+	}
+
+	signups = append(signups, signup)
+	return ufmt.Sprintf("%s signed up at block #%d!", signup.account, signup.height)
+}
+
+func GetSignedUpInRange(page, pageSize int) []Signup {
+	if page < 1 {
+		panic("page number cannot be less than 1")
+	}
+
+	if pageSize < 1 || pageSize >= 50 {
+		panic("page size must be between 1 and 50")
+	}
+
+	// Pagination
+	// Calculate indexes
+	startIndex := (page - 1) * pageSize
+	endIndex := startIndex + pageSize
+
+	// If page does not contain any posts
+	if startIndex >= len(signups) {
+		return nil
+	}
+
+	// If page contains fewer posts than the page size
+	if endIndex > len(signups) {
+		endIndex = len(signups)
+	}
+
+	return signups[startIndex:endIndex]
+}
+
+func renderHelper(res *mux.ResponseWriter, req *mux.Request) {
+	totalSignups := len(signups)
+
+	res.Write("# Welcome to Gno.land!\n\n")
+	res.Write(ufmt.Sprintf("## Signed up users (%d):\n\n", totalSignups))
+
+	page, err := strconv.Atoi(req.GetVar("number"))
+	if err != nil {
+		page = 1 // render first page on bad input
+	}
+
+	if totalSignups == 0 {
+		res.Write("No users are signed up currently.")
+		return
+	}
+
+	fetchedSignups := GetSignedUpInRange(page, pageSize)
+	if totalSignups == 0 {
+		res.Write("No users on this page\n\n")
+	}
+
+	pageStartIndex := pageSize * (page - 1)
+	for i, signup := range fetchedSignups {
+		out := ufmt.Sprintf("#### User #%d - %s - signed up at Block #%d\n", pageStartIndex+i, signup.account, signup.height)
+		res.Write(out)
+	}
+
+	res.Write("---\n\n")
+
+	latestSignup := signups[totalSignups-1]
+	res.Write(ufmt.Sprintf("Latest signup: %s at Block #%d\n\n", latestSignup.account, latestSignup.height))
+
+	res.Write("---\n\n")
+
+	res.Write(ufmt.Sprintf("You're viewing page #%d\n\n", page))
+
+	var prevPage string
+	var nextPage string
+	if page < 2 {
+		prevPage = ""
+	} else {
+		prevPage = ufmt.Sprintf("[Previous page](/r/demo/pagination:page/%d)\n\n", page-1)
+	}
+
+	if len(fetchedSignups) >= pageSize {
+		nextPage = ufmt.Sprintf("[Next page](/r/demo/pagination:page/%d)\n\n", page+1)
+	} else {
+		nextPage = ""
+	}
+
+	res.Write(prevPage)
+	res.Write(nextPage)
+}
+
+func Render(path string) string {
+	router := mux.NewRouter()
+	router.HandleFunc("", renderHelper)
+	router.HandleFunc("page/{number}", renderHelper)
+	return router.Render(path)
+}

examples/gno.land/r/demo/pagination/pagination_test.gno

@@ -0,0 +1,61 @@
+package pagination
+
+import (
+	"std"
+	"testing"
+
+	"gno.land/p/demo/testutils"
+	"gno.land/p/demo/ufmt"
+)
+
+func TestRenderHome(t *testing.T) {
+	// Sign up 50 users
+	for i := 0; i < 50; i++ {
+		addrName := ufmt.Sprintf("test%d", i)
+		caller := testutils.TestAddress(addrName)
+		std.TestSetOrigCaller(caller)
+		SignUp()
+	}
+
+	render := Render("")
+
+	expected := `# Welcome to Gno.land!
+
+## Signed up users (51):
+
+#### User #0 - g1wymu47drhr0kuq2098m792lytgtj2nyx77yrsm - signed up at Block #123
+#### User #1 - g1w3jhxapsta047h6lta047h6lta047h6l2jx7pq - signed up at Block #123
+#### User #2 - g1w3jhxap3ta047h6lta047h6lta047h6l4mfnm7 - signed up at Block #123
+#### User #3 - g1w3jhxapjta047h6lta047h6lta047h6laqcyu4 - signed up at Block #123
+#### User #4 - g1w3jhxapnta047h6lta047h6lta047h6lzfhfxt - signed up at Block #123
+#### User #5 - g1w3jhxap5ta047h6lta047h6lta047h6ldlnrjr - signed up at Block #123
+#### User #6 - g1w3jhxap4ta047h6lta047h6lta047h6ljkuwga - signed up at Block #123
+#### User #7 - g1w3jhxapkta047h6lta047h6lta047h6l6dde0k - signed up at Block #123
+#### User #8 - g1w3jhxaphta047h6lta047h6lta047h6l9yz54g - signed up at Block #123
+#### User #9 - g1w3jhxapcta047h6lta047h6lta047h6lyg9dwx - signed up at Block #123
+#### User #10 - g1w3jhxapeta047h6lta047h6lta047h6lmp2q5c - signed up at Block #123
+#### User #11 - g1w3jhxap3xp047h6lta047h6lta047h6l0pgx4l - signed up at Block #123
+#### User #12 - g1w3jhxap3x9047h6lta047h6lta047h6ls3mqfl - signed up at Block #123
+#### User #13 - g1w3jhxap3xf047h6lta047h6lta047h6lcg82yl - signed up at Block #123
+#### User #14 - g1w3jhxap3xd047h6lta047h6lta047h6l8c5vcl - signed up at Block #123
+#### User #15 - g1w3jhxap3x3047h6lta047h6lta047h6lgnk77l - signed up at Block #123
+#### User #16 - g1w3jhxap3x4047h6lta047h6lta047h6lhr9czl - signed up at Block #123
+#### User #17 - g1w3jhxap3xe047h6lta047h6lta047h6ll6ej0l - signed up at Block #123
+#### User #18 - g1w3jhxap3xa047h6lta047h6lta047h6lq225nl - signed up at Block #123
+#### User #19 - g1w3jhxap38p047h6lta047h6lta047h6lac9qrr - signed up at Block #123
+---
+
+Latest signup: g1w3jhxap589047h6lta047h6lta047h6l6vvkk7 at Block #123
+
+---
+
+You're viewing page #1
+
+[Next page](/r/demo/pagination:page/2)
+
+`
+
+	if render != expected {
+		t.Fatalf("got %s, expected %s", render, expected)
+	}
+}