feat(examples): add simple userbook realm

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

@@ -0,0 +1,8 @@
+module gno.land/r/demo/userbook
+
+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/userbook/userbook.gno

@@ -0,0 +1,153 @@
+// This realm demonstrates a small userbook system working with gnoweb
+package userbook
+
+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
+	router  *mux.Router
+)
+
+const (
+	defaultPageSize = 20
+	pathArgument    = "number"
+	subPath         = "page/{" + pathArgument + "}"
+)
+
+func init() {
+	// Set up tracker tree
+	tracker = avl.NewTree()
+
+	// Set up route handling
+	router = mux.NewRouter()
+	router.HandleFunc("", renderHelper)
+	router.HandleFunc(subPath, renderHelper)
+
+	// Sign up the deployer
+	SignUp()
+}
+
+func SignUp() string {
+	// Get transaction caller
+	caller := std.PrevRealm().Addr().String()
+	height := std.GetHeight()
+
+	if _, exists := tracker.Get(caller); exists {
+		panic(caller + " is already signed up!")
+	}
+
+	tracker.Set(caller, struct{}{})
+	signup := Signup{
+		caller,
+		height,
+	}
+
+	signups = append(signups, signup)
+	return ufmt.Sprintf("%s added to userbook up at block #%d!", signup.account, signup.height)
+}
+
+func GetSignupsInRange(page, pageSize int) ([]Signup, int) {
+	if page < 1 {
+		panic("page number cannot be less than 1")
+	}
+
+	if pageSize < 1 || pageSize > 50 {
+		panic("page size must be from 1 to 50")
+	}
+
+	// Pagination
+	// Calculate indexes
+	startIndex := (page - 1) * pageSize
+	endIndex := startIndex + pageSize
+
+	// If page does not contain any users
+	if startIndex >= len(signups) {
+		return nil, -1
+	}
+
+	// If page contains fewer users than the page size
+	if endIndex > len(signups) {
+		endIndex = len(signups)
+	}
+
+	return signups[startIndex:endIndex], endIndex
+}
+
+func renderHelper(res *mux.ResponseWriter, req *mux.Request) {
+	totalSignups := len(signups)
+	res.Write("# Welcome to UserBook!\n\n")
+
+	// Get URL parameter
+	page, err := strconv.Atoi(req.GetVar("number"))
+	if err != nil {
+		page = 1 // render first page on bad input
+	}
+
+	// Fetch paginated signups
+	fetchedSignups, endIndex := GetSignupsInRange(page, defaultPageSize)
+	// Handle empty page case
+	if len(fetchedSignups) == 0 {
+		res.Write("No users on this page!\n\n")
+		res.Write("---\n\n")
+		res.Write("[Back to Page #1](/r/demo/userbook:page/1)\n\n")
+		return
+	}
+
+	// Write page title
+	res.Write(ufmt.Sprintf("## UserBook - Page #%d:\n\n", page))
+
+	// Write signups
+	pageStartIndex := defaultPageSize * (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")
+
+	// Write UserBook info
+	latestSignupIndex := totalSignups - 1
+	res.Write(ufmt.Sprintf("#### Total users: %d\n", totalSignups))
+	res.Write(ufmt.Sprintf("#### Latest signup: User #%d at Block #%d\n", latestSignupIndex, signups[latestSignupIndex].height))
+
+	res.Write("---\n\n")
+
+	// Write page number
+	res.Write(ufmt.Sprintf("You're viewing page #%d", page))
+
+	// Write navigation buttons
+	var prevPage string
+	var nextPage string
+	// If we are on any page that is not the first page
+	if page > 1 {
+		prevPage = ufmt.Sprintf(" - [Previous page](/r/demo/userbook:page/%d)", page-1)
+	}
+
+	// If there are more pages after the current one
+	if endIndex < totalSignups {
+		nextPage = ufmt.Sprintf(" - [Next page](/r/demo/userbook:page/%d)\n\n", page+1)
+	}
+
+	res.Write(prevPage)
+	res.Write(nextPage)
+}
+
+func Render(path string) string {
+	return router.Render(path)
+}

examples/gno.land/r/demo/userbook/userbook_test.gno

@@ -0,0 +1,79 @@
+package userbook
+
+import (
+	"std"
+	"strings"
+	"testing"
+
+	"gno.land/p/demo/testutils"
+	"gno.land/p/demo/ufmt"
+)
+
+func TestRender(t *testing.T) {
+	// Sign up 20 users + deployer
+	for i := 0; i < 20; i++ {
+		addrName := ufmt.Sprintf("test%d", i)
+		caller := testutils.TestAddress(addrName)
+		std.TestSetOrigCaller(caller)
+		SignUp()
+	}
+
+	testCases := []struct {
+		name                  string
+		nextPage              bool
+		prevPage              bool
+		path                  string
+		expectedNumberOfUsers int
+	}{
+		{
+			name:                  "1st page render",
+			nextPage:              true,
+			prevPage:              false,
+			path:                  "page/1",
+			expectedNumberOfUsers: 20,
+		},
+		{
+			name:                  "2nd page render",
+			nextPage:              false,
+			prevPage:              true,
+			path:                  "page/2",
+			expectedNumberOfUsers: 1,
+		},
+		{
+			name:                  "Invalid path render",
+			nextPage:              true,
+			prevPage:              false,
+			path:                  "page/invalidtext",
+			expectedNumberOfUsers: 20,
+		},
+		{
+			name:                  "Empty Page",
+			nextPage:              false,
+			prevPage:              false,
+			path:                  "page/1000",
+			expectedNumberOfUsers: 0,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			got := Render(tc.path)
+			numUsers := countUsers(got)
+
+			if tc.prevPage && !strings.Contains(got, "Previous page") {
+				t.Fatalf("expected to find Previous page, didn't find it")
+			}
+			if tc.nextPage && !strings.Contains(got, "Next page") {
+				t.Fatalf("expected to find Next page, didn't find it")
+			}
+
+			if tc.expectedNumberOfUsers != numUsers {
+				t.Fatalf("expected %d, got %d users", tc.expectedNumberOfUsers, numUsers)
+			}
+		})
+	}
+}
+
+func countUsers(input string) int {
+	return strings.Count(input, "#### User #")
+}