refac: article title rules are the same in the API request and the domain; an invalid title returns 400 instead of 500

api/handlers/article/articleHandler.go

@@ -23,7 +23,7 @@ type Handler struct {
 }
 
 type PostArticle struct {
-	Title string `json:"title" validate:"required,min=3,max=50"`
+	Title string `json:"title" validate:"required,min=3,max=200"`
 	Body  string `json:"body" validate:"required,max=10000"`
 }
 
@@ -81,6 +81,10 @@ func (h *Handler) PostArticle(w http.ResponseWriter, r *http.Request) {
 		Body:  localArticle.Body,
 	})
 	if err != nil {
+		if errors.Is(err, domain.ErrInvalidTitle) {
+			http.Error(w, apperr.ArticleTitleErrorMessage, http.StatusBadRequest)
+			return
+		}
 		http.Error(w, "Failed to create article", http.StatusInternalServerError)
 		return
 	}

api/pkg/apperr/messages.go

@@ -4,3 +4,4 @@ const LogsErrorMessage = "Access to the requested resource is forbidden due to i
 const BodyErrorMessage = "The request cannot be processed due to a mismatch in the format of the body."
 const IdUint32ErrorMessage = "The server expects the ID to be in the format of an unsigned 32-bit integer (uint32)."
 const ArticleNotFoundErrorMessage = "Article not found"
+const ArticleTitleErrorMessage = "Article title must be between 3 and 200 characters."

features/article_title_rules.feature

@@ -0,0 +1,85 @@
+Feature: The article title rule is the same in the request and the domain
+
+  As the maintainer of RenewCMS
+  I want PostArticle's title validation and article.CreateArticle's title validation to
+  enforce the identical rule, counted the identical way
+  So that a title the request layer accepts can never be rejected by the domain as a
+  surprise 500, and a domain title rejection that does happen is always reported as a
+  400 with a client-facing apperr message instead of a raw 500
+
+  Background:
+    Given internal/domain/article defines the sentinel article.ErrInvalidTitle
+    And CreateArticleUseCase.CreateArticle rejects a title whose length, counted with
+      utf8.RuneCountInString (runes, not bytes), is below 3 or above 200, returning
+      article.ErrInvalidTitle and storing nothing
+    And api/handlers/article/articleHandler.go's PostArticle.Title carries
+      validate:"required,min=3,max=200", and go-playground/validator's min/max on a
+      string already count runes with utf8.RuneCountInString, so the request tag and the
+      domain check now agree on both the bound (3-200) and the unit (runes)
+    And api/pkg/apperr defines ArticleTitleErrorMessage as "Article title must be
+      between 3 and 200 characters.", a client-facing string distinct from both the raw
+      validator error text and "Failed to create article"
+    And Handler.PostArticle maps errors.Is(err, article.ErrInvalidTitle) from
+      CreateArticleUseCase.CreateArticle to a 400 response with body
+      apperr.ArticleTitleErrorMessage; any other error from CreateArticle still answers
+      500 with body "Failed to create article"
+    And POST /v1/article/ sits behind the jwtauth Verifier and Authenticator group and
+      requires a valid jwt cookie
+    And UpdateArticleUseCase exposes only UpdateBody, AddImage and UpdateIsOnline; no
+      route or use case updates an article's title after creation, so this feature only
+      concerns article creation
+
+  Scenario Outline: CreateArticle now measures title length in runes, not bytes
+    Given an empty article repository fake
+    When CreateArticle is called with a title made of <rune_count> repetitions of the
+      4-byte rune "😀" and a body "Some body text"
+    Then the result is <outcome>
+
+    Examples:
+      | rune_count | outcome                          |
+      | 2          | ErrInvalidTitle, nothing stored  |
+      | 3          | created                          |
+      | 200        | created                          |
+      | 201        | ErrInvalidTitle, nothing stored  |
+
+  Scenario Outline: POST /v1/article/ enforces the same 3-200 rune boundary over HTTP
+    Given a valid jwt cookie for a user with id 1
+    When the client sends POST /v1/article/ with that cookie, a title of <length> ASCII
+      characters and a body "Some body text"
+    Then the response status is <status>
+    And <storage_effect>
+
+    Examples:
+      | length | status | storage_effect          |
+      | 2      | 400    | not created             |
+      | 3      | 201    | created, is_online false |
+      | 200    | 201    | created, is_online false |
+      | 201    | 400    | not created              |
+
+  Scenario: A 200-rune multibyte title is accepted end to end over HTTP
+    Given a valid jwt cookie for a user with id 1
+    When the client sends POST /v1/article/ with that cookie, a title made of 200
+      repetitions of the 4-byte rune "😀" (200 runes, 800 bytes) and a body
+      "Some body text"
+    Then the response status is 201
+    And the response body is the created article's JSON with that title
+
+  Scenario: The handler maps a domain title rejection to 400, not 500
+    Given a valid jwt cookie for a user with id 1
+    And the article repository fake is configured so its next Create call returns
+      article.ErrInvalidTitle directly, standing in for any layer beneath the use
+      case's own check rejecting the title with that same sentinel
+    When the client sends POST /v1/article/ with that cookie, title "Valid Title" and
+      body "Some body text" (both already satisfying PostArticle's own validate tags)
+    Then the response status is 400
+    And the response body is the text apperr.ArticleTitleErrorMessage
+    And the response body is not "Failed to create article"
+
+  Scenario: A non-title repository failure during creation still answers 500
+    Given a valid jwt cookie for a user with id 1
+    And the article repository fake is configured to fail on its next Create call with
+      a generic repository error, not article.ErrInvalidTitle
+    When the client sends POST /v1/article/ with that cookie, title "Valid Title" and
+      body "Some body text"
+    Then the response status is 500
+    And the response body is the text "Failed to create article"

features/article_title_rules.qa.md

@@ -0,0 +1,76 @@
+# QA procedure: article_title_rules
+
+Package: `test` (black-box, alongside `article_test.go` / `use_case_baseline_test.go` /
+`not_found_errors_test.go` / the hasher-domain-interface tests).
+
+## Fakes needed
+1. Extend `mockArticleRepo` (`test/article_test.go`) / its shared `failSwitch`
+   (`test/fakes_common.go`) so a configured failure can return a specific error, not
+   only the generic `errRepositoryFailure`. Today `failSwitch.trigger` always returns
+   the same sentinel; add a way to say "the next call to `Create` returns
+   `article.ErrInvalidTitle`" specifically, distinct from "the next call to `Create`
+   returns a generic repository error" (e.g. a `failNextWith(method string, err error)`
+   on `failSwitch`, keeping `errRepositoryFailure` as the default so existing
+   generic-failure tests don't change).
+2. Add a `createCalled` flag (or equivalent) to `mockArticleRepo` if not already
+   present, so a test can assert `Create` was never reached when request-layer
+   validation rejects a title first.
+
+## Use-case-level checks (fake repo, no HTTP)
+3. `useCases.NewCreateArticleUseCase(repo)`, `CreateArticle(...)` with an empty fake
+   repo:
+   - Title `strings.Repeat("😀", 2)` (2 runes, 8 bytes) -> `errors.Is(err,
+     article.ErrInvalidTitle)`, nothing stored.
+   - Title `strings.Repeat("😀", 3)` (3 runes, 12 bytes) -> no error, created,
+     `is_online` false, one article stored.
+   - Title `strings.Repeat("😀", 200)` (200 runes, 800 bytes) -> no error, created.
+     Proves the check counts runes (`utf8.RuneCountInString`), not `len()` bytes.
+   - Title `strings.Repeat("😀", 201)` (201 runes, 804 bytes) -> `errors.Is(err,
+     article.ErrInvalidTitle)`, nothing stored.
+   - Keep the existing ASCII boundary cases in `TestCreateArticleTitleLengthLimit`
+     (0/2/3/200/201) passing unchanged, as a regression check that byte length and
+     rune length coincide for ASCII.
+
+## HTTP checks (real CreateArticleUseCase over the fake repo, mirroring api/router.go)
+4. Call `validator.InitValidator()`.
+5. Build `useCases.NewCreateArticleUseCase(fakeRepo)` plus `GetArticleUseCase`,
+   `ListArticlesUseCase`, `DeleteArticleUseCase` (real, over the same fake repo). Build
+   `article.NewHandler(create, get, list, delete)`. Mount its routes inside a group
+   wrapped by `jwtauth.Verifier(token)` + `jwtauth.Authenticator(token)` on a fresh
+   `chi.NewRouter()`, with a test `jwtauth.New("HS256", []byte("test-secret"), nil)`, as
+   in `api/router.go`.
+6. Mint a valid jwt cookie for user id 1 (`token.Encode(map[string]any{"user_id":
+   uint32(1)})`, set as the `jwt` cookie on each `httptest.NewRequest`).
+7. `POST /v1/article/` with a 2-ASCII-character title (`"ab"`) and a valid body ->
+   status `400`, `fakeRepo.createCalled` is false. Assert the body is neither
+   `apperr.ArticleTitleErrorMessage` nor `"Failed to create article"`, to keep the two
+   400 sources (request-layer vs. domain-layer) distinguishable in the test.
+8. `POST /v1/article/` with a 3-ASCII-character title -> status `201`, response body
+   decodes to the created article JSON, `is_online` false.
+9. `POST /v1/article/` with a 200-ASCII-character title (`strings.Repeat("a", 200)`) ->
+   status `201`, created.
+10. `POST /v1/article/` with a 201-ASCII-character title -> status `400`, `Create`
+    never called.
+11. `POST /v1/article/` with a title of 200 repetitions of "😀" (200 runes, 800 bytes)
+    and a valid body -> status `201`, created, response JSON's `title` equals the sent
+    title.
+12. Configure the fake repo (per step 1) so its next `Create` call returns
+    `article.ErrInvalidTitle` directly. `POST /v1/article/` with title "Valid Title"
+    and a valid body (both well inside 3-200 runes, so `validator.Validate.Struct`
+    passes and `CreateArticleUseCase`'s own check would also pass) -> status `400`,
+    body `apperr.ArticleTitleErrorMessage + "\n"`. This scenario is deliberately
+    artificial: with the rule aligned, no real HTTP input can make
+    `CreateArticleUseCase.CreateArticle`'s own check return `article.ErrInvalidTitle`
+    once `validator.Validate.Struct` has already accepted the same title, so the only
+    way to exercise `Handler.PostArticle`'s mapping branch today is to have the fake
+    repository hand back that sentinel directly, standing in for a future or
+    repository-level source of the same error.
+13. Configure the fake repo to fail on its next `Create` with the generic
+    `errRepositoryFailure` (existing `failNext("Create")`). `POST /v1/article/` with
+    title "Valid Title" and a valid body -> status `500`, body `"Failed to create
+    article\n"` -- regression proof a non-title failure still answers 500.
+14. `POST /v1/article/` with no jwt cookie -> status `401` (regression: the route is
+    still gated).
+
+## Manual verification (not exercised by the Go test)
+- None. This slice has no SPA-visible behaviour and no SMTP involvement.

internal/domain/article/articleDomain.go

@@ -4,6 +4,7 @@ import (
 	domain "RenewCMS/internal/domain/image"
 	"errors"
 	"time"
+	"unicode/utf8"
 )
 
 var (
@@ -12,6 +13,19 @@ var (
 	ErrArticleOffline  = errors.New("article is offline")
 )
 
+const (
+	MinTitleRunes = 3
+	MaxTitleRunes = 200
+)
+
+func ValidateTitle(title string) error {
+	runeCount := utf8.RuneCountInString(title)
+	if runeCount < MinTitleRunes || runeCount > MaxTitleRunes {
+		return ErrInvalidTitle
+	}
+	return nil
+}
+
 type Article struct {
 	ID        uint32          `json:"id"`
 	Title     string          `json:"title"`

internal/infrastructure/useCases/CreateArticle.go

@@ -18,8 +18,8 @@ func NewCreateArticleUseCase(articleRepository article.Repository) *CreateArticl
 }
 
 func (g *CreateArticleUseCase) CreateArticle(createArticle CreateArticleCommand) (article.Article, error) {
-	if len(createArticle.Title) < 3 || len(createArticle.Title) > 200 {
+	if err := article.ValidateTitle(createArticle.Title); err != nil {
-		return article.Article{}, article.ErrInvalidTitle
+		return article.Article{}, err
 	}
 
 	return g.articleRepository.Create(article.Article{

test/article_test.go

@@ -16,6 +16,7 @@ type mockArticleRepo struct {
 	images       map[uint32]*imageDomain.Image
 	nextID       uint32
 	fail         failSwitch
+	createCalled bool
 }
 
 func newMockArticleRepo() *mockArticleRepo {
@@ -82,6 +83,7 @@ func (m *mockArticleRepo) GetAll() []article.Article {
 }
 
 func (m *mockArticleRepo) Create(a article.Article) (article.Article, error) {
+	m.createCalled = true
 	if err := m.fail.trigger("Create"); err != nil {
 		return article.Article{}, err
 	}

test/article_title_rules_test.go

@@ -0,0 +1,255 @@
+package test
+
+import (
+	"RenewCMS/api/handlers/article"
+	"RenewCMS/api/pkg/apperr"
+	validator "RenewCMS/api/pkg/validator"
+	domainArticle "RenewCMS/internal/domain/article"
+	"RenewCMS/internal/infrastructure/useCases"
+	"bytes"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"reflect"
+	"strings"
+	"testing"
+
+	"github.com/go-chi/chi/v5"
+	"github.com/go-chi/jwtauth/v5"
+)
+
+func newArticleTitleRulesRouter(repo *mockArticleRepo, token *jwtauth.JWTAuth) *chi.Mux {
+	articleHandler := article.NewHandler(
+		useCases.NewCreateArticleUseCase(repo),
+		useCases.NewGetArticleUseCase(repo),
+		useCases.NewListArticlesUseCase(repo),
+		useCases.NewDeleteArticleUseCase(repo),
+	)
+
+	r := chi.NewRouter()
+	r.Route("/v1", func(r chi.Router) {
+		r.Group(func(r chi.Router) {
+			r.Use(jwtauth.Verifier(token))
+			r.Use(jwtauth.Authenticator(token))
+			r.Route("/article", func(r chi.Router) {
+				r.Post("/", articleHandler.PostArticle)
+			})
+		})
+	})
+	return r
+}
+
+func postArticleRequest(t *testing.T, token *jwtauth.JWTAuth, title string, body string) *http.Request {
+	t.Helper()
+	payload, err := json.Marshal(map[string]string{"title": title, "body": body})
+	if err != nil {
+		t.Fatalf("failed to marshal body: %v", err)
+	}
+	req := httptest.NewRequest(http.MethodPost, "/v1/article/", bytes.NewReader(payload))
+	req.Header.Set("Content-Type", "application/json")
+	setJwtCookie(t, req, token, 1)
+	return req
+}
+
+func TestArticleTitleTagMatchesDomainBounds(t *testing.T) {
+	field, ok := reflect.TypeOf(article.PostArticle{}).FieldByName("Title")
+	if !ok {
+		t.Fatal("expected PostArticle to have a Title field")
+	}
+
+	expected := fmt.Sprintf("required,min=%d,max=%d", domainArticle.MinTitleRunes, domainArticle.MaxTitleRunes)
+	got := field.Tag.Get("validate")
+	if got != expected {
+		t.Errorf("expected validate tag %q, got %q", expected, got)
+	}
+}
+
+func TestArticleTitleRunesInUseCase(t *testing.T) {
+	cases := []struct {
+		runeCount int
+		created   bool
+	}{
+		{2, false},
+		{3, true},
+		{200, true},
+		{201, false},
+	}
+
+	for _, tc := range cases {
+		t.Run(fmt.Sprintf("rune_count_%d", tc.runeCount), func(t *testing.T) {
+			repo := newMockArticleRepo()
+			uc := useCases.NewCreateArticleUseCase(repo)
+
+			title := strings.Repeat("\U0001F600", tc.runeCount)
+			result, err := uc.CreateArticle(useCases.CreateArticleCommand{Title: title, Body: "Some body text"})
+
+			if tc.created {
+				if err != nil {
+					t.Fatalf("expected no error, got %v", err)
+				}
+				if !repo.createCalled {
+					t.Errorf("expected the repository's Create to have been called")
+				}
+				if len(repo.articles) != 1 {
+					t.Errorf("expected 1 article stored, got %d", len(repo.articles))
+				}
+				if result.Title != title {
+					t.Errorf("expected title %q, got %q", title, result.Title)
+				}
+			} else {
+				if !errors.Is(err, domainArticle.ErrInvalidTitle) {
+					t.Errorf("expected ErrInvalidTitle, got %v", err)
+				}
+				if repo.createCalled {
+					t.Errorf("expected the repository's Create not to have been called")
+				}
+				if len(repo.articles) != 0 {
+					t.Errorf("expected nothing stored, got %d article(s)", len(repo.articles))
+				}
+			}
+		})
+	}
+}
+
+func TestArticleTitleRunesOverHttp(t *testing.T) {
+	validator.InitValidator()
+	token := jwtauth.New("HS256", []byte("test-secret"), nil)
+
+	cases := []struct {
+		length  int
+		status  int
+		created bool
+	}{
+		{2, http.StatusBadRequest, false},
+		{3, http.StatusCreated, true},
+		{200, http.StatusCreated, true},
+		{201, http.StatusBadRequest, false},
+	}
+
+	for _, tc := range cases {
+		t.Run(fmt.Sprintf("length_%d", tc.length), func(t *testing.T) {
+			repo := newMockArticleRepo()
+			router := newArticleTitleRulesRouter(repo, token)
+
+			title := strings.Repeat("a", tc.length)
+			req := postArticleRequest(t, token, title, "Some body text")
+			rec := httptest.NewRecorder()
+			router.ServeHTTP(rec, req)
+
+			if rec.Code != tc.status {
+				t.Fatalf("expected status %d, got %d, body %q", tc.status, rec.Code, rec.Body.String())
+			}
+
+			if !tc.created {
+				if repo.createCalled {
+					t.Errorf("expected Create not to have been called")
+				}
+				if strings.Contains(rec.Body.String(), apperr.ArticleTitleErrorMessage) {
+					t.Errorf("expected a request-layer validation error, got the domain error message: %q", rec.Body.String())
+				}
+				if strings.Contains(rec.Body.String(), "Failed to create article") {
+					t.Errorf("expected a request-layer validation error, got the generic failure message: %q", rec.Body.String())
+				}
+			}
+
+			if tc.created {
+				var got domainArticle.Article
+				if err := json.Unmarshal(rec.Body.Bytes(), &got); err != nil {
+					t.Fatalf("failed to decode response: %v", err)
+				}
+				if got.IsOnline {
+					t.Errorf("expected is_online false, got true")
+				}
+				if len(repo.articles) != 1 {
+					t.Errorf("expected 1 article stored, got %d", len(repo.articles))
+				}
+			} else {
+				if len(repo.articles) != 0 {
+					t.Errorf("expected nothing stored, got %d article(s)", len(repo.articles))
+				}
+			}
+		})
+	}
+
+	t.Run("A 200-rune multibyte title is accepted end to end over HTTP", func(t *testing.T) {
+		repo := newMockArticleRepo()
+		router := newArticleTitleRulesRouter(repo, token)
+
+		title := strings.Repeat("\U0001F600", 200)
+		req := postArticleRequest(t, token, title, "Some body text")
+		rec := httptest.NewRecorder()
+		router.ServeHTTP(rec, req)
+
+		if rec.Code != http.StatusCreated {
+			t.Fatalf("expected status 201, got %d, body %q", rec.Code, rec.Body.String())
+		}
+
+		var got domainArticle.Article
+		if err := json.Unmarshal(rec.Body.Bytes(), &got); err != nil {
+			t.Fatalf("failed to decode response: %v", err)
+		}
+		if got.Title != title {
+			t.Errorf("expected title %q, got %q", title, got.Title)
+		}
+	})
+
+	t.Run("The handler maps a domain title rejection to 400, not 500", func(t *testing.T) {
+		repo := newMockArticleRepo()
+		repo.fail.failNextWith("Create", domainArticle.ErrInvalidTitle)
+		router := newArticleTitleRulesRouter(repo, token)
+
+		req := postArticleRequest(t, token, "Valid Title", "Some body text")
+		rec := httptest.NewRecorder()
+		router.ServeHTTP(rec, req)
+
+		if rec.Code != http.StatusBadRequest {
+			t.Fatalf("expected status 400, got %d", rec.Code)
+		}
+		if rec.Body.String() != apperr.ArticleTitleErrorMessage+"\n" {
+			t.Errorf("unexpected body: %q", rec.Body.String())
+		}
+		if strings.Contains(rec.Body.String(), "Failed to create article") {
+			t.Errorf("did not expect the generic failure message, got %q", rec.Body.String())
+		}
+	})
+
+	t.Run("A non-title repository failure during creation still answers 500", func(t *testing.T) {
+		repo := newMockArticleRepo()
+		repo.fail.failNext("Create")
+		router := newArticleTitleRulesRouter(repo, token)
+
+		req := postArticleRequest(t, token, "Valid Title", "Some body text")
+		rec := httptest.NewRecorder()
+		router.ServeHTTP(rec, req)
+
+		if rec.Code != http.StatusInternalServerError {
+			t.Fatalf("expected status 500, got %d", rec.Code)
+		}
+		if rec.Body.String() != "Failed to create article\n" {
+			t.Errorf("unexpected body: %q", rec.Body.String())
+		}
+	})
+
+	t.Run("POST /v1/article/ without a jwt cookie is rejected", func(t *testing.T) {
+		repo := newMockArticleRepo()
+		router := newArticleTitleRulesRouter(repo, token)
+
+		payload, err := json.Marshal(map[string]string{"title": "Valid Title", "body": "Some body text"})
+		if err != nil {
+			t.Fatalf("failed to marshal body: %v", err)
+		}
+		req := httptest.NewRequest(http.MethodPost, "/v1/article/", bytes.NewReader(payload))
+		req.Header.Set("Content-Type", "application/json")
+		rec := httptest.NewRecorder()
+		router.ServeHTTP(rec, req)
+
+		if rec.Code != http.StatusUnauthorized {
+			t.Fatalf("expected status 401, got %d", rec.Code)
+		}
+		if repo.createCalled {
+			t.Errorf("expected Create not to have been called")
+		}
+	})
+}

test/fakes_common.go

@@ -6,15 +6,27 @@ var errRepositoryFailure = errors.New("repository failure")
 
 type failSwitch struct {
 	method string
+	err    error
 }
 
 func (f *failSwitch) failNext(method string) {
 	f.method = method
+	f.err = nil
+}
+
+func (f *failSwitch) failNextWith(method string, err error) {
+	f.method = method
+	f.err = err
 }
 
 func (f *failSwitch) trigger(method string) error {
 	if f.method == method {
 		f.method = ""
+		if f.err != nil {
+			err := f.err
+			f.err = nil
+			return err
+		}
 		return errRepositoryFailure
 	}
 	return nil