added validation when adding a book

api_test.go

@@ -63,6 +63,26 @@ func TestPostBookHandler_WrongRating(t *testing.T) {
 	testPostBookHandler(t, bookJson, 400)
 }
 
+func TestPostBookHandler_TitleTooLong(t *testing.T) {
+	bookJson :=
+		`{
+		  "title": "Noisy outlaws, unfriendly blobs, and some other things that aren't as scary, maybe, depending on how you feel about lost lands, stray cellphones, creatures from the sky, parents who disappear in Peru, a man named Lars Farf, and one other story we couldn't quite finish, so maybe you could help us out.",
+			"author": "Eli Horowitz",
+			"rating": 2
+		}`
+	testPostBookHandler(t, bookJson, 400)
+}
+
+func TestPostBookHandler_AuthorTooLong(t *testing.T) {
+	bookJson :=
+		`{
+		  "title": "something",
+			"author": "Wolfeschlegelsteinhausenbergerdorffwelchevoralternwarengewissenhaftschaferswessenschafewarenwohlgepflegeundsorgfaltigkeitbeschutzenvonangreifendurchihrraubgierigfeindewelchevoralternzwolftausendjahresvorandieerscheinenvanderersteerdemenschderraumschiffgebrauchlichtalsseinursprungvonkraftgestartseinlangefahrthinzwischensternartigraumaufdersuchenachdiesternwelchegehabtbewohnbarplanetenkreisedrehensichundwohinderneurassevonverstandigmenschlichkeitkonntefortpflanzenundsicherfreuenanlebenslanglichfreudeundruhemitnichteinfurchtvorangreifenvonandererintelligentgeschopfsvonhinzwischensternartigraum",
+			"rating": 2
+		}`
+	testPostBookHandler(t, bookJson, 400)
+}
+
 func testPostBookHandler(t *testing.T, bookJson string, expectedCode int) {
 	router := testSetup()
 	w := httptest.NewRecorder()

demodata.sql

@@ -25,3 +25,4 @@ INSERT INTO books(created_at, title, author, rating) VALUES ('NOW', 'Sa majesté
 INSERT INTO books(created_at, title, author, rating) VALUES ('NOW', 'Le Pavillon d''or','Yukio Mishima', 8);
 INSERT INTO books(created_at, title, author, rating) VALUES ('NOW', 'Le meurtre d''O-tsuya','Junichiro Tanizaki', 7);
 INSERT INTO books(created_at, title, author, rating) VALUES ('NOW', 'Dojoji et autres nouvelles','Yukio Mishima', 8);
+INSERT INTO books(created_at, title, author, rating) VALUES ('NOW', 'Noisy outlaws, unfriendly blobs, and some other things that aren''t as scary, maybe, depending on how you feel about lost lands, stray cellphones, creatures from the sky, parents who disappear in Peru, a man named Lars Farf, and one other story we couldn''t quite finish, so maybe you could help us out','Wolfeschlegelsteinhausenbergerdorffwelchevoralternwarengewissenhaftschaferswessenschafewarenwohlgepf', 2);

front/src/AddBook.vue

@@ -1,5 +1,5 @@
 <script setup>
-  import { ref } from 'vue'
+  import { ref, reactive, computed } from 'vue'
   import { postBook } from './api.js'
   import { useRouter, useRoute } from 'vue-router'
 
@@ -9,10 +9,36 @@
     title: "",
     author: ""
   });
+  const errors = ref(null)
+  const titleError = computed(() => {
+    return extractErrorFromField("Title");
+  })
+  const authorError = computed(() => {
+    return extractErrorFromField("Author");
+  })
+
+  function extractErrorFromField(fieldName) {
+    if (errors.value === null) {
+     return "";
+    }
+    const titleErr = errors.value.find((e) => e["field"] === fieldName);
+    if (typeof titleErr !== 'undefined') {
+      return titleErr.error
+    } else {
+      return "";
+    }
+  }
 
   function onSubmit(e) {
-    postBook(book);
+    postBook(book)
+      .then((res) => {
+        if (res.ok) {
           router.push('/');
+          return;
+        } else {
+          res.json().then((json) => (errors.value = json));
+        }
+      })
   }
 </script>
 
@@ -21,14 +47,17 @@
     <div class="field">
       <label class="label">Title</label>
       <div class="control">
-        <input class="input" type="text" v-model="book.title" placeholder="Title">
+        <input :class="'input ' + (titleError ? 'is-danger' : '')" type="text" maxlength="300"
+        required v-model="book.title" placeholder="Title">
       </div>
+      <p v-if="titleError" class="help is-danger">{{titleError}}</p>
     </div>
     <div class="field">
       <label class="label">Author</label>
       <div class="control">
-        <input class="input" type="text" v-model="book.author" placeholder="Author">
+        <input :class="'input ' + (authorError ? 'is-danger' : '')" type="text" maxlength="100" v-model="book.author" placeholder="Author">
       </div>
+      <p v-if="authorError" class="help is-danger">{{authorError}}</p>
     </div>
     <div class="field">
       <div class="control">

front/src/api.js

@@ -3,13 +3,13 @@ import { ref } from 'vue'
 const baseUrl = "http://localhost:8080"
 
 function useFetch(url) {
-  const data = ref(null)
+  const data = ref(null);
-  const error = ref(null)
+  const error = ref(null);
 
   fetch(url)
     .then((res) => res.json())
     .then((json) => (data.value = json))
-    .catch((err) => (error.value = err))
+    .catch((err) => (error.value = err));
 
   return { data, error }
 }
@@ -19,11 +19,11 @@ export function getBooks() {
 }
 
 export function postBook(book) {
-  fetch(baseUrl + '/book', {
+  return fetch(baseUrl + '/book', {
     method: 'POST',
     headers: {
       'Content-Type': 'application/json'
     },
     body: JSON.stringify(book.value)
-  });
+  })
 }

internal/api/dto.go

@@ -1,7 +1,7 @@
 package api
 
 type bookPostCreate struct {
-	Title  string `json:"title" binding:"required"`
+	Title  string `json:"title" binding:"required,max=300"`
-	Author string `json:"author"`
+	Author string `json:"author" binding:"max=100"`
 	Rating int    `json:"rating" binding:"min=0,max=10"`
 }

internal/api/routes.go

@@ -1,10 +1,12 @@
 package api
 
 import (
+	"errors"
 	"net/http"
 
 	"git.artlef.fr/PersonalLibraryManager/internal/model"
 	"github.com/gin-gonic/gin"
+	"github.com/go-playground/validator/v10"
 	"gorm.io/gorm"
 )
 
@@ -18,7 +20,12 @@ func PostBookHandler(c *gin.Context, db *gorm.DB) {
 	var book bookPostCreate
 	err := c.ShouldBindJSON(&book)
 	if err != nil {
+		var ve validator.ValidationErrors
+		if errors.As(err, &ve) {
+			c.JSON(http.StatusBadRequest, getValidationErrors(&ve))
+		} else {
 			c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		}
 		return
 	}
 	bookDb := book.toBook()

internal/api/validator.go

@@ -0,0 +1,35 @@
+package api
+
+import (
+	"fmt"
+
+	"github.com/go-playground/validator/v10"
+)
+
+type apiValidationError struct {
+	Field string `json:"field"`
+	Err   string `json:"error"`
+}
+
+func getValidationErrors(ve *validator.ValidationErrors) []apiValidationError {
+	errors := make([]apiValidationError, len(*ve))
+	for i, fe := range *ve {
+		errors[i] = apiValidationError{
+			Field: fe.Field(),
+			Err:   computeValidationMessage(&fe),
+		}
+	}
+	return errors
+}
+
+func computeValidationMessage(fe *validator.FieldError) string {
+	tag := (*fe).Tag()
+	switch tag {
+	case "required":
+		return fmt.Sprintf("%s is required.", (*fe).Field())
+	case "max":
+		return fmt.Sprintf("%s is too long. It should be under %s characters.", (*fe).Field(), (*fe).Param())
+	default:
+		return fmt.Sprintf("Validation failed for '%s' property.", tag)
+	}
+}