Add metadata headers

client/client.go

@@ -46,6 +46,7 @@ type CreateAnswerRequest struct {
 
 type CreateUpdateQuizRequest struct {
 	*Quiz
+	*models.Meta
 }
 
 type DeleteQuizRequest struct {

go.mod

@@ -5,6 +5,7 @@ go 1.17
 require github.com/sirupsen/logrus v1.8.1
 
 require (
+	github.com/go-yaml/yaml v2.1.0+incompatible // indirect
 	github.com/google/uuid v1.3.0 // indirect
 	github.com/julienschmidt/httprouter v1.3.0 // indirect
 	github.com/kr/pretty v0.2.1 // indirect

go.sum

@@ -1,4 +1,6 @@
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/go-yaml/yaml v2.1.0+incompatible h1:RYi2hDdss1u4YE7GwixGzWwVo47T8UQwnTLB6vQiq+o=
+github.com/go-yaml/yaml v2.1.0+incompatible/go.mod h1:w2MrLa16VYP0jy6N7M5kHaCkaLENm+P+Tv+MfurjSw0=
 github.com/google/uuid v1.3.0 h1:t6JiXgmwXMjEs8VusXIJk2BXHsn+wx8BZdTaoZ5fu7I=
 github.com/google/uuid v1.3.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/julienschmidt/httprouter v1.3.0 h1:U0609e9tgbseu3rBINet9P48AI/D3oJs4dN7jwJOQ1U=

models/meta.go

@@ -0,0 +1,8 @@
+package models
+
+import "time"
+
+type Meta struct {
+	ID        string    `json:"id" yaml:"id"`
+	CreatedAt time.Time `json:"created_at" yaml:"created_at"`
+}

models/quiz.go

@@ -1,7 +1,8 @@
 package models
 
 type Quiz struct {
-	ID       string    `json:"id"`
+	Meta
+	//	ID       string    `json:"id"`
 	Hash     string    `json:"hash"`
 	Question *Question `json:"question"`
 	Answers  []*Answer `json:"answers"`

store/file/file.go

@@ -1,11 +1,15 @@
 package file
 
 import (
+	"bufio"
+	"bytes"
 	"errors"
 	"fmt"
+	"io"
 	"io/fs"
 	"io/ioutil"
 	"os"
+	"path"
 	"path/filepath"
 	"strings"
 	"sync"
@@ -15,8 +19,11 @@ import (
 	"git.andreafazzi.eu/andrea/probo/hasher/sha256"
 	"git.andreafazzi.eu/andrea/probo/models"
 	"git.andreafazzi.eu/andrea/probo/store/memory"
+	"github.com/go-yaml/yaml"
 )
 
+var ErrorMetaHeaderIsNotPresent = errors.New("Meta header was not found in file.")
+
 type FileProboCollectorStore struct {
 	Dir string
 
@@ -73,17 +80,25 @@ func (s *FileProboCollectorStore) Reindex() error {
 		if err != nil {
 			return err
 		}
-		quiz, err := QuizFromMarkdown(string(content))
+		quiz, meta, err := QuizFromMarkdown(string(content))
 		if err != nil {
 			return err
 		}
+
 		q, err := s.memoryStore.CreateQuiz(&client.CreateUpdateQuizRequest{
 			Quiz: quiz,
+			Meta: meta,
 		})
 		if err != nil {
 			return err
 		}
 
+		if meta == nil {
+			s.WriteMetaHeaderToFile(filename, &models.Meta{
+				ID:        q.ID,
+				CreatedAt: time.Now(),
+			})
+		}
 		s.SetPath(q, fullPath)
 	}
 
@@ -202,8 +217,13 @@ func MarkdownFromQuiz(quiz *models.Quiz) (string, error) {
 	return markdown, nil
 }
 
-func QuizFromMarkdown(markdown string) (*client.Quiz, error) {
+func QuizFromMarkdown(markdown string) (*client.Quiz, *models.Meta, error) {
-	lines := strings.Split(markdown, "\n")
+	meta, remainingMarkdown, err := parseMetaHeaderFromMarkdown(markdown)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	lines := strings.Split(remainingMarkdown, "\n")
 
 	questionText := ""
 	answers := []*client.Answer{}
@@ -225,17 +245,113 @@ func QuizFromMarkdown(markdown string) (*client.Quiz, error) {
 	questionText = strings.TrimRight(questionText, "\n")
 
 	if questionText == "" {
-		return nil, fmt.Errorf("Question text should not be empty.")
+		return nil, nil, fmt.Errorf("Question text should not be empty.")
 	}
 
 	if len(answers) < 2 {
-		return nil, fmt.Errorf("Number of answers should be at least 2 but parsed answers are %d.", len(answers))
+		return nil, nil, fmt.Errorf("Number of answers should be at least 2 but parsed answers are %d.", len(answers))
 	}
 
 	question := &client.Question{Text: questionText}
 	quiz := &client.Quiz{Question: question, Answers: answers}
 
-	return quiz, nil
+	return quiz, meta, nil
+}
+
+func (s *FileProboCollectorStore) ReadMetaHeaderFromFile(filename string) (*models.Meta, error) {
+	data, err := ioutil.ReadFile(path.Join(s.Dir, filename))
+	if err != nil {
+		return nil, err
+	}
+	meta, _, err := parseMetaHeaderFromMarkdown(string(data))
+	if err != nil {
+		return nil, err
+	}
+	return meta, nil
+}
+
+func (s *FileProboCollectorStore) WriteMetaHeaderToFile(filename string, meta *models.Meta) (*models.Meta, error) {
+	readMeta, err := s.ReadMetaHeaderFromFile(filename)
+	if err != nil {
+		return nil, err
+	}
+
+	if readMeta == nil {
+		_, err := writeMetaHeader(path.Join(s.Dir, filename), meta)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return meta, nil
+}
+
+func (s *FileProboCollectorStore) removeMetaFromFile(filename string) (*models.Meta, error) {
+	file, err := os.Open(path.Join(s.Dir, filename))
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	var buffer bytes.Buffer
+
+	reader := bufio.NewReader(file)
+
+	var meta models.Meta
+	var line string
+	var sb strings.Builder
+	for {
+		line, err = reader.ReadString('\n')
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+			return nil, err
+		}
+
+		if strings.TrimSpace(line) == "---" {
+			break
+		}
+	}
+
+	for {
+		line, err = reader.ReadString('\n')
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+			return nil, err
+		}
+
+		if strings.TrimSpace(line) == "---" {
+			break
+		}
+
+		sb.WriteString(line)
+	}
+
+	err = yaml.Unmarshal([]byte(sb.String()), &meta)
+	if err != nil {
+		return nil, err
+	}
+
+	_, err = io.Copy(&buffer, reader)
+	if err != nil {
+		return nil, err
+	}
+
+	file, err = os.Create(path.Join(s.Dir, filename))
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	_, err = io.Copy(file, &buffer)
+	if err != nil {
+		return nil, err
+	}
+
+	return &meta, nil
 }
 
 func (s *FileProboCollectorStore) createOrUpdateMarkdownFile(quiz *models.Quiz) error {
@@ -253,10 +369,14 @@ func (s *FileProboCollectorStore) createOrUpdateMarkdownFile(quiz *models.Quiz)
 	if err != nil {
 		return err
 	}
-
 	defer file.Close()
 
-	_, err = file.Write([]byte(markdown))
+	markdownWithMetaHeader, err := addMetaHeaderToMarkdown(markdown, &quiz.Meta)
+	if err != nil {
+		return err
+	}
+
+	_, err = file.Write([]byte(markdownWithMetaHeader))
 	if err != nil {
 		return err
 	}
@@ -265,3 +385,136 @@ func (s *FileProboCollectorStore) createOrUpdateMarkdownFile(quiz *models.Quiz)
 
 	return nil
 }
+
+func addMetaHeaderToMarkdown(content string, meta *models.Meta) (string, error) {
+	var buffer bytes.Buffer
+
+	header, err := yaml.Marshal(meta)
+	if err != nil {
+		return "", err
+	}
+	_, err = buffer.WriteString("---\n" + string(header) + "---\n")
+	if err != nil {
+		return "", err
+	}
+
+	_, err = buffer.WriteString(content)
+	if err != nil {
+		return "", err
+	}
+
+	return buffer.String(), nil
+}
+
+func parseMetaHeaderFromMarkdown(markdown string) (*models.Meta, string, error) {
+	reader := strings.NewReader(markdown)
+	var sb strings.Builder
+	var line string
+	var err error
+	for {
+		line, err = readLine(reader)
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+			return nil, "", err
+		}
+
+		if strings.TrimSpace(line) == "---" {
+			break
+		}
+	}
+
+	for {
+		line, err = readLine(reader)
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+			return nil, "", err
+		}
+
+		if strings.TrimSpace(line) == "---" {
+			break
+		}
+
+		sb.WriteString(line)
+	}
+
+	if sb.String() == "" {
+		return nil, markdown, nil
+	}
+
+	var meta models.Meta
+	err = yaml.Unmarshal([]byte(sb.String()), &meta)
+	if err != nil {
+		return nil, markdown, err
+	}
+
+	remainingMarkdown := markdown[strings.Index(markdown, "---\n"+sb.String()+"---\n")+len("---\n"+sb.String()+"---\n"):]
+
+	return &meta, remainingMarkdown, nil
+}
+
+func readLine(reader *strings.Reader) (string, error) {
+	var sb strings.Builder
+	for {
+		r, _, err := reader.ReadRune()
+		if err != nil {
+			if err == io.EOF {
+				return sb.String(), io.EOF
+			}
+			return "", err
+		}
+
+		sb.WriteRune(r)
+		if r == '\n' {
+			break
+		}
+	}
+
+	return sb.String(), nil
+}
+
+func writeMetaHeader(filename string, meta *models.Meta) (*models.Meta, error) {
+	// Apri il file in lettura
+	file, err := os.Open(filename)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	// Crea un buffer in memoria
+	var buffer bytes.Buffer
+
+	// Scrivi l'intestazione YAML nel buffer
+	header, err := yaml.Marshal(meta)
+	if err != nil {
+		return nil, err
+	}
+	_, err = buffer.WriteString("---\n" + string(header) + "---\n")
+	if err != nil {
+		return nil, err
+	}
+
+	// Copia il contenuto del file originale nel buffer
+	_, err = io.Copy(&buffer, file)
+	if err != nil {
+		return nil, err
+	}
+
+	// Riapri il file in scrittura
+	file, err = os.Create(filename)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	// Scrivi il contenuto del buffer nel file
+	_, err = io.Copy(file, &buffer)
+	if err != nil {
+		return nil, err
+	}
+
+	return meta, nil
+}

store/file/file_test.go

@@ -46,7 +46,7 @@ Question text (3).
 		},
 	}
 
-	quiz, err := QuizFromMarkdown(markdown)
+	quiz, _, err := QuizFromMarkdown(markdown)
 	t.Nil(err, fmt.Sprintf("Quiz should be parsed without errors: %v", err))
 
 	if !t.Failed() {
@@ -65,9 +65,9 @@ func (t *testSuite) TestReadAllQuizzes() {
 
 		if !t.Failed() {
 			t.Equal(
-				2,
+				4,
 				len(result),
-				fmt.Sprintf("The store contains 3 files but only 2 should be parsed (duplicated quiz). Total of parsed quizzes are instead %v", len(result)),
+				fmt.Sprintf("The store contains 5 files but only 4 should be parsed (duplicated quiz). Total of parsed quizzes are instead %v", len(result)),
 			)
 		}
 	}
@@ -136,7 +136,7 @@ func (t *testSuite) TestCreateQuiz() {
 				if !t.Failed() {
 					t.True(exists != nil, "The new quiz file was not created.")
 					if !t.Failed() {
-						quizFromDisk, err := readQuizFromDisk(path)
+						quizFromDisk, _, err := readQuizFromDisk(path)
 						t.Nil(err, "Quiz should be read from disk without errors.")
 						if !t.Failed() {
 							t.True(reflect.DeepEqual(quizFromDisk, clientQuiz), "Quiz read from disk and stored in memory should be equal.")
@@ -205,7 +205,7 @@ func (t *testSuite) TestUpdateQuiz() {
 
 		if !t.Failed() {
 			clientQuiz := &client.Quiz{
-				Question: &client.Question{Text: "Newly created question text."},
+				Question: &client.Question{Text: "Updated question text."},
 				Answers: []*client.Answer{
 					{Text: "Answer 1", Correct: true},
 					{Text: "Answer 2", Correct: false},
@@ -220,7 +220,7 @@ func (t *testSuite) TestUpdateQuiz() {
 				}, quiz.ID)
 
 			t.Nil(err, fmt.Sprintf("Quiz should be updated without errors: %v", err))
-			//			t.Equal(updatedQuiz.ID, quiz.ID, "Quiz ID should remain the same")
+			t.Equal(updatedQuiz.ID, quiz.ID, fmt.Sprintf("IDs should remain the same after an update: updated ID %v original ID %v", updatedQuiz.ID, quiz.ID))
 
 			if !t.Failed() {
 				path, err := store.GetPath(updatedQuiz)
@@ -229,7 +229,7 @@ func (t *testSuite) TestUpdateQuiz() {
 					t.Nil(err, "GetPath should not raise an error.")
 
 					if !t.Failed() {
-						quizFromDisk, err := readQuizFromDisk(path)
+						quizFromDisk, _, err := readQuizFromDisk(path)
 						t.Nil(err, "Quiz should be read from disk without errors.")
 						if !t.Failed() {
 							t.True(reflect.DeepEqual(clientQuiz, quizFromDisk), "Quiz should be updated.")
@@ -244,15 +244,52 @@ func (t *testSuite) TestUpdateQuiz() {
 
 }
 
+func (t *testSuite) TestReadMetaHeaderFromFile() {
+	dirname := "./testdata/quizzes"
+	store, err := NewFileProboCollectorStore(dirname)
+	t.True(err == nil, fmt.Sprintf("A file store should be initialized without problems but an error occurred: %v", err))
+
+	meta, err := store.ReadMetaHeaderFromFile("quiz_4.md")
+	t.True(err == nil, fmt.Sprintf("An error occurred: %v", err))
+	if !t.Failed() {
+		t.True(meta.ID != "")
+		t.True(meta.CreatedAt.String() != "")
+	}
+}
+
+func (t *testSuite) TestWriteMetaHeaderToFile() {
+	dirname := "./testdata/quizzes"
+	store, err := NewFileProboCollectorStore(dirname)
+
+	t.True(err == nil, fmt.Sprintf("A file store should be initialized without problems but an error occurred: %v", err))
+
+	if !t.Failed() {
+		meta, err := store.ReadMetaHeaderFromFile("quiz_5.md")
+		t.True(err == nil)
+		if !t.Failed() {
+			t.True(meta != nil, "Meta header should not be nil")
+
+			if !t.Failed() {
+				t.True(meta.ID != "", "ID should not be empty")
+
+				if !t.Failed() {
+					_, err = store.removeMetaFromFile("quiz_5.md")
+					t.True(err == nil)
+				}
+			}
+		}
+	}
+}
+
 func createQuizOnDisk(store *FileProboCollectorStore, req *client.CreateUpdateQuizRequest) (*models.Quiz, error) {
 	return store.CreateQuiz(req)
 
 }
 
-func readQuizFromDisk(path string) (*client.Quiz, error) {
+func readQuizFromDisk(path string) (*client.Quiz, *models.Meta, error) {
 	content, err := os.ReadFile(path)
 	if err != nil {
-		return nil, err
+		return nil, nil, err
 	}
 	return QuizFromMarkdown(string(content))
 }

store/file/testdata/quizzes/quiz_1.md

@@ -1,3 +1,7 @@
+---
+id: 42982769-2168-45e8-b307-8764c18bec55
+created_at: !!timestamp 2023-09-22T09:07:47.744571823+02:00
+---
 Question text 1.
 
 * Answer 1

store/file/testdata/quizzes/quiz_2.md

@@ -1,3 +1,7 @@
+---
+id: a09045c3-af87-4a83-a2bb-7283a2ac67d6
+created_at: !!timestamp 2023-09-22T09:08:50.366639817+02:00
+---
 Question text 2.
 
 * Answer 1

store/file/testdata/quizzes/quiz_3.md

@@ -1,3 +1,7 @@
+---
+id: a09045c3-af87-4a83-a2bb-7283a2ac67d6
+created_at: !!timestamp 2023-09-22T09:08:50.366772426+02:00
+---
 Question text 2.
 
 * Answer 1

store/file/testdata/quizzes/quiz_4.md

@@ -0,0 +1,10 @@
+---
+id: 0000-1234-5678-9101
+created_at: 2006-01-02T15:04:05Z
+---
+This quiz file contains a meta header.
+
+* Answer 1
+* Answer 2
+* Answer 3
+* Answer 4

store/file/testdata/quizzes/quiz_5.md

@@ -0,0 +1,7 @@
+This quiz is initially without metadata.
+
+* Answer 1
+* Answer 2
+* Answer 3
+* Answer 4
+

store/memory/memory.go

@@ -154,7 +154,6 @@ func (s *MemoryProboCollectorStore) CalculateQuizHash(quiz *client.Quiz) string
 }
 
 func (s *MemoryProboCollectorStore) createOrUpdateQuiz(r *client.CreateUpdateQuizRequest, id string) (*models.Quiz, bool, error) {
-
 	hashes := s.hasher.QuizHashes(r.Quiz)
 	quizHash := hashes[len(hashes)-1]
 
@@ -163,13 +162,19 @@ func (s *MemoryProboCollectorStore) createOrUpdateQuiz(r *client.CreateUpdateQui
 		return quiz, false, nil
 	}
 
-	if id != "" {
+	if id != "" { // we're updating a quiz
 		quiz = s.getQuizFromID(id)
 		if quiz == nil { // Quiz is not present in the store
 			return nil, false, fmt.Errorf("Quiz ID %v doesn't exist in the store!", id)
 		}
 	} else {
-		id = uuid.New().String()
+		if r.Meta != nil {
+			if r.Meta.ID != "" {
+				id = r.Meta.ID
+			}
+		} else {
+			id = uuid.New().String()
+		}
 		quiz = new(models.Quiz)
 	}