From 1e1174f9ca4b0c4d2cda3060d40812b4c78f5bf7 Mon Sep 17 00:00:00 2001
From: Maximilian Friedersdorff <max@gwairfelin.com>
Date: Sun, 26 Jan 2025 22:23:42 +0000
Subject: [PATCH] Initial commit with cru (no delete) of notes

---
 .gitignore                    |  1 +
 cmd/server/main.go            | 19 +++++++++
 conf.toml                     |  3 ++
 go.mod                        |  7 ++++
 go.sum                        |  4 ++
 internal/conf/conf.go         | 30 +++++++++++++++
 internal/notes/notes.go       | 52 +++++++++++++++++++++++++
 internal/notes/views/views.go | 72 +++++++++++++++++++++++++++++++++++
 internal/urls/urls.go         | 47 +++++++++++++++++++++++
 templates/edit.html           |  6 +++
 templates/view.html           |  3 ++
 11 files changed, 244 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 cmd/server/main.go
 create mode 100644 conf.toml
 create mode 100644 go.mod
 create mode 100644 go.sum
 create mode 100644 internal/conf/conf.go
 create mode 100644 internal/notes/notes.go
 create mode 100644 internal/notes/views/views.go
 create mode 100644 internal/urls/urls.go
 create mode 100644 templates/edit.html
 create mode 100644 templates/view.html

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..ba2906d
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+main
diff --git a/cmd/server/main.go b/cmd/server/main.go
new file mode 100644
index 0000000..b07945d
--- /dev/null
+++ b/cmd/server/main.go
@@ -0,0 +1,19 @@
+package main
+
+import (
+	"log"
+	"net/http"
+
+	"gitea.gwairfelin.com/max/gonotes/internal/conf"
+	"gitea.gwairfelin.com/max/gonotes/internal/notes/views"
+)
+
+func main() {
+	conf.LoadConfig("./conf.toml")
+
+	router := http.NewServeMux()
+	notesRouter := views.GetRoutes("/notes")
+
+	router.Handle("/notes/", http.StripPrefix("/notes", notesRouter))
+	log.Fatal(http.ListenAndServe(":8080", router))
+}
diff --git a/conf.toml b/conf.toml
new file mode 100644
index 0000000..488492c
--- /dev/null
+++ b/conf.toml
@@ -0,0 +1,3 @@
+extension = "md"
+notesdir = "saved_notes"
+templatesdir = "templates"
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..d1334e1
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,7 @@
+module gitea.gwairfelin.com/max/gonotes
+
+go 1.23.5
+
+require github.com/yuin/goldmark v1.7.8
+
+require github.com/pelletier/go-toml v1.9.5
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..1449848
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,4 @@
+github.com/pelletier/go-toml v1.9.5 h1:4yBQzkHv+7BHq2PQUZF3Mx0IYxG7LsP222s7Agd3ve8=
+github.com/pelletier/go-toml v1.9.5/go.mod h1:u1nR/EPcESfeI/szUZKdtJ0xRNbUoANCkoOuaOx1Y+c=
+github.com/yuin/goldmark v1.7.8 h1:iERMLn0/QJeHFhxSt3p6PeN9mGnvIKSpG9YYorDMnic=
+github.com/yuin/goldmark v1.7.8/go.mod h1:uzxRWxtg69N339t3louHJ7+O03ezfj6PlliRlaOzY1E=
diff --git a/internal/conf/conf.go b/internal/conf/conf.go
new file mode 100644
index 0000000..dce5fcf
--- /dev/null
+++ b/internal/conf/conf.go
@@ -0,0 +1,30 @@
+package conf
+
+import (
+	"log"
+	"os"
+
+	"github.com/pelletier/go-toml"
+)
+
+type Config struct {
+	Extension    string
+	NotesDir     string
+	TemplatesDir string
+}
+
+var Conf Config
+
+func LoadConfig(path string) {
+	var err error
+
+	b, err := os.ReadFile(path)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	err = toml.Unmarshal([]byte(b), &Conf)
+	if err != nil {
+		log.Fatal(err)
+	}
+}
diff --git a/internal/notes/notes.go b/internal/notes/notes.go
new file mode 100644
index 0000000..060d9f1
--- /dev/null
+++ b/internal/notes/notes.go
@@ -0,0 +1,52 @@
+// Notes implements a data structure for reasoning about and rendering
+// markdown notes
+package notes
+
+import (
+	"bytes"
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+
+	"gitea.gwairfelin.com/max/gonotes/internal/conf"
+	"github.com/yuin/goldmark"
+)
+
+// Note is the central data structure.  It can be Saved, Rendered and Loaded
+// using the Save, Render and LoadNote functions.
+type Note struct {
+	Title        string
+	BodyRendered string
+	Body         []byte
+}
+
+func fmtPath(path string) string {
+	return fmt.Sprintf("%s.%s", path, conf.Conf.Extension)
+}
+
+// Save a note to a path derived from the title
+func (n *Note) Save() error {
+	filename := filepath.Join(conf.Conf.NotesDir, fmtPath(n.Title))
+	return os.WriteFile(filename, n.Body, 0600)
+}
+
+// Render the markdown content of the note to HTML
+func (n *Note) Render() {
+	var buf bytes.Buffer
+	err := goldmark.Convert(n.Body, &buf)
+	if err != nil {
+		log.Fatal(err)
+	}
+	n.BodyRendered = buf.String()
+}
+
+// Load a note from the disk. The path is derived from the title
+func LoadNote(title string) (*Note, error) {
+	filename := filepath.Join(conf.Conf.NotesDir, fmtPath(title))
+	body, err := os.ReadFile(filename)
+	if err != nil {
+		return nil, err
+	}
+	return &Note{Title: title, Body: body}, nil
+}
diff --git a/internal/notes/views/views.go b/internal/notes/views/views.go
new file mode 100644
index 0000000..b52b7f5
--- /dev/null
+++ b/internal/notes/views/views.go
@@ -0,0 +1,72 @@
+package views
+
+import (
+	"html/template"
+	"log"
+	"net/http"
+	"path/filepath"
+
+	"gitea.gwairfelin.com/max/gonotes/internal/conf"
+	"gitea.gwairfelin.com/max/gonotes/internal/notes"
+	"gitea.gwairfelin.com/max/gonotes/internal/urls"
+)
+
+var myurls urls.URLs
+
+func GetRoutes(prefix string) *http.ServeMux {
+	myurls = urls.URLs{
+		Prefix: prefix,
+		URLs: map[string]urls.URL{
+			"view": {Path: "/{note}/", Protocol: "GET", Handler: viewHandler},
+			"edit": {Path: "/{note}/edit/", Protocol: "GET", Handler: editHandler},
+			"save": {Path: "/{note}/edit/save/", Protocol: "POST", Handler: saveHandler},
+		},
+	}
+	return myurls.GetRouter()
+}
+
+func viewHandler(w http.ResponseWriter, r *http.Request) {
+	title := r.PathValue("note")
+	note, err := notes.LoadNote(title)
+	if err != nil {
+		http.Redirect(w, r, myurls.Reverse("edit", map[string]string{"note": title}), http.StatusFound)
+		return
+	}
+
+	note.Render()
+	err = renderTemplate(w, "view.html", note)
+	if err != nil {
+		log.Println(err)
+		http.Error(w, "Couldn't load template", http.StatusInternalServerError)
+		return
+	}
+}
+
+func editHandler(w http.ResponseWriter, r *http.Request) {
+	title := r.PathValue("note")
+	note, err := notes.LoadNote(title)
+	if err != nil {
+		note = &notes.Note{Title: title}
+	}
+
+	err = renderTemplate(w, "edit.html", note)
+	if err != nil {
+		log.Println(err)
+		http.Error(w, "Couldn't load template", http.StatusInternalServerError)
+		return
+	}
+}
+
+func saveHandler(w http.ResponseWriter, r *http.Request) {
+	title := r.PathValue("note")
+	body := r.FormValue("body")
+	note := &notes.Note{Title: title, Body: []byte(body)}
+	note.Save()
+	http.Redirect(w, r, myurls.Reverse("view", map[string]string{"note": title}), http.StatusFound)
+}
+
+func renderTemplate(w http.ResponseWriter, tmpl string, note *notes.Note) error {
+	t, err := template.ParseFiles(filepath.Join(conf.Conf.TemplatesDir, tmpl))
+	t.Execute(w, note)
+	return err
+}
diff --git a/internal/urls/urls.go b/internal/urls/urls.go
new file mode 100644
index 0000000..2e3f08a
--- /dev/null
+++ b/internal/urls/urls.go
@@ -0,0 +1,47 @@
+// Package to manage routing of urls in net/http
+// URLs type is the main thing of interest
+package urls
+
+import (
+	"fmt"
+	"net/http"
+	"regexp"
+)
+
+// Represent a single URL with a name, a pattern and supported protocol
+type URL struct {
+	Handler  func(http.ResponseWriter, *http.Request)
+	Path     string
+	Protocol string
+}
+
+// Return the corresponding net/http pattern for a URL
+func (url *URL) GetPattern() string {
+	return fmt.Sprintf("%s %s", url.Protocol, url.Path)
+}
+
+// Represent a set of URLs at a prefix
+type URLs struct {
+	URLs   map[string]URL
+	Prefix string
+}
+
+// Given a name and replacements, return a rendered path component of a URL
+func (urls URLs) Reverse(name string, replacements map[string]string) string {
+	pattern := urls.URLs[name].Path
+
+	for key, val := range replacements {
+		re := regexp.MustCompile("{" + key + "}")
+		pattern = re.ReplaceAllString(pattern, val)
+	}
+	return urls.Prefix + pattern
+}
+
+// Return router for the urls
+func (urls URLs) GetRouter() *http.ServeMux {
+	router := http.NewServeMux()
+	for _, url := range urls.URLs {
+		router.HandleFunc(url.GetPattern(), url.Handler)
+	}
+	return router
+}
diff --git a/templates/edit.html b/templates/edit.html
new file mode 100644
index 0000000..80a1b49
--- /dev/null
+++ b/templates/edit.html
@@ -0,0 +1,6 @@
+<h1>Editing {{.Title}}</h1>
+
+<form action="save/" method="POST">
+    <textarea name="body">{{printf "%s" .Body}}</textarea>
+    <input type="submit" value="Save">
+</form>
diff --git a/templates/view.html b/templates/view.html
new file mode 100644
index 0000000..59e2cce
--- /dev/null
+++ b/templates/view.html
@@ -0,0 +1,3 @@
+<h1>{{.Title}}</h1>
+
+<div>{{printf "%s" .BodyRendered}}</div>