Add support for gemtext posts

src/cmd/load-test-data/test-data.yml

@@ -8,6 +8,7 @@ published_posts:
     tags:
       - foo
     series: testing
+    format: md
     body: |
 
       This here's a test post containing various markdown elements in its body.
@@ -59,17 +60,83 @@ published_posts:
 
       Here's a real picture of cyberspace.
 
-      ![not a sound stage]({{ AssetURL "galaxy.jpg" }})
+      {{ Image "galaxy.jpg" }}
 
       This has been a great post.
 
-  - id: empty-test
-    title: Empty Test
+  - id: gemtext-test
+    title: Gemtext Test
+    description: A little post containing different kinds of gemtext elements.
+    tags:
+      - foo
+    series: testing
+    format: gmi
+    body: |
+
+      This here's a test post containing various markdown elements in its body. It's useful for making sure that posts will look good (generally).
+
+      ## Let's Begin
+
+      There's various things worth testing. Like lists:
+
+      * Foo
+      * Bar
+      * Baz
+
+      So many!
+
+      ### A Subsection
+
+      And it only gets crazier from here!
+
+      Check out this code block.
+
+      ```
+      // It's like actually being in the matrix
+      for !dead {
+        if awake {
+          work()
+        } else {
+          continue
+        }
+      }
+      ```
+
+      Edgy.
+
+      #### Side-note
+
+      Did you know that the terms "cyberspace" and "matrix" are attributable to a book from 1984 called _Neuromancer_?
+
+      > The 1999 cyberpunk science fiction film The Matrix particularly draws from Neuromancer both eponym and usage of the term "matrix".
+      > - Wikipedia
+
+      Here's a real picture of cyberspace.
+
+      {{ Image "galaxy.jpg" "Definitely not a sound stage" }}
+
+      This has been a great post.
+
+      => / Here's a link outa here!
+
+  - id: empty-markdown-test
+    title: Empty Markdown Test
     description:
     tags:
       - foo
       - bar
     series: testing
+    format: md
+    body: ""
+
+  - id: empty-gemtext-test
+    title: Empty Gemtext Test
+    description:
+    tags:
+      - foo
+      - bar
+    series: testing
+    format: gmi
     body: ""
 
   - id: little-markdown-test
@@ -78,6 +145,17 @@ published_posts:
     tags:
       - bar
     series: testing
+    format: md
+    body: |
+      This page is almost empty.
+
+  - id: little-gemtext-test
+    title: Little Gemtext Test
+    description: A post with almost no content.
+    tags:
+      - bar
+    series: testing
+    format: gmi
     body: |
       This page is almost empty.
 

src/gmi/gemtext.go

@@ -0,0 +1,73 @@
+package gmi
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"io"
+	"log"
+	"path"
+	"regexp"
+	"strings"
+)
+
+func hasImgExt(p string) bool {
+	switch path.Ext(strings.ToLower(p)) {
+	case ".jpg", ".jpeg", ".png", ".gif", ".svg":
+		return true
+	default:
+		return false
+	}
+}
+
+// matches `=> dstURL [optional description]`
+var linkRegexp = regexp.MustCompile(`^=>\s+(\S+)\s*(.*?)\s*$`)
+
+// GemtextToMarkdown reads a gemtext formatted body from the Reader and writes
+// the markdown version of that body to the Writer.
+func GemtextToMarkdown(dst io.Writer, src io.Reader) error {
+
+	bufSrc := bufio.NewReader(src)
+
+	for {
+
+		line, err := bufSrc.ReadString('\n')
+		if err != nil && !errors.Is(err, io.EOF) {
+			return fmt.Errorf("reading: %w", err)
+		}
+
+		last := err == io.EOF
+
+		if match := linkRegexp.FindStringSubmatch(line); len(match) > 0 {
+
+			isImg := hasImgExt(match[1])
+
+			descr := match[2]
+
+			if descr != "" {
+				// ok
+			} else if isImg {
+				descr = "Image"
+			} else {
+				descr = "Link"
+			}
+
+			log.Printf("descr:%q", descr)
+
+			line = fmt.Sprintf("[%s](%s)\n", descr, match[1])
+
+			if isImg {
+				line = "!" + line
+			}
+		}
+
+		if _, err := dst.Write([]byte(line)); err != nil {
+			return fmt.Errorf("writing: %w", err)
+		}
+
+		if last {
+			return nil
+		}
+	}
+
+}

src/gmi/gemtext_test.go

@@ -0,0 +1,51 @@
+package gmi
+
+import (
+	"bytes"
+	"strconv"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGemtextToMarkdown(t *testing.T) {
+
+	tests := []struct {
+		in, exp string
+	}{
+		{
+			in:  "",
+			exp: "",
+		},
+		{
+			in:  "=> foo",
+			exp: "[Link](foo)\n",
+		},
+		{
+			in:  "what\n=> foo\n=> bar",
+			exp: "what\n[Link](foo)\n[Link](bar)\n",
+		},
+		{
+			in:  "=> foo description is here   ",
+			exp: "[description is here](foo)\n",
+		},
+		{
+			in:  "=> img.png",
+			exp: "![Image](img.png)\n",
+		},
+		{
+			in:  "=> img.png description is here   ",
+			exp: "![description is here](img.png)\n",
+		},
+	}
+
+	for i, test := range tests {
+		t.Run(strconv.Itoa(i), func(t *testing.T) {
+
+			got := new(bytes.Buffer)
+			err := GemtextToMarkdown(got, bytes.NewBufferString(test.in))
+			assert.NoError(t, err)
+			assert.Equal(t, test.exp, got.String())
+		})
+	}
+}

src/gmi/gmi.go

@@ -0,0 +1,2 @@
+// Package gmi contains utilities for working with gemini and gemtext
+package gmi

src/http/posts.go

@@ -15,24 +15,30 @@ import (
 	"github.com/gomarkdown/markdown"
 	"github.com/gomarkdown/markdown/html"
 	"github.com/gomarkdown/markdown/parser"
+	"github.com/mediocregopher/blog.mediocregopher.com/srv/gmi"
 	"github.com/mediocregopher/blog.mediocregopher.com/srv/http/apiutil"
 	"github.com/mediocregopher/blog.mediocregopher.com/srv/post"
 	"github.com/mediocregopher/mediocre-go-lib/v2/mctx"
 )
 
-func (a *api) parsePostBody(post post.Post) (*txttpl.Template, error) {
+func (a *api) parsePostBody(p post.Post) (*txttpl.Template, error) {
 	tpl := txttpl.New("root")
 	tpl = tpl.Funcs(txttpl.FuncMap(a.tplFuncs()))
 
 	tpl = txttpl.Must(tpl.New("image.html").Parse(mustReadTplFile("image.html")))
+
+	if p.Format == post.FormatMarkdown {
 		tpl = tpl.Funcs(txttpl.FuncMap{
 			"Image": func(id string) (string, error) {
 
 				tplPayload := struct {
 					ID        string
+					Descr     string
 					Resizable bool
 				}{
 					ID: id,
+					// I could use variadic args to make this work, I think
+					Descr:     "TODO: proper alt text",
 					Resizable: isImgResizable(id),
 				}
 
@@ -44,8 +50,33 @@ func (a *api) parsePostBody(post post.Post) (*txttpl.Template, error) {
 				return buf.String(), nil
 			},
 		})
+	}
 
-	tpl, err := tpl.New(post.ID + "-body.html").Parse(post.Body)
+	if p.Format == post.FormatGemtext {
+		tpl = tpl.Funcs(txttpl.FuncMap{
+			"Image": func(id, descr string) (string, error) {
+
+				tplPayload := struct {
+					ID        string
+					Descr     string
+					Resizable bool
+				}{
+					ID:        id,
+					Descr:     descr,
+					Resizable: isImgResizable(id),
+				}
+
+				buf := new(bytes.Buffer)
+				if err := tpl.ExecuteTemplate(buf, "image.html", tplPayload); err != nil {
+					return "", err
+				}
+
+				return buf.String(), nil
+			},
+		})
+	}
+
+	tpl, err := tpl.New(p.ID + "-body.html").Parse(p.Body)
 
 	if err != nil {
 		return nil, err
@@ -73,6 +104,16 @@ func (a *api) postToPostTplPayload(storedPost post.StoredPost) (postTplPayload,
 		return postTplPayload{}, fmt.Errorf("executing post body as template: %w", err)
 	}
 
+	if storedPost.Format == post.FormatGemtext {
+
+		prevBodyBuf := bodyBuf
+		bodyBuf = new(bytes.Buffer)
+
+		if err := gmi.GemtextToMarkdown(bodyBuf, prevBodyBuf); err != nil {
+			return postTplPayload{}, fmt.Errorf("converting gemtext to markdown: %w", err)
+		}
+	}
+
 	// this helps the markdown renderer properly parse pages which end in a
 	// `</script>` tag... I don't know why.
 	_, _ = bodyBuf.WriteString("\n")
@@ -324,10 +365,12 @@ func (a *api) editPostHandler(isDraft bool) http.Handler {
 			Post    post.StoredPost
 			Tags    []string
 			IsDraft bool
+			Formats []post.Format
 		}{
 			Post:    storedPost,
 			Tags:    tags,
 			IsDraft: isDraft,
+			Formats: post.Formats,
 		}
 
 		executeTemplate(rw, r, tpl, tplPayload)
@@ -336,12 +379,23 @@ func (a *api) editPostHandler(isDraft bool) http.Handler {
 
 func postFromPostReq(r *http.Request) (post.Post, error) {
 
+	formatStr := r.PostFormValue("format")
+	if formatStr == "" {
+		return post.Post{}, errors.New("format is required")
+	}
+
+	format, err := post.FormatFromString(formatStr)
+	if err != nil {
+		return post.Post{}, fmt.Errorf("parsing format: %w", err)
+	}
+
 	p := post.Post{
 		ID:          r.PostFormValue("id"),
 		Title:       r.PostFormValue("title"),
 		Description: r.PostFormValue("description"),
 		Tags:        strings.Fields(r.PostFormValue("tags")),
 		Series:      r.PostFormValue("series"),
+		Format:      format,
 	}
 
 	// textareas encode newlines as CRLF for historical reasons
@@ -353,7 +407,7 @@ func postFromPostReq(r *http.Request) (post.Post, error) {
 		p.Title == "" ||
 		p.Body == "" ||
 		len(p.Tags) == 0 {
-		return post.Post{}, errors.New("ID, Title, Tags, and Body are all required")
+		return post.Post{}, errors.New("id, ritle, tags, and body are all required")
 	}
 
 	return p, nil

src/http/tpl.go

@@ -61,6 +61,11 @@ func (a *api) manageAssetsURL(abs bool) string {
 	return a.blogURL("assets?method=manage", abs)
 }
 
+func (a *api) assetURL(id string, abs bool) string {
+	path := filepath.Join("assets", id)
+	return a.blogURL(path, false)
+}
+
 func (a *api) draftPostURL(id string, abs bool) string {
 	path := filepath.Join("drafts", id)
 	return a.blogURL(path, abs)
@@ -96,8 +101,7 @@ func (a *api) tplFuncs() template.FuncMap {
 			return a.postURL(id, false)
 		},
 		"AssetURL": func(id string) string {
-			path := filepath.Join("assets", id)
-			return a.blogURL(path, false)
+			return a.assetURL(id, false)
 		},
 		"DraftURL": func(id string) string {
 			return a.draftPostURL(id, false)

src/http/tpl/image.html

@@ -1,5 +1,8 @@
 <div style="text-align: center;">
   <a href="{{ AssetURL .ID }}" target="_blank">
-    <img src="{{ AssetURL .ID }}{{ if .Resizable }}?w=800{{ end }}" />
+    <img
+      src="{{ AssetURL .ID }}{{ if .Resizable }}?w=800{{ end }}"
+      alt="{{ .Descr }}"
+      />
   </a>
 </div>

src/http/tpl/post-edit.html

@@ -25,6 +25,7 @@
         <input
             name="id"
             type="text"
+            required
             placeholder="e.g. how-to-fly-a-kite"
             value="{{ .Payload.Post.ID }}" />
         {{ else if .Payload.IsDraft }}
@@ -43,6 +44,7 @@
         <input
             name="tags"
             type="text"
+            required
             value="{{- range $i, $tag := .Payload.Post.Tags -}}
                      {{- if ne $i 0 }} {{ end }}{{ $tag -}}
                    {{- end -}}
@@ -75,6 +77,7 @@
         <input
             name="title"
             type="text"
+            required
             value="{{ .Payload.Post.Title }}" />
       </td>
     </tr>
@@ -89,11 +92,33 @@
       </td>
     </tr>
 
+    <tr>
+      <td>Format</td>
+      <td>
+        <select name="format" required>
+          <option value=""></option>
+
+          {{ $format := .Payload.Post.Format }}
+          {{ range .Payload.Formats -}}
+          <option
+            {{- if eq . $format }}
+            selected
+            {{- end }}
+            value="{{ . }}" >
+            {{ . }}
+          </option>
+          {{- end }}
+
+        </select>
+      </td>
+    </tr>
+
   </table>
 
   <p>
     <textarea
       name="body"
+      required
       placeholder="Post body"
       style="width:100%;height: 75vh;"
       >