Completed markdown and HTML conversion.

author: tjpcc <tjp@ctrl-c.club> 2023-01-15 19:59:58 -0700
committer: tjpcc <tjp@ctrl-c.club> 2023-01-15 19:59:58 -0700
commit: 4c2630752f7367fff491a6ba53303e9102da7da0 (patch)
tree: 7819a03ddd08e9ee017e7245dfd58cde9f51857d /gemtext
parent: cec3718bdd089bcf58575740c5ae4f86b27226d1 (diff)
5 files changed, 337 insertions, 56 deletions
diff --git a/gemtext/htmlconv/convert.go b/gemtext/htmlconv/convert.go
new file mode 100644
index 0000000..c703211
--- /dev/null
+++ b/gemtext/htmlconv/convert.go
@@ -0,0 +1,86 @@
+package htmlconv
+
+import (
+	"html/template"
+	"io"
+
+	"tildegit.org/tjp/gus/gemtext"
+	"tildegit.org/tjp/gus/gemtext/internal"
+)
+
+// Convert writes markdown to a writer from the provided gemtext document.
+//
+// Templates can be provided to override the output for different line types.
+// The templates supported are:
+//   - "header" is called before any lines and is passed the full Document.
+//   - "footer" is called after the lines and is passed the full Document.
+//   - "textline" is called once per line of text and is passed a gemtext.TextLine.
+//   - "linkline" is called once per link line and is passed an object which wraps
+//     a gemtext.LinkLine but also supports a ValidatedURL() method returning a
+//     string which html/template will always allow as href attributes.
+//   - "preformattedtextlines" is called once for a block of preformatted text and is
+//     passed a slice of gemtext.PreformattedTextLines.
+//   - "heading1line" is called once per h1 line and is passed a gemtext.Heading1Line.
+//   - "heading2line" is called once per h2 line and is passed a gemtext.Heading2Line.
+//   - "heading3line" is called once per h3 line and is passed a gemtext.Heading3Line.
+//   - "listitemlines" is called once for a block of contiguous list item lines and
+//     is passed a slice of gemtext.ListItemLines.
+//   - "quoteline" is passed once per blockquote line and is passed a gemtext.QuoteLine.
+//
+// There exist default implementations of each of these templates, so the "overrides"
+// argument can be nil.
+func Convert(wr io.Writer, doc gemtext.Document, overrides *template.Template) error {
+	if err := internal.ValidateLinks(doc); err != nil {
+		return err
+	}
+
+	tmpl, err := baseTmpl.Clone()
+	if err != nil {
+		return err
+	}
+
+	tmpl, err = internal.AddHTMLTemplates(tmpl, overrides)
+	if err != nil {
+		return err
+	}
+
+	for _, item := range internal.RenderItems(doc) {
+		if err := tmpl.ExecuteTemplate(wr, item.Template, item.Object); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+var baseTmpl = template.Must(template.New("htmlconv").Parse(`
+{{ define "header" }}<html><body>{{ end }}
+{{ define "textline" }}{{ if ne .String "\n" }}<p>{{ . }}</p>{{ end }}{{ end }}
+{{ define "linkline" -}}
+	<p>=> <a href="{{ .ValidatedURL }}">{{ if eq .Label "" -}}
+		{{ .URL }}
+	{{- else -}}
+		{{ .Label }}
+	{{- end -}}
+	</a></p>
+{{- end }}
+{{ define "preformattedtextlines" -}}
+	<pre>
+	{{- range . -}}
+		{{ . }}
+	{{- end -}}
+	</pre>
+{{- end }}
+{{ define "heading1line" }}<h1>{{ .Body }}</h1>{{ end }}
+{{ define "heading2line" }}<h2>{{ .Body }}</h2>{{ end }}
+{{ define "heading3line" }}<h3>{{ .Body }}</h3>{{ end }}
+{{ define "listitemlines" -}}
+	<ul>
+	{{- range . -}}
+		<li>{{ .Body }}</li>
+	{{- end -}}
+	</ul>
+{{- end }}
+{{ define "quoteline" }}<blockquote>{{ .Body }}</blockquote>{{ end }}
+{{ define "footer" }}</body></html>{{ end }}
+`))
diff --git a/gemtext/htmlconv/convert_test.go b/gemtext/htmlconv/convert_test.go
new file mode 100644
index 0000000..967cece
--- /dev/null
+++ b/gemtext/htmlconv/convert_test.go
@@ -0,0 +1,46 @@
+package htmlconv_test
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"tildegit.org/tjp/gus/gemtext"
+	"tildegit.org/tjp/gus/gemtext/htmlconv"
+)
+
+var gmiDoc = `
+# top-level header line
+
+## subtitle
+
+This is some non-blank regular text.
+
+* an
+* unordered
+* list
+
+=> gemini://google.com/ as if
+=> https://google.com/
+
+> this is a quote
+> -tjp
+
+`[1:] + "```pre-formatted code\ndoc := gemtext.Parse(req.Body)\n```ignored closing alt-text\n"
+
+func TestConvert(t *testing.T) {
+	htmlDoc := `
+<html><body><h1>top-level header line</h1><h2>subtitle</h2><p>This is some non-blank regular text.
+</p><ul><li>an</li><li>unordered</li><li>list</li></ul><p>=> <a href="gemini://google.com/">as if</a></p><p>=> <a href="https://google.com/">https://google.com/</a></p><blockquote> this is a quote</blockquote><blockquote> -tjp</blockquote><pre>doc := gemtext.Parse(req.Body)
+</pre></body></html>`[1:]
+
+	doc, err := gemtext.Parse(bytes.NewBufferString(gmiDoc))
+	require.Nil(t, err)
+
+	buf := &bytes.Buffer{}
+	require.Nil(t, htmlconv.Convert(buf, doc, nil))
+
+	assert.Equal(t, htmlDoc, buf.String())
+}
diff --git a/gemtext/internal/templates.go b/gemtext/internal/templates.go
new file mode 100644
index 0000000..dea528a
--- /dev/null
+++ b/gemtext/internal/templates.go
@@ -0,0 +1,150 @@
+package internal
+
+import (
+	htemplate "html/template"
+	"net/url"
+	"text/template"
+
+	"tildegit.org/tjp/gus/gemtext"
+)
+
+var Renderers = map[gemtext.LineType]string{
+	gemtext.LineTypeText:     "textline",
+	gemtext.LineTypeLink:     "linkline",
+	gemtext.LineTypeHeading1: "heading1line",
+	gemtext.LineTypeHeading2: "heading2line",
+	gemtext.LineTypeHeading3: "heading3line",
+	gemtext.LineTypeQuote:    "quoteline",
+}
+
+func AddAllTemplates(base *template.Template, additions *template.Template) (*template.Template, error) {
+	if additions == nil {
+		return base, nil
+	}
+
+	tmpl := base
+	var err error
+	for _, addition := range additions.Templates() {
+		tmpl, err = tmpl.AddParseTree(addition.Name(), addition.Tree)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return tmpl, nil
+}
+
+func AddHTMLTemplates(base *htemplate.Template, additions *htemplate.Template) (*htemplate.Template, error) {
+	if additions == nil {
+		return base, nil
+	}
+
+	tmpl := base
+	var err error
+	for _, addition := range additions.Templates() {
+		tmpl, err = tmpl.AddParseTree(addition.Name(), addition.Tree)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return tmpl, nil
+}
+
+func ValidateLinks(doc gemtext.Document) error {
+	for _, line := range doc {
+		if linkLine, ok := line.(gemtext.LinkLine); ok {
+			_, err := url.Parse(linkLine.URL())
+			if err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+type RenderItem struct {
+	Template string
+	Object   any
+}
+
+func RenderItems(doc gemtext.Document) []RenderItem {
+	out := make([]RenderItem, 0, len(doc))
+	out = append(out, RenderItem{
+		Template: "header",
+		Object:   doc,
+	})
+
+	inUL := false
+	ulStart := 0
+	inPF := false
+	pfStart := 0
+
+	for i, line := range doc {
+		switch line.Type() {
+		case gemtext.LineTypeListItem:
+			if !inUL {
+				inUL = true
+				ulStart = i
+			}
+		case gemtext.LineTypePreformatToggle:
+			if inUL {
+				inUL = false
+				out = append(out, RenderItem{
+					Template: "listitemlines",
+					Object:   doc[ulStart:i],
+				})
+			}
+			if !inPF {
+				inPF = true
+				pfStart = i
+			} else {
+				inPF = false
+				out = append(out, RenderItem{
+					Template: "preformattedtextlines",
+					Object:   doc[pfStart+1 : i],
+				})
+			}
+		case gemtext.LineTypePreformattedText:
+		default:
+			if inUL {
+				inUL = false
+				out = append(out, RenderItem{
+					Template: "listitemlines",
+					Object:   doc[ulStart:i],
+				})
+			}
+
+			if linkLine, ok := line.(gemtext.LinkLine); ok {
+				line = validatedLinkLine{linkLine}
+			}
+
+			out = append(out, RenderItem{
+				Template: Renderers[line.Type()],
+				Object:   line,
+			})
+		}
+	}
+
+	if inUL {
+		out = append(out, RenderItem{
+			Template: "listitemlines",
+			Object:   doc[ulStart:],
+		})
+	}
+
+	out = append(out, RenderItem{
+		Template: "footer",
+		Object:   doc,
+	})
+
+	return out
+}
+
+type validatedLinkLine struct {
+	gemtext.LinkLine
+}
+
+func (vll validatedLinkLine) ValidatedURL() htemplate.URL {
+	return htemplate.URL(vll.URL())
+}
diff --git a/gemtext/mdconv/convert.go b/gemtext/mdconv/convert.go
index 0c92f9f..9371d92 100644
--- a/gemtext/mdconv/convert.go
+++ b/gemtext/mdconv/convert.go
@@ -1,72 +1,72 @@
 package mdconv
 
 import (
-	"fmt"
 	"io"
 	"text/template"
 
 	"tildegit.org/tjp/gus/gemtext"
+	"tildegit.org/tjp/gus/gemtext/internal"
 )
 
+// Convert writes markdown to a writer from the provided gemtext document.
+//
+// Templates can be provided to override the output for different line types.
+// The templates supported are:
+//   - "header" is called before any lines and is passed the full Document.
+//   - "footer" is called after the lines and is passed the full Document.
+//   - "textline" is called once per line of text and is passed a gemtext.TextLine.
+//   - "linkline" is called once per link line and is passed a gemtext.LinkLine.
+//   - "preformattedtextlines" is called once for a block of preformatted text and is
+//     passed a slice of gemtext.PreformattedTextLines.
+//   - "heading1line" is called once per h1 line and is passed a gemtext.Heading1Line.
+//   - "heading2line" is called once per h2 line and is passed a gemtext.Heading2Line.
+//   - "heading3line" is called once per h3 line and is passed a gemtext.Heading3Line.
+//   - "listitemlines" is called once for a block of contiguous list item lines and
+//     is passed a slice of gemtext.ListItemLines.
+//   - "quoteline" is passed once per blockquote line and is passed a gemtext.QuoteLine.
+//
+// There exist default implementations of each of these templates, so the "overrides"
+// argument can be nil.
 func Convert(wr io.Writer, doc gemtext.Document, overrides *template.Template) error {
+	if err := internal.ValidateLinks(doc); err != nil {
+		return err
+	}
+
 	tmpl, err := baseTmpl.Clone()
 	if err != nil {
 		return err
 	}
 
-	if overrides != nil {
-		for _, override := range overrides.Templates() {
-			tmpl, err = tmpl.AddParseTree(override.Name(), override.Tree)
-			if err != nil {
-				return err
-			}
+	tmpl, err = internal.AddAllTemplates(tmpl, overrides)
+	if err != nil {
+		return err
+	}
+
+	for _, item := range internal.RenderItems(doc) {
+		if err := tmpl.ExecuteTemplate(wr, item.Template, item.Object); err != nil {
+			return err
 		}
 	}
 
-	return tmpl.ExecuteTemplate(wr, "mdconv", doc)
+	return nil
 }
 
-var baseTmpl = template.Must(template.New("mdconv").Parse(fmt.Sprintf((`
-{{block "header" .}}{{end -}}
-{{range . -}}
-{{if .Type | eq %d}}{{block "textline" . -}}
-	{{. -}}
-{{end -}}
-{{else if .Type | eq %d}}{{block "linkline" . -}}
-	=> [{{if eq .Label ""}}{{.URL}}{{else}}{{.Label}}{{end}}]({{.URL}})
-{{end -}}
-{{else if .Type | eq %d}}{{block "preformattoggleline" . -}}
-	` + "```" + `
-{{end -}}
-{{else if .Type | eq %d}}{{block "preformattedtextline" . -}}
-	{{. -}}
-{{end -}}
-{{else if .Type | eq %d}}{{block "heading1line" . -}}
-	# {{.Body}}
-{{end -}}
-{{else if .Type | eq %d}}{{block "heading2line" . -}}
-	## {{.Body}}
-{{end -}}
-{{else if .Type | eq %d}}{{block "heading3line" . -}}
-	### {{.Body}}
-{{end -}}
-{{else if .Type | eq %d}}{{block "listitemline" . -}}
-	* {{.Body}}
-{{end -}}
-{{else if .Type | eq %d}}{{block "quoteline" . -}}
-	> {{.Body}}
-{{end -}}
-{{end -}}
-{{end -}}
-{{block "footer" .}}{{end -}}
-`)[1:],
-	gemtext.LineTypeText,
-	gemtext.LineTypeLink,
-	gemtext.LineTypePreformatToggle,
-	gemtext.LineTypePreformattedText,
-	gemtext.LineTypeHeading1,
-	gemtext.LineTypeHeading2,
-	gemtext.LineTypeHeading3,
-	gemtext.LineTypeListItem,
-	gemtext.LineTypeQuote,
-)))
+var baseTmpl = template.Must(template.New("mdconv").Parse(`
+{{ define "header" }}{{ end }}
+{{ define "textline" }}{{ . }}{{ end }}
+{{ define "linkline" -}}
+	=> [{{ if eq .Label "" }}{{ .URL }}{{ else }}{{ .Label }}{{ end }}]({{ .URL }})
+{{ end }}
+{{ define "preformattedtextlines" }}` + "```\n" + `{{ range . }}{{ . }}{{ end }}` + "```\n" + `{{ end }}
+{{ define "heading1line" }}# {{ .Body }}
+{{ end }}
+{{ define "heading2line" }}## {{ .Body }}
+{{ end }}
+{{ define "heading3line" }}### {{ .Body }}
+{{ end }}
+{{ define "listitemlines" }}{{ range . }}* {{ .Body }}
+{{ end }}{{ end }}
+{{ define "quoteline" }}> {{ .Body }}
+{{ end }}
+{{ define "footer" }}{{ end }}
+`))
diff --git a/gemtext/mdconv/convert_test.go b/gemtext/mdconv/convert_test.go
index 6cde08b..010ddce 100644
--- a/gemtext/mdconv/convert_test.go
+++ b/gemtext/mdconv/convert_test.go
@@ -78,17 +78,16 @@ text:
 > quote:  this is a quote
 > quote:  -tjp
 text: 
-`[1:] + "pftoggle: ```\npf: doc := gemtext.Parse(req.Body)\npftoggle: ```\n"
+`[1:] + "```\npf: doc := gemtext.Parse(req.Body)\n```\n"
 
 	overrides := template.Must(template.New("overrides").Parse((`
 		{{define "textline"}}text: {{.}}{{end}}
 		{{define "linkline"}}=> link: [{{if eq .Label ""}}{{.URL}}{{else}}{{.Label}}{{end}}]({{.URL}})` + "\n" + `{{end}}
-		{{define "preformattoggleline"}}pftoggle: ` + "```\n" + `{{end}}
-		{{define "preformattedtextline"}}pf: {{.}}{{end}}
+		{{define "preformattedtextlines"}}` + "```\n" + `{{range . }}pf: {{.}}{{end}}` + "```\n" + `{{end}}
 		{{define "heading1line"}}# h1: {{.Body}}` + "\n" + `{{end}}
 		{{define "heading2line"}}## h2: {{.Body}}` + "\n" + `{{end}}
 		{{define "heading3line"}}### h3: {{.Body}}` + "\n" + `{{end}}
-		{{define "listitemline"}}* li: {{.Body}}` + "\n" + `{{end}}
+		{{define "listitemlines"}}{{range .}}* li: {{.Body}}` + "\n" + `{{end}}{{end}}
 		{{define "quoteline"}}> quote: {{.Body}}` + "\n" + `{{end}}
 		`)[1:]))
author	tjpcc <tjp@ctrl-c.club>	2023-01-15 19:59:58 -0700
committer	tjpcc <tjp@ctrl-c.club>	2023-01-15 19:59:58 -0700
commit	4c2630752f7367fff491a6ba53303e9102da7da0 (patch)
tree	7819a03ddd08e9ee017e7245dfd58cde9f51857d /gemtext
parent	cec3718bdd089bcf58575740c5ae4f86b27226d1 (diff)