tpl: Rework to handle both text and HTML templates

Before this commit, Hugo used `html/template` for all Go templates.

While this is a fine choice for HTML and maybe also RSS feeds, it is painful for plain text formats such as CSV, JSON etc.

This commit fixes that by using the `IsPlainText` attribute on the output format to decide what to use.

A couple of notes:

* The above requires a nonambiguous template name to type mapping. I.e. `/layouts/_default/list.json` will only work if there is only one JSON output format, `/layouts/_default/list.mytype.json` will always work.
* Ambiguous types will fall back to HTML.
* Partials inherits the text vs HTML identificator of the container template. This also means that plain text templates can only include plain text partials.
* Shortcode templates are, by definition, currently HTML templates only.

Fixes #3221

1 files changed, 70 insertions, 5 deletions

diff --git a/hugolib/site_output_test.go b/hugolib/site_output_test.go
index 86e1a55ca..0edd8e1f0 100644
--- a/hugolib/site_output_test.go
+++ b/hugolib/site_output_test.go
@@ -18,6 +18,8 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/spf13/afero"
+
 	"github.com/stretchr/testify/require"
 
 	"fmt"
@@ -75,6 +77,21 @@ disableKinds = ["page", "section", "taxonomy", "taxonomyTerm", "RSS", "sitemap",
 [Taxonomies]
 tag = "tags"
 category = "categories"
+
+defaultContentLanguage = "en"
+
+[languages]
+
+[languages.en]
+title = "Title in English"
+languageName = "English"
+weight = 1
+
+[languages.nn]
+languageName = "Nynorsk"
+weight = 2
+title = "Tittel på Nynorsk"
+
 `
 
 	pageTemplate := `---
@@ -84,27 +101,59 @@ outputs: %s
 # Doc
 `
 
-	th, h := newTestSitesFromConfig(t, siteConfig,
-		"layouts/_default/list.json", `List JSON|{{ .Title }}|{{ .Content }}|Alt formats: {{ len .AlternativeOutputFormats -}}|
+	mf := afero.NewMemMapFs()
+
+	writeToFs(t, mf, "i18n/en.toml", `
+[elbow]
+other = "Elbow"
+`)
+	writeToFs(t, mf, "i18n/nn.toml", `
+[elbow]
+other = "Olboge"
+`)
+
+	th, h := newTestSitesFromConfig(t, mf, siteConfig,
+
+		"layouts/_default/baseof.json", `START JSON:{{block "main" .}}default content{{ end }}:END JSON`,
+		"layouts/_default/baseof.html", `START HTML:{{block "main" .}}default content{{ end }}:END HTML`,
+
+		"layouts/_default/list.json", `{{ define "main" }}
+List JSON|{{ .Title }}|{{ .Content }}|Alt formats: {{ len .AlternativeOutputFormats -}}|
 {{- range .AlternativeOutputFormats -}}
 Alt Output: {{ .Name -}}|
 {{- end -}}|
 {{- range .OutputFormats -}}
-Output/Rel: {{ .Name -}}/{{ .Rel }}|
+Output/Rel: {{ .Name -}}/{{ .Rel }}|{{ .MediaType }}
+{{- end -}}
+ {{ with .OutputFormats.Get "JSON" }}
+<atom:link href={{ .Permalink }} rel="self" type="{{ .MediaType }}" />
+{{ end }}
+{{ .Site.Language.Lang }}: {{ T "elbow" -}}
+{{ end }}
+`,
+		"layouts/_default/list.html", `{{ define "main" }}
+List HTML|{{.Title }}|
+{{- with .OutputFormats.Get "HTML" -}}
+<atom:link href={{ .Permalink }} rel="self" type="{{ .MediaType }}" />
 {{- end -}}
+{{ .Site.Language.Lang }}: {{ T "elbow" -}}
+{{ end }}
 `,
 	)
-	require.Len(t, h.Sites, 1)
+	require.Len(t, h.Sites, 2)
 
 	fs := th.Fs
 
 	writeSource(t, fs, "content/_index.md", fmt.Sprintf(pageTemplate, "JSON Home", outputsStr))
+	writeSource(t, fs, "content/_index.nn.md", fmt.Sprintf(pageTemplate, "JSON Nynorsk Heim", outputsStr))
 
 	err := h.Build(BuildCfg{})
 
 	require.NoError(t, err)
 
 	s := h.Sites[0]
+	require.Equal(t, "en", s.Language.Lang)
+
 	home := s.getPage(KindHome)
 
 	require.NotNil(t, home)
@@ -113,7 +162,6 @@ Output/Rel: {{ .Name -}}/{{ .Rel }}|
 
 	require.Len(t, home.outputFormats, lenOut)
 
-	// TODO(bep) output assert template/text
 	// There is currently always a JSON output to make it simpler ...
 	altFormats := lenOut - 1
 	hasHTML := helpers.InStringArray(outputs, "html")
@@ -127,10 +175,27 @@ Output/Rel: {{ .Name -}}/{{ .Rel }}|
 			"Alt Output: HTML",
 			"Output/Rel: JSON/alternate|",
 			"Output/Rel: HTML/canonical|",
+			"en: Elbow",
+		)
+
+		th.assertFileContent("public/index.html",
+			// The HTML entity is a deliberate part of this test: The HTML templates are
+			// parsed with html/template.
+			`List HTML|JSON Home|<atom:link href=http://example.com/blog/ rel="self" type="text/html&#43;html" />`,
+			"en: Elbow",
 		)
+		th.assertFileContent("public/nn/index.html",
+			"List HTML|JSON Nynorsk Heim|",
+			"nn: Olboge")
 	} else {
 		th.assertFileContent("public/index.json",
 			"Output/Rel: JSON/canonical|",
+			// JSON is plain text, so no need to safeHTML this and that
+			`<atom:link href=http://example.com/blog/index.json rel="self" type="application/json+json" />`,
+		)
+		th.assertFileContent("public/nn/index.json",
+			"List JSON|JSON Nynorsk Heim|",
+			"nn: Olboge",
 		)
 	}