Add Hugo Piper with SCSS support and much more

Before this commit, you would have to use page bundles to do image processing etc. in Hugo.

This commit adds

* A new `/assets` top-level project or theme dir (configurable via `assetDir`)
* A new template func, `resources.Get` which can be used to "get a resource" that can be further processed.

This means that you can now do this in your templates (or shortcodes):

```bash
{{ $sunset := (resources.Get "images/sunset.jpg").Fill "300x200" }}
```

This also adds a new `extended` build tag that enables powerful SCSS/SASS support with source maps. To compile this from source, you will also need a C compiler installed:

```
HUGO_BUILD_TAGS=extended mage install
```

Note that you can use output of the SCSS processing later in a non-SCSSS-enabled Hugo.

The `SCSS` processor is a _Resource transformation step_ and it can be chained with the many others in a pipeline:

```bash
{{ $css := resources.Get "styles.scss" | resources.ToCSS | resources.PostCSS | resources.Minify | resources.Fingerprint }}
<link rel="stylesheet" href="{{ $styles.RelPermalink }}" integrity="{{ $styles.Data.Digest }}" media="screen">
```

The transformation funcs above have aliases, so it can be shortened to:

```bash
{{ $css := resources.Get "styles.scss" | toCSS | postCSS | minify | fingerprint }}
<link rel="stylesheet" href="{{ $styles.RelPermalink }}" integrity="{{ $styles.Data.Digest }}" media="screen">
```

A quick tip would be to avoid the fingerprinting part, and possibly also the not-superfast `postCSS` when you're doing development, as it allows Hugo to be smarter about the rebuilding.

Documentation will follow, but have a look at the demo repo in https://github.com/bep/hugo-sass-test

New functions to create `Resource` objects:

* `resources.Get` (see above)
* `resources.FromString`: Create a Resource from a string.

New `Resource` transformation funcs:

* `resources.ToCSS`: Compile `SCSS` or `SASS` into `CSS`.
* `resources.PostCSS`: Process your CSS with PostCSS. Config file support (project or theme or passed as an option).
* `resources.Minify`: Currently supports `css`, `js`, `json`, `html`, `svg`, `xml`.
* `resources.Fingerprint`: Creates a fingerprinted version of the given Resource with Subresource Integrity..
* `resources.Concat`: Concatenates a list of Resource objects. Think of this as a poor man's bundler.
* `resources.ExecuteAsTemplate`: Parses and executes the given Resource and data context (e.g. .Site) as a Go template.

Fixes #4381
Fixes #4903
Fixes #4858

1 files changed, 14 insertions, 0 deletions

diff --git a/media/mediaType_test.go b/media/mediaType_test.go
index 0cdecdeb1..f3ddb086c 100644
--- a/media/mediaType_test.go
+++ b/media/mediaType_test.go
@@ -30,12 +30,15 @@ func TestDefaultTypes(t *testing.T) {
 	}{
 		{CalendarType, "text", "calendar", "ics", "text/calendar", "text/calendar+ics"},
 		{CSSType, "text", "css", "css", "text/css", "text/css+css"},
+		{SCSSType, "text", "x-scss", "scss", "text/x-scss", "text/x-scss+scss"},
 		{CSVType, "text", "csv", "csv", "text/csv", "text/csv+csv"},
 		{HTMLType, "text", "html", "html", "text/html", "text/html+html"},
 		{JavascriptType, "application", "javascript", "js", "application/javascript", "application/javascript+js"},
 		{JSONType, "application", "json", "json", "application/json", "application/json+json"},
 		{RSSType, "application", "rss", "xml", "application/rss", "application/rss+xml"},
+		{SVGType, "image", "svg", "svg", "image/svg", "image/svg+svg"},
 		{TextType, "text", "plain", "txt", "text/plain", "text/plain+txt"},
+		{XMLType, "application", "xml", "xml", "application/xml", "application/xml+xml"},
 	} {
 		require.Equal(t, test.expectedMainType, test.tp.MainType)
 		require.Equal(t, test.expectedSubType, test.tp.SubType)
@@ -60,6 +63,13 @@ func TestGetByType(t *testing.T) {
 	require.False(t, found)
 }
 
+func TestGetFirstBySuffix(t *testing.T) {
+	assert := require.New(t)
+	f, found := DefaultTypes.GetFirstBySuffix("xml")
+	assert.True(found)
+	assert.Equal(Type{MainType: "application", SubType: "rss", Suffix: "xml", Delimiter: "."}, f)
+}
+
 func TestFromTypeString(t *testing.T) {
 	f, err := FromString("text/html")
 	require.NoError(t, err)
@@ -76,6 +86,10 @@ func TestFromTypeString(t *testing.T) {
 	_, err = FromString("noslash")
 	require.Error(t, err)
 
+	f, err = FromString("text/xml; charset=utf-8")
+	require.NoError(t, err)
+	require.Equal(t, Type{MainType: "text", SubType: "xml", Suffix: "xml", Delimiter: "."}, f)
+
 }
 
 func TestDecodeTypes(t *testing.T) {