hugo/resource/resource_metadata.go
Bjørn Erik Pedersen dea71670c0
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
2018-07-06 11:46:12 +02:00

129 lines
3.5 KiB
Go

// Copyright 2018 The Hugo Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package resource
import (
"fmt"
"strconv"
"github.com/spf13/cast"
"strings"
"github.com/gohugoio/hugo/common/maps"
)
var (
_ metaAssigner = (*genericResource)(nil)
)
// metaAssigner allows updating metadata in resources that supports it.
type metaAssigner interface {
setTitle(title string)
setName(name string)
updateParams(params map[string]interface{})
}
const counterPlaceHolder = ":counter"
// AssignMetadata assigns the given metadata to those resources that supports updates
// and matching by wildcard given in `src` using `filepath.Match` with lower cased values.
// This assignment is additive, but the most specific match needs to be first.
// The `name` and `title` metadata field support shell-matched collection it got a match in.
// See https://golang.org/pkg/path/#Match
func AssignMetadata(metadata []map[string]interface{}, resources ...Resource) error {
counters := make(map[string]int)
for _, r := range resources {
if _, ok := r.(metaAssigner); !ok {
continue
}
var (
nameSet, titleSet bool
nameCounter, titleCounter = 0, 0
nameCounterFound, titleCounterFound bool
resourceSrcKey = strings.ToLower(r.Name())
)
ma := r.(metaAssigner)
for _, meta := range metadata {
src, found := meta["src"]
if !found {
return fmt.Errorf("missing 'src' in metadata for resource")
}
srcKey := strings.ToLower(cast.ToString(src))
glob, err := getGlob(srcKey)
if err != nil {
return fmt.Errorf("failed to match resource with metadata: %s", err)
}
match := glob.Match(resourceSrcKey)
if match {
if !nameSet {
name, found := meta["name"]
if found {
name := cast.ToString(name)
if !nameCounterFound {
nameCounterFound = strings.Contains(name, counterPlaceHolder)
}
if nameCounterFound && nameCounter == 0 {
counterKey := "name_" + srcKey
nameCounter = counters[counterKey] + 1
counters[counterKey] = nameCounter
}
ma.setName(replaceResourcePlaceholders(name, nameCounter))
nameSet = true
}
}
if !titleSet {
title, found := meta["title"]
if found {
title := cast.ToString(title)
if !titleCounterFound {
titleCounterFound = strings.Contains(title, counterPlaceHolder)
}
if titleCounterFound && titleCounter == 0 {
counterKey := "title_" + srcKey
titleCounter = counters[counterKey] + 1
counters[counterKey] = titleCounter
}
ma.setTitle((replaceResourcePlaceholders(title, titleCounter)))
titleSet = true
}
}
params, found := meta["params"]
if found {
m := cast.ToStringMap(params)
// Needed for case insensitive fetching of params values
maps.ToLower(m)
ma.updateParams(m)
}
}
}
}
return nil
}
func replaceResourcePlaceholders(in string, counter int) string {
return strings.Replace(in, counterPlaceHolder, strconv.Itoa(counter), -1)
}