diff options
Diffstat (limited to 'resource/postcss/postcss.go')
-rw-r--r-- | resource/postcss/postcss.go | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/resource/postcss/postcss.go b/resource/postcss/postcss.go new file mode 100644 index 000000000..7dd27b2f9 --- /dev/null +++ b/resource/postcss/postcss.go @@ -0,0 +1,175 @@ +// 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 postcss + +import ( + "fmt" + "io" + "path/filepath" + + "github.com/gohugoio/hugo/hugofs" + + "github.com/mitchellh/mapstructure" + // "io/ioutil" + "os" + "os/exec" + + "github.com/gohugoio/hugo/common/errors" + + "github.com/gohugoio/hugo/resource" +) + +// Some of the options from https://github.com/postcss/postcss-cli +type Options struct { + + // Set a custom path to look for a config file. + Config string + + NoMap bool `mapstructure:"no-map"` // Disable the default inline sourcemaps + + // Options for when not using a config file + Use string // List of postcss plugins to use + Parser string // Custom postcss parser + Stringifier string // Custom postcss stringifier + Syntax string // Custom postcss syntax +} + +func DecodeOptions(m map[string]interface{}) (opts Options, err error) { + if m == nil { + return + } + err = mapstructure.WeakDecode(m, &opts) + return +} + +func (opts Options) toArgs() []string { + var args []string + if opts.NoMap { + args = append(args, "--no-map") + } + if opts.Use != "" { + args = append(args, "--use", opts.Use) + } + if opts.Parser != "" { + args = append(args, "--parser", opts.Parser) + } + if opts.Stringifier != "" { + args = append(args, "--stringifier", opts.Stringifier) + } + if opts.Syntax != "" { + args = append(args, "--syntax", opts.Syntax) + } + return args +} + +// Client is the client used to do PostCSS transformations. +type Client struct { + rs *resource.Spec +} + +// New creates a new Client with the given specification. +func New(rs *resource.Spec) *Client { + return &Client{rs: rs} +} + +type postcssTransformation struct { + options Options + rs *resource.Spec +} + +func (t *postcssTransformation) Key() resource.ResourceTransformationKey { + return resource.NewResourceTransformationKey("postcss", t.options) +} + +// Transform shells out to postcss-cli to do the heavy lifting. +// For this to work, you need some additional tools. To install them globally: +// npm install -g postcss-cli +// npm install -g autoprefixer +func (t *postcssTransformation) Transform(ctx *resource.ResourceTransformationCtx) error { + + const binary = "postcss" + + if _, err := exec.LookPath(binary); err != nil { + // This may be on a CI server etc. Will fall back to pre-built assets. + return errors.FeatureNotAvailableErr + } + + var configFile string + logger := t.rs.Logger + + if t.options.Config != "" { + configFile = t.options.Config + } else { + configFile = "postcss.config.js" + } + + configFile = filepath.Clean(configFile) + + // We need an abolute filename to the config file. + if !filepath.IsAbs(configFile) { + // We resolve this against the virtual Work filesystem, to allow + // this config file to live in one of the themes if needed. + fi, err := t.rs.BaseFs.Work.Fs.Stat(configFile) + if err != nil { + if t.options.Config != "" { + // Only fail if the user specificed config file is not found. + return fmt.Errorf("postcss config %q not found: %s", configFile, err) + } + configFile = "" + } else { + configFile = fi.(hugofs.RealFilenameInfo).RealFilename() + } + } + + var cmdArgs []string + + if configFile != "" { + logger.INFO.Println("postcss: use config file", configFile) + cmdArgs = []string{"--config", configFile} + } + + if optArgs := t.options.toArgs(); len(optArgs) > 0 { + cmdArgs = append(cmdArgs, optArgs...) + } + + cmd := exec.Command(binary, cmdArgs...) + + cmd.Stdout = ctx.To + cmd.Stderr = os.Stderr + + stdin, err := cmd.StdinPipe() + if err != nil { + return err + } + + go func() { + defer stdin.Close() + io.Copy(stdin, ctx.From) + }() + + err = cmd.Run() + if err != nil { + return err + } + + return nil +} + +// Process transforms the given Resource with the PostCSS processor. +func (c *Client) Process(res resource.Resource, options Options) (resource.Resource, error) { + return c.rs.Transform( + res, + &postcssTransformation{rs: c.rs, options: options}, + ) +} |