index.js

const path = require('path')
const fs = require('fs')
const co = require('co')
const oss = require('ali-oss')
const postcss = require('postcss')

function getAbsolutePath(dir, relative) {
	const absolute = path.resolve(dir, relative)

	const reg = /\.(jpg|jpeg|png|gif|svg|bmp)\b/i
	if (!reg.test(absolute)) {
        console.log(`File is not a image: ${absolute}`)
		return
	}

	if (!fs.existsSync(absolute) && (relative.indexOf('../') > -1)) {
		relative = relative.replace('../', '')
		absolute = path.resolve(dir, relative)
	}

	return absolute
}

module.exports = postcss.plugin('postcss-imgpost-alioss', options => {
    return function (css) {
        const client = new oss({
            accessKeyId: options.accessKeyId,
            accessKeySecret: options.accessKeySecret,
            region: options.region,
            bucket: options.bucket
        })
        css.walkRules(ruler => {
            ruler.walkDecls(/^background(-image)?$/, decl => {
                const imageReg = /url\(['\"]?([^)'\"]+)['\"]?\)/
                const matchValue = imageReg.exec(decl.value)
                if (!matchValue || matchValue[1].indexOf('data:') === 0) {
                    return
                }

                const relativePath = matchValue[1]
                const inputDir = path.dirname(decl.source.input.file)
                const absolutePath = getAbsolutePath(inputDir, relativePath)
                if (!absolutePath) return

                const imageData = fs.readFileSync(absolutePath)
                const urls = relativePath.split(/^\.+\//)
                let filename = options.name || ''
                const url = filename + urls[1]
                let protol = options.https ? 'https://' : 'http://'
                let cssUrl = options.domain
                    ? `url('${protol + options.domain + url}')`
                    : `url('${protol + options.bucket}.${options.region}.aliyuncs.com/${url}')`
                decl.value = decl.value.replace(imageReg, cssUrl)

                co(function* () {
                    const result = yield client.put(url, imageData)
                }).catch(err => {
                    console.log(err)
                })
            })
        })
    }
})