139 lines
		
	
	
		
			3.7 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
			
		
		
	
	
			139 lines
		
	
	
		
			3.7 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
const data = {
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  name: 'imgcache',
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  prefix: 'imgcache_'
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}
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function ImgCache (vm) {
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  this.vm = vm // 保存实例在其他周期使用
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  this.i = 0 // 用于标记第几张图
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  vm.imgCache = {
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    get list () {
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      return uni
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        .getStorageInfoSync()
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        .keys.filter((key) => key.startsWith(data.prefix))
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        .map((key) => key.split(data.prefix)[1])
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    },
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    get (url) {
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      return uni.getStorageSync(data.prefix + url)
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    },
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    delete (url) {
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      const path = uni.getStorageSync(data.prefix + url)
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      if (!path) return false
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      plus.io.resolveLocalFileSystemURL(path, (entry) => {
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        entry.remove()
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      })
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      uni.removeStorageSync(data.prefix + url)
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      return true
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    },
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    async add (url) {
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      const filename = await download(url)
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      if (filename) {
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        uni.setStorageSync(data.prefix + url, filename)
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        return 'file://' + plus.io.convertLocalFileSystemURL(filename)
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      }
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      return null
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    },
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    clear () {
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      uni
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        .getStorageInfoSync()
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        .keys.filter((key) => key.startsWith(data.prefix))
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        .forEach((key) => {
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          uni.removeStorageSync(key)
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        })
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      plus.io.resolveLocalFileSystemURL(`_doc/${data.name}/`, (entry) => {
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        entry.removeRecursively(
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          (entry) => {
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            console.log(`${data.name}缓存删除成功`, entry)
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          },
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          (e) => {
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            console.log(`${data.name}缓存删除失败`, e)
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          }
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        )
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      })
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    }
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  }
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}
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// #ifdef APP-PLUS
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ImgCache.prototype.onParse = function (node, parser) {
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  // 启用本插件 && 解析图片标签 && 拥有src属性 && 是网络图片
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  if (
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    this.vm.ImgCache &&
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    node.name === 'img' &&
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    node.attrs.src &&
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    /^https?:\/\//.test(node.attrs.src)
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  ) {
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    const src = node.attrs.src
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    node.attrs.src = ''
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    node.attrs.i = this.vm.imgList.length + this.i++
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    parser.expose()
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    async function getUrl (path) {
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      if (await resolveFile(path)) return path
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      const filename = await download(src)
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      filename && uni.setStorageSync(data.prefix + src, filename)
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      return filename
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    }
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    uni.getStorage({
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      key: data.prefix + src,
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      success: async (res) => {
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        const path = await getUrl(res.data)
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        const url = path
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          ? 'file://' + plus.io.convertLocalFileSystemURL(path)
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          : src
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        node.attrs.src = url
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        this.vm.imgList[node.attrs.i] = path || src
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      },
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      fail: async () => {
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        const path = await getUrl()
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        const url = path
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          ? 'file://' + plus.io.convertLocalFileSystemURL(path)
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          : src
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        node.attrs.src = url
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        this.vm.imgList[node.attrs.i] = path || src
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      }
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    })
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  }
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}
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const taskQueue = new Set()
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function download (url) {
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  return new Promise((resolve) => {
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    if (taskQueue.has(url)) return
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    taskQueue.add(url)
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    const suffix = /.+\.(jpg|jpeg|png|bmp|gif|webp)/.exec(url)
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    const name = `${makeid(8)}_${Date.now()}${suffix ? '.' + suffix[1] : ''}`
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    const task = plus.downloader.createDownload(
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      url,
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      { filename: `_doc/${data.name}/${name}` },
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      (download, status) => {
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        taskQueue.delete(url)
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        resolve(status === 200 ? download.filename : null)
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      }
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    )
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    task.start()
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  })
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}
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// 判断文件存在
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function resolveFile (url) {
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  return new Promise((resolve) => {
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    plus.io.resolveLocalFileSystemURL(url, resolve, () => resolve(null))
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  })
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}
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// 生成uuid
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function makeid (length) {
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  let result = ''
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  const characters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'
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  for (let i = 0; i < length; i++) {
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    result += characters.charAt(Math.floor(Math.random() * characters.length))
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  }
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  return result
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}
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// #endif
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module.exports = ImgCache
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