try use Web Worker to load

Hi,

I’m trying to use Web Worker to load dicom, because the page has some carton when load.

But I encounter a problem now.

//worker.js

//some code...

var loader

function loadWithUrls (links) {
  var fileType = null
  if (typeof links === 'string') {
    var array = links.split('.')
    fileType = array[array.length - 1].toLowerCase()
  }

  return new Promise((resolve, reject) => {
    if (fileType === 'zip') {
      axios.get(
        links, {
          responseType: 'blob',
          onDownloadProgress: e => self.postMessage({type: 'downloading', value: {loaded: e.loaded, total: e.total}})
        })
        .then(res => {
          self.postMessage({type: 'parseBegin'})
          return Promise.resolve(res.data)
        })
        .then(JSZip.loadAsync)
        .then(zip => {
          // console.log(zip, loader);
          let seriesContainer = []
          let fileArray = Object.keys(zip.files)
          let fileArrayLength = fileArray.length
          fileArray.forEach(item => {
            zip.file(item).async('arraybuffer')
              .then(buffer => this.loader.parse({ url: item, buffer }))
              .then(series => {
                seriesContainer.push(series)
                let seriesContainerLength = seriesContainer.length
                self.postMessage({type: 'parsing', value: {parsed: seriesContainerLength, total: fileArrayLength}})
                if (seriesContainerLength >= fileArrayLength) {
                  resolve(seriesContainer[0].mergeSeries(seriesContainer)[0])
                  loader = null
                }
              })
              .catch(e => reject(e))
          })
        })
        .catch(e => reject(e))
    } else {
      loader.load(links)
        .then(() => {
          resolve(loader.data[0].mergeSeries(loader.data)[0])
          loader = null
        })
        .catch(e => reject(e))
    }
  })
}

self.onmessage = ({data}) => {
  loader = new VolumeLoader(false, () => {
    return {
      update: (v, t, mode) => {
        if (mode === 'load') {
          self.postMessage({type: 'downloading', value: {loaded: v, total: t}})
          if (v / t === 1) self.postMessage({type: 'parseBegin'})
        } else {
          self.postMessage({type: 'parsing', value: {loaded: v, total: t}})
        }
      }
    }
  })

  loadWithUrls(data.links)
    .then(value => {
      // if (!value.stack[0].packed) {
      //   value.stack[0].prepare()
      //   value.stack[0].pack()
      // }
      self.postMessage({type: 'result', value})
    })
    .catch(value => self.postMessage({type: 'error', value}))
}

//index.js

//some code...

var wk = new Worker('./worker.js')

wk.postMessage({type, links})

wk.onmessage = ({data}) => {
      switch (data.type) {
        //some code...

        case 'result':
          console.log('result', data)
          resultFn(data.value)
          break
      }
}

In index.js I get the series data.But the series data lost all function include get/set.

I can’t new StackHelper use the series._stack[0] ( I also can’t get stack by series.stack[0] ).

So…, I want know how to restore function, or Is there a better way to do this?

[NicolasRannou]

Yes, I see what you mean, it is just the way web workers work. You can not pass objects between the worker and the main thread. The expensive bit in term of time is the DICOM downloading, parsing then packing. So all that should happen in the WW as you are doing.

I think you may have to run one worker per file to be parsed but I am not too sure yet which is the best approach.

But I agree with you that it is the way to go.

You may be able to create “empty” stacks, frames, series on the main thread and just get the important bits from the web workers by posting…

[hurryhuang1007]

@NicolasRannou Sorry to have kept you waiting so long. And I am finish it now. https://github.com/hurryhuang1007/ami-worker-loader