在浏览器中替换文件blob？

Question

I asked this earlier but someone down voted and accused me of trying to write files to local filesystem without reading.

I have website in an enterprise environment which will only ever be accessed in chrome so keep that in mind.

I am able to select a local folder on my PC and open all sub-folders and files in the browser. I'm using client side javascript to parse these files and look for a particular kind of .xml file that is used internally to render a powerpoint like presentation. I can make changes to this xml file and spit it back out as a blob.

What I would like to do but don't know how is replace the data or blob in the original file with the modified data/blob.

Answer 1

Can the user interact with the data blob? If so, you can use a save file function and overwrite the original.

function saveFile( data )
{
  var textFileAsBlob = new Blob([yourData], {type:'text/plain'});
  //or replace the code above with your already formed blob

  var fileNameToSaveAs = "File_Name_Goes_Here.xml";

  var downloadLink = document.createElement("a");
  downloadLink.download = fileNameToSaveAs;
  //downloadLink.innerHTML = "Download File";
  if (window.webkitURL != null){
      // Chrome allows the link to be clicked
      // without actually adding it to the DOM.
      downloadLink.href = window.webkitURL.createObjectURL(textFileAsBlob);
  }
  else{
      // Firefox requires the link to be added to the DOM
      // before it can be clicked.
      try {
          downloadLink.href = window.URL.createObjectURL(textFileAsBlob);
          downloadLink.onclick = destroyClickedElement;
          downloadLink.style.display = "none";
          document.body.appendChild(downloadLink);
      }
      catch( e ){
          console.log("error saving firefox file")
      }
      // IE 10+
      try {
          window.navigator.msSaveBlob(textFileAsBlob, fileNameToSaveAs);
      }
      catch(e){
          console.log("error saving IE file")
      }
  }

  try {
      downloadLink.click();
  }
  catch(e) {
      console.log("Unable to click the download link.  Are you using IE?")
  }

}

I grabbed this code from somewhere else on stack overflow. I can't remember who it's from though to provide attribution :-(