javascript - How to download and then upload the file? - Stack Overflow

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Tried to use the following code, but it doesn't work properly:

  // download the file first
  var req = new XMLHttpRequest();
  req.open('GET', url, false);
  req.overrideMimeType('text/plain; charset=x-user-defined');
  req.send(null);
  if (req.status != 200) return '';

  // upload the file
  req.open("POST", "", false);
  req.setRequestHeader("Content-Length", req.responseText.length);
  req.sendAsBinary(req.responseText); // What should I pass here?

  if (req.status != 200) return '';
  return req.responseText;

sendAsBinary is firefox function.

Upd. Also I've tried to upload that as part of the form:

var response = req.responseText;
var formData = new FormData();
formData.append("file", response);
req.open("POST", "", false);
req.send(formData);

But still not full data is received by the server.

Tried to use the following code, but it doesn't work properly:

  // download the file first
  var req = new XMLHttpRequest();
  req.open('GET', url, false);
  req.overrideMimeType('text/plain; charset=x-user-defined');
  req.send(null);
  if (req.status != 200) return '';

  // upload the file
  req.open("POST", "http://mysite./upload", false);
  req.setRequestHeader("Content-Length", req.responseText.length);
  req.sendAsBinary(req.responseText); // What should I pass here?

  if (req.status != 200) return '';
  return req.responseText;

sendAsBinary is firefox function.

Upd. Also I've tried to upload that as part of the form:

var response = req.responseText;
var formData = new FormData();
formData.append("file", response);
req.open("POST", "http://mysite./upload", false);
req.send(formData);

But still not full data is received by the server.

• javascript
• firefox-addon
• xmlhttprequest

Share Improve this question Follow edited Jul 28, 2011 at 19:27 LA_ asked Jul 28, 2011 at 18:25 LA_LA_ 20.4k6060 gold badges179179 silver badges318318 bronze badges 2

• 4 Define: "...doesn't work properly" – James Hill Commented Jul 28, 2011 at 18:31
• The file I am working with is binary file. Looks responseText corrupts that. – LA_ Commented Jul 28, 2011 at 19:08

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2 Answers 2

Sorted by: Reset to default 3

Finally I've used the approach with temp file:

  var downloadCompleted = false;

  // download the file first
  var persist = Components.classes["@mozilla/embedding/browser/nsWebBrowserPersist;1"]
                  .createInstance(Components.interfaces.nsIWebBrowserPersist);
  // get OS temp folder
  var file = Components.classes["@mozilla/file/directory_service;1"]
                .getService(Components.interfaces.nsIProperties)
                .get("TmpD", Components.interfaces.nsIFile);
  file.append("temp.ext");
  file.createUnique(Components.interfaces.nsIFile.NORMAL_FILE_TYPE, 0666);

  var fURI = Services.io.newURI(url,null,null);
    const nsIWBP = Components.interfaces.nsIWebBrowserPersist;
    const flags = nsIWBP.PERSIST_FLAGS_REPLACE_EXISTING_FILES;
    persist.persistFlags = flags | nsIWBP.PERSIST_FLAGS_FROM_CACHE;

  persist.progressListener = {
    onProgressChange: function(aWebProgress, aRequest, aCurSelfProgress, aMaxSelfProgress, aCurTotalProgress, aMaxTotalProgress) {
      },
    onStateChange: function(aWebProgress, aRequest, aStateFlags, aStatus) {
      if (aStateFlags & Components.interfaces.nsIWebProgressListener.STATE_STOP) {
         downloadCompleted = true; // file has been downloaded        
      }
    }
  }
  persist.saveURI(fURI, null, null, null, "", file);  

  var thread = Components.classes["@mozilla/thread-manager;1"]
                        .getService(Components.interfaces.nsIThreadManager)
                        .currentThread;
  while (!downloadCompleted) // emulate synchronous request, not remended approach
    thread.processNextEvent(true); 

  // upload the file
  var stream = Components.classes["@mozilla/network/file-input-stream;1"]
                       .createInstance(Components.interfaces.nsIFileInputStream);
  stream.init(file, 0x04 | 0x08, 0644, 0x04); // file is an nsIFile instance   

  // try to determine the MIME type of the file
  var mimeType = "text/plain";
  try {
    var mimeService = Components.classes["@mozilla/mime;1"]
            .getService(Components.interfaces.nsIMIMEService);
    mimeType = mimeService.getTypeFromFile(file); // file is an nsIFile instance
  }
  catch(e) { /* just use text/plain */ }

  var req = Components.classes["@mozilla/xmlextras/xmlhttprequest;1"]
                      .createInstance(Components.interfaces.nsIXMLHttpRequest);
  req.open('POST', "http://mysite./upload", false); 
  req.setRequestHeader('Content-Type', mimeType);
  req.send(stream);

  // delete the file
  file.remove(false);

You need to store the responseText in an intermediate variable before reusing the req object.

// download the file first
var req = new XMLHttpRequest();
req.open('GET', url, false);
req.overrideMimeType('text/plain; charset=x-user-defined');
req.send(null);
if (req.status != 200) return '';
var response = req.responseText;

// upload the file
req.open("POST", "http://mysite./upload", false);
req.setRequestHeader("Content-Length", response.length);
req.sendAsBinary(response);
if (req.status != 200) return '';
return req.responseText;

---

Update

Per the MDN page Using XMLHttpRequest, it looks like the above code won't work. Following is the proper way to get the binary response. In the end, you will have an array of unsigned integers which you could send back to the server and convert to binary. I think.

//req.responseType is only defined for FF6+
req.responseType = "arraybuffer";
req.send(null);

//req.response is for FF6+, req.mozResponseArrayBuffer is for FF < 6
var buffer = req.mozResponseArrayBuffer || req.response;
if (buffer) {
  var byteArray = new Uint8Array(buffer);
}

---

Update 2

To submit the byteArray to a server, I would try something like the following untested, almost guaranteed not to work code.

req.open("POST", "http://mysite./upload", false);
req.setRequestHeader("Content-Length", byteArray.length);
//if this doesn't work, try byteArray.buffer
//if byteArray.buffer works, try skipping 'var byteArray = new Uint8Array(buffer);' altogether and just sending the buffer directly
req.send(byteArray); 

---

Update 3

Could Using XMLHttpRequest from JavaScript modules / XPCOM ponents have anything to do with your issue?

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