javascript - How can I get a buffer for a file (image) from CollectionFS - Stack Overflow

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I'm trying to insert an image into a pdf I'm creating server-side with PDFkit. I'm using cfs:dropbox to store my files. Before when I was using cvs:filesystem, it was easy to add the images to my pdf's cause they were right there. Now that they're stored remotely, I'm not sure how to add them, since PDFkit does not support adding images with just the url. It will, however, accept a buffer. How can I get a buffer from my CollectionFS files?

So far I have something like this:

var portrait = Portraits.findOne('vS2yFy4gxXdjTtz5d');
readStream = portrait.createReadStream('portraits');

I tried getting the buffer two ways so far:

First using dataMan, but the last mand never es back:

var dataMan = new DataMan.ReadStream(readStream, portrait.type());
var buffer = Meteor.wrapAsync(Function.prototype.bind(dataMan.getBuffer, dataMan))();

Second buffering the stream manually:

var buffer = new Buffer(0);
readStream.on('readable', function() {
    buffer = Buffer.concat([buffer, readStream.read()]);
});
readStream.on('end', function() {
    console.log(buffer.toString('base64'));
});

That never seems to e back either. I double-checked my doc to make sure it was there and it has a valid url and the image appears when I put the url in my browser. Am I missing something?

I'm trying to insert an image into a pdf I'm creating server-side with PDFkit. I'm using cfs:dropbox to store my files. Before when I was using cvs:filesystem, it was easy to add the images to my pdf's cause they were right there. Now that they're stored remotely, I'm not sure how to add them, since PDFkit does not support adding images with just the url. It will, however, accept a buffer. How can I get a buffer from my CollectionFS files?

So far I have something like this:

var portrait = Portraits.findOne('vS2yFy4gxXdjTtz5d');
readStream = portrait.createReadStream('portraits');

I tried getting the buffer two ways so far:

First using dataMan, but the last mand never es back:

var dataMan = new DataMan.ReadStream(readStream, portrait.type());
var buffer = Meteor.wrapAsync(Function.prototype.bind(dataMan.getBuffer, dataMan))();

Second buffering the stream manually:

var buffer = new Buffer(0);
readStream.on('readable', function() {
    buffer = Buffer.concat([buffer, readStream.read()]);
});
readStream.on('end', function() {
    console.log(buffer.toString('base64'));
});

That never seems to e back either. I double-checked my doc to make sure it was there and it has a valid url and the image appears when I put the url in my browser. Am I missing something?

• javascript
• node.js
• meteor
• node-pdfkit
• collectionfs

Share Improve this question Follow asked Jun 23, 2015 at 0:03 Jared MartinJared Martin 66377 silver badges2121 bronze badges 6

• what do you mean by "never es back"? How/where in your code are you using these solutions. The second one should work. – Christian Fritz Commented Jul 3, 2015 at 23:51
• also, are you calling readStream.read() anywhere? – Christian Fritz Commented Jul 3, 2015 at 23:56
• By "never es back" I mean the callback for the 'end' event is never executed (I don't see the log message in the console). – Jared Martin Commented Jul 7, 2015 at 17:51
• In my second attempt, I called readStream.read() at the end of the third line. – Jared Martin Commented Jul 7, 2015 at 17:51
• github./CollectionFS/Meteor-CollectionFS/issues/457 Check the example Icellan posts toward the bottom of the thread. Note: make sure to replace readable with data in the event handler. – Brian Shamblen Commented Jul 7, 2015 at 23:45

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1 Answer 1

Sorted by: Reset to default 5

I had to do something similar and since there's no answer to this question, here is how I do it:

// take a cfs file and return a base64 string
var getBase64Data = function(file, callback) {
  // callback has the form function (err, res) {}
  var readStream = file.createReadStream();
  var buffer = [];
  readStream.on('data', function(chunk) {
    buffer.push(chunk);
  });
  readStream.on('error', function(err) {
    callback(err, null);
  });
  readStream.on('end', function() {
    callback(null, buffer.concat()[0].toString('base64'));
  });
};

// wrap it to make it sync    
var getBase64DataSync = Meteor.wrapAsync(getBase64Data);

// get a cfs file
var file = Files.findOne();

// get the base64 string
var base64str = getBase64DataSync(file);

// get the buffer from the string
var buffer = new Buffer(base64str, 'base64')

Hope it'll help!

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