Passing array buffer to Meteor gridFS
MongoDB has a document size limit of 16MB. To store larger file sizes, it is recommended to use GridFS.
Now, if you are a meteor user, you can very easily use the Meteor Collection-FS package to store and upload files. But it is slightly different when you actually want to store an object of size larger than 16MB which is not a file. Usually, these scenarios will come in the server side when you generate a large content and want to store that.
I was doing something like this -
//Collection initialisation
var Store = new FS.Store.GridFS("fileuploads");
FileUploads = new FS.Collection("fileuploads", {
stores: [Store]
});
var buffer = new Buffer(JSON.stringify(jsonObj));
FileUploads.insert(buffer);I found myself stuck with this error when I tried to use the insert function with the generated data.
DataMan constructor requires a type argument when passed a Buffer
This is actually a mistake in the documentation here - https://github.com/CollectionFS/Meteor-CollectionFS#initiate-the-upload which says the insert function accepts a Buffer object at the server side. It doesn’t. Issue raised here. It accepts a file object with its data set as a buffer object along with a mime type.
Here is how to get it done-
var buffer = new Buffer(JSON.stringify(jsonObj));
var newFile = new FS.File();
newFile.attachData(buffer, {type: 'application/javascript'});
FileUploads.insert(newFile)Now this will work :)
But we are not done yet !
How are we going to read the data back, if we are doing it at the client side ?
var fs = FileUploads.findOne({_id: fileId});
$.ajax({
url: fs.url(),
type: "GET",
dataType: "binary",
processData: false,
success: function(data){
var reader = new FileReader();
reader.onload = function (event) {
// event.target.result contains your data .. TADA!
// console.log(event.target.result)
};
reader.onerror = function (event) {
console.error(event.target.error);
};
reader.readAsBinaryString(new Blob([ data ],
{ type: 'application/octet-stream' }));
}
});Any comments and feedback is most appreciated
Update (May 25th, 2016): I just saw that the author of the repo has stopped from maintaining the project. Sorry to hear it. Its still a great library and I hope will help users who might still use this.