I feel I got lack of understanding about Buffer and File Stream, but I can't find any specific idea from other answers which is treating base64 string as a actual file.
I used 'request' package from Npm, to send a file to other server by http, multipart protocol.
The code below is working well, read a file from actual file by 'fs' package and send it by ReadStream object by createReadStream method.
(The codes is coffeescript)
#working
res = request.postSync 'http://anotherUrl/uploadDocument',
formData: file: fs.createReadStream('/path/' + 'myfile.doc')
What I want to do is creating a same ReadStream object by fs module from a file Based64 encoded String.
I tested something like this, but it's not working properly.
#not working
res = request.postSync 'http://anotherUrl/uploadDocument',
formData: file: new Buffer(base64EncodedString, 'base64')
#not working
res = request.postSync 'http://anotherUrl/uploadDocument',
formData: file: _base64ToArrayBuffer(base64EncodedString)
#not working
res = request.postSync 'http://anotherUrl/uploadDocument',
formData: file: convertDataURIToBinary(base64EncodedString)
##(used function)
_base64ToArrayBuffer = (base64) ->
binary_string = require('atob')(base64)
len = binary_string.length
bytes = new Uint8Array(len)
i = 0
while i < len
bytes[i] = binary_string.charCodeAt(i)
i++
bytes.buffer
convertDataURIToBinary = (dataURI) ->
BASE64_MARKER = ';base64,'
base64Index = dataURI.indexOf(BASE64_MARKER) + BASE64_MARKER.length
base64 = dataURI.substring(base64Index)
raw = require('atob')(base64)
rawLength = raw.length
array = new Uint8Array(new ArrayBuffer(rawLength))
i = 0
while i < rawLength
array[i] = raw.charCodeAt(i)
i++
array
question conclusion
The 'base64EncodedString' is validated by decode & creating file, so i don't doubt it is the matter, so I think I could have this achievement with write file from base64 and read it again with fs module, but I believe that's not the proper way.
The point of question is, 1. How could I send the base64encoded string as a ReadStream object properly in this case 2. How could I figure out relationship clearly between buffer and dataview(uint8array ...) something like that
Thanks in advance.
appendix
From @Alex Nikulin 's comment, I've tested stream-buffers package.
streamBuffers = require('stream-buffers')
myReadableStreamBuffer = new (streamBuffers.ReadableStreamBuffer)(
frequency: 10
chunkSize: 2048)
myReadableStreamBuffer.put base64.decode example
myReadableStreamBuffer.stop()
And when I tried bellow it failed again, and the 'AnotherUrl' returns Error message like this, 'unexpected end of part'
res = request.postSync 'http://anotherUrl/uploadDocument',
formData: file: myReadableStreamBuffer
I figured out the myReadableStreamBuffer object is Readable object, so it might be different with ReadStream object. Can I get it as a ReadStream from myReadableStreamBuffer?
1 Answer 1
Try this
//if you need just a buffer
var base64ToBuffer = function(base64) {
var byteString = new Buffer(base64, 'base64').toString('binary');
var ab = new Buffer(byteString.length);
var ia = new Uint8Array(ab);
for (var i = 0; i < byteString.length; i++) {
ia[i] = byteString.charCodeAt(i);
}
return ab;
}
//if you need a stream, not a buffer
var stream = require('stream');
// Initiate the source
var bufferStream = new stream.PassThrough();
// Write your buffer
bufferStream.end(base64ToBuffer(base64));
bufferStream.pipe( process.stdout );