hash in nodejs is different from hash in terminal

Question

I would like to get the md5 hash of a file in nodejs, but the hash i'm getting is different from the hash i can get directly from the terminal.

In nodejs, I'm doing this (from here)

var fd = fs.createReadStream('path/to/my/file');
var hash = crypto.createHash('md5');
hash.setEncoding('hex');

fd.on('end', function() {
    hash.end();
    console.log(hash.read()); // the desired sha1sum
});

fd.pipe(hash);

and the output is d41d8cd98f00b204e9800998ecf8427e

And in my terminal I do:

md5sum path/to/my/file

and the ouput is f6ef86836065f2370ebd9b1caadce3b4

Do you have any idea about why ?

Thanks

EDIT

Here is my code:

//Download file
var firmware = fs.createWriteStream(desiredFirmwareProperties.fwName);
var r = https.get(desiredFirmwareProperties.fwURI, function(response) {
    response.pipe(firmware);
});

//Checksum
var fd = fs.createReadStream(desiredFirmwareProperties.fwName);
var hash = crypto.createHash(desiredFirmwareProperties.fwChecksumAlgo);     
hash.setEncoding('hex');
fd.on('end', function() {
    hash.end();
    console.log(desiredFirmwareProperties.fwChecksum);
    console.log(hash.read());
});
fd.pipe(hash);

Yes I know it's working, but why the hash is different from the one i can get in my terminal ? — iAmoric, May 02 '19 at 09:30
a problem from content differ in function of your environment ? — np42, May 02 '19 at 09:38
are you sure the two files you hash (via shell and via node) have the same content ? it should of course, but the experience show me some error like this refer a different file with same name, in different location, or different server, ... — np42, May 02 '19 at 10:19
@iAmoric after a quick search on google about d41d8cd98f00b204e9800998ecf8427e it appear that it is an empty string, add `fd.on('error', e => console.log(e))` — np42, May 02 '19 at 10:25
@Nicolas Ok thanks for pointing that out to me. I will re-check my code — iAmoric, May 02 '19 at 11:28
I added my code, could you please check what is wrong ? Thanks — iAmoric, May 02 '19 at 11:59
@iAmoric you should check each step until the file open: url is correct, ssl certificate is not rejected, server respond a 200 status code, content downloaded length > 0 — np42, May 02 '19 at 13:04
The file is downloaded correctly, I checked it. The problem comes from the second part (checksum) — iAmoric, May 02 '19 at 13:05

score 0 · Answer 1 · answered May 02 '19 at 13:09

0

I got it, it's an asynchronous procedure, you tried to read the file before the download finished

place the checksum procedure in 'close' event:

firmware.on('close', () => {
  <checksum here>
})

answered May 02 '19 at 13:09

np42

847
7
13

I don't think, i use `async.waterfall` to avoid this situation – iAmoric May 03 '19 at 10:00
1

can you share the bind callback to let async.waterfall execute the next step ? – np42 May 03 '19 at 10:42
Ok I get it, the callback was indeed not placed in the right place. Solved – iAmoric May 08 '19 at 08:43

hash in nodejs is different from hash in terminal

1 Answers1