Incorrect hash on chunks whereas merging into Blob produces correct hash

[satazor]

Incorrect hash on chunks whereas merging into Blob produces correct hash

[silverbucket]

And just to cover my bases. I also tried this with a for loop, instead of a forEach on the off chance that somehow the items were not being appended in order:

for (var i = 0, len = collectedArray.length; i < len; i += 1) {
  spark.append(collectedArray[i]);
}

[satazor]

I can't see anything wrong from the usage perspective. Can you create a small reproducible fiddle so I can play around and identify the issue? A zip file would also sufice.

[silverbucket]

Hi @satazor, I created a small demo that performs the following steps:

• downloads an image
• slices it up
• stores it
• displays it
  ...
• loads it
• displays a second one (from the idb data)
• runs append on the array of elements (attached md5 to html)
• merges arrays of arraybuffers into one
• displays the md5 for that

You can check it out, run a local http server in the directory, and view the index.html. Be sure to open the console as a lot info is contained there.

As you'll see the original md5 is displayed first (static), then the one from the series of appends (incorrect) then another from a merged arraybuffer (correct).

I tried to keep it very simple, give it a shot and let me know what you think.
https://github.com/silverbucket/md5example

[satazor]

Thanks @silverbucket will look at it later today, after work.

[satazor]

There was a bug indeed in the SparkMD5.ArrayBuffer but that was fixed in 9f54482. Your example is using an outdated version of SparkMD5. I've tested your example with 2.0.0 and 1.0.1 versions and it works correctly!

[satazor]

[silverbucket]

Oh, I missed that update. Since I use node as my build environment (with
browserify) I cannot simply include a file from the SparkMD5 repository, I
must manually copy it into the project whenever I see an update.

Any chance for adding a build step which creates a file that uses the node
module system of module.exports ? I know it's not meant to run in node, but
taking into account the npm+node build environment, it still has a lot of
benefits.

On Mon, Nov 2, 2015 at 1:29 PM André Cruz [email protected] wrote:

[image: screen shot 2015-11-02 at 12 27 55]
https://cloud.githubusercontent.com/assets/1017236/10881728/4a9b00cc-815d-11e5-89cd-0e17435b7be6.png

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Reply to this email directly or view it on GitHub
#31 (comment).

[silverbucket]

ie. so that there's a third file: node-sparkmd5.js or something?

[silverbucket]

Are you sure you published the latest version(s) of SparkMD5 to npm? I'm still getting v1.0.0

[satazor]

Sorry, it should be published now. Totally forgot.

[satazor]

Regarding the npm/node usage, it should work out of the box, see: https://github.com/satazor/SparkMD5/blob/master/spark-md5.js#L4 and https://github.com/satazor/SparkMD5/blob/master/package.json#L5

[silverbucket]

Ah, right, not sure why I decided that wouldn't work before. Works fine for me now :)
Thanks!

[db2190]

I want to upload a file of 1GB with chunk size of 1MB each and i wish to calculate and validate each chunk with checksum on server, can someone point me in correct direction?