SHA-256 Hash

[Alexander-Ger-Reich]

I wrote an add-on that requires the client to provide the SHA-256 hash of the uploaded files and chunks.

[Alexander-Ger-Reich]

DCO is happy

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[alperozturk96]

Hello

Thank you for the PR.

I've suggested a few naming changes to align with the naming conventions used throughout the project for consistency. I will also be testing the PR shortly.

[alperozturk96]

If possible, could you apply the fail fast here?

[Alexander-Ger-Reich]

What do you mean by that?

[alperozturk96]

Instead of having nested if-else blocks, you can return early. However, I think the downloadFile() function is too complex for that. We can skip it, if it’s too much work to refactor.

e.g.

Before:

public void checkAge(int age) {
    if (age >= 0) {
        if (age >= 18) {
            System.out.println("User is an adult.");
        } else {
            System.out.println("User is a minor.");
        }
    } else {
        System.out.println("Invalid age.");
    }
}

After:

public void checkAge(int age) {
    if (age < 0) {
        System.out.println("Invalid age.");
        return;
    }

    if (age >= 18) {
        System.out.println("User is an adult.");
        return;
    }
    
    System.out.println("User is a minor.");
}

[tobiasKaminsky]

I am very late to this, sorry for that!
I see that this function setHashDownloadCheck is not being used inside library.
Thus I assume that this is within the customized files app?

Since we want to have only code that is actually used by the core Nextcloud system, what do you about this:

• move sha check/generation to your customized app
• enhance library to allow to pass/read any header
  --> this way the customized sha logic would be in your app, but the library will support it?

[Alexander-Ger-Reich]

I am very late to this, sorry for that! I see that this function setHashDownloadCheck is not being used inside library. Thus I assume that this is within the customized files app?

Since we want to have only code that is actually used by the core Nextcloud system, what do you about this:

• move sha check/generation to your customized app
• enhance library to allow to pass/read any header
  --> this way the customized sha logic would be in your app, but the library will support it?

Do you know if there is already another method to check whether the file on the client is 100% the same as the file on the server during upload? Is this already happening? Is a hash already being generated somewhere else and communicated to the server? I only started doing this because I hadn't seen anything like it before.

[tobiasKaminsky]

Do you know if there is already another method to check whether the file on the client is 100% the same as the file on the server during upload? Is this already happening? Is a hash already being generated somewhere else and communicated to the server? I only started doing this because I hadn't seen anything like it before.

No, we do not do this.
But we have for each and every upload/chunked upload a status code.
So it is assumed that if one transfer/chunk is working, then also the resulting file is correct.

[Alexander-Ger-Reich]

Man

Do you know if there is already another method to check whether the file on the client is 100% the same as the file on the server during upload? Is this already happening? Is a hash already being generated somewhere else and communicated to the server? I only started doing this because I hadn't seen anything like it before.

No, we do not do this. But we have for each and every upload/chunked upload a status code. So it is assumed that if one transfer/chunk is working, then also the resulting file is correct.

I could add MD5 as an algorithm. To save power and time, it would only apply to the entire file, not individual chunks. The server would then have to enter this information into the file without changing it (metadata). All official changes to a file would change it, but any tampering would be immediately detected by a different hash.