ipfs/kubo

Ability to specify known hash when adding

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#1,957 opened on Nov 10, 2015

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help wantedkind/enhancement

Description

ipfs add should have an option that lets the user specify a hash that is known ahead of time. Then when IPFS computes the hash, if they don't match, adding should fail with an error.

This defends against corruption during adding, or lets the user detect that the file was corrupted before it was added at all (for example, a truncated download).

In theory this can also be an optimization, where if the IPFS repo already has a file with the given hash, the file doesn't need to be hashed or added at all.

This depends on the user being able to compute the hash in advance. If the file came from IPFS, then that's not a problem. Otherwise, applications need to be able to compute IPFS hashes for themselves (see #1953).

Contributor guide

Tech stack
go
Domain
cli
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Familiarity with IPFS add commandKnowledge of Go flag parsing
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
45
Research direction
Examine the current implementation of the `ipfs add` command in the Go codebase, specifically how files are added and hashed. Look at the flag parsing to add a new ` known hash` option. Review issue #1953 for context on computing IPFS hashes externally. The implementer should ensure that when the flag is provided, the computed hash is compared to the given value and an error is raised on mismatch.
Ability to specify known hash when adding · ipfs/kubo#1957 | Good First Issue