Add Bech32 Command Tree

[clarkmoody]

Wanted to add a quick interface to the Bech32 library. This will allow encoding and decoding of Bech32 strings and payloads.

Decode

decode bech32 format

USAGE:
    hal bech32 decode [FLAGS] <string>

FLAGS:
    -c, --convert-bits    Attempt to convert payload from 5-bit to 8-bit values.
                          NOTE: Does not work for BIP-173 addresses.
    -h, --help            Prints help information
    -v, --verbose         Print verbose logging output to stderr
    -y, --yaml            print output in YAML instead of JSON

ARGS:
    <string>    a bech32 string

Sample output:

$ hal bech32 decode bc1svu3ak479v954vrpxe0wst
{
  "bech32": "bc1svu3ak479v954vrpxe0wst",
  "hrp": "bc",
  "payload": "100c1c111d16151e050c0514150c0301"
}

# Convert 5-bit to 8-bit values
$ hal bech32 decode -c bc1svu3ak479v954vrpxe0wst
{
  "bech32": "bc1svu3ak479v954vrpxe0wst",
  "hrp": "bc",
  "payload": "100c1c111d16151e050c0514150c0301",
  "payload_base256": "83391edabe2b0b4ab061"
}

Encode

encode bech32 format

USAGE:
    hal bech32 encode [FLAGS] <hrp> <payload-hex>

FLAGS:
    -h, --help          Prints help information
        --no-convert    Do not convert payload to base32
    -v, --verbose       Print verbose logging output to stderr
    -y, --yaml          print output in YAML instead of JSON

ARGS:
    <hrp>            human-readable part
    <payload-hex>    hex-encoded payload bytes, 8-bit values
                     unless --no-convert is specified

Sample output:

$ hal bech32 encode bc 83391edabe2b0b4ab061
{
  "bech32": "bc1svu3ak479v954vrpxe0wst",
  "hrp": "bc",
  "payload": "100c1c111d16151e050c0514150c0301",
  "payload_base256": "83391edabe2b0b4ab061"
}

# Consume payload as 5-bit data directly with no conversion
hal bech32 encode --no-convert bc 100c1c111d16151e050c0514150c0301`
{
  "bech32": "bc1svu3ak479v954vrpxe0wst",
  "hrp": "bc",
  "payload": "100c1c111d16151e050c0514150c0301",
  "payload_base256": "83391edabe2b0b4ab061"
}

[stevenroose]

One thing I'm trying to think about is to avoid short flags if they could collide with global ones. -x for example could be one day. And since you're returning json anyway, you can just have two fields, one for bytes and one hex.

I didn't know it's possible to flag a PR as "draft", TIL!

[stevenroose]

We should be able to drop the bitcoin-bech32 dep as well once rust-bitcoin v0.19 lands. But I have some more branches ready related to addresses for when v0.19 lands.

[clarkmoody]

And since you're returning json anyway, you can just have two fields, one for bytes and one hex.

Great point. We might as well just output both, if we're in structured data mode.

On another note, would it be possible to output a trailing newline after the JSON or YAML, so the command prompt is clean for the next input?

[clarkmoody]

And since you're returning json anyway, you can just have two fields, one for bytes and one hex.

Great point. We might as well just output both, if we're in structured data mode.

On second thought, I'd like to move the "payload" output to non-default, since it displays each byte of a separate line, which is ultra-verbose.

[stevenroose]

On another note, would it be possible to output a trailing newline after the JSON or YAML, so the command prompt is clean for the next input?

Sure.

On second thought, I'd like to move the "payload" output to non-default, since it displays each byte of a separate line, which is ultra-verbose.

Yeah personally I don't really see much value in an interger-list-representation of bytes over hex.

[clarkmoody]

Ok, ready for review here. I've tweaked the interface and options again. Please let me know if it makes any sense or if we can word the help text better for what's going on with 5-bit and 8-bit values.

[stevenroose]

Nice! The first real contributor! I left some minor remarks!

[stevenroose]

Just curious: what would this field be useful for?

[clarkmoody]

The payload field is the 5-bit values, and payload_base256 is the result of convert_bits from 5- to 8-bit, so we get back the original bytes. This does not work for BIP-173 addresses, since they abuse the encoding format with the version number taking the first 5-bit slot.

[stevenroose]

Aaaah, lol, I was reading "base256" as 256-bit. The base thing confuses me, though. Do you think "payload_base256" is more clear than "payload_bytes"? By definition a "byte" is base256, right?

[clarkmoody]

Let's go with payload_bytes and see how that feels.

[clarkmoody]

Ok, renamed.

[clarkmoody]

Ok, first round of feedback addressed.