If you want to do it against an existing server application, you just execute the necessary queries.

https://github.com/libbitcoin/libbitcoin-server/wiki/Client-Server-Interface

fetch-block-height (defaults to top)
fetch-block-header (by hash or height)
fetch-block-transaction-hashes (merkle)
fetch-transaction

There are also subscriptions for blocks, transactions and addresses.

The client API provides C++ query call stubs. It's also straightforward to build a customized server using the library.

e

> On Apr 2, 2017, at 6:20 AM, mlmikael <mlmikael@???> wrote:
>
> Hi,
>
> There are some usecases where you want a computer to be able to peek into individual transactions on the Bitcoin blockchain.
>
> To do that, all you need is to download the chain of block headers, and then check for the transaction via merkle root and parse its content e.g. to see that it has a particular OP_RETURN as claimed etc. .
>
> Is that viable to implement oneself via LibBitcoin or something that LibBitcoin may want to implement itself?
>
>
> There is a gap in the C/C++ library world today in that space. Javascript has some libraries for that e.g. https://github.com/bcoin-org/bcoin . In the C world, libbtc https://github.com/libbtc/libbtc almost does it but not quite.
>
> Thanks,
> Mlmikael
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