Manually creating transactions

Question

Due to complete lack of documentation on the subject, how would the pseucode for creating a transaction look using the following functions: createrawtransaction signrawtransaction and sendrawtransaction.

I receive the user transaction for incoming coins on IncomingTxID, when I create a raw transction I want to include at least some of those coins so if they won't confirm, neither will his payout.

Related: [C# API for Bitcoin](http://bitcoin.stackexchange.com/q/5461/1878) — makerofthings7, Nov 26 '12 at 17:37
How to do this is documented in [_Mastering Bitcoin_ (1st ed.), §"Using Bitcoin Core’s JSON-RPC API from the Command Line"](http://chimera.labs.oreilly.com/books/1234000001802/ch03.html#_using_bitcoin_core_8217_s_json_rpc_api_from_the_command_line), §§"Creating, Signing, and Submitting Transactions Based on Unspent Outputs". — Geremia, Nov 28 '17 at 19:53

score 3 · Answer 1 · edited Mar 18 '13 at 17:47

3

I am assuming you want to accomplish something akin to what SatoshiDice does. Here is how it can be done, using API calls with the Bitcoin-Qt/bitcoind client:

listunspent - you get the list of all unspent transactions
You determine which ones you want to spend
You use createrawtransaction to create your inputs / outputs, taking txid and vout from the list of transactions that you have that are playing, as well as a list of transactions that constitute a "money supply" for you.
Use signrawtransaction to sign the created transaction
Use sendrawtransaction to send the signed transaction

That should be pretty much it. I have implemented some of that code myself and it is pretty easy once you get a hang of it all.

edited Mar 18 '13 at 17:47

Stephen Gornick

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answered Mar 07 '13 at 12:56

ThePiachu

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One bit of caution -- in the raw transaction, any inputs used that are not fully spent go to the miner. So be very careful when composing raw transactions. – Stephen Gornick Mar 18 '13 at 17:49
How about fee calculation? – Shamoon Jul 29 '13 at 14:12
@Shamoon http://bitcoinfees.com/ - you base them on the number of inputs and outputs. – ThePiachu Jul 29 '13 at 15:26

score 2 · Answer 2 · answered Mar 18 '13 at 17:50

2

A good way to see this (and also a non-automated method to do this) is available through BrainWallet:

http://brainwallet.org/#tx

answered Mar 18 '13 at 17:50

Stephen Gornick

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One bit of caution -- in the raw transaction, any inputs used that are not fully spent go to the miner. So be very careful when composing raw transactions. – Stephen Gornick Mar 18 '13 at 17:50

Manually creating transactions

2 Answers2

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