trn_construct_transaction.md

How to Construct Any Transaction - Manually

Contents:

• General Procedure
• Example: Transfer

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General Procedure

The general principle for generating, singing and broadcasting an arbitrary transactions works as follows:

1. Create an instance of the transaction builder
2. Add arbitrary operation types
3. Add the required amount of fees
4. Sign and broadcast your transaction

The corresponding API calls in the CLI Wallet are:

>>> begin_builder_transaction
>>> add_operation_to_builder_transaction $HANDLE [opId, {operation}]
>>> set_fees_on_builder_transaction $HANDLE BTS
>>> sign_builder_transaction $HANDLE true

The begin_builder_transaction call returns a number we call $HANDLE It allows to construct several transactions in parallel and identify them individually!

The opId and the JSON structure of the operation can be obtained with:

get_prototype_operation <operation-type>

• Available Operation Types: typedef fc::static_variant<.... >

In practice, each operation has to pay a fee, and hence, each operation has to carry a fee member. When crafting a transaction, you now have the choice between either defining each fee for your operations individually, or you use set_fees_on_builder_transaction that sets the fee for each operation automatically to the chosen asset.

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Example: Transfer

A simple transfer takes the following form

The operation id for the transfer_operation is thus 0 (third line)

get_prototype_operation transfer_operation
[
  0,{
    "fee": {
      "amount": 0,
      "asset_id": "1.3.0"
    },
    "from": "1.2.0",
    "to": "1.2.0",
    "amount": {
      "amount": 0,
      "asset_id": "1.3.0"
    },
    "extensions": []
  }
]

form - core elements (removing fee) of this operation

{
  "from": "1.2.0",
  "to": "1.2.0",
  "amount": {
    "amount": 0,
    "asset_id": "1.3.0"
  }
}

Transaction

1. Add an operation to a transaction as follows (line breaks inserted for readability):

    >>> begin_builder_transaction
    0
    >>> add_operation_to_builder_transaction
         0
        [0,{
               "from": "1.2.0",
               "to": "1.2.0",
               "amount": {
                 "amount": 0,
                 "asset_id": "1.3.0"
               }
           }]
   

The corresponding id can be obtained with get_account, and get_asset.

2. Add a fee payed in BTS, sign and broadcast the transaction (if valid):

    >>> set_fees_on_builder_transaction 0 BTS
    >>> sign_builder_transaction 0 true
   

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(ref)

• http://docs.bitshares.org/bitshares/tutorials/construct-transaction.html