Data Types

Different types of objects are uniquely identified in different ways:

Accounts are identified by their Address, for example "r9cZA1mLK5R5Am25ArfXFmqgNwjZgnfk59". Addresses always start with "r". Many rippled methods also accept a hexadecimal representation.

Transactions are identified by a Hash of the transaction's binary format. You can also identify a transaction by its sending account and Sequence Number.

Each closed Ledger has a Ledger Index and a Hash value. When [Specifying Ledgers][] you can use either one.

Addresses

Hashes

Hash Prefixes

[Source]

In many cases, Xahau prefixes an object's binary data with a 4-byte code before calculating its hash, so that objects of different types have different hashes even if their binary formats are the same. The existing 4-byte codes are structured as three alphabetic characters, encoded as ASCII, followed by a zero byte.

Some types of hash appear in API requests and responses. Others are only calculated as the first step of signing a certain type of data, or calculating a higher-level hash. The following table shows all 4-byte hash prefixes Xahau uses:

Object Type	API Fields	Hash Prefix (Hex)	Hash Prefix (Text)
Consensus proposal	N/A	0x50525000	PRP\0
Ledger Version	ledger_hash	0x4C575200	LWR\0
Ledger state data	account_state in ledger header	0x4D4C4E00	MLN\0
Ledger data inner node	N/A	0x4D494E00	MIN\0
Ledger data inner node (SHAMapv2)	N/A	0x494E5200	INR\0
Payment Channel Claim	N/A	0x434C4D00	CLM\0
Signed Transaction	hash of transactions	0x54584E00	TXN\0
Transaction with metadata	N/A	0x534E4400	SND\0
Unsigned Transaction (Single-signing)	N/A	0x53545800	STX\0
Unsigned Transaction (Multi-signing)	N/A	0x534D5400	SMT\0
Validation vote	N/A	0x56414C00	VAL\0
Validator manifest	N/A	0x4D414E00	MAN\0

Ledger objects IDs are calculated in a similar way, but they use a 2-byte prefix called a "space key" instead of a prefix in the form described here.

Account Sequence

Ledger Index

Specifying Ledgers

Many API methods require you to specify an instance of the ledger, with the data retrieved being considered up-to-date as of that particular version of the shared ledger. The commands that accept a ledger version all work the same way. There are three ways you can specify which ledger you want to use:

1. Specify a ledger by its Ledger Index in the ledger_index parameter. Each closed ledger has a ledger index that is 1 higher than the previous ledger. (The very first ledger had ledger index 1.)

    "ledger_index": 61546724

2. Specify a ledger by its Hash value in the ledger_hash parameter.

    "ledger_hash": "8BB204CE37CFA7A021A16B5F6143400831C4D1779E6FE538D9AC561ABBF4A929"

3. Specify a ledger by one of the following shortcuts, in the ledger_index parameter:

   • validated for the most recent ledger that has been validated by consensus

       "ledger_index": "validated"

   • closed for the most recent ledger that has been closed for modifications and proposed for validation

   • current for the server's current working version of the ledger.

There is also a deprecated ledger parameter which accepts any of the above three formats. Do not use this parameter; it may be removed without further notice.

If you do not specify a ledger, the server decides which ledger to use to serve the request. By default, the server chooses the current (in-progress) ledger. In Reporting Mode, the server uses the most recent validated ledger instead. Do not provide more than one field specifying ledgers.

Note: Do not rely on the default behavior for specifying a ledger; it is subject to change. Always specify a ledger version in the request if you can.

Reporting Mode does not record ledger data until it has been validated. If you make a request to a Reporting Mode server for the current or closed ledger, the server forwards the request to a P2P Mode server. If you request a ledger index or hash that is not validated, a Reporting Mode server responds with a lgrNotFound error.

Specifying Currency Amounts

There are two kinds of currencies in Xahau: XAH and tokens. These two types of currencies are specified in different formats, with different precision and rounding behavior.

Some fields, such as the destination Amount of a [Payment transaction][], can be either type. Some fields only accept XAH specifically, such as the Fee field (transaction cost).

XAH is specified as a string containing an integer number of "drops" of XAH, where 1 million drops equals 1 XAH. Tokens are instead specified as an object with fields for the decimal amount, currency code, and issuer. For example:

• XAH - To specify an Amount field with a value of 13.1 XAH:

    "Amount": "13100000"

• Token - To specify an Amount field with a value of 13.1 FOO issued by or to rf1B...:

    "Amount": {
        "value": "13.1",
        "currency": "FOO",
        "issuer": "rf1BiGeXwwQoi8Z2ueFYTEXSwuJYfV2Jpn"
    }

For more information, see Currency Formats.

Specifying Time

The xahaud server and its APIs represent time as an unsigned integer. This number measures the number of seconds since the "Ripple Epoch" of January 1, 2000 (00:00 UTC). This is like the way the Unix epoch works, except the Ripple Epoch is 946684800 seconds after the Unix Epoch.

Don't convert Ripple Epoch times to UNIX Epoch times in 32-bit variables: this could lead to integer overflows.