Tutorials
How to use TrueBlocks to get useful data.
A few more examples in more detail.
Getting help
Every chifra sub-command comes with an associated help page. To get help for chifra itself, simply type
chifra
A long list of commands should show. (If you have trouble, see the Installation page.)
To get help for a specific command, type
chifra <cmd> --help
To get more detailed help, type
chifra <cmd> --help --verbose 2
Getting system status
The chifra command gives you access to all of TrueBlocks’ functionality. Get system status by typing
chifra config
Getting blockchain data
Let’s see if we can get some actual blockchain data.
Getting Blocks
The following command returns block data from block 2,001,002. The data is returned as JSON.
chifra blocks 2001002
Notice the full transactional details are included for each of the seven transactions in the block. You can show just the transaction hashes with
chifra blocks 2001002 --hashes
Copy one of those transaction hashes and paste it into the next command
chifra transactions 0x5f965c...9f26e12 # use the full hash
This command shows a single transaction’s data. But, you may have noticed that the data is shown as tab separated rows. In general, block data (which is structured) is presented as JSON while primarily non-structured data is presented as TXT.
Formatting Output
Every chifra command accepts a few optional parameters including --verbose and --fmt. --verbose is useful when debugging. The --fmt option allows you to specify the format of the output. It accepts three values:
chifra blocks 2002 --fmt json # the default for blocks
chifra blocks 2002 --fmt txt # tab delimited text
chifra blocks 2002 --fmt csv # comma separated values
These options are available for all chifra commands. (Although in some cases, they are ignored.) One might wish to use the csv and txt options if one is engaged in data science for example.
More data commands
Below, we present a few of the other chifra commands without a lot of description.
Transactions and Logs and Traces, Oh My!
# The first transaction in block 2,002,002
chifra transactions 2001002.0
# All transactions in block 2,002,002 as comma separated values
chifra transactions --fmt csv 2001002.\*
# Every event in block 4,503,002
chifra logs --fmt json 4503002.\*
# Every event in block 4,503,002 -- articulated (see below)
chifra logs --fmt json --articulate 4503002.\*
# Every trace in the second transaction of block 4,503,002
chifra traces --fmt json --articulate 4503002.1
Please see the help files for chifra blocks --help and chifra transactions --help for more information, including all the options for specifying blocks and transactions (which are many and varied).
Articulated Data
Most TrueBlocks’ commands accept an option called --articulate. The easiest way to explain articulated data is to say it is “ugly blockchain data turned into human readable text”.
For example, the following command shows logs from the third transaction in block 4,503,002
chifra logs --fmt json 4503002.2
Pretty ugly. Compare that to this command
chifra logs --fmt json --articulate 4503002.2
You’ll see additional (and much more easy to understand) data. In particular, you’ll see an articulatedLog. That is “ugly log data presented in human-readable form.”
See Getting ERC20 Transfer Events for an example of using articulation.
Links to more detail
There are many other chifra commands including list and export that we still study next. Other commands allow you to serve a JSON API presenting each command as an API route, init which pulls parts of the index data from IPFS, and scrape which builds the index.
In the following sections, each command is presented with its options and in more detail. In addition,
- Our blog has a few longer “tutorials”for accomplishing various tasks.
- Our data model reference describes the fields that are returned with each command