corda/docs/source/node-administration.rst

Node administration

When a node is running, it exposes an embedded web server that lets you monitor it, upload and download attachments, access a REST API and so on.

Uploading and downloading attachments

Attachments are files that add context to and influence the behaviour of transactions. They are always identified by hash and they are public, in that they propagate through the network to wherever they are needed.

All attachments are zip files. Thus to upload a file to the ledger you must first wrap it into a zip (or jar) file. Then you can upload it by running this command from a UNIX terminal:

curl -F myfile=@path/to/my/file.zip http://localhost:31338/upload/attachment

The attachment will be identified by the SHA-256 hash of the contents, which you can get by doing:

shasum -a 256 file.zip

on a Mac or by using sha256sum on Linux. Alternatively, the hash will be returned to you when you upload the attachment.

An attachment may be downloaded by fetching:

http://localhost:31338/attachments/DECD098666B9657314870E192CED0C3519C2C9D395507A238338F8D003929DE9

where DECD... is of course replaced with the hash identifier of your own attachment. Because attachments are always containers, you can also fetch a specific file within the attachment by appending its path, like this:

http://localhost:31338/attachments/DECD098666B9657314870E192CED0C3519C2C9D395507A238338F8D003929DE9/path/within/zip.txt

Uploading interest rate fixes

If you would like to operate an interest rate fixing service (oracle), you can upload fix data by uploading data in a simple text format to the /upload/interest-rates path on the web server.

The file looks like this:

# Some pretend noddy rate fixes, for the interest rate oracles.

LIBOR 2016-03-16 30 = 0.678
LIBOR 2016-03-16 60 = 0.655
EURIBOR 2016-03-15 30 = 0.123
EURIBOR 2016-03-15 60 = 0.111

The columns are:

• Name of the fix
• Date of the fix
• The tenor / time to maturity in days
• The interest rate itself