File Message Format

This page describes a format for transporting a file in a xbus message.

The message is divided in Two parts:

Header

The header is a single json object.

Its fields are the file metadata.

The standard metadata are:

• filename (required)

• type (MIME type)

• size

• encoding

• hash: A list of strings of the following format: “<digest>:<hash>”. Example: [“sha256:7509e5bda0c762d2bac7f90d758b5b2263fa01ccbc542ab5e3df163be08e6ca9”]

• location (see below)

Typical custom metadata would be: - customtype

Location

The location is an optional object describing where to find the file data.

The only mandatory field is “type”: one of “embedded”, “s3”, “http”

Depending on the type, other fields are needed:

embedded

This is the default location type. The file data are appended in the message after the header.

http

The file data is available at a given URL.

Specific fields:

• url: the file URL. Can be http or https

s3

The file is stored in a s3 bucket.

Specific fields:

• provider (optional): the api endpoint url

• region (optional): the region name

• bucket-name

• objectid

The actors that need to access the file are supposed to know the credentials.

Body

If the file is embedded, the remaining chunks contain the raw data of the file.

Examples

Simple text file

chunk1: {"filename":"simple.txt","type":"text/plain","size":12} chunk2: Hello World!