API reference

API

The binding exposes the following AFB API:

helloworld

It provides three verbs: hello, sum and info.

For the AFB V4 API model, verb declaration and request handling concepts used by this sample, see the AFB Binding V4 tutorial.

hello

Returns a greeting.

Request hello

The first argument is optional. When it can be converted to a string, it is used as the name in the reply.

Without an argument:

afb-client -H localhost:1234/api helloworld hello

With an argument:

afb-client -H localhost:1234/api helloworld hello Bob

Reply hello

Without an argument:

Hello world!

With Bob as the first argument:

Hello Bob!

Event hello

Each call publishes helloworld/verb_called with hello as payload.

sum

Computes the sum of a JSON array of integers.

Request sum

Exactly one argument is expected. It must be a JSON array containing only integers.

Example:

afb-client -H localhost:1234/api helloworld sum '[1,2,3,4]'

Reply sum

The reply is a signed 64-bit integer containing the sum of all array elements. The accumulation uses signed 64-bit wrapping semantics as part of the shared sum API contract.

For the previous example, the result is:

10

An empty array returns 0.

Error sum

If the request does not contain exactly one parameter, if the parameter is not a JSON array, or if one of its elements is not an integer, the request fails with:

parameter should be a JSON array of integers

Event sum

Each successful or rejected call publishes helloworld/verb_called with sum as payload before the request parameters are validated.

info

Returns the static metadata describing the sample API and its verbs.

Request info

No argument is required:

afb-client -H localhost:1234/api helloworld info

Reply info

The reply is a JSON object containing the binding metadata and the descriptions of the hello, sum and info verbs.

Event reference

helloworld/verb_called

The verb_called event demonstrates AFB event publication and client subscription.

The client context records whether the client has already been subscribed, preventing repeated subscription setup on subsequent requests.