Overview

fnExchange is a scalable, open source API layer (also called an API "router") that provides a consistent proxy web interface for invoking various web APIs without the caller having to write separate, special-purpose code for each of them.

This works as follows:

• The caller invokes the fnExchange service in the prescribed standard fnExchange API data format
• The fnExchange API server receives this request, and "routes" it to the appropriate plugin (based on request body parameters) with the request data
• The plugin takes in the data, does its magic, and returns data in the prescribed standard format
• The fnExchange handler returns this response with appropriate metadata

fnExchange is packaged as a command line interface executable fnexchange which starts the web service. The CLI also supports a mode to run the service as a daemon.

Installation

fnExchange

$ pip install fnexchange

Plugins

Publicly fnExchange plugins available on PyPi can simply be installed using pip

$ pip install fnexchange-<pluginname>

Alternatively, plugins created using the plugin sample project format but not available on PyPi can be installed using:

$ cd /path/to/plugin/source
$ pip install .

The only thing required for the plugins to function is that they should be available on the $PYTHONPATH. This enables using standalone plugins that are not available via PyPi and don't have a setup.py

Configuration

A configuration file needs to be supplied to the fnExchange server requires a configuration. A sample configuration file, with detailed documentation on the available options can be found at sample.fnexchange-config.yml

The configuration file can be validated using the fnexchange CLI by running

$ fnexchange configtest --conf=/path/to/conf.yml

Running the API service

The service can simply be run using the following command.

$ fnexchange runserver --conf=conf.yml [--port=<port number>] [--background]

The conf argument is required. The port number can be provided either in the conf.yml or via the command line option. If the port is provided in the conf file, providing it via the CLI is not required. In the case that port numbers are provided both via CLI and the conf file, the one provided on the CLI is used.

An optional --background flag is also available, using it runs the server as a background process. This is currently not implemented.

Plugin Development

It is incredibly easy to create fnExchange plugins! The fnexchange sample plugin provides the sample project and developer docs for creating your own custom plugins.