Application Programming Interface

Command line, RESTful and JavaScript APIs that integrate NETS into systems.

NETS has two kinds of API - application APIs and library APIs. Application APIs help to run NETS on the command line, as a web service or from JavaScript. Library APIs allow compiled grammars to be built using a set of C library functions. This section deals with application APIs.

Command Line Interface

The NETS Command Line Interface (CLI) allows the parser to be executed from an operating system terminal. It can be executed independently or as part of a script or batch process. The nets-parser command is followed by a number of command line parameters as follows. These parameters are by convention used in the RESTful API and the JavaScript API.

The command line is called either as a native executable (MacOS/Linux/Windows, NodeJS WASM executable or a Wasmtime WASI executable.

Command line arguments are specified using either the - or / character followed by the name of the parameter and followed optionally by an equal sign and the value of the paramater.

RESTful Interface

The NETS RESTful Interface allows the parser to be executed over an HTTP(S) protocol. The endpoint is http://europe-west2-nets3-webapp.cloudfunctions.net/process and responds to a POST with multi-part form data containing the input and the grammar. A form which uses the endpoint is available at http://www.nets3.com/1.0/cloudplayground.xhtml.

An example using the cURL utility is shown below.

> curl --location --request POST \
'http://europe-west2-nets3-webapp.cloudfunctions.net/process' \
--form 'output="default.out"' \
--form 'grammar=@"default.g"' \
--form 'input=@"default.in"' \
--form 'loglevel="4"' \
--form 'error="default.log"'


The curl command returns the output to the terminal. Any valid commandline argument can be used as part of the POST. In addition the result_file argument can be used to return any file generated during processing. For example result_file=default.log returns the log file. The /process POST endpoint is synchronous with results returned as soon as processing is finished.

/process POST returns the following HTTP message response codes.

JavaScript Interface

The NETS JavaScript Interface allows the parser to be executed from JavaScript code either using Node or a web browser. A Node example is shown below which requires the installation of the nets-parser npm module.

const Nets = require('nets-parser.js');

var args = {
input:'default_ouch.in',
output:'default.out',
grammar:'default.g',
error:'stderr',
loglevel:'3'
};

Nets().then(function(app) {
var parser=0;
parser=app.init(parser,args);
console.log(app.getContext(parser,'input'));
app.setContext(parser,'input','default.in')
console.log(app.getContext(parser,'input'));
app.start(parser);
process.exit();
});


An example Node project using NETS is available on Runkit.