Custom CLI arguments

On this page

    As explained within the guide to expose your custom config as an npm package, custom command line tools can be created as follows:

    bin/query.js:

    #!/usr/bin/env node
import { runArgsInProcessStatic } from '@comunica/runner-cli';
runArgsInProcessStatic(require('../engine-default.js'));

    bin/http.js:

    #!/usr/bin/env node
import { HttpServiceSparqlEndpoint } from '@comunica/actor-init-query';
const defaultConfigPath = `${__dirname}/../config/config-default.json`;
HttpServiceSparqlEndpoint.runArgsInProcess(process.argv.slice(2), process.stdout, process.stderr, `${__dirname}/../`, process.env, defaultConfigPath, code => process.exit(code))
  .catch(error => process.stderr.write(`${error.message}/n`));

    bin/query-dynamic.js:

    #!/usr/bin/env node
import { runArgsInProcess } from '@comunica/runner-cli';
runArgsInProcess(`${__dirname}/../`, `${__dirname}/../config/config-default.json`);

    This will cause the built-in CLI arguments from comunica-sparql to be inherited. It is however also possible to extend these arguments so that you can add additional ones, which can be processed in any way.

    Creating CLI Arguments Handlers

    This argument handling can be done using one or more instances of ICliArgsHandler, which may be implemented as follows:

    export class MyCliArgsHandler implements ICliArgsHandler {
  public populateYargs(argumentsBuilder: Argv<any>): Argv<any> {
    return argumentsBuilder
      .options({
        myOption: {
          alias: 'm',
          type: 'string',
          describe: 'Just some option',
          default: 'A default value',
        },
      });
  }

  public async handleArgs(args: Record<string, any>, context: Record<string, any>): Promise<void> {
    context['this-is-a-context-key'] = args.myOption;
  }
}

    The populateYargs method allows you to declare options within the argumentsBuilder using the yargs API. Then, the handleArgs is invoked after the CLI tool has been invoked with some options, so that you can extract the defined option, and modify the query context if needed (which is still mutable at this stage).

    Passing CLI Arguments Handlers

    Then, in order to pass your instances of ICliArgsHandler to the CLI tools, you can do this as follows:

    bin/query.js:

    #!/usr/bin/env node
import { runArgsInProcessStatic } from "@comunica/runner-cli";
import { KeysInitSparql } from '@comunica/context-entries';
import { ActionContext } from '@comunica/core';
runArgsInProcessStatic(require('../engine-default.js'), {
  context: ActionContext({
    [KeysInitSparql.cliArgsHandlers]: [ new MyCliArgsHandler() ],
  }),
});

    bin/http.js:

    #!/usr/bin/env node
import {HttpServiceSparqlEndpoint} from "@comunica/query-sparql";
HttpServiceSparqlEndpoint.runArgsInProcess(process.argv.slice(2), process.stdout, process.stderr,
  __dirname + '/../', process.env, __dirname + '/../config/config-default.json', () => process.exit(1), [ new MyCliArgsHandler() ]);

    bin/query-dynamic.js:

    #!/usr/bin/env node
import { runArgsInProcess } from "@comunica/runner-cli";
import { KeysInitSparql } from '@comunica/context-entries';
import { ActionContext } from '@comunica/core';
runArgsInProcess(__dirname + '/../', __dirname + '/../config/config-default.json', {
  context: ActionContext({
    [KeysInitSparql.cliArgsHandlers]: [ new MyCliArgsHandler() ],
  }),
});