spoty-query-engine

This is an attempt to compile a Comunica Query Engine by following the tutorial at https://comunica.dev/docs/modify/getting_started/

Test the default query engine

• npm init
• Add dependency npm install @comunica/query-sparql
• Copy code in query-sparql-engine.js
• Make sure to use an "await" function
• Run code with node query-sparql-engine.js

Test the use of a custom config

• Copy query-sparql-engine.js into query-custom.js
• Create a config file in config/config.json and copy inside it the default Comunica config file found at https://github.com/comunica/comunica/blob/master/engines/config-query-sparql/config/config-default.json (/!\ do NOT use the one provided in the documentation)
• Adapt the code:

	const myEngine = await new QueryEngineFactory().create({
	    configPath: 'config/config.json', // Relative or absolute path 
	});

• run with node query-custom.js

Test a link traversal config

• Make a copy of the config file from https://github.com/comunica/comunica-feature-link-traversal/blob/2d170e26821d6f242ac1aefd4b7a2e011c5c87ee/engines/config-query-sparql-link-traversal/config/config-solid-single-pod.json
• Added the dependency : :
  • @comunica/config-query-sparql-link-traversal
  • @comunica/query-sparql-link-traversal
  • @comunica/config-query-sparql-solid
  • @comunica/query-sparql-link-traversal-solid
• Make a copy of query-custom.js into query-custom-link-traversal.js
• Adapt the code:

	const myEngine = await new QueryEngineFactory().create({
	    // configPath: 'config/config.json', // Relative or absolute path 
	    configPath: 'config/config-spoty.json', // Relative or absolute path 
	});

	const bindingsStream = await myEngine.queryBindings(`
	  SELECT ?s ?p ?o WHERE {
	    ?s ?p ?o
	  } LIMIT 10`, {
	  sources: ['https://fragments.dbpedia.org/2015/en'],
	});

• run with node query-custom-link-traversal.js

Compile as an NPM package

• Follow documentation at https://comunica.dev/docs/modify/getting_started/custom_init/
• Copy the config file into config-default.json : cp config/config-spoty.json config/config-default.json
• Added compile script in package.json:

{
  ...
  "scripts": {
    ...
    "build:engine": "comunica-compile-config config/config-default.json > engine-default.js",
    "build:lib": "tsc",
    "build": "npm run build:lib && npm run build:engine",
    "prepare": "npm run build"
  },
}

• Compile with npm run build:engine

• Create lib folder

• Add in lib folder QueryEngine.ts, QueryEngineFactory.ts, index.ts and index-browser.ts with the content as provided in the doc

• Added entries in the package.json file:

"main": "lib/index.js",
  "types": "lib/index",
  "browser": {
    "./lib/index.js": "./lib/index-browser.js",
    "./lib/index.js.map": "./lib/index-browser.js.map"
  },

• Added .npmignore and .gitignore as documented
• Added files section in package.json as documented:

"files": [
    "components",
    "config",
    "bin/**/*.d.ts",
    "bin/**/*.js",
    "bin/**/*.js.map",
    "lib/**/*.d.ts",
    "lib/**/*.js",
    "lib/**/*.js.map",
    "engine-default.js"
  ]

• added a tsconfig.json to allow Typescript compiling
• added Typescript dependency : npm i typescript --save-dev
• /!\ downgrade Typescript version to 5.5.4 to avoid error with LRUCache. See isaacs/node-lru-cache#354 (comment):

  "devDependencies": {
    "typescript": "5.5.4"
  }

Add as a dependency to the SPoTy project

• See https://medium.com/dailyjs/how-to-use-npm-link-7375b6219557
• in spoty-query-engine, run sudo npm link
• Then in project spoty, link to the local dependency:

cd ../spoty
npm link spoty-query-engine

Use the dependency:

  import { QueryEngine } from 'spoty-query-engine';

  const myEngine = new QueryEngine();