DracoQL is a an embeddable query language for processing and transforming data from the web resources and writing it to files and databases.
Language actively in development, please report any bugs under issues.
npm install dracoql
import draco from "dracoql";
draco.eval(`PIPE "Hello world!" TO STDOUT`);
Additionally, you can get runtime variables from the caller
import draco from "dracoql";
draco.eval(`VAR data = FETCH https://jsonplaceholder.typicode.com/todos/ AS JSON`, (ctx) => {
console.log(ctx.getVar("data"))
});
A variable can hold either an INT_LITERAL
, STRING_LITERAL
or an expression. Draco does not support string escaping, you can instead use ''
for that.
VAR foo = 1
VAR bar = "hello world!"
VAR baz = FETCH "https://example.org" AS HTML
Draco provides FETCH
as the primary method for interacting with a url
VAR data = FETCH "https://example.org"
HEADER "User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/112.0"
HEADER "Content-type: application/json"
METHOD "GET"
AS HTML
Additionaly, you can also make POST requests
VAR data = FETCH "https://reqres.in/api/users" METHOD "POST"
HEADER "User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/112.0"
HEADER "Content-type: application/json"
BODY JSON '{"name": "morpheus", "job": "leader"}'
AS JSON
To extract data out of the evaluater, you can use the PIPE
keyword
PIPE "hello world" TO STDOUT
you can also output data to a file
PIPE "Draco was here" TO FILE "draco.txt"
Draco provides in-built support for parsing HTML selectors and JSON queries
VAR res = FETCH "https://reqres.in/api/users" AS JSON
VAR data = EXTRACT "data[0].id" FROM res
PIPE data TO STDOUT
VAR res = FETCH "https://reqres.in" AS HTML
VAR headline = EXTRACT "h2.tagline:nth-child(1)" FROM res
PIPE headline TO STDOUT
VAR data = FETCH "https://www.cs.cmu.edu/afs/cs/project/ai-repository/ai/areas/nlp/corpora/names/male.txt"
PIPE title TO STDOUT
VAR data = FETCH "https://jsonplaceholder.typicode.com/users/1"
AS JSON
OR DIE
PIPE data TO FILE "user.json"
VAR data = FETCH https://www.cnet.com/
VAR headline = EXTRACT
".c-pageHomeHightlights>div:nth-child(1)>div:nth-child(2)>div:nth-child(1)>a:nth-child(1)>div:nth-child(1)>div:nth-child(2)>div:nth-child(1)>h3:nth-child(1)>span:nth-child(1)"
FROM data
AS HTML
VAR txt = EXTRACT innerText FROM headline
AS JSON
PIPE txt TO STDOUT
module draco, exports the lexer, interpreter and an parser.
import draco from "dracoql";
const lexer = new draco.lexer(`PIPE "hello world" TO STDOUT`);
const parser = new draco.parser(lexer.lex());
const interpreter = new draco.interpreter(parser.parse());
(async () => {
await interpreter.run();
})()