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Migrates to json-event-parser #43

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Migrates to json-event-parser #43

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110 changes: 68 additions & 42 deletions lib/SparqlJsonParser.ts
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Original file line number Diff line number Diff line change
@@ -1,9 +1,7 @@
import {DataFactory} from "rdf-data-factory";
import * as RDF from "@rdfjs/types";
import {Transform} from "readable-stream";

// tslint:disable-next-line:no-var-requires
const JsonParser = require('jsonparse');
import {JsonEvent, JsonStreamPathTransformer, JsonEventParser, IQueryResult, JsonValue} from "json-event-parser";

/**
* Parser for the SPARQL 1.1 Query Results JSON format.
Expand Down Expand Up @@ -42,40 +40,57 @@ export class SparqlJsonParser {
*/
public parseJsonResultsStream(sparqlResponseStream: NodeJS.ReadableStream): NodeJS.ReadableStream {
const errorListener = (error: Error) => resultStream.emit('error', error);
sparqlResponseStream.on('error', errorListener);

const jsonParser = new JsonParser();
jsonParser.onError = errorListener;
let variablesFound = false;
let resultsFound = false;
jsonParser.onValue = (value: any) => {
if(jsonParser.key === "vars" && jsonParser.stack.length === 2 && jsonParser.stack[1].key === 'head') {
resultStream.emit('variables', value.map((v: string) => this.dataFactory.variable(v)));
variablesFound = true;
} else if(jsonParser.key === "results" && jsonParser.stack.length === 1) {
resultsFound = true;
} else if(typeof jsonParser.key === 'number' && jsonParser.stack.length === 3 && jsonParser.stack[1].key === 'results' && jsonParser.stack[2].key === 'bindings') {
resultStream.push(this.parseJsonBindings(value))
} else if(jsonParser.key === "metadata" && jsonParser.stack.length === 1) {
resultStream.emit('metadata', value);
}
}

const parser = this;
const resultStream = sparqlResponseStream
.on("end", _ => {
if (!resultsFound && !this.suppressMissingStreamResultsError) {
resultStream.emit("error", new Error("No valid SPARQL query results were found."))
} else if (!variablesFound) {
resultStream.emit('variables', []);
}
})
.pipe(new Transform({
objectMode: true,
transform(chunk: any, encoding: string, callback: (error?: Error | null, data?: any) => void) {
jsonParser.write(chunk);
callback();
}
}));
.on('error', errorListener)
.pipe(new JsonEventParser())
.on('error', errorListener)
.pipe(new JsonStreamPathTransformer([
{id: 'vars', query: ['head', 'vars'], returnContent: true},
{id: 'bindings', query: ['results', 'bindings'], returnContent: false},
{id: 'binding', query: ['results', 'bindings', null], returnContent: true},
{id: 'metadata', query: ['metadata'], returnContent: true},
]))
.on('error', errorListener)
.pipe(
new Transform({
writableObjectMode: true,
readableObjectMode: true,
transform(result: IQueryResult, encoding: string, callback: (error?: Error | null, data?: any) => void): void {
try {
switch (result.query) {
case 'vars':
variablesFound = true;
this.emit('variables', parser.parseVariableList(result.value));
break;
case 'bindings':
resultsFound = true;
break;
case 'binding':
this.push(parser.parseJsonBindings(result.value));
break;
case 'metadata':
this.emit('metadata', result.value);
}
callback();
} catch (e: any) {
callback(e);
}
},
flush(callback: (error?: Error | null, data?: any) => void): void {
if (!resultsFound && !this.suppressMissingStreamResultsError) {
callback(new Error("No valid SPARQL query results were found."));
return;
}
if (!variablesFound) {
this.emit('variables', []);
}
callback();
}
})
);
return resultStream;
}

Expand Down Expand Up @@ -136,20 +151,31 @@ export class SparqlJsonParser {
*/
public parseJsonBooleanStream(sparqlResponseStream: NodeJS.ReadableStream): Promise<boolean> {
return new Promise((resolve, reject) => {
const parser = new JsonParser();
parser.onError = reject;
parser.onValue = (value: any) => {
if(parser.key === "boolean" && typeof value === 'boolean' && parser.stack.length === 1) {
resolve(value);
}
}
sparqlResponseStream
.on('error', reject)
.on('data', d => parser.write(d))
.pipe(new JsonEventParser())
.on('error', reject)
.on('data', (event: JsonEvent) => {
if(event.type === 'value' && event.key === 'boolean' && typeof event.value === 'boolean') {
resolve(event.value);
}
})
.on('end', () => reject(new Error('No valid ASK response was found.')));
});
}

private parseVariableList(variables: JsonValue): RDF.Variable[] {
if(!Array.isArray(variables)) {
throw new Error("The variable list should be an array");
}
return variables.map(v => {
if(typeof v === "string") {
return this.dataFactory.variable(v);
} else {
throw new Error("Variable names should be strings");
}
});
}
}

/**
Expand Down
8 changes: 3 additions & 5 deletions package.json
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Original file line number Diff line number Diff line change
Expand Up @@ -32,6 +32,7 @@
"devDependencies": {
"@types/jest": "^28.0.0",
"@types/minimist": "^1.2.0",
"@types/readable-stream": "^2.3.14",
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I guess this one should be added as non-dev dep to json-event-parser.

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@Tpt Tpt Oct 10, 2022 •
edited
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Not sure it's required. json-event-parser works from plain JS projects without needing @types/readable-stream. What do you think about it?

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The convention in TS is that typings packages are included as non-dev deps, so that downstream users don't have to include all of these typing packages manually (which can incur in a lot of overhead for many transitive deps). And since typings packages are usually very small, this is not a problem for non-TS projects.

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@Tpt Tpt Oct 11, 2022 •
edited
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Thank you! Done: comunica/json-event-parser.js#2

"arrayify-stream": "^2.0.0",
"coveralls": "^3.0.0",
"jest": "^28.0.0",
Expand Down Expand Up @@ -82,11 +83,8 @@
},
"dependencies": {
"@rdfjs/types": "*",
"@types/readable-stream": "^2.3.13",
"buffer": "^6.0.3",
"jsonparse": "^1.3.1",
"rdf-data-factory": "^1.1.0",
"readable-stream": "^4.0.0"
"json-event-parser": "1.0.0-beta.2",
"rdf-data-factory": "^1.1.0"
},
"sideEffects": false
}
19 changes: 19 additions & 0 deletions test/SparqlJsonParser-test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -96,6 +96,17 @@ describe('SparqlJsonParser', () => {
`)))).toEqual([]);
});

it('should convert a slightly invalid empty SPARQL JSON response (common PHP error)', async () => {
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Why is this slightly invalid? (looks valid to me at first glance)

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Because the "bindings" key value should be an array and not an object.

return expect(await arrayifyStream(parser.parseJsonResultsStream(streamifyString(`
{
"head": { "vars": [] },
"results": {
"bindings": {}
}
}
`)))).toEqual([]);
});

it('should convert an empty SPARQL JSON response and emit the variables', async () => {
const stream = parser.parseJsonResultsStream(streamifyString(`
{
Expand Down Expand Up @@ -172,6 +183,14 @@ describe('SparqlJsonParser', () => {
return expect(arrayifyStream(parser.parseJsonResultsStream(streamifyString('{')))).rejects.toBeTruthy();
});

it('should reject on an invalid variables', async () => {
return expect(arrayifyStream(parser.parseJsonResultsStream(streamifyString('{"head": {"vars": null}, "results": {"bindings": []}}')))).rejects.toBeTruthy();
});

it('should reject on an invalid variables 2', async () => {
return expect(arrayifyStream(parser.parseJsonResultsStream(streamifyString('{"head": {"vars": [[]]}, "results": {"bindings": []}}')))).rejects.toBeTruthy();
});

it('should emit an error on an erroring stream', async () => {
const errorStream = new PassThrough();
errorStream._read = () => errorStream.emit('error', new Error('Some stream error'));
Expand Down
38 changes: 24 additions & 14 deletions yarn.lock
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Original file line number Diff line number Diff line change
Expand Up @@ -695,10 +695,10 @@
resolved "https://registry.yarnpkg.com/@types/prettier/-/prettier-2.6.3.tgz#68ada76827b0010d0db071f739314fa429943d0a"
integrity sha512-ymZk3LEC/fsut+/Q5qejp6R9O1rMxz3XaRHDV6kX8MrGAhOSPqVARbDi+EZvInBpw+BnCX3TD240byVkOfQsHg==

"@types/readable-stream@^2.3.13":
version "2.3.13"
resolved "https://registry.yarnpkg.com/@types/readable-stream/-/readable-stream-2.3.13.tgz#46451c1b87cb61010e420ac02a76cfc1b2c2089a"
integrity sha512-4JSCx8EUzaW9Idevt+9lsRAt1lcSccoQfE+AouM1gk8sFxnnytKNIO3wTl9Dy+4m6jRJ1yXhboLHHT/LXBQiEw==
"@types/readable-stream@^2.3.14":
version "2.3.14"
resolved "https://registry.yarnpkg.com/@types/readable-stream/-/readable-stream-2.3.14.tgz#1282cdc03a1fc9ed52982aa8f0553d7c251070b9"
integrity sha512-8jQ5Mp7bsDJEnW/69i6nAaQMoLwAVJVc7ZRAVTrdh/o6XueQsX38TEvKuYyoQj76/mg7WdlRfMrtl9pDLCJWsg==
dependencies:
"@types/node" "*"
safe-buffer "*"
Expand Down Expand Up @@ -1527,7 +1527,7 @@ event-target-shim@^5.0.0:
resolved "https://registry.yarnpkg.com/event-target-shim/-/event-target-shim-5.0.1.tgz#5d4d3ebdf9583d63a5333ce2deb7480ab2b05789"
integrity sha512-i/2XbnSz/uxRCU6+NdVJgKWDTM427+MqYbkQzD321DuCQJUqOuJKIA0IM2+W2xtYHdKOmZ4dR6fExsd4SXL+WQ==

events@^3.2.0:
events@^3.2.0, events@^3.3.0:
version "3.3.0"
resolved "https://registry.yarnpkg.com/events/-/events-3.3.0.tgz#31a95ad0a924e2d2c419a813aeb2c4e878ea7400"
integrity sha512-mQw+2fkQbALzQ7V0MY0IqdnXNOeTtP4r0lN9z7AAawCXgqea7bDii20AYrIBrFd/Hx0M2Ocz6S111CaFkUcb0Q==
Expand Down Expand Up @@ -2369,6 +2369,13 @@ jsesc@^2.5.1:
resolved "https://registry.yarnpkg.com/jsesc/-/jsesc-2.5.2.tgz#80564d2e483dacf6e8ef209650a67df3f0c283a4"
integrity sha512-OYu7XEzjkCQ3C5Ps3QIZsQfNpqoJyZZA99wd9aWd05NCtC5pWOkShK2mkL6HXQR6/Cy2lbNdPlZBpuQHXE63gA==

[email protected]:
version "1.0.0-beta.2"
resolved "https://registry.yarnpkg.com/json-event-parser/-/json-event-parser-1.0.0-beta.2.tgz#9a77f624bffeefd21b232b168c7051962db6eb3f"
integrity sha512-ibZRC+dzDmpsJkoHJ5yUONOL3x5i4LPgN7cyGW/iBras3h+KnPnslHNOuZRA1l20/XKXyj6roRasfa6Dx9nFww==
dependencies:
readable-stream "^4.2.0"

json-parse-better-errors@^1.0.1:
version "1.0.2"
resolved "https://registry.yarnpkg.com/json-parse-better-errors/-/json-parse-better-errors-1.0.2.tgz#bb867cfb3450e69107c131d1c514bab3dc8bcaa9"
Expand Down Expand Up @@ -2399,11 +2406,6 @@ json5@^2.2.1:
resolved "https://registry.yarnpkg.com/json5/-/json5-2.2.1.tgz#655d50ed1e6f95ad1a3caababd2b0efda10b395c"
integrity sha512-1hqLFMSrGHRHxav9q9gNjJ5EXznIxGVO09xQRrwplcS8qs28pZ8s8hupZAmqDwZUmVZ2Qb2jnyPOWcDH8m8dlA==

jsonparse@^1.3.1:
version "1.3.1"
resolved "https://registry.yarnpkg.com/jsonparse/-/jsonparse-1.3.1.tgz#3f4dae4a91fac315f71062f8521cc239f1366280"
integrity sha512-POQXvpdL69+CluYsillJ7SUhKvytYjW9vG/GKpnf+xP8UWgYEM/RaMzHHofbALDiKbbP1W8UEYmgGl39WkPZsg==

jsprim@^1.2.2:
version "1.4.2"
resolved "https://registry.yarnpkg.com/jsprim/-/jsprim-1.4.2.tgz#712c65533a15c878ba59e9ed5f0e26d5b77c5feb"
Expand Down Expand Up @@ -2885,6 +2887,11 @@ process-nextick-args@~2.0.0:
resolved "https://registry.yarnpkg.com/process-nextick-args/-/process-nextick-args-2.0.1.tgz#7820d9b16120cc55ca9ae7792680ae7dba6d7fe2"
integrity sha512-3ouUOpQhtgrbOa17J7+uxOTpITYWaGP7/AhoR3+A+/1e9skrzelGi/dXzEYyvbxubEF6Wn2ypscTKiKJFFn1ag==

process@^0.11.10:
version "0.11.10"
resolved "https://registry.yarnpkg.com/process/-/process-0.11.10.tgz#7332300e840161bda3e69a1d1d91a7d4bc16f182"
integrity sha512-cdGef/drWFoydD1JsMzuFf8100nZl+GT+yacc2bEced5f9Rjk4z+WtFUTBu9PhOi9j/jfmBPu0mMEY4wIdAF8A==

prompts@^2.0.1:
version "2.4.2"
resolved "https://registry.yarnpkg.com/prompts/-/prompts-2.4.2.tgz#7b57e73b3a48029ad10ebd44f74b01722a4cb069"
Expand Down Expand Up @@ -3027,12 +3034,15 @@ readable-stream@^2.2.2, readable-stream@~2.3.6:
string_decoder "~1.1.1"
util-deprecate "~1.0.1"

readable-stream@^4.0.0:
version "4.0.0"
resolved "https://registry.yarnpkg.com/readable-stream/-/readable-stream-4.0.0.tgz#da7105d03430a28ef4080785a43e6a45d4cdc4d1"
integrity sha512-Mf7ilWBP6AV3tF3MjtBrHMH3roso7wIrpgzCwt9ybvqiJQVWIEBMnp/W+S//yvYSsUUi2cJIwD7q7m57l0AqZw==
readable-stream@^4.2.0:
version "4.2.0"
resolved "https://registry.yarnpkg.com/readable-stream/-/readable-stream-4.2.0.tgz#a7ef523d3b39e4962b0db1a1af22777b10eeca46"
integrity sha512-gJrBHsaI3lgBoGMW/jHZsQ/o/TIWiu5ENCJG1BB7fuCKzpFM8GaS2UoBVt9NO+oI+3FcrBNbUkl3ilDe09aY4A==
dependencies:
abort-controller "^3.0.0"
buffer "^6.0.3"
events "^3.3.0"
process "^0.11.10"

rechoir@^0.7.0:
version "0.7.1"
Expand Down