Removes JSONStream dependency

Works directly using jsonparse.
rubensworks · Jul 8, 2022 · 4637324 · 4637324
1 parent 2109894
commit 4637324
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Showing 6 changed files with 51 additions and 68 deletions.
diff --git a/index.ts b/index.ts
@@ -1,2 +1 @@
 export * from "./lib/SparqlJsonParser";
-export * from "./lib/SparqlJsonBindingsTransformer";
diff --git a/lib/SparqlJsonBindingsTransformer.ts b/lib/SparqlJsonBindingsTransformer.ts
diff --git a/lib/SparqlJsonParser.ts b/lib/SparqlJsonParser.ts
@@ -1,6 +1,9 @@
 import {DataFactory} from "rdf-data-factory";
 import * as RDF from "@rdfjs/types";
-import {SparqlJsonBindingsTransformer} from "./SparqlJsonBindingsTransformer";
+import {Transform} from "readable-stream";
+
+// tslint:disable-next-line:no-var-requires
+const JsonParser = require('jsonparse');
 
 /**
  * Parser for the SPARQL 1.1 Query Results JSON format.
@@ -38,14 +41,25 @@ export class SparqlJsonParser {
   public parseJsonResultsStream(sparqlResponseStream: NodeJS.ReadableStream): NodeJS.ReadableStream {
     const errorListener = (error: Error) => resultStream.emit('error', error);
     sparqlResponseStream.on('error', errorListener);
-    const variables: RDF.Variable[] = [];
-    sparqlResponseStream
-      .pipe(require('JSONStream').parse('head.vars.*').on('error', errorListener))
-      .on('data', (variable: string) => variables.push(this.dataFactory.variable(variable)))
-      .on('end',  () => resultStream.emit('variables', variables));
+
+    const jsonParser = new JsonParser();
+    jsonParser.onError = errorListener;
+    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)))
+      } 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))
+      }
+    }
+
     const resultStream = sparqlResponseStream
-      .pipe(require('JSONStream').parse('results.bindings.*').on('error', errorListener))
-      .pipe(new SparqlJsonBindingsTransformer(this));
+      .pipe(new Transform({
+        objectMode: true,
+        transform(chunk: any, encoding: string, callback: (error?: Error | null, data?: any) => void) {
+          jsonParser.write(chunk);
+          callback();
+        }
+      }));
     return resultStream;
   }
 
@@ -102,14 +116,21 @@ export class SparqlJsonParser {
    * Convert a SPARQL JSON boolean response stream to a promise resolving to a boolean.
    * This will reject if the given reponse was not a valid boolean response.
    * @param {NodeJS.ReadableStream} sparqlResponseStream A SPARQL JSON response stream.
-   * @return {NodeJS.ReadableStream} A stream of bindings.
+   * @return {Promise<boolean>} The response boolean.
    */
   public parseJsonBooleanStream(sparqlResponseStream: NodeJS.ReadableStream): Promise<boolean> {
     return new Promise((resolve, reject) => {
-      sparqlResponseStream.on('error', reject);
-      sparqlResponseStream.pipe(require('JSONStream').parse('boolean'))
-        .on('data', resolve)
-        .on('end', () => reject(new Error('No valid ASK response was found.')));
+      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))
+          .on('end', () => reject(new Error('No valid ASK response was found.')));
     });
   }
 
@@ -135,3 +156,4 @@ export interface ISettings {
 export interface IBindings {
   [key: string]: RDF.Term;
 }
+
diff --git a/package.json b/package.json
@@ -81,7 +81,7 @@
     "@rdfjs/types": "*",
     "@types/node": "^18.0.0",
     "@types/readable-stream": "^2.3.13",
-    "JSONStream": "^1.3.3",
+    "jsonparse": "^1.3.1",
     "rdf-data-factory": "^1.1.0"
   },
   "sideEffects": false

diff --git a/test/SparqlJsonParser-test.ts b/test/SparqlJsonParser-test.ts
@@ -112,43 +112,39 @@ describe('SparqlJsonParser', () => {
     it('should convert a SPARQL JSON response', async () => {
       return expect(await arrayifyStream(parser.parseJsonResultsStream(streamifyString(`
 {
-  "head": { "vars": [ "book" ] },
+  "head": { "vars": [ "book", "library" ] },
   "results": {
     "bindings": [
-      { "book": { "type": "uri", "value": "http://example.org/book/book1" } },
-      { "book": { "type": "uri", "value": "http://example.org/book/book2" } },
-      { "book": { "type": "uri", "value": "http://example.org/book/book3" } },
-      { "book": { "type": "uri", "value": "http://example.org/book/book4" } },
-      { "book": { "type": "uri", "value": "http://example.org/book/book5" } }
+      { "book": { "type": "uri", "value": "http://example.org/book/book1" }, "library": { "type": "uri", "value": "http://example.org/book/library1" } },
+      { "book": { "type": "uri", "value": "http://example.org/book/book2" }, "library": { "type": "uri", "value": "http://example.org/book/library2" } },
+      { "book": { "type": "uri", "value": "http://example.org/book/book3" }, "library": { "type": "uri", "value": "http://example.org/book/library3" } },
+      { "book": { "type": "uri", "value": "http://example.org/book/book4" }, "library": { "type": "uri", "value": "http://example.org/book/library4" } },
+      { "book": { "type": "uri", "value": "http://example.org/book/book5" }, "library": { "type": "uri", "value": "http://example.org/book/library5" } }
     ]
   }
 }
 `)))).toEqual([
-        { '?book': DF.namedNode('http://example.org/book/book1') },
-        { '?book': DF.namedNode('http://example.org/book/book2') },
-        { '?book': DF.namedNode('http://example.org/book/book3') },
-        { '?book': DF.namedNode('http://example.org/book/book4') },
-        { '?book': DF.namedNode('http://example.org/book/book5') },
+        { '?book': DF.namedNode('http://example.org/book/book1'), '?library': DF.namedNode('http://example.org/book/library1') },
+        { '?book': DF.namedNode('http://example.org/book/book2'), '?library': DF.namedNode('http://example.org/book/library2') },
+        { '?book': DF.namedNode('http://example.org/book/book3'), '?library': DF.namedNode('http://example.org/book/library3') },
+        { '?book': DF.namedNode('http://example.org/book/book4'), '?library': DF.namedNode('http://example.org/book/library4') },
+        { '?book': DF.namedNode('http://example.org/book/book5'), '?library': DF.namedNode('http://example.org/book/library5') },
 ]);
     });
 
     it('should convert a SPARQL JSON response and emit the variables', async () => {
       const stream = parser.parseJsonResultsStream(streamifyString(`
 {
-  "head": { "vars": [ "book" ] },
+  "head": { "vars": [ "book", "library" ] },
   "results": {
     "bindings": [
-      { "book": { "type": "uri", "value": "http://example.org/book/book1" } },
-      { "book": { "type": "uri", "value": "http://example.org/book/book2" } },
-      { "book": { "type": "uri", "value": "http://example.org/book/book3" } },
-      { "book": { "type": "uri", "value": "http://example.org/book/book4" } },
-      { "book": { "type": "uri", "value": "http://example.org/book/book5" } }
+      { "book": { "type": "uri", "value": "http://example.org/book/book1" }, "library": { "type": "uri", "value": "http://example.org/book/library1" } }
     ]
   }
 }
 `));
       return expect(new Promise((resolve) => stream.on('variables', resolve))).resolves.toEqualRdfTermArray([
-        DF.variable('book'),
+        DF.variable('book'), DF.variable('library')
       ]);
     });
 

diff --git a/yarn.lock b/yarn.lock
@@ -676,14 +676,6 @@
   dependencies:
     "@types/yargs-parser" "*"
 
-JSONStream@^1.3.3:
-  version "1.3.5"
-  resolved "https://registry.yarnpkg.com/JSONStream/-/JSONStream-1.3.5.tgz#3208c1f08d3a4d99261ab64f92302bc15e111ca0"
-  integrity sha512-E+iruNOY8VV9s4JEbe1aNEm6MiszPRr/UfcHMz0TQh1BXSxHK+ASV1R6W4HpjBhSeS+54PIsAMCBmwD06LLsqQ==
-  dependencies:
-    jsonparse "^1.2.0"
-    through ">=2.2.7 <3"
-
 ajv@^6.12.3:
   version "6.12.6"
   resolved "https://registry.yarnpkg.com/ajv/-/ajv-6.12.6.tgz#baf5a62e802b07d977034586f8c3baf5adf26df4"
@@ -2062,7 +2054,7 @@ json5@^2.2.1:
   resolved "https://registry.yarnpkg.com/json5/-/json5-2.2.1.tgz#655d50ed1e6f95ad1a3caababd2b0efda10b395c"
   integrity sha512-1hqLFMSrGHRHxav9q9gNjJ5EXznIxGVO09xQRrwplcS8qs28pZ8s8hupZAmqDwZUmVZ2Qb2jnyPOWcDH8m8dlA==
 
-jsonparse@^1.2.0:
+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==
@@ -3051,11 +3043,6 @@ through2@^4.0.0:
   dependencies:
     readable-stream "3"
 
-"through@>=2.2.7 <3":
-  version "2.3.8"
-  resolved "https://registry.yarnpkg.com/through/-/through-2.3.8.tgz#0dd4c9ffaabc357960b1b724115d7e0e86a2e1f5"
-  integrity sha512-w89qg7PI8wAdvX60bMDP+bFoD5Dvhm9oLheFp5O4a2QF0cSBGsBX4qZmadPMvVqlLJBBci+WqGGOAPvcDeNSVg==
-
 tmpl@1.0.5:
   version "1.0.5"
   resolved "https://registry.yarnpkg.com/tmpl/-/tmpl-1.0.5.tgz#8683e0b902bb9c20c4f726e3c0b69f36518c07cc"