Merge c86eae9 into 5fa0686

.eslintrc.js

@@ -5,6 +5,9 @@ module.exports = {
     tsconfigRootDir: __dirname, // this is the reason this is a .js file
     project: ['./tsconfig.json'],
   },
+  globals:  {
+    NodeJS: 'readonly'
+  },
   plugins: [
     'eslint-plugin-tsdoc',
     'eslint-plugin-import',

index.ts

@@ -84,6 +84,7 @@ export * from './src/server/HttpResponse';
 export * from './src/storage/accessors/DataAccessor';
 export * from './src/storage/accessors/FileDataAccessor';
 export * from './src/storage/accessors/InMemoryDataAccessor';
+export * from './src/storage/accessors/SparqlDataAccessor';
 
 // Storage/Conversion
 export * from './src/storage/conversion/ChainedConverter';
@@ -102,6 +103,7 @@ export * from './src/storage/Conditions';
 export * from './src/storage/ContainerManager';
 export * from './src/storage/DataAccessorBasedStore';
 export * from './src/storage/ExtensionBasedMapper';
+export * from './src/storage/FixedConvertingStore';
 export * from './src/storage/Lock';
 export * from './src/storage/LockingResourceStore';
 export * from './src/storage/PassthroughStore';

package.json

@@ -71,6 +71,7 @@
     "@types/n3": "^1.4.4",
     "@types/node": "^14.10.2",
     "@types/rdf-js": "^4.0.0",
+    "@types/sparqljs": "^3.1.0",
     "@types/streamify-array": "^1.0.0",
     "@types/uuid": "^8.3.0",
     "@types/yargs": "^15.0.5",
@@ -79,12 +80,14 @@
     "componentsjs": "^3.6.0",
     "cors": "^2.8.5",
     "express": "^4.17.1",
+    "fetch-sparql-endpoint": "^1.8.0",
     "mime-types": "^2.1.27",
     "n3": "^1.6.3",
     "rdf-parse": "^1.5.0",
     "rdf-serialize": "^1.0.0",
     "rdf-terms": "^1.5.1",
     "sparqlalgebrajs": "^2.3.1",
+    "sparqljs": "^3.1.2",
     "streamify-array": "^1.0.1",
     "uuid": "^8.3.0",
     "winston": "^3.3.3",

src/storage/FixedConvertingStore.ts

@@ -0,0 +1,45 @@
+import type { Representation } from '../ldp/representation/Representation';
+import type { RepresentationPreference } from '../ldp/representation/RepresentationPreference';
+import type { ResourceIdentifier } from '../ldp/representation/ResourceIdentifier';
+import type { Conditions } from './Conditions';
+import type { RepresentationConverter } from './conversion/RepresentationConverter';
+import { PassthroughStore } from './PassthroughStore';
+import type { ResourceStore } from './ResourceStore';
+
+/**
+ * Store that converts incoming data when required.
+ * If the content-type of an incoming representation does not match one of the stored types it will be converted.
+ */
+export class FixedConvertingStore extends PassthroughStore {
+  private readonly types: string[];
+  private readonly converter: RepresentationConverter;
+
+  public constructor(source: ResourceStore, converter: RepresentationConverter, types: string[]) {
+    super(source);
+    this.converter = converter;
+    this.types = types;
+  }
+
+  public async addResource(container: ResourceIdentifier, representation: Representation,
+    conditions?: Conditions): Promise<ResourceIdentifier> {
+    // We can potentially run into problems here if we convert a turtle document where the base IRI is required,
+    // since we don't know the resource IRI yet at this point.
+    representation = await this.convertRepresentation(container, representation);
+    return this.source.addResource(container, representation, conditions);
+  }
+
+  public async setRepresentation(identifier: ResourceIdentifier, representation: Representation,
+    conditions?: Conditions): Promise<void> {
+    representation = await this.convertRepresentation(identifier, representation);
+    return this.source.setRepresentation(identifier, representation, conditions);
+  }
+
+  private async convertRepresentation(identifier: ResourceIdentifier, representation: Representation):
+  Promise<Representation> {
+    if (this.types.includes(representation.metadata.contentType!)) {
+      return representation;
+    }
+    const preferences = this.types.map((type): RepresentationPreference => ({ value: type, weight: 1 }));
+    return this.converter.handleSafe({ identifier, representation, preferences: { type: preferences }});
+  }
+}