refactor: Create BaseTypedRepresentationConverter

src/index.ts

@@ -250,6 +250,7 @@ export * from './storage/accessors/InMemoryDataAccessor';
 export * from './storage/accessors/SparqlDataAccessor';
 
 // Storage/Conversion
+export * from './storage/conversion/BaseTypedRepresentationConverter';
 export * from './storage/conversion/ChainedConverter';
 export * from './storage/conversion/ConstantConverter';
 export * from './storage/conversion/ContainerToTemplateConverter';

src/storage/conversion/BaseTypedRepresentationConverter.ts

@@ -0,0 +1,76 @@
+import type { ValuePreferences } from '../../http/representation/RepresentationPreferences';
+import { NotImplementedHttpError } from '../../util/errors/NotImplementedHttpError';
+import { getConversionTarget, getTypeWeight } from './ConversionUtil';
+import { RepresentationConverter } from './RepresentationConverter';
+import type { RepresentationConverterArgs } from './RepresentationConverter';
+
+type PromiseOrValue<T> = T | Promise<T>;
+type ValuePreferencesArg =
+  PromiseOrValue<string> |
+  PromiseOrValue<string[]> |
+  PromiseOrValue<ValuePreferences>;
+
+async function toValuePreferences(arg: ValuePreferencesArg): Promise<ValuePreferences> {
+  const resolved = await arg;
+  if (typeof resolved === 'string') {
+    return { [resolved]: 1 };
+  }
+  if (Array.isArray(resolved)) {
+    return Object.fromEntries(resolved.map((type): [string, number] => [ type, 1 ]));
+  }
+  return resolved;
+}
+
+/**
+ * A {@link RepresentationConverter} that allows requesting the supported types.
+ */
+export abstract class BaseTypedRepresentationConverter extends RepresentationConverter {
+  protected inputTypes: Promise<ValuePreferences>;
+  protected outputTypes: Promise<ValuePreferences>;
+
+  public constructor(inputTypes: ValuePreferencesArg = {}, outputTypes: ValuePreferencesArg = {}) {
+    super();
+    this.inputTypes = toValuePreferences(inputTypes);
+    this.outputTypes = toValuePreferences(outputTypes);
+  }
+
+  /**
+   * Gets the supported input content types for this converter, mapped to a numerical priority.
+   */
+  public async getInputTypes(): Promise<ValuePreferences> {
+    return this.inputTypes;
+  }
+
+  /**
+   * Gets the supported output content types for this converter, mapped to a numerical quality.
+   */
+  public async getOutputTypes(): Promise<ValuePreferences> {
+    return this.outputTypes;
+  }
+
+  /**
+   * Determines whether the given conversion request is supported,
+   * given the available content type conversions:
+   *  - Checks if there is a content type for the input.
+   *  - Checks if the input type is supported by the parser.
+   *  - Checks if the parser can produce one of the preferred output types.
+   * Throws an error with details if conversion is not possible.
+   */
+  public async canHandle(args: RepresentationConverterArgs): Promise<void> {
+    const types = [ this.getInputTypes(), this.getOutputTypes() ];
+    const { contentType } = args.representation.metadata;
+
+    if (!contentType) {
+      throw new NotImplementedHttpError('Can not convert data without a Content-Type.');
+    }
+
+    const [ inputTypes, outputTypes ] = await Promise.all(types);
+    const outputPreferences = args.preferences.type ?? {};
+    if (getTypeWeight(contentType, inputTypes) === 0 || !getConversionTarget(outputTypes, outputPreferences)) {
+      throw new NotImplementedHttpError(
+        `Cannot convert from ${contentType} to ${Object.keys(outputPreferences)
+        }, only from ${Object.keys(inputTypes)} to ${Object.keys(outputTypes)}.`,
+      );
+    }
+  }
+}

src/storage/conversion/ContainerToTemplateConverter.ts

@@ -11,8 +11,8 @@ import { isContainerIdentifier, isContainerPath } from '../../util/PathUtil';
 import { endOfStream } from '../../util/StreamUtil';
 import type { TemplateEngine } from '../../util/templates/TemplateEngine';
 import { LDP } from '../../util/Vocabularies';
+import { BaseTypedRepresentationConverter } from './BaseTypedRepresentationConverter';
 import type { RepresentationConverterArgs } from './RepresentationConverter';
-import { TypedRepresentationConverter } from './TypedRepresentationConverter';
 
 interface ResourceDetails {
   name: string;
@@ -23,7 +23,7 @@ interface ResourceDetails {
 /**
  * A {@link RepresentationConverter} that creates a templated representation of a container.
  */
-export class ContainerToTemplateConverter extends TypedRepresentationConverter {
+export class ContainerToTemplateConverter extends BaseTypedRepresentationConverter {
   private readonly identifierStrategy: IdentifierStrategy;
   private readonly templateEngine: TemplateEngine;
   private readonly contentType: string;

src/storage/conversion/ErrorToJsonConverter.ts

@@ -3,13 +3,13 @@ import type { Representation } from '../../http/representation/Representation';
 import { APPLICATION_JSON, INTERNAL_ERROR } from '../../util/ContentTypes';
 import { HttpError } from '../../util/errors/HttpError';
 import { getSingleItem } from '../../util/StreamUtil';
+import { BaseTypedRepresentationConverter } from './BaseTypedRepresentationConverter';
 import type { RepresentationConverterArgs } from './RepresentationConverter';
-import { TypedRepresentationConverter } from './TypedRepresentationConverter';
 
 /**
  * Converts an Error object to JSON by copying its fields.
  */
-export class ErrorToJsonConverter extends TypedRepresentationConverter {
+export class ErrorToJsonConverter extends BaseTypedRepresentationConverter {
   public constructor() {
     super(INTERNAL_ERROR, APPLICATION_JSON);
   }

src/storage/conversion/ErrorToQuadConverter.ts

@@ -4,13 +4,13 @@ import { RepresentationMetadata } from '../../http/representation/Representation
 import { INTERNAL_ERROR, INTERNAL_QUADS } from '../../util/ContentTypes';
 import { getSingleItem } from '../../util/StreamUtil';
 import { DC, SOLID_ERROR } from '../../util/Vocabularies';
+import { BaseTypedRepresentationConverter } from './BaseTypedRepresentationConverter';
 import type { RepresentationConverterArgs } from './RepresentationConverter';
-import { TypedRepresentationConverter } from './TypedRepresentationConverter';
 
 /**
  * Converts an error object into quads by creating a triple for each of name/message/stack.
  */
-export class ErrorToQuadConverter extends TypedRepresentationConverter {
+export class ErrorToQuadConverter extends BaseTypedRepresentationConverter {
   public constructor() {
     super(INTERNAL_ERROR, INTERNAL_QUADS);
   }

src/storage/conversion/ErrorToTemplateConverter.ts

@@ -6,8 +6,8 @@ import { HttpError } from '../../util/errors/HttpError';
 import { modulePathPlaceholder } from '../../util/PathUtil';
 import { getSingleItem } from '../../util/StreamUtil';
 import type { TemplateEngine } from '../../util/templates/TemplateEngine';
+import { BaseTypedRepresentationConverter } from './BaseTypedRepresentationConverter';
 import type { RepresentationConverterArgs } from './RepresentationConverter';
-import { TypedRepresentationConverter } from './TypedRepresentationConverter';
 
 // Fields optional due to https://github.com/LinkedSoftwareDependencies/Components.js/issues/20
 export interface TemplateOptions {
@@ -35,7 +35,7 @@ const DEFAULT_TEMPLATE_OPTIONS: TemplateOptions = {
  * That result will be passed as an additional parameter to the main templating call,
  * using the variable `codeMessage`.
  */
-export class ErrorToTemplateConverter extends TypedRepresentationConverter {
+export class ErrorToTemplateConverter extends BaseTypedRepresentationConverter {
   private readonly templateEngine: TemplateEngine;
   private readonly mainTemplatePath: string;
   private readonly codeTemplatesPath: string;

src/storage/conversion/FormToJsonConverter.ts

@@ -5,14 +5,14 @@ import { RepresentationMetadata } from '../../http/representation/Representation
 import { APPLICATION_JSON, APPLICATION_X_WWW_FORM_URLENCODED } from '../../util/ContentTypes';
 import { readableToString } from '../../util/StreamUtil';
 import { CONTENT_TYPE } from '../../util/Vocabularies';
+import { BaseTypedRepresentationConverter } from './BaseTypedRepresentationConverter';
 import type { RepresentationConverterArgs } from './RepresentationConverter';
-import { TypedRepresentationConverter } from './TypedRepresentationConverter';
 
 /**
  * Converts application/x-www-form-urlencoded data to application/json.
  * Due to the nature of form data, the result will be a simple key/value JSON object.
  */
-export class FormToJsonConverter extends TypedRepresentationConverter {
+export class FormToJsonConverter extends BaseTypedRepresentationConverter {
   public constructor() {
     super(APPLICATION_X_WWW_FORM_URLENCODED, APPLICATION_JSON);
   }

src/storage/conversion/MarkdownToHtmlConverter.ts

@@ -4,8 +4,8 @@ import type { Representation } from '../../http/representation/Representation';
 import { TEXT_HTML, TEXT_MARKDOWN } from '../../util/ContentTypes';
 import { readableToString } from '../../util/StreamUtil';
 import type { TemplateEngine } from '../../util/templates/TemplateEngine';
+import { BaseTypedRepresentationConverter } from './BaseTypedRepresentationConverter';
 import type { RepresentationConverterArgs } from './RepresentationConverter';
-import { TypedRepresentationConverter } from './TypedRepresentationConverter';
 
 /**
  * Converts Markdown data to HTML.
@@ -13,7 +13,7 @@ import { TypedRepresentationConverter } from './TypedRepresentationConverter';
  * A standard Markdown string will be converted to a <p> tag, so html and body tags should be part of the template.
  * In case the Markdown body starts with a header (#), that value will also be used as `title` parameter.
  */
-export class MarkdownToHtmlConverter extends TypedRepresentationConverter {
+export class MarkdownToHtmlConverter extends BaseTypedRepresentationConverter {
   private readonly templateEngine: TemplateEngine;
 
   public constructor(templateEngine: TemplateEngine) {

src/storage/conversion/QuadToRdfConverter.ts

@@ -7,14 +7,14 @@ import type { ValuePreferences } from '../../http/representation/RepresentationP
 import { INTERNAL_QUADS } from '../../util/ContentTypes';
 import { pipeSafely } from '../../util/StreamUtil';
 import { PREFERRED_PREFIX_TERM } from '../../util/Vocabularies';
+import { BaseTypedRepresentationConverter } from './BaseTypedRepresentationConverter';
 import { getConversionTarget } from './ConversionUtil';
 import type { RepresentationConverterArgs } from './RepresentationConverter';
-import { TypedRepresentationConverter } from './TypedRepresentationConverter';
 
 /**
  * Converts `internal/quads` to most major RDF serializations.
  */
-export class QuadToRdfConverter extends TypedRepresentationConverter {
+export class QuadToRdfConverter extends BaseTypedRepresentationConverter {
   private readonly outputPreferences?: ValuePreferences;
 
   public constructor(options: { outputPreferences?: Record<string, number> } = {}) {

src/storage/conversion/RdfToQuadConverter.ts

@@ -5,13 +5,13 @@ import type { Representation } from '../../http/representation/Representation';
 import { INTERNAL_QUADS } from '../../util/ContentTypes';
 import { BadRequestHttpError } from '../../util/errors/BadRequestHttpError';
 import { pipeSafely } from '../../util/StreamUtil';
+import { BaseTypedRepresentationConverter } from './BaseTypedRepresentationConverter';
 import type { RepresentationConverterArgs } from './RepresentationConverter';
-import { TypedRepresentationConverter } from './TypedRepresentationConverter';
 
 /**
  * Converts most major RDF serializations to `internal/quads`.
  */
-export class RdfToQuadConverter extends TypedRepresentationConverter {
+export class RdfToQuadConverter extends BaseTypedRepresentationConverter {
   public constructor() {
     super(rdfParser.getContentTypesPrioritized(), INTERNAL_QUADS);
   }

src/storage/conversion/TypedRepresentationConverter.ts

@@ -1,76 +1,17 @@
 import type { ValuePreferences } from '../../http/representation/RepresentationPreferences';
-import { NotImplementedHttpError } from '../../util/errors/NotImplementedHttpError';
-import { getConversionTarget, getTypeWeight } from './ConversionUtil';
 import { RepresentationConverter } from './RepresentationConverter';
-import type { RepresentationConverterArgs } from './RepresentationConverter';
-
-type PromiseOrValue<T> = T | Promise<T>;
-type ValuePreferencesArg =
-  PromiseOrValue<string> |
-  PromiseOrValue<string[]> |
-  PromiseOrValue<ValuePreferences>;
-
-async function toValuePreferences(arg: ValuePreferencesArg): Promise<ValuePreferences> {
-  const resolved = await arg;
-  if (typeof resolved === 'string') {
-    return { [resolved]: 1 };
-  }
-  if (Array.isArray(resolved)) {
-    return Object.fromEntries(resolved.map((type): [string, number] => [ type, 1 ]));
-  }
-  return resolved;
-}
 
 /**
  * A {@link RepresentationConverter} that allows requesting the supported types.
  */
 export abstract class TypedRepresentationConverter extends RepresentationConverter {
-  protected inputTypes: Promise<ValuePreferences>;
-  protected outputTypes: Promise<ValuePreferences>;
-
-  public constructor(inputTypes: ValuePreferencesArg = {}, outputTypes: ValuePreferencesArg = {}) {
-    super();
-    this.inputTypes = toValuePreferences(inputTypes);
-    this.outputTypes = toValuePreferences(outputTypes);
-  }
-
   /**
    * Gets the supported input content types for this converter, mapped to a numerical priority.
    */
-  public async getInputTypes(): Promise<ValuePreferences> {
+  public abstract getInputTypes(): Promise<ValuePreferences>;
-    return this.inputTypes;
-  }
 
   /**
    * Gets the supported output content types for this converter, mapped to a numerical quality.
    */
-  public async getOutputTypes(): Promise<ValuePreferences> {
+  public abstract getOutputTypes(): Promise<ValuePreferences>;
-    return this.outputTypes;
-  }
-
-  /**
-   * Determines whether the given conversion request is supported,
-   * given the available content type conversions:
-   *  - Checks if there is a content type for the input.
-   *  - Checks if the input type is supported by the parser.
-   *  - Checks if the parser can produce one of the preferred output types.
-   * Throws an error with details if conversion is not possible.
-   */
-  public async canHandle(args: RepresentationConverterArgs): Promise<void> {
-    const types = [ this.getInputTypes(), this.getOutputTypes() ];
-    const { contentType } = args.representation.metadata;
-
-    if (!contentType) {
-      throw new NotImplementedHttpError('Can not convert data without a Content-Type.');
-    }
-
-    const [ inputTypes, outputTypes ] = await Promise.all(types);
-    const outputPreferences = args.preferences.type ?? {};
-    if (getTypeWeight(contentType, inputTypes) === 0 || !getConversionTarget(outputTypes, outputPreferences)) {
-      throw new NotImplementedHttpError(
-        `Cannot convert from ${contentType} to ${Object.keys(outputPreferences)
-        }, only from ${Object.keys(inputTypes)} to ${Object.keys(outputTypes)}.`,
-      );
-    }
-  }
 }

test/integration/GuardedStream.test.ts

@@ -1,6 +1,5 @@
 import {
   RepresentationMetadata,
-  TypedRepresentationConverter,
   readableToString,
   ChainedConverter,
   guardedStreamFrom,
@@ -12,6 +11,7 @@ import {
 import type { Representation,
   RepresentationConverterArgs,
   Logger } from '../../src';
+import { BaseTypedRepresentationConverter } from '../../src/storage/conversion/BaseTypedRepresentationConverter';
 
 jest.mock('../../src/logging/LogUtil', (): any => {
   const logger: Logger =
@@ -20,7 +20,7 @@ jest.mock('../../src/logging/LogUtil', (): any => {
 });
 const logger: jest.Mocked<Logger> = getLoggerFor('GuardedStream') as any;
 
-class DummyConverter extends TypedRepresentationConverter {
+class DummyConverter extends BaseTypedRepresentationConverter {
   public constructor() {
     super('*/*', 'custom/type');
   }

test/unit/storage/conversion/BaseTypedRepresentationConverter.test.ts

@@ -1,12 +1,12 @@
+import { BaseTypedRepresentationConverter } from '../../../../src/storage/conversion/BaseTypedRepresentationConverter';
 import type { RepresentationConverterArgs } from '../../../../src/storage/conversion/RepresentationConverter';
-import { TypedRepresentationConverter } from '../../../../src/storage/conversion/TypedRepresentationConverter';
 import { NotImplementedHttpError } from '../../../../src/util/errors/NotImplementedHttpError';
 
-class CustomTypedRepresentationConverter extends TypedRepresentationConverter {
+class CustomTypedRepresentationConverter extends BaseTypedRepresentationConverter {
   public handle = jest.fn();
 }
 
-describe('A TypedRepresentationConverter', (): void => {
+describe('A BaseTypedRepresentationConverter', (): void => {
   it('defaults to allowing everything.', async(): Promise<void> => {
     const converter = new CustomTypedRepresentationConverter();
     await expect(converter.getInputTypes()).resolves.toEqual({

test/unit/storage/conversion/ChainedConverter.test.ts

@@ -4,13 +4,13 @@ import type {
   RepresentationPreferences,
   ValuePreferences,
 } from '../../../../src/http/representation/RepresentationPreferences';
+import { BaseTypedRepresentationConverter } from '../../../../src/storage/conversion/BaseTypedRepresentationConverter';
 import { ChainedConverter } from '../../../../src/storage/conversion/ChainedConverter';
 import { matchesMediaType } from '../../../../src/storage/conversion/ConversionUtil';
 import type { RepresentationConverterArgs } from '../../../../src/storage/conversion/RepresentationConverter';
-import { TypedRepresentationConverter } from '../../../../src/storage/conversion/TypedRepresentationConverter';
 import { CONTENT_TYPE } from '../../../../src/util/Vocabularies';
 
-class DummyConverter extends TypedRepresentationConverter {
+class DummyConverter extends BaseTypedRepresentationConverter {
   private readonly inTypes: ValuePreferences;
   private readonly outTypes: ValuePreferences;