feat: Create a RoutingResourceStore that takes routing rules

src/storage/RoutingResourceStore.ts

@@ -2,12 +2,16 @@ import type { Patch } from '../ldp/http/Patch';
 import type { Representation } from '../ldp/representation/Representation';
 import type { RepresentationPreferences } from '../ldp/representation/RepresentationPreferences';
 import type { ResourceIdentifier } from '../ldp/representation/ResourceIdentifier';
+import { NotFoundHttpError } from '../util/errors/NotFoundHttpError';
+import { UnsupportedHttpError } from '../util/errors/UnsupportedHttpError';
 import type { Conditions } from './Conditions';
 import type { ResourceStore } from './ResourceStore';
 import type { RouterRule } from './routing/RouterRule';
 
 /**
- * Store that calls a specific store based on certain routing defined by the ResourceRouter.
+ * Store that routes the incoming request to a specific store based on the stored ResourceRouter.
+ * In case no store was found for one of the functions that take no data (GET/PATCH/DELETE),
+ * a 404 will be thrown. In the other cases the error of the router will be thrown (which would probably be 400).
  */
 export class RoutingResourceStore implements ResourceStore {
   private readonly rule: RouterRule;
@@ -18,28 +22,41 @@ export class RoutingResourceStore implements ResourceStore {
 
   public async getRepresentation(identifier: ResourceIdentifier, preferences: RepresentationPreferences,
     conditions?: Conditions): Promise<Representation> {
-    return (await this.rule.getMatchingResourceStore(identifier))
-      .getRepresentation(identifier, preferences, conditions);
+    return (await this.getStore(identifier)).getRepresentation(identifier, preferences, conditions);
   }
 
   public async addResource(container: ResourceIdentifier, representation: Representation,
     conditions?: Conditions): Promise<ResourceIdentifier> {
-    return (await this.rule.getMatchingResourceStore(container, representation))
-      .addResource(container, representation, conditions);
+    return (await this.getStore(container, representation)).addResource(container, representation, conditions);
   }
 
   public async setRepresentation(identifier: ResourceIdentifier, representation: Representation,
     conditions?: Conditions): Promise<void> {
-    return (await this.rule.getMatchingResourceStore(identifier, representation))
-      .setRepresentation(identifier, representation, conditions);
+    return (await this.getStore(identifier, representation)).setRepresentation(identifier, representation, conditions);
   }
 
   public async deleteResource(identifier: ResourceIdentifier, conditions?: Conditions): Promise<void> {
-    return (await this.rule.getMatchingResourceStore(identifier)).deleteResource(identifier, conditions);
+    return (await this.getStore(identifier)).deleteResource(identifier, conditions);
   }
 
   public async modifyResource(identifier: ResourceIdentifier, patch: Patch, conditions?: Conditions):
   Promise<void> {
-    return (await this.rule.getMatchingResourceStore(identifier)).modifyResource(identifier, patch, conditions);
+    return (await this.getStore(identifier)).modifyResource(identifier, patch, conditions);
+  }
+
+  private async getStore(identifier: ResourceIdentifier, representation?: Representation): Promise<ResourceStore> {
+    if (representation) {
+      return this.rule.handleSafe({ identifier, representation });
+    }
+
+    // In case there is no incoming data we want to return 404 if no store was found
+    try {
+      return await this.rule.handleSafe({ identifier });
+    } catch (error: unknown) {
+      if (error instanceof UnsupportedHttpError) {
+        throw new NotFoundHttpError();
+      }
+      throw error;
+    }
   }
 }

src/storage/routing/ConvertingRouterRule.ts

@@ -0,0 +1,80 @@
+import type { Representation } from '../../ldp/representation/Representation';
+import type { ResourceIdentifier } from '../../ldp/representation/ResourceIdentifier';
+import { NotFoundHttpError } from '../../util/errors/NotFoundHttpError';
+import type { ResourceStore } from '../ResourceStore';
+import type { PreferenceSupport } from './PreferenceSupport';
+import { RouterRule } from './RouterRule';
+
+export interface ConvertingStoreEntry {
+  store: ResourceStore;
+  supportChecker: PreferenceSupport;
+}
+
+/**
+ * Rule that directs requests based on how the data would need to be converted.
+ * In case the given converter can convert the data to the requested type,
+ * it will be directed to the `convertStore`.
+ * Otherwise the `defaultStore` will be chosen.
+ *
+ * In case there is no data and only an identifier the `defaultStore` will be checked
+ * if it contains the given identifier.
+ * If not, the `convertStore` will be returned.
+ */
+export class ConvertingRouterRule extends RouterRule {
+  private readonly typedStores: ConvertingStoreEntry[];
+  private readonly defaultStore: ResourceStore;
+
+  public constructor(typedStores: ConvertingStoreEntry[], defaultStore: ResourceStore) {
+    super();
+    this.typedStores = typedStores;
+    this.defaultStore = defaultStore;
+  }
+
+  public async handle(input: { identifier: ResourceIdentifier; representation?: Representation }):
+  Promise<ResourceStore> {
+    const { identifier, representation } = input;
+    let store: ResourceStore;
+    if (representation) {
+      // TS type checking is not smart enough to let us reuse the input object
+      store = await this.findStore(async(entry): Promise<boolean> =>
+        entry.supportChecker.supports({ identifier, representation }));
+    } else {
+      // No content-type given so we can only check if one of the stores has data for the identifier
+      store = await this.findStore(async(entry): Promise<boolean> =>
+        this.hasResource(entry.store, input.identifier));
+    }
+    return store;
+  }
+
+  /**
+   * Helper function that checks if the given store contains the given identifier or not.
+   */
+  private async hasResource(store: ResourceStore, identifier: ResourceIdentifier): Promise<boolean> {
+    try {
+      const response = await store.getRepresentation(identifier, {});
+      response.data.destroy();
+      return true;
+    } catch (error: unknown) {
+      if (error instanceof NotFoundHttpError) {
+        return false;
+      }
+      throw error;
+    }
+  }
+
+  /**
+   * Helper function that runs the given callback function for all the stores
+   * and returns the first one that does not throw an error.
+   *
+   * Returns the default store if no match was found.
+   */
+  private async findStore(supports: (entry: ConvertingStoreEntry) => Promise<boolean>): Promise<ResourceStore> {
+    // Try all the stores, return default if there is no match
+    for (const entry of this.typedStores) {
+      if (await supports(entry)) {
+        return entry.store;
+      }
+    }
+    return this.defaultStore;
+  }
+}

src/storage/routing/PathRouterRule.ts

@@ -1,35 +0,0 @@
-import type { Representation } from '../../ldp/representation/Representation';
-import type { ResourceIdentifier } from '../../ldp/representation/ResourceIdentifier';
-import { NotFoundHttpError } from '../../util/errors/NotFoundHttpError';
-import { UnsupportedHttpError } from '../../util/errors/UnsupportedHttpError';
-import type { ResourceStore } from '../ResourceStore';
-import type { RouterRule } from './RouterRule';
-
-// TODO:
-export class PathRouterRule implements RouterRule {
-  private readonly pathMap: { [path: string]: ResourceStore };
-
-  public constructor(pathMap: { [path: string]: ResourceStore }) {
-    this.pathMap = pathMap;
-  }
-
-  public async getMatchingResourceStore(identifier: ResourceIdentifier, representation?: Representation):
-  Promise<ResourceStore> {
-    const paths = Object.keys(this.pathMap);
-    const matches = paths.filter((path): boolean => identifier.path.includes(path));
-    if (matches.length !== 1) {
-      // Incoming data, need to reject
-      if (representation) {
-        throw new UnsupportedHttpError(
-          `Identifiers need to have exactly 1 of the following in them: [${paths.join(', ')}]`,
-        );
-
-      // Because of the above requirement, we know this will always be a 404 for requests
-      } else {
-        throw new NotFoundHttpError();
-      }
-    }
-
-    return this.pathMap[matches[0]];
-  }
-}

src/storage/routing/PreferenceSupport.ts

@@ -0,0 +1,31 @@
+import type { Representation } from '../../ldp/representation/Representation';
+import type { RepresentationPreferences } from '../../ldp/representation/RepresentationPreferences';
+import type { ResourceIdentifier } from '../../ldp/representation/ResourceIdentifier';
+import type { RepresentationConverter } from '../conversion/RepresentationConverter';
+
+/**
+ * Helper class that checks if the stored {@link RepresentationConverter} and {@link RepresentationPreferences}
+ * support the given input {@link RepresentationPreferences} and {@link Representation}.
+ *
+ * Creates a new object by combining the input arguments together with the stored preferences and checks
+ * if the converter can handle that object.
+ */
+export class PreferenceSupport {
+  private readonly preferences: RepresentationPreferences;
+  private readonly converter: RepresentationConverter;
+
+  public constructor(preferences: RepresentationPreferences, converter: RepresentationConverter) {
+    this.preferences = preferences;
+    this.converter = converter;
+  }
+
+  public async supports(input: { identifier: ResourceIdentifier; representation: Representation }): Promise<boolean> {
+    const newInput = { ...input, preferences: this.preferences };
+    try {
+      await this.converter.canHandle(newInput);
+      return true;
+    } catch {
+      return false;
+    }
+  }
+}

src/storage/routing/RdfConvertingRouterRule.ts

@@ -1,42 +0,0 @@
-import type { Representation } from '../../ldp/representation/Representation';
-import type { ResourceIdentifier } from '../../ldp/representation/ResourceIdentifier';
-import { INTERNAL_QUADS } from '../../util/ContentTypes';
-import type { RepresentationConverter } from '../conversion/RepresentationConverter';
-import type { ResourceStore } from '../ResourceStore';
-import type { RouterRule } from './RouterRule';
-
-// TODO:
-export class RdfConvertingRouterRule implements RouterRule {
-  private readonly rdfStore: ResourceStore;
-  private readonly binaryStore: ResourceStore;
-  private readonly converter: RepresentationConverter;
-
-  public constructor(rdfStore: ResourceStore, binaryStore: ResourceStore, converter: RepresentationConverter) {
-    this.rdfStore = rdfStore;
-    this.binaryStore = binaryStore;
-    this.converter = converter;
-  }
-
-  public async getMatchingResourceStore(identifier: ResourceIdentifier, representation?: Representation):
-  Promise<ResourceStore> {
-    if (representation) {
-      try {
-        const preferences = { type: [{ value: INTERNAL_QUADS, weight: 1 }]};
-        await this.converter.canHandle({ identifier, representation, preferences });
-        return this.rdfStore;
-      } catch {
-        return this.binaryStore;
-      }
-    } else {
-      // No content-type given so we can only check if one of the stores has data for the identifier
-      // Any of the two stores can be used. Using the binary one here since that one would be faster in current cases.
-      try {
-        const response = await this.binaryStore.getRepresentation(identifier, {});
-        response.data.destroy();
-        return this.binaryStore;
-      } catch {
-        return this.rdfStore;
-      }
-    }
-  }
-}

src/storage/routing/RegexRouterRule.ts

@@ -0,0 +1,61 @@
+import type { Representation } from '../../ldp/representation/Representation';
+import type { ResourceIdentifier } from '../../ldp/representation/ResourceIdentifier';
+import { UnsupportedHttpError } from '../../util/errors/UnsupportedHttpError';
+import { trimTrailingSlashes } from '../../util/Util';
+import type { ResourceStore } from '../ResourceStore';
+import { RouterRule } from './RouterRule';
+
+/**
+ * Routes requests to a store based on the path of the identifier.
+ * The identifier will be stripped of the base URI after which regexes will be used to find the correct store.
+ * The trailing slash of the base URI will still be present so the first character a regex can match would be that `/`.
+ * This way regexes such as `/container/` can match containers in any position.
+ *
+ * In case none of the regexes match an error will be thrown.
+ */
+export class RegexRouterRule extends RouterRule {
+  private readonly base: string;
+  private readonly regexes: Map<RegExp, ResourceStore>;
+
+  /**
+   * The keys of the `storeMap` will be converted into actual RegExp objects that will be used for testing.
+   */
+  public constructor(base: string, storeMap: Record<string, ResourceStore>) {
+    super();
+    this.base = trimTrailingSlashes(base);
+    this.regexes = new Map(Object.keys(storeMap).map((regex): [ RegExp, ResourceStore ] =>
+      [ new RegExp(regex, 'u'), storeMap[regex] ]));
+  }
+
+  public async canHandle(input: { identifier: ResourceIdentifier; representation?: Representation }): Promise<void> {
+    this.matchStore(input.identifier);
+  }
+
+  public async handle(input: { identifier: ResourceIdentifier }): Promise<ResourceStore> {
+    return this.matchStore(input.identifier);
+  }
+
+  /**
+   * Finds the store corresponding to the regex that matches the given identifier.
+   * Throws an error if none is found.
+   */
+  private matchStore(identifier: ResourceIdentifier): ResourceStore {
+    const path = this.toRelative(identifier);
+    for (const regex of this.regexes.keys()) {
+      if (regex.test(path)) {
+        return this.regexes.get(regex)!;
+      }
+    }
+    throw new UnsupportedHttpError(`No stored regexes match ${identifier.path}`);
+  }
+
+  /**
+   * Strips the base of the identifier and throws an error if there is no overlap.
+   */
+  private toRelative(identifier: ResourceIdentifier): string {
+    if (!identifier.path.startsWith(this.base)) {
+      throw new UnsupportedHttpError(`Identifiers need to start with ${this.base}`);
+    }
+    return identifier.path.slice(this.base.length);
+  }
+}

src/storage/routing/RouterRule.ts

@@ -1,20 +1,11 @@
 import type { Representation } from '../../ldp/representation/Representation';
 import type { ResourceIdentifier } from '../../ldp/representation/ResourceIdentifier';
+import { AsyncHandler } from '../../util/AsyncHandler';
 import type { ResourceStore } from '../ResourceStore';
 
 /**
- * A RouterRule represents a rule that decides which instance of a
- * ResourceStore should be used to handle the incoming request.
+ * Finds which store needs to be accessed for the given resource,
+ * potentially based on the Representation of incoming data.
  */
-export interface RouterRule {
-
-  /**
-   * Find the appropriate ResourceStore to which the request should be routed based on the incoming parameters.
-   * @param identifier - Incoming ResourceIdentifier.
-   * @param representation - Optional incoming Representation.
-   */
-  getMatchingResourceStore: (
-    identifier: ResourceIdentifier,
-    representation?: Representation,
-  ) => Promise<ResourceStore>;
-}
+export abstract class RouterRule
+  extends AsyncHandler<{ identifier: ResourceIdentifier; representation?: Representation }, ResourceStore> {}