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| 1 | +import { Observable, BehaviorSubject } from 'rxjs'; |
| 2 | +import { HeadersCore, RequestInfoUtilities, InMemoryDbService, InMemoryBackendConfigArgs, ParsedRequestUrl, PassThruBackend, RequestCore, RequestInfo, ResponseOptions, UriInfo } from './interfaces'; |
| 3 | +/** |
| 4 | + * Base class for in-memory web api back-ends |
| 5 | + * Simulate the behavior of a RESTy web api |
| 6 | + * backed by the simple in-memory data store provided by the injected `InMemoryDbService` service. |
| 7 | + * Conforms mostly to behavior described here: |
| 8 | + * http://www.restapitutorial.com/lessons/httpmethods.html |
| 9 | + */ |
| 10 | +export declare abstract class BackendService { |
| 11 | + protected inMemDbService: InMemoryDbService; |
| 12 | + protected config: InMemoryBackendConfigArgs; |
| 13 | + protected db: Object; |
| 14 | + protected dbReadySubject: BehaviorSubject<boolean>; |
| 15 | + private passThruBackend; |
| 16 | + protected requestInfoUtils: RequestInfoUtilities; |
| 17 | + constructor(inMemDbService: InMemoryDbService, config?: InMemoryBackendConfigArgs); |
| 18 | + protected readonly dbReady: Observable<boolean>; |
| 19 | + /** |
| 20 | + * Process Request and return an Observable of Http Response object |
| 21 | + * in the manner of a RESTy web api. |
| 22 | + * |
| 23 | + * Expect URI pattern in the form :base/:collectionName/:id? |
| 24 | + * Examples: |
| 25 | + * // for store with a 'customers' collection |
| 26 | + * GET api/customers // all customers |
| 27 | + * GET api/customers/42 // the character with id=42 |
| 28 | + * GET api/customers?name=^j // 'j' is a regex; returns customers whose name starts with 'j' or 'J' |
| 29 | + * GET api/customers.json/42 // ignores the ".json" |
| 30 | + * |
| 31 | + * Also accepts direct commands to the service in which the last segment of the apiBase is the word "commands" |
| 32 | + * Examples: |
| 33 | + * POST commands/resetDb, |
| 34 | + * GET/POST commands/config - get or (re)set the config |
| 35 | + * |
| 36 | + * HTTP overrides: |
| 37 | + * If the injected inMemDbService defines an HTTP method (lowercase) |
| 38 | + * The request is forwarded to that method as in |
| 39 | + * `inMemDbService.get(requestInfo)` |
| 40 | + * which must return either an Observable of the response type |
| 41 | + * for this http library or null|undefined (which means "keep processing"). |
| 42 | + */ |
| 43 | + protected handleRequest(req: RequestCore): Observable<any>; |
| 44 | + protected handleRequest_(req: RequestCore): Observable<any>; |
| 45 | + /** |
| 46 | + * Add configured delay to response observable unless delay === 0 |
| 47 | + */ |
| 48 | + protected addDelay(response: Observable<any>): Observable<any>; |
| 49 | + /** |
| 50 | + * Apply query/search parameters as a filter over the collection |
| 51 | + * This impl only supports RegExp queries on string properties of the collection |
| 52 | + * ANDs the conditions together |
| 53 | + */ |
| 54 | + protected applyQuery(collection: any[], query: Map<string, string[]>): any[]; |
| 55 | + /** |
| 56 | + * Get a method from the `InMemoryDbService` (if it exists), bound to that service |
| 57 | + */ |
| 58 | + protected bind<T extends Function>(methodName: string): T; |
| 59 | + protected bodify(data: any): any; |
| 60 | + protected clone(data: any): any; |
| 61 | + protected collectionHandler(reqInfo: RequestInfo): ResponseOptions; |
| 62 | + /** |
| 63 | + * Commands reconfigure the in-memory web api service or extract information from it. |
| 64 | + * Commands ignore the latency delay and respond ASAP. |
| 65 | + * |
| 66 | + * When the last segment of the `apiBase` path is "commands", |
| 67 | + * the `collectionName` is the command. |
| 68 | + * |
| 69 | + * Example URLs: |
| 70 | + * commands/resetdb (POST) // Reset the "database" to its original state |
| 71 | + * commands/config (GET) // Return this service's config object |
| 72 | + * commands/config (POST) // Update the config (e.g. the delay) |
| 73 | + * |
| 74 | + * Usage: |
| 75 | + * http.post('commands/resetdb', undefined); |
| 76 | + * http.get('commands/config'); |
| 77 | + * http.post('commands/config', '{"delay":1000}'); |
| 78 | + */ |
| 79 | + protected commands(reqInfo: RequestInfo): Observable<any>; |
| 80 | + protected createErrorResponseOptions(url: string, status: number, message: string): ResponseOptions; |
| 81 | + /** |
| 82 | + * Create standard HTTP headers object from hash map of header strings |
| 83 | + * @param headers |
| 84 | + */ |
| 85 | + protected abstract createHeaders(headers: { |
| 86 | + [index: string]: string; |
| 87 | + }): HeadersCore; |
| 88 | + /** |
| 89 | + * create the function that passes unhandled requests through to the "real" backend. |
| 90 | + */ |
| 91 | + protected abstract createPassThruBackend(): PassThruBackend; |
| 92 | + /** |
| 93 | + * return a search map from a location query/search string |
| 94 | + */ |
| 95 | + protected abstract createQueryMap(search: string): Map<string, string[]>; |
| 96 | + /** |
| 97 | + * Create a cold response Observable from a factory for ResponseOptions |
| 98 | + * @param resOptionsFactory - creates ResponseOptions when observable is subscribed |
| 99 | + * @param withDelay - if true (default), add simulated latency delay from configuration |
| 100 | + */ |
| 101 | + protected createResponse$(resOptionsFactory: () => ResponseOptions, withDelay?: boolean): Observable<any>; |
| 102 | + /** |
| 103 | + * Create a Response observable from ResponseOptions observable. |
| 104 | + */ |
| 105 | + protected abstract createResponse$fromResponseOptions$(resOptions$: Observable<ResponseOptions>): Observable<any>; |
| 106 | + /** |
| 107 | + * Create a cold Observable of ResponseOptions. |
| 108 | + * @param resOptionsFactory - creates ResponseOptions when observable is subscribed |
| 109 | + */ |
| 110 | + protected createResponseOptions$(resOptionsFactory: () => ResponseOptions): Observable<ResponseOptions>; |
| 111 | + protected delete({ collection, collectionName, headers, id, url }: RequestInfo): ResponseOptions; |
| 112 | + /** |
| 113 | + * Find first instance of item in collection by `item.id` |
| 114 | + * @param collection |
| 115 | + * @param id |
| 116 | + */ |
| 117 | + protected findById<T extends { |
| 118 | + id: any; |
| 119 | + }>(collection: T[], id: any): T; |
| 120 | + /** |
| 121 | + * Generate the next available id for item in this collection |
| 122 | + * Use method from `inMemDbService` if it exists and returns a value, |
| 123 | + * else delegates to `genIdDefault`. |
| 124 | + * @param collection - collection of items with `id` key property |
| 125 | + */ |
| 126 | + protected genId<T extends { |
| 127 | + id: any; |
| 128 | + }>(collection: T[], collectionName: string): any; |
| 129 | + /** |
| 130 | + * Default generator of the next available id for item in this collection |
| 131 | + * This default implementation works only for numeric ids. |
| 132 | + * @param collection - collection of items with `id` key property |
| 133 | + * @param collectionName - name of the collection |
| 134 | + */ |
| 135 | + protected genIdDefault<T extends { |
| 136 | + id: any; |
| 137 | + }>(collection: T[], collectionName: string): any; |
| 138 | + protected get({ collection, collectionName, headers, id, query, url }: RequestInfo): ResponseOptions; |
| 139 | + /** Get JSON body from the request object */ |
| 140 | + protected abstract getJsonBody(req: any): any; |
| 141 | + /** |
| 142 | + * Get location info from a url, even on server where `document` is not defined |
| 143 | + */ |
| 144 | + protected getLocation(url: string): UriInfo; |
| 145 | + /** |
| 146 | + * get or create the function that passes unhandled requests |
| 147 | + * through to the "real" backend. |
| 148 | + */ |
| 149 | + protected getPassThruBackend(): PassThruBackend; |
| 150 | + /** |
| 151 | + * Get utility methods from this service instance. |
| 152 | + * Useful within an HTTP method override |
| 153 | + */ |
| 154 | + protected getRequestInfoUtils(): RequestInfoUtilities; |
| 155 | + /** |
| 156 | + * return canonical HTTP method name (lowercase) from the request object |
| 157 | + * e.g. (req.method || 'get').toLowerCase(); |
| 158 | + * @param req - request object from the http call |
| 159 | + * |
| 160 | + */ |
| 161 | + protected abstract getRequestMethod(req: any): string; |
| 162 | + protected indexOf(collection: any[], id: number): number; |
| 163 | + /** Parse the id as a number. Return original value if not a number. */ |
| 164 | + protected parseId(collection: any[], collectionName: string, id: string): any; |
| 165 | + /** |
| 166 | + * return true if can determine that the collection's `item.id` is a number |
| 167 | + * This implementation can't tell if the collection is empty so it assumes NO |
| 168 | + * */ |
| 169 | + protected isCollectionIdNumeric<T extends { |
| 170 | + id: any; |
| 171 | + }>(collection: T[], collectionName: string): boolean; |
| 172 | + /** |
| 173 | + * Parses the request URL into a `ParsedRequestUrl` object. |
| 174 | + * Parsing depends upon certain values of `config`: `apiBase`, `host`, and `urlRoot`. |
| 175 | + * |
| 176 | + * Configuring the `apiBase` yields the most interesting changes to `parseRequestUrl` behavior: |
| 177 | + * When apiBase=undefined and url='http://localhost/api/collection/42' |
| 178 | + * {base: 'api/', collectionName: 'collection', id: '42', ...} |
| 179 | + * When apiBase='some/api/root/' and url='http://localhost/some/api/root/collection' |
| 180 | + * {base: 'some/api/root/', collectionName: 'collection', id: undefined, ...} |
| 181 | + * When apiBase='/' and url='http://localhost/collection' |
| 182 | + * {base: '/', collectionName: 'collection', id: undefined, ...} |
| 183 | + * |
| 184 | + * The actual api base segment values are ignored. Only the number of segments matters. |
| 185 | + * The following api base strings are considered identical: 'a/b' ~ 'some/api/' ~ `two/segments' |
| 186 | + * |
| 187 | + * To replace this default method, assign your alternative to your InMemDbService['parseRequestUrl'] |
| 188 | + */ |
| 189 | + protected parseRequestUrl(url: string): ParsedRequestUrl; |
| 190 | + protected post({ collection, collectionName, headers, id, req, resourceUrl, url }: RequestInfo): ResponseOptions; |
| 191 | + protected put({ collection, collectionName, headers, id, req, url }: RequestInfo): ResponseOptions; |
| 192 | + protected removeById(collection: any[], id: number): boolean; |
| 193 | + /** |
| 194 | + * Tell your in-mem "database" to reset. |
| 195 | + * returns Observable of the database because resetting it could be async |
| 196 | + */ |
| 197 | + protected resetDb(reqInfo?: RequestInfo): Observable<boolean>; |
| 198 | +} |
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