Press n or j to go to the next uncovered block, b, p or k for the previous block.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 | 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 2x 2x 2x 1x 1x 1x 2x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 108x 108x 1x 1x 1x 20x 20x 1x 1x 1x 4x 4x 4x 4x 4x 4x 4x 4x 4x 4x 4x 4x 108x 108x 108x 108x 108x 108x 108x 4x 4x 4x 4x 4x 4x 1x 1x 1x 2x 2x 1x 1x 1x 1x 2x 1x 1x 1x 1x 2x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 2x 2x 2x 2x 1x 1x 2x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 7x 20x 20x 20x 20x 20x 20x 20x 20x 20x 20x 20x 20x 20x 20x 20x 18x 18x 20x 20x 18x 18x 20x 20x 7x 1x 1x 1x 20x 186x 20x 20x 36x 36x 36x 36x 18x 18x 18x 36x 18x 18x 18x 18x 36x 2x 2x 1x 1x 1x 2x 2x 2x 2x 2x 2x 2x 1x 1x 1x 1x 1x 1x 2x 1x 1x 1x 4x 4x 4x 4x 4x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 3x 3x 3x 3x 3x 3x 4x 4x 4x 1x 1x 2x 1x 1x 1x 2x 2x 2x 2x 2x 4x 2x 2x 1x 1x 1x 4x 4x 4x 1x 1x 1x 6x 6x 6x 6x 1x 1x 1x 4x 4x 4x 4x 4x 4x 4x 4x 4x 4x 1x 1x 1x 1x 1x 2x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x | import { AVAILABILITY, CACHE, UOM } from '@/constants/common';
import { CURRENCY_SYMBOL_MAP } from '@/constants/currency';
import { findCAS } from '@/helpers/cas';
import { parseQuantity } from '@/helpers/quantity';
import { findFormulaInText, findMolarMass } from '@/helpers/science';
import { firstMap, htmlToAscii, mapDefined } from '@/helpers/utils';
import type {
EpagesProductPage,
EpagesSearchProduct,
EpagesSearchResponse,
EpagesVariationItem,
} from '@/types/labchem';
import { ProductBuilder } from '@/utils/ProductBuilder';
import { scoreAstMatch } from '@/utils/search-query/evaluateAst';
import { cstorage } from '@/utils/storage';
import { isQuantityObject } from '@/utils/typeGuards/common';
import {
isEpagesProductPage,
isEpagesSearchResponse,
isEpagesVariationsResponse,
} from '@/utils/typeGuards/labchem';
import { type JsonValue } from 'type-fest';
import { SupplierBase } from './SupplierBase';
import { getErrorMessage } from '@/helpers/exceptions';
/** ePages catalog-search endpoint (relative to `baseURL`). */
const SEARCH_PATH = '/api/v2/search';
/** Storefront locale sent with every search request. */
const LOCALE = 'de_DE';
/** Products requested per catalog page (ePages caps this at 100). */
const RESULTS_PER_PAGE = 100;
/** Safety cap on catalog pages fetched (~1000 products). */
const MAX_CATALOG_PAGES = 10;
/** How long a cached catalog snapshot stays fresh (24h). */
const CATALOG_TTL_MS = 24 * 60 * 60 * 1000;
/** Max products carried into the (expensive) per-product detail phase. */
const MAX_CANDIDATES = 10;
/** Max variations enumerated per product. */
const MAX_VARIANTS = 4;
/** A parsed quantity (value + unit) as returned by {@link parseQuantity}. */
interface ParsedQuantity {
quantity: number;
uom: string;
}
/** Persisted catalog snapshot: the full product list plus its capture time. */
interface CatalogCacheEntry {
cachedAt: number;
products: EpagesSearchProduct[];
}
/**
* Narrows an unknown cached value to a {@link CatalogCacheEntry}.
* @param value - The value read back from storage
* @returns True when `value` has a numeric `cachedAt` and a `products` array
* @source
*/
function isCatalogCacheEntry(value: unknown): value is CatalogCacheEntry {
return (
typeof value === 'object' &&
value !== null &&
typeof (value as CatalogCacheEntry).cachedAt === 'number' &&
Array.isArray((value as CatalogCacheEntry).products)
);
}
/**
* Supplier module for LabChem (`labchem.de`), a German chemical retailer on the
* ePages platform.
*
* @remarks
* ePages spreads product data across several endpoints and its per-term search
* relevance is unreliable, so instead of translating queries into native searches
* this module fetches the **entire catalog once** (an empty-query, paginated
* `POST /api/v2/search`), caches it for 24h, and filters it locally with
* {@link fuzzyFilterAst} — giving deterministic, complete matching for the full
* AND/OR/NOT predicate. Live price and stock are never taken from the catalog;
* each candidate's variations list and per-variation product pages are fetched in
* the detail phase (`getProductData`).
*
* @category Suppliers
* @example
* ```typescript
* const supplier = new SupplierLabChem("aceton", 5, new AbortController());
* for await (const product of supplier.execute()) {
* console.log(product.title, product.price, product.currencyCode);
* }
* ```
* @source
*/
export class SupplierLabChem
extends SupplierBase<EpagesSearchProduct, Product>
implements ISupplier
{
/** Name of supplier (for display purposes). */
public static readonly supplierName: string = 'LabChem';
/** Base URL for HTTP(s) requests. */
public static readonly baseURL: string = 'https://www.labchem.de';
/** Shipping scope for LabChem. */
public static readonly shipping: ShippingRange = 'international';
/** The country code of the supplier. */
public static readonly country: CountryCode = 'DE';
/** The payment methods accepted by the supplier. */
public static readonly paymentMethods: PaymentMethod[] = ['mastercard', 'visa'];
/** ePages shop id, used as the `shop` search parameter and in REST paths. */
protected readonly shopId: string = '87762263';
/** REST base for product/variation resources (trailing slash intentional). */
protected readonly apiUrl: string = 'https://www.labchem.de/rs/shops/87762263/';
// We hold the whole catalog and apply the full boolean predicate locally via
// fuzzyFilterAst, so the base performs a single queryProducts call (no
// keyword-fallback union).
protected readonly supportsNativeAdvancedSearch: boolean = true;
// Budget: <=6 catalog pages once per 24h + up to 10 products x (1 variations +
// <=4 variation pages) ~= 56.
protected httpRequestHardLimit: number = 80;
/**
* Selects the title used for fuzzy matching from a raw catalog product.
* @param data - The raw catalog product
* @returns The product's title (falling back to its short name)
* @example
* ```typescript
* this.titleSelector({ title: "Aceton reinst - LabChem", name: "Aceton reinst" }); // "Aceton reinst - LabChem"
* ```
* @source
*/
protected titleSelector(data: EpagesSearchProduct): string {
return data.title ?? data.name;
}
/**
* Derives the stable product key from a catalog product: its `productId` (which,
* for a variation master, is also the id used to build the variations/detail URLs).
* @param data - The raw catalog product
* @returns The product's UUID
* @example
* ```typescript
* this.getUniqueProductKey({ productId: "5DDD5B1C-..." }); // "5DDD5B1C-..."
* ```
* @source
*/
protected getUniqueProductKey(data: EpagesSearchProduct): string {
return data.productId;
}
/**
* Resolves the search for the current query. Loads the full catalog (cached 24h),
* drops hidden products, and keeps those whose title satisfies the parsed query — the
* gate is a case-insensitive substring predicate (honoring AND/OR/NOT), so a partial
* term like "acet" matches "Aceton" but nothing unrelated. Survivors are then ranked by
* fuzzy relevance (the supplier's `fuzzScorer`, `ratio` by default) so the closest
* titles come first, and capped at `MAX_CANDIDATES`. `scoreAstMatch` supplies both:
* its leaf gate is substring-based regardless of scorer, while its returned score is the
* scorer's similarity. The `query` argument is unused; the parsed AST is read from
* {@link getAst}.
* @param query - The raw search term (unused; the parsed AST is used instead)
* @param limit - Maximum number of candidates to return
* @returns Product builders for the ranked matches, or void when the catalog is empty
* @example
* ```typescript
* const builders = await this.queryProducts("acet", 5); // Aceton, Acetamid, …, Ethylacetat
* ```
* @source
*/
protected async queryProducts(
query: string,
limit: number = this.limit,
): Promise<ProductBuilder<Product>[] | void> {
this.logger.debug('Starting product search', { query, limit });
const catalog = (await this.loadCatalog()).filter((product) => product.isVisible !== false);
if (catalog.length === 0) {
this.logger.warn('LabChem: catalog is empty');
return;
}
// Substring gate + fuzzy ranking in one pass: scoreAstMatch keeps a title only when
// the boolean predicate holds by case-insensitive substring (fuzzyWords: false, so no
// noise), and returns the scorer's similarity so the survivors can be ranked.
const ast = this.getAst().ast;
const scorer = this.fuzzScorerOverride ?? this.fuzzScorer;
const ranked = mapDefined(catalog, (product) => {
const score = scoreAstMatch(this.titleSelector(product), ast, {
scorer,
threshold: 0,
fuzzyWords: false,
});
return score === null ? undefined : { product, score };
});
ranked.sort((a, b) => b.score - a.score);
const candidates = ranked
.slice(0, Math.min(limit, MAX_CANDIDATES))
.map((entry) => entry.product);
return this.initProductBuilders(candidates);
}
/**
* Loads the full product catalog, preferring a fresh 24h cache entry. On a cache
* miss it fetches page 1 (to learn the total count), then fetches the remaining
* pages concurrently, persists the combined list, and returns it. A failed page is
* skipped rather than failing the whole search.
* @returns The catalog products (possibly empty if page 1 fails)
* @example
* ```typescript
* const products = await this.loadCatalog(); // [{ productId, name, ... }, ...]
* ```
* @source
*/
private async loadCatalog(): Promise<EpagesSearchProduct[]> {
const cached = await this.readCachedCatalog();
if (cached) {
this.logger.debug('LabChem: catalog cache hit', { count: cached.length });
return cached;
}
const firstPage = await this.fetchCatalogPage(1);
if (!firstPage) {
return [];
}
const pageCount = Math.min(
Math.ceil(firstPage.totalNumberOfProducts / RESULTS_PER_PAGE),
MAX_CATALOG_PAGES,
);
const products = [...firstPage.products];
if (pageCount > 1) {
// Page 1 is the only serial dependency (it tells us how many pages exist);
// fetch the rest concurrently.
const rest = await Promise.all(
Array.from({ length: pageCount - 1 }, (_value, index) => this.fetchCatalogPage(index + 2)),
);
for (const page of rest) {
if (page) {
products.push(...page.products);
}
}
}
await this.writeCachedCatalog(products);
return products;
}
/**
* Fetches a single catalog page via the empty-query search. Tolerates a failed or
* malformed response by returning undefined so pagination can skip it.
* @param page - The 1-based page number
* @returns The validated search response, or undefined on failure
* @source
*/
private async fetchCatalogPage(page: number): Promise<EpagesSearchResponse | undefined> {
try {
const response = await this.httpPostJson({
path: SEARCH_PATH,
params: {
shop: this.shopId,
resultsPerPage: String(RESULTS_PER_PAGE),
page: String(page),
locale: LOCALE,
},
body: { filters: [], query: '', sort: 'relevance' },
headers: { 'Content-Type': 'application/json' },
});
if (!isEpagesSearchResponse(response)) {
this.logger.warn('LabChem: invalid catalog page response', { page, response });
return undefined;
}
return response;
} catch (error: unknown) {
this.logger.warn(`LabChem: catalog page request failed: ${getErrorMessage(error)}`, {
page,
error,
});
return undefined;
}
}
/**
* Reads a fresh (within `CATALOG_TTL_MS`) catalog snapshot from local storage.
* @returns The cached products, or undefined when absent or expired
* @source
*/
private async readCachedCatalog(): Promise<EpagesSearchProduct[] | undefined> {
try {
const stored = await cstorage.local.get([CACHE.LABCHEM_CATALOG]);
const entry = stored?.[CACHE.LABCHEM_CATALOG];
if (isCatalogCacheEntry(entry) && Date.now() - entry.cachedAt < CATALOG_TTL_MS) {
return entry.products;
}
} catch (error: unknown) {
this.logger.warn(`LabChem: failed to read catalog cache: ${getErrorMessage(error)}`, {
error,
});
}
return undefined;
}
/**
* Persists the catalog snapshot to local storage, stamped with the current time.
* @param products - The catalog products to cache
* @returns A promise that resolves once the write completes
* @source
*/
private async writeCachedCatalog(products: EpagesSearchProduct[]): Promise<void> {
try {
const entry: CatalogCacheEntry = { cachedAt: Date.now(), products };
await cstorage.local.set({ [CACHE.LABCHEM_CATALOG]: entry });
} catch (error: unknown) {
this.logger.warn(`LabChem: failed to write catalog cache: ${getErrorMessage(error)}`, {
error,
});
}
}
/**
* Builds a {@link ProductBuilder} per catalog hit, seeding the fields available
* from the search response — title, URL, SKU, id/cache key, and the chemical
* identifiers parsed out of the HTML description (CAS, formula, molar mass). Price,
* quantity and images are resolved later in {@link getProductData}.
* @param products - The ranked catalog candidates
* @returns The seeded product builders
* @source
*/
private initProductBuilders(products: EpagesSearchProduct[]): ProductBuilder<Product>[] {
return mapDefined(products, (product) => {
const url = product.slug
? `${this.baseURL}/${product.slug}`
: product.links.find((link) => link.rel === 'self')?.href;
if (!url) {
return;
}
const description = product.description ?? '';
const builder = new ProductBuilder<Product>(this.baseURL);
builder
.setBasicInfo(product.title ?? product.name, url, this.supplierName)
.setMatchPercentage(this.matchScoreOf(product))
.setSku(product.sku)
.setID(product.productId)
.setCacheKey(this.getUniqueProductKey(product))
.setDescription(htmlToAscii(description))
.setCAS(findCAS(description));
const formula = this.extractFormula(description);
if (formula) {
builder.setFormula(formula);
}
const moleweight = findMolarMass(description);
if (moleweight !== undefined) {
builder.setMoleweight(moleweight);
}
return builder;
});
}
/**
* Extracts the chemical formula from LabChem's German `<ul><li>` spec list. Prefers
* the "Summenformel" row (the molecular/Hill formula), falling back to any other
* "…Formel…" row (e.g. "Chem. Formel") whose value validates as a formula. Each
* candidate is verified with {@link findFormulaInText} in a single pass.
* @param html - The product's HTML description
* @returns The validated formula (with any sub/superscripts normalized), or undefined
* @example
* ```typescript
* this.extractFormula("<ul><li>Summenformel n. Hill: C3H6O</li></ul>"); // "C3H6O"
* ```
* @source
*/
private extractFormula(html: string): string | undefined {
const rows = [...html.matchAll(/<li[^>]*>([\s\S]*?)<\/li>/gi)].map((match) =>
htmlToAscii(match[1]),
);
let fallback: string | undefined;
for (const row of rows) {
const idx = row.indexOf(':');
if (idx === -1) {
continue;
}
const key = row.slice(0, idx);
if (!/formel/i.test(key)) {
continue;
}
const formula = findFormulaInText(row.slice(idx + 1).trim());
if (!formula) {
continue;
}
// "Summenformel" (the molecular/Hill formula) wins; anything else is a fallback.
if (/sum/i.test(key)) {
return formula;
}
fallback ??= formula;
}
return fallback;
}
/**
* Enriches a candidate with live detail data. Fetches the master's variations
* list, then each purchasable variation's product page (in parallel, capped at
* `MAX_VARIANTS`), and applies the authoritative price/quantity/permalink and
* images from the cheapest variation, with the remaining sizes added as variants.
* @param product - The product builder to enrich
* @returns The enriched builder (or void if it was excluded/uncacheable)
* @example
* ```typescript
* const enriched = await this.getProductData(builder);
* ```
* @source
*/
protected async getProductData(
product: ProductBuilder<Product>,
): Promise<ProductBuilder<Product> | void> {
return this.getProductDataWithCache(product, async (builder) => {
const masterId = String(builder.get('id') ?? '');
if (!masterId) {
return builder;
}
const variationItems = await this.fetchVariationItems(masterId);
if (variationItems.length === 0) {
this.logger.warn('LabChem: no purchasable variations', { masterId });
return builder;
}
const pages = (
await Promise.all(variationItems.map((item) => this.fetchProductPage(item.link.href)))
).filter((page): page is EpagesProductPage => page !== undefined && page.forSale === true);
if (pages.length === 0) {
this.logger.warn('LabChem: no for-sale variation pages', { masterId });
return builder;
}
// The variations list is size-ascending, so pages[0] is the cheapest — use it
// as the headline row (and its image set); the rest become variants.
pages.forEach((page, index) => {
const amount = page.priceInfo?.price?.amount;
const currency = page.priceInfo?.price?.currency ?? 'EUR';
const quantity = this.variantQuantity(page);
const title = page.productVariationSelection?.[0]?.displayValue ?? page.title;
if (index === 0) {
if (typeof amount === 'number') {
builder.setPricing(amount, currency, CURRENCY_SYMBOL_MAP[currency] ?? currency);
}
if (quantity) {
builder.setQuantity(quantity.quantity, quantity.uom);
} else {
builder.setQuantity(1, UOM.EA);
}
if (page.sfUrl) {
builder.setPermalink(page.sfUrl);
}
builder.addImages(this.productImages(page));
return;
}
builder.addVariant({
id: page.productId,
title,
sku: page.productNumber,
price: amount,
status: AVAILABILITY.IN_STOCK,
...(quantity ?? { quantity: 1, uom: UOM.EA }),
});
});
return builder;
});
}
/**
* Fetches and filters a master's variations list: keeps only entries linked as a
* `variation` that aren't flagged `purchasable: false`, capped at `MAX_VARIANTS`.
* @param masterId - The variation-master product id
* @returns The purchasable variation items (possibly empty)
* @source
*/
private async fetchVariationItems(masterId: string): Promise<EpagesVariationItem[]> {
const response = await this.fetchJson(`${this.apiUrl}products/${masterId}/variations`);
if (!isEpagesVariationsResponse(response)) {
return [];
}
return response.items
.filter(
(item) =>
item.link?.rel === 'variation' && item.additionalAttributes?.purchasable !== false,
)
.slice(0, MAX_VARIANTS);
}
/**
* Fetches and validates a single variation product page.
* @param href - The absolute product-page URL from the variation link
* @returns The validated product page, or undefined on failure
* @source
*/
private async fetchProductPage(href: string): Promise<EpagesProductPage | undefined> {
const response = await this.fetchJson(href);
return isEpagesProductPage(response) ? response : undefined;
}
/**
* GET a JSON resource, tolerating network/HTTP failures by returning undefined so a
* single bad request doesn't abort the whole enrichment.
* @param url - The absolute resource URL
* @returns The parsed JSON value, or undefined on failure
* @source
*/
private async fetchJson(url: string): Promise<Maybe<JsonValue>> {
try {
return await this.httpGetJson({ path: url });
} catch (error: unknown) {
this.logger.warn(`LabChem: GET failed: ${getErrorMessage(error)}`, { url, error });
return undefined;
}
}
/**
* Derives a variation's quantity from its selected size attribute (e.g. "2,5 l"),
* falling back to the product number and title.
* @param page - The variation product page
* @returns The parsed quantity, or undefined when none can be parsed
* @source
*/
private variantQuantity(page: EpagesProductPage): ParsedQuantity | undefined {
const selections = page.productVariationSelection ?? [];
const candidates = [
...selections.map((selection) => selection.displayValue),
...selections.map((selection) => selection.value),
page.productNumber ?? '',
page.title ?? '',
];
const quantity = firstMap(parseQuantity, candidates);
return isQuantityObject(quantity) ? quantity : undefined;
}
/**
* Maps a variation page's images to the full-size + thumbnail entries the product
* expects, using the ePages size classifiers (Medium for the full image, Thumbnail
* for the thumbnail), with sensible fallbacks.
* @param page - The variation product page
* @returns The image entries (empty when the page has no images)
* @source
*/
private productImages(page: EpagesProductPage): ProductImage[] {
const images = page.images ?? [];
const byClassifier = (classifier: string): string | undefined =>
images.find((image) => image.classifier === classifier)?.url;
const full = byClassifier('Medium') ?? byClassifier('Large') ?? images[0]?.url;
const thumbnail = byClassifier('Thumbnail') ?? byClassifier('Small');
const result: ProductImage[] = [];
if (full) {
result.push({ href: full, type: 'image' });
}
if (thumbnail) {
result.push({ href: thumbnail, type: 'thumbnail' });
}
return result;
}
}
|