added generic adapter

backend/Cargo.lock

@@ -19,6 +19,19 @@ dependencies = [
  "version_check",
 ]
 
+[[package]]
+name = "ahash"
+version = "0.8.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5a15f179cd60c4584b8a8c596927aadc462e27f2ca70c04e0071964a73ba7a75"
+dependencies = [
+ "cfg-if",
+ "getrandom 0.3.4",
+ "once_cell",
+ "version_check",
+ "zerocopy",
+]
+
 [[package]]
 name = "aho-corasick"
 version = "1.1.4"
@@ -404,6 +417,29 @@ dependencies = [
  "typenum",
 ]
 
+[[package]]
+name = "cssparser"
+version = "0.31.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5b3df4f93e5fbbe73ec01ec8d3f68bba73107993a5b1e7519273c32db9b0d5be"
+dependencies = [
+ "cssparser-macros",
+ "dtoa-short",
+ "itoa",
+ "phf 0.11.3",
+ "smallvec",
+]
+
+[[package]]
+name = "cssparser-macros"
+version = "0.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "13b588ba4ac1a99f7f2964d24b3d896ddc6bf847ee3855dbd4366f058cfcd331"
+dependencies = [
+ "quote",
+ "syn 2.0.118",
+]
+
 [[package]]
 name = "darling"
 version = "0.20.11"
@@ -459,6 +495,17 @@ dependencies = [
  "serde_core",
 ]
 
+[[package]]
+name = "derive_more"
+version = "0.99.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6edb4b64a43d977b8e99788fe3a04d483834fba1215a7e02caa415b626497f7f"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.118",
+]
+
 [[package]]
 name = "digest"
 version = "0.10.7"
@@ -488,6 +535,27 @@ version = "0.15.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1aaf95b3e5c8f23aa320147307562d361db0ae0d51242340f558153b4eb2439b"
 
+[[package]]
+name = "dtoa"
+version = "1.0.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4c3cf4824e2d5f025c7b531afcb2325364084a16806f6d47fbc1f5fbd9960590"
+
+[[package]]
+name = "dtoa-short"
+version = "0.3.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cd1511a7b6a56299bd043a9c167a6d2bfb37bf84a6dfceaba651168adfb43c87"
+dependencies = [
+ "dtoa",
+]
+
+[[package]]
+name = "ego-tree"
+version = "0.6.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "12a0bb14ac04a9fcf170d0bbbef949b44cc492f4452bd20c095636956f653642"
+
 [[package]]
 name = "either"
 version = "1.16.0"
@@ -611,6 +679,16 @@ version = "2.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e6d5a32815ae3f33302d95fdcb2ce17862f8c65363dcfd29360480ba1001fc9c"
 
+[[package]]
+name = "futf"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "df420e2e84819663797d1ec6544b13c5be84629e7bb00dc960d6917db2987843"
+dependencies = [
+ "mac",
+ "new_debug_unreachable",
+]
+
 [[package]]
 name = "futures"
 version = "0.3.32"
@@ -708,6 +786,15 @@ dependencies = [
  "slab",
 ]
 
+[[package]]
+name = "fxhash"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c31b6d751ae2c7f11320402d34e41349dd1016f8d5d45e48c4312bc8625af50c"
+dependencies = [
+ "byteorder",
+]
+
 [[package]]
 name = "generic-array"
 version = "0.14.7"
@@ -718,6 +805,15 @@ dependencies = [
  "version_check",
 ]
 
+[[package]]
+name = "getopts"
+version = "0.2.24"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cfe4fbac503b8d1f88e6676011885f34b7174f46e59956bba534ba83abded4df"
+dependencies = [
+ "unicode-width",
+]
+
 [[package]]
 name = "getrandom"
 version = "0.2.17"
@@ -764,7 +860,7 @@ version = "0.12.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8a9ee70c43aaf417c914396645a0fa852624801b24ebb7ae78fe8272889ac888"
 dependencies = [
- "ahash",
+ "ahash 0.7.8",
 ]
 
 [[package]]
@@ -843,6 +939,20 @@ dependencies = [
  "windows-link",
 ]
 
+[[package]]
+name = "html5ever"
+version = "0.27.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c13771afe0e6e846f1e67d038d4cb29998a6779f93c809212e4e9c32efd244d4"
+dependencies = [
+ "log",
+ "mac",
+ "markup5ever",
+ "proc-macro2",
+ "quote",
+ "syn 2.0.118",
+]
+
 [[package]]
 name = "http"
 version = "1.4.2"
@@ -1203,6 +1313,26 @@ version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "112b39cec0b298b6c1999fee3e31427f74f676e4cb9879ed1a121b43661a4154"
 
+[[package]]
+name = "mac"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c41e0c4fef86961ac6d6f8a82609f55f31b05e4fce149ac5710e439df7619ba4"
+
+[[package]]
+name = "markup5ever"
+version = "0.12.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "16ce3abbeba692c8b8441d036ef91aea6df8da2c6b6e21c7e14d3c18e526be45"
+dependencies = [
+ "log",
+ "phf 0.11.3",
+ "phf_codegen 0.11.3",
+ "string_cache",
+ "string_cache_codegen",
+ "tendril",
+]
+
 [[package]]
 name = "matchers"
 version = "0.2.0"
@@ -1261,6 +1391,12 @@ dependencies = [
  "windows-sys 0.61.2",
 ]
 
+[[package]]
+name = "new_debug_unreachable"
+version = "1.0.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "650eef8c711430f1a879fdd01d4745a7deea475becfb90269c06775983bbf086"
+
 [[package]]
 name = "nom"
 version = "8.0.0"
@@ -1392,6 +1528,96 @@ version = "2.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9b4f627cb1b25917193a259e49bdad08f671f8d9708acfd5fe0a8c1455d87220"
 
+[[package]]
+name = "phf"
+version = "0.10.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fabbf1ead8a5bcbc20f5f8b939ee3f5b0f6f281b6ad3468b84656b658b455259"
+dependencies = [
+ "phf_shared 0.10.0",
+]
+
+[[package]]
+name = "phf"
+version = "0.11.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1fd6780a80ae0c52cc120a26a1a42c1ae51b247a253e4e06113d23d2c2edd078"
+dependencies = [
+ "phf_macros",
+ "phf_shared 0.11.3",
+]
+
+[[package]]
+name = "phf_codegen"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4fb1c3a8bc4dd4e5cfce29b44ffc14bedd2ee294559a294e2a4d4c9e9a6a13cd"
+dependencies = [
+ "phf_generator 0.10.0",
+ "phf_shared 0.10.0",
+]
+
+[[package]]
+name = "phf_codegen"
+version = "0.11.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "aef8048c789fa5e851558d709946d6d79a8ff88c0440c587967f8e94bfb1216a"
+dependencies = [
+ "phf_generator 0.11.3",
+ "phf_shared 0.11.3",
+]
+
+[[package]]
+name = "phf_generator"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5d5285893bb5eb82e6aaf5d59ee909a06a16737a8970984dd7746ba9283498d6"
+dependencies = [
+ "phf_shared 0.10.0",
+ "rand 0.8.6",
+]
+
+[[package]]
+name = "phf_generator"
+version = "0.11.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3c80231409c20246a13fddb31776fb942c38553c51e871f8cbd687a4cfb5843d"
+dependencies = [
+ "phf_shared 0.11.3",
+ "rand 0.8.6",
+]
+
+[[package]]
+name = "phf_macros"
+version = "0.11.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f84ac04429c13a7ff43785d75ad27569f2951ce0ffd30a3321230db2fc727216"
+dependencies = [
+ "phf_generator 0.11.3",
+ "phf_shared 0.11.3",
+ "proc-macro2",
+ "quote",
+ "syn 2.0.118",
+]
+
+[[package]]
+name = "phf_shared"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b6796ad771acdc0123d2a88dc428b5e38ef24456743ddb1744ed628f9815c096"
+dependencies = [
+ "siphasher 0.3.11",
+]
+
+[[package]]
+name = "phf_shared"
+version = "0.11.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "67eabc2ef2a60eb7faa00097bd1ffdb5bd28e62bf39990626a582201b7a754e5"
+dependencies = [
+ "siphasher 1.0.3",
+]
+
 [[package]]
 name = "pin-project-lite"
 version = "0.2.17"
@@ -1455,6 +1681,12 @@ dependencies = [
  "zerocopy",
 ]
 
+[[package]]
+name = "precomputed-hash"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "925383efa346730478fb4838dbe9137d2a47675ad789c546d150a6e1dd4ab31c"
+
 [[package]]
 name = "prettyplease"
 version = "0.2.37"
@@ -1925,12 +2157,47 @@ version = "1.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "94143f37725109f92c262ed2cf5e59bce7498c01bcc1502d7b9afe439a4e9f49"
 
+[[package]]
+name = "scraper"
+version = "0.20.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b90460b31bfe1fc07be8262e42c665ad97118d4585869de9345a84d501a9eaf0"
+dependencies = [
+ "ahash 0.8.12",
+ "cssparser",
+ "ego-tree",
+ "getopts",
+ "html5ever",
+ "once_cell",
+ "selectors",
+ "tendril",
+]
+
 [[package]]
 name = "seahash"
 version = "4.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1c107b6f4780854c8b126e228ea8869f4d7b71260f962fefb57b996b8959ba6b"
 
+[[package]]
+name = "selectors"
+version = "0.25.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4eb30575f3638fc8f6815f448d50cb1a2e255b0897985c8c59f4d37b72a07b06"
+dependencies = [
+ "bitflags",
+ "cssparser",
+ "derive_more",
+ "fxhash",
+ "log",
+ "new_debug_unreachable",
+ "phf 0.10.1",
+ "phf_codegen 0.10.0",
+ "precomputed-hash",
+ "servo_arc",
+ "smallvec",
+]
+
 [[package]]
 name = "semver"
 version = "1.0.28"
@@ -2003,6 +2270,15 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "servo_arc"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d036d71a959e00c77a63538b90a6c2390969f9772b096ea837205c6bd0491a44"
+dependencies = [
+ "stable_deref_trait",
+]
+
 [[package]]
 name = "sha1"
 version = "0.10.6"
@@ -2053,6 +2329,7 @@ dependencies = [
  "rand 0.8.6",
  "reqwest",
  "rust_decimal",
+ "scraper",
  "serde",
  "serde_json",
  "sha2",
@@ -2103,6 +2380,18 @@ version = "0.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e3a9fe34e3e7a50316060351f37187a3f546bce95496156754b601a5fa71b76e"
 
+[[package]]
+name = "siphasher"
+version = "0.3.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "38b58827f4464d87d377d175e90bf58eb00fd8716ff0a62f80356b5e61555d0d"
+
+[[package]]
+name = "siphasher"
+version = "1.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8ee5873ec9cce0195efcb7a4e9507a04cd49aec9c83d0389df45b1ef7ba2e649"
+
 [[package]]
 name = "slab"
 version = "0.4.12"
@@ -2354,6 +2643,31 @@ version = "1.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6ce2be8dc25455e1f91df71bfa12ad37d7af1092ae736f3a6cd0e37bc7810596"
 
+[[package]]
+name = "string_cache"
+version = "0.8.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bf776ba3fa74f83bf4b63c3dcbbf82173db2632ed8452cb2d891d33f459de70f"
+dependencies = [
+ "new_debug_unreachable",
+ "parking_lot",
+ "phf_shared 0.11.3",
+ "precomputed-hash",
+ "serde",
+]
+
+[[package]]
+name = "string_cache_codegen"
+version = "0.5.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c711928715f1fe0fe509c53b43e993a9a557babc2d0a3567d0a3006f1ac931a0"
+dependencies = [
+ "phf_generator 0.11.3",
+ "phf_shared 0.11.3",
+ "proc-macro2",
+ "quote",
+]
+
 [[package]]
 name = "stringprep"
 version = "0.1.5"
@@ -2425,6 +2739,17 @@ version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "55937e1799185b12863d447f42597ed69d9928686b8d88a1df17376a097d8369"
 
+[[package]]
+name = "tendril"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d24a120c5fc464a3458240ee02c299ebcb9d67b5249c8848b09d639dca8d7bb0"
+dependencies = [
+ "futf",
+ "mac",
+ "utf-8",
+]
+
 [[package]]
 name = "thiserror"
 version = "1.0.69"
@@ -2855,6 +3180,12 @@ version = "0.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7df058c713841ad818f1dc5d3fd88063241cc61f49f5fbea4b951e8cf5a8d71d"
 
+[[package]]
+name = "unicode-width"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b4ac048d71ede7ee76d585517add45da530660ef4390e49b098733c6e897f254"
+
 [[package]]
 name = "unicode-xid"
 version = "0.2.6"
@@ -2879,6 +3210,12 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "utf-8"
+version = "0.7.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "09cc8ee72d2a9becf2f2febe0205bbed8fc6615b7cb429ad062dc7b7ddd036a9"
+
 [[package]]
 name = "utf8_iter"
 version = "1.0.4"

backend/Cargo.toml

@@ -38,3 +38,4 @@ rust_decimal = { version = "1", features = ["serde-float"] }
 dotenvy = "0.15"
 reqwest = { version = "0.12", default-features = false, features = ["json", "rustls-tls", "gzip"] }
 url = "2"
+scraper = "0.20"

backend/src/fetch/generic.rs

@@ -0,0 +1,280 @@
+//! Generic structured-data adapter.
+//!
+//! The Shopify adapter speaks a specific platform API. This one is the
+//! catch-all: it fetches the product page HTML and reads whatever standard
+//! product metadata it carries, in order of reliability:
+//!
+//!   1. **JSON-LD** (`<script type="application/ld+json">`) — a schema.org
+//!      `Product` with an `offers` block. The richest, most common source.
+//!   2. **Microdata** — `itemprop="price"`, `priceCurrency`, `availability`
+//!      attributes scattered on the page (schema.org again, inline).
+//!   3. **OpenGraph / meta** — `og:title`, `og:image`, `product:price:amount`.
+//!
+//! Each source fills gaps left by the previous, so a page with JSON-LD title
+//! but microdata price still resolves. No shop is hardcoded; this works on any
+//! store that emits standard product markup (Shopware, Magento, WooCommerce, …).
+
+use std::str::FromStr;
+
+use rust_decimal::Decimal;
+use scraper::{Html, Selector};
+
+use super::FetchedProduct;
+
+/// Fields gathered from the page, each independently optional.
+#[derive(Default)]
+struct Candidate {
+    title: Option<String>,
+    price: Option<Decimal>,
+    currency: Option<String>,
+    image: Option<String>,
+    in_stock: Option<bool>,
+}
+
+impl Candidate {
+    /// Fill any still-empty field from `other` (earlier sources win).
+    fn fill_from(&mut self, other: Candidate) {
+        self.title = self.title.take().or(other.title);
+        self.price = self.price.take().or(other.price);
+        self.currency = self.currency.take().or(other.currency);
+        self.image = self.image.take().or(other.image);
+        self.in_stock = self.in_stock.take().or(other.in_stock);
+    }
+}
+
+/// Returns `Ok(None)` when the page carries no usable product data (so this is
+/// a true fallback that doesn't mask "couldn't read it" as success); `Err` on a
+/// network/HTTP failure.
+pub async fn fetch(
+    client: &reqwest::Client,
+    raw_url: &str,
+    default_currency: &str,
+) -> anyhow::Result<Option<FetchedProduct>> {
+    let resp = client.get(raw_url).send().await?;
+    if !resp.status().is_success() {
+        anyhow::bail!("product page returned HTTP {}", resp.status());
+    }
+    let body = resp.text().await?;
+
+    // Parsing the DOM is sync + uses non-Send types (scraper/Html), so confine
+    // it to a closure with no awaits across it.
+    let mut c = Candidate::default();
+    {
+        let doc = Html::parse_document(&body);
+        // JSON-LD first (a properly-scoped Product, most reliable). Then OG meta
+        // for title/image — those are explicitly the product, unlike loose
+        // page-wide microdata `name`/`image`, which often hit a breadcrumb or
+        // logo. Microdata last: it still supplies price/currency/availability
+        // (which OG usually omits) without clobbering the good title/image.
+        c.fill_from(from_json_ld(&doc));
+        c.fill_from(from_meta(&doc));
+        c.fill_from(from_microdata(&doc));
+    }
+
+    let Some(price) = c.price else {
+        return Ok(None);
+    };
+
+    Ok(Some(FetchedProduct {
+        title: c.title.unwrap_or_else(|| "Untitled product".to_string()),
+        price,
+        currency: c.currency.unwrap_or_else(|| default_currency.to_string()),
+        image_url: c.image,
+        in_stock: c.in_stock,
+        source: "generic",
+    }))
+}
+
+/// schema.org Product from any JSON-LD block (handles bare objects, arrays and
+/// `@graph` wrappers).
+fn from_json_ld(doc: &Html) -> Candidate {
+    let sel = Selector::parse(r#"script[type="application/ld+json"]"#).unwrap();
+    for el in doc.select(&sel) {
+        let raw = el.text().collect::<String>();
+        let Ok(json) = serde_json::from_str::<serde_json::Value>(&raw) else {
+            continue;
+        };
+        if let Some(node) = find_product(&json) {
+            return product_from_json(node);
+        }
+    }
+    Candidate::default()
+}
+
+/// Depth-first search for a node whose `@type` is (or includes) `Product`.
+fn find_product(v: &serde_json::Value) -> Option<&serde_json::Value> {
+    match v {
+        serde_json::Value::Object(map) => {
+            if let Some(t) = map.get("@type") {
+                let is_product = match t {
+                    serde_json::Value::String(s) => s == "Product",
+                    serde_json::Value::Array(a) => {
+                        a.iter().any(|x| x.as_str() == Some("Product"))
+                    }
+                    _ => false,
+                };
+                if is_product {
+                    return Some(v);
+                }
+            }
+            // Descend (covers `@graph`, `mainEntity`, nested arrays, …).
+            map.values().find_map(find_product)
+        }
+        serde_json::Value::Array(a) => a.iter().find_map(find_product),
+        _ => None,
+    }
+}
+
+fn product_from_json(p: &serde_json::Value) -> Candidate {
+    // `offers` may be an object or an array of offers; take the first.
+    let offer = match p.get("offers") {
+        Some(serde_json::Value::Array(a)) => a.first(),
+        other => other,
+    };
+
+    let price = offer
+        .and_then(|o| o.get("price"))
+        .and_then(json_to_price)
+        .or_else(|| {
+            offer
+                .and_then(|o| o.get("priceSpecification"))
+                .and_then(|s| s.get("price"))
+                .and_then(json_to_price)
+        });
+
+    let currency = offer
+        .and_then(|o| o.get("priceCurrency"))
+        .and_then(|c| c.as_str())
+        .map(normalize_currency);
+
+    let in_stock = offer
+        .and_then(|o| o.get("availability"))
+        .and_then(|a| a.as_str())
+        .map(availability_in_stock);
+
+    Candidate {
+        title: p.get("name").and_then(|n| n.as_str()).map(str::to_string),
+        price,
+        currency,
+        image: p.get("image").and_then(json_first_string),
+        in_stock,
+    }
+}
+
+/// Inline schema.org microdata (`itemprop` attributes).
+fn from_microdata(doc: &Html) -> Candidate {
+    Candidate {
+        title: itemprop_value(doc, "name"),
+        price: itemprop_value(doc, "price").and_then(|s| parse_price(&s)),
+        currency: itemprop_value(doc, "priceCurrency").map(|s| normalize_currency(&s)),
+        image: itemprop_value(doc, "image"),
+        in_stock: itemprop_availability(doc).map(|s| availability_in_stock(&s)),
+    }
+}
+
+/// OpenGraph / product meta tags.
+fn from_meta(doc: &Html) -> Candidate {
+    Candidate {
+        title: meta_content(doc, "property", "og:title"),
+        price: meta_content(doc, "property", "product:price:amount")
+            .and_then(|s| parse_price(&s)),
+        currency: meta_content(doc, "property", "product:price:currency")
+            .map(|s| normalize_currency(&s)),
+        image: meta_content(doc, "property", "og:image"),
+        in_stock: meta_content(doc, "property", "og:availability")
+            .or_else(|| meta_content(doc, "property", "product:availability"))
+            .map(|s| availability_in_stock(&s)),
+    }
+}
+
+// --- small extraction helpers -------------------------------------------------
+
+/// Value of an `itemprop` element: its `content` attribute if present, else its
+/// trimmed text.
+fn itemprop_value(doc: &Html, prop: &str) -> Option<String> {
+    let sel = Selector::parse(&format!(r#"[itemprop="{prop}"]"#)).ok()?;
+    let el = doc.select(&sel).next()?;
+    if let Some(c) = el.value().attr("content") {
+        let c = c.trim();
+        if !c.is_empty() {
+            return Some(c.to_string());
+        }
+    }
+    let txt = el.text().collect::<String>();
+    let txt = txt.trim();
+    (!txt.is_empty()).then(|| txt.to_string())
+}
+
+/// Availability is carried in `content` or `href` (`href="…/InStock"`).
+fn itemprop_availability(doc: &Html) -> Option<String> {
+    let sel = Selector::parse(r#"[itemprop="availability"]"#).ok()?;
+    let el = doc.select(&sel).next()?;
+    el.value()
+        .attr("content")
+        .or_else(|| el.value().attr("href"))
+        .map(str::to_string)
+}
+
+fn meta_content(doc: &Html, attr: &str, key: &str) -> Option<String> {
+    let sel = Selector::parse(&format!(r#"meta[{attr}="{key}"]"#)).ok()?;
+    let v = doc.select(&sel).next()?.value().attr("content")?.trim();
+    (!v.is_empty()).then(|| v.to_string())
+}
+
+fn json_to_price(v: &serde_json::Value) -> Option<Decimal> {
+    match v {
+        serde_json::Value::String(s) => parse_price(s),
+        serde_json::Value::Number(n) => Decimal::from_str(&n.to_string()).ok(),
+        _ => None,
+    }
+}
+
+/// `image` may be a string, an array of strings, or an `ImageObject`.
+fn json_first_string(v: &serde_json::Value) -> Option<String> {
+    match v {
+        serde_json::Value::String(s) => Some(s.clone()),
+        serde_json::Value::Array(a) => a.iter().find_map(json_first_string),
+        serde_json::Value::Object(o) => o.get("url").and_then(json_first_string),
+        _ => None,
+    }
+}
+
+/// A schema.org availability URL/string maps to in-stock truth.
+fn availability_in_stock(s: &str) -> bool {
+    let s = s.to_ascii_lowercase();
+    // Treat InStock / PreOrder / BackOrder as "can be had"; everything else
+    // (OutOfStock, SoldOut, Discontinued) as not.
+    s.contains("instock") || s.contains("preorder") || s.contains("backorder")
+}
+
+fn normalize_currency(s: &str) -> String {
+    s.trim().to_uppercase()
+}
+
+/// Parse a price string like `17.95`, `1.234,56`, `€ 17,95` into a Decimal.
+fn parse_price(raw: &str) -> Option<Decimal> {
+    // Keep only digits and separators.
+    let mut s: String = raw
+        .chars()
+        .filter(|c| c.is_ascii_digit() || *c == '.' || *c == ',')
+        .collect();
+    if s.is_empty() {
+        return None;
+    }
+    match (s.rfind('.'), s.rfind(',')) {
+        // Both present: the rightmost separator is the decimal point; the other
+        // is a thousands separator and gets stripped.
+        (Some(dot), Some(comma)) => {
+            if comma > dot {
+                s = s.replace('.', "").replace(',', ".");
+            } else {
+                s = s.replace(',', "");
+            }
+        }
+        // Only a comma: it's the decimal separator (European style).
+        (None, Some(_)) => s = s.replace(',', "."),
+        // Only a dot, or neither: already parseable.
+        _ => {}
+    }
+    Decimal::from_str(&s).ok()
+}

backend/src/fetch/mod.rs

@@ -4,6 +4,7 @@
 
 use rust_decimal::Decimal;
 
+mod generic;
 mod shopify;
 
 /// Normalised product snapshot produced by an adapter.
@@ -35,5 +36,10 @@ pub async fn fetch_product(
     if let Some(p) = shopify::fetch(client, url, default_currency).await? {
         return Ok(p);
     }
-    anyhow::bail!("no adapter could read this URL (only Shopify storefronts are supported for now)")
+    // Catch-all: read standard product metadata (JSON-LD / microdata / OG) from
+    // the page HTML. Works on any store emitting schema.org markup.
+    if let Some(p) = generic::fetch(client, url, default_currency).await? {
+        return Ok(p);
+    }
+    anyhow::bail!("no adapter could read this URL (no Shopify API and no readable product metadata)")
 }