Square

use square.qweruse square_new_key, square_money from square      // Quillo 0.6: only these

ureq = "2"hmac = "0.12"sha2 = "0.10"base64 = "0.22"serde_json = { version = "1", features = ["preserve_order"] }

// Taking money with Square: a card payment, one authorized and captured later, a refund, a// customer found by email, an item in the catalog, lists past one page, and a webhook checked.////   SQUARE_ACCESS_TOKEN=... SQUARE_API_URL=https://connect.squareupsandbox.com quillo run square.qwe//   then open /pay, /later, /refund, /customers, /catalog, /lists, /hook-check and /failures//// In the sandbox, `cnon:card-nonce-ok` is a good card and `cnon:card-nonce-declined` a declined// one. Point a webhook subscription at POST /square/webhook, and set SQUARE_WEBHOOK_KEY and// SQUARE_WEBHOOK_URL to its signature key and exact URL.use "square.qwer"route GET /pay {    let paid = square_pay("cnon:card-nonce-ok", square_money("19.99", "USD")?, { reference_id: "order-1001", note: "Blue mug" })?    let read = square_payment(paid.id)?    { state: read.status, amount: read.amount_money.amount, reference: read.reference_id }}// The same key sent twice is one payment; a changed amount with that key is refused.route GET /again {    let key = square_new_key()    let one = square_pay("cnon:card-nonce-ok", square_money("5.00", "USD")?, { idempotency_key: key })?    let two = square_pay("cnon:card-nonce-ok", square_money("5.00", "USD")?, { idempotency_key: key })?    {        same: one.id == two.id,        changed: square_pay("cnon:card-nonce-ok", square_money("6.00", "USD")?, { idempotency_key: key }).error,        long: square_pay("cnon:card-nonce-ok", square_money("6.00", "USD")?, { idempotency_key: repeat("k", 46) }).error,    }}route GET /later {    let held = square_pay("cnon:card-nonce-ok", square_money("40", "USD")?, { autocomplete: false })?    let done = square_payment_complete(held.id)?    let other = square_pay("cnon:card-nonce-ok", square_money("7", "USD")?, { autocomplete: false })?    { held: held.status, done: done.status, cancelled: square_payment_cancel(other.id)?.status, twice: square_payment_complete(other.id).error }}route GET /refund {    let paid = square_pay("cnon:card-nonce-ok", square_money("30", "USD")?, {})?    let back = square_refund(paid.id, square_money("10", "USD")?, "Chipped mug", "")?    {        state: back.status,        settled: square_refund_get(back.id)?.status,        too_much: square_refund(paid.id, square_money("99", "USD")?, "", "").error,    }}route GET /customers {    let ada = square_customer_create({ given_name: "Ada", family_name: "Lovelace", email_address: "ada@example.com" })?    square_customer_update(ada.id, { note: "Prefers mail", version: ada.version })?    {        name: square_customer(ada.id)?.given_name,        note: square_customer(ada.id)?.note,        found: map(square_customer_by_email("ada@example.com")?, (c) => c.family_name),        stale: square_customer_update(ada.id, { note: "x", version: 0 }).error,        bad: square_customer_create({ email_address: "not an address" }).error,    }}route GET /catalog {    let made = square_catalog_item("Blue mug", [{ name: "Small", price: "12.50", currency: "USD" }, { name: "Large", price: "1500", currency: "JPY" }])?    let item = made.object    {        name: item.item_data.name,        prices: map(item.item_data.variations, (v) => v.item_variation_data.price_money.amount),        temp_ids: map(made.id_mappings, (m) => m.client_object_id),        deleted: len(square_catalog_delete(item.id)?),        none: square_catalog_item("x", []).error,    }}route GET /lists = {    payments: len(square_payments({ location_id: "L1" }, 0)?),    capped: len(square_payments({ location_id: "L1" }, 130)?),    customers: len(square_customers(0)?),    items: len(square_catalog_list("ITEM", 0)?),    categories: len(square_catalog_list("CATEGORY", 0)?),}route GET /money = {    dollars: square_money("19.99", "usd")?,    yen: square_money("1500", "JPY")?,    dinars: square_money("1.250", "KWD")?,    too_fine: square_money("10.5", "JPY").error,    not_money: square_money("ten", "USD").error,    code: square_money("1", "US").error,}route POST /square/webhook {    let event = square_webhook(env("SQUARE_WEBHOOK_URL", ""), request.body, request.headers["x-square-hmacsha256-signature"] ?? "", env("SQUARE_WEBHOOK_KEY", ""))    if is_err(event) { reply 403 event.error }    { got: event.type }}// A signature made outside this plugin, by node's crypto.route GET /hook-check {    let url = "https://example.com/square/webhook"    let body = "{\"merchant_id\":\"6SSW7HV8K2ST5\",\"type\":\"payment.updated\",\"event_id\":\"e1\"}"    let sig = "wIOiyGj8OCbrrClH8Rvf4GlTu6SITiDf5SqDHCIAbYk="    {        good: square_webhook(url, body, sig, "whk-test-key")?.type,        tampered: square_webhook(url, body + " ", sig, "whk-test-key").error,        other_url: square_webhook("https://example.com/other", body, sig, "whk-test-key").error,        unsigned: square_webhook(url, body, "", "whk-test-key").error,    }}route GET /failures = {    declined: square_pay("cnon:card-nonce-declined", square_money("1", "USD")?, {}).error,    missing: square_payment("nope").error,    waited: square_pay("cnon:rate-limit-once", square_money("2", "USD")?, {})?.status,}

//! Square's API without an SDK: payments taken, completed and cancelled, refunds, customers and catalog items, every list followed through its cursors, an idempotency key on each write that a retry reuses, money in each currency's smallest unit, Square's error lists read, and webhook signatures checked over the notification URL and body.//! version: 1.0.0//!//! [dependencies]//! ureq = "2"//! hmac = "0.12"//! sha2 = "0.10"//! base64 = "0.22"//! serde_json = { version = "1", features = ["preserve_order"] }use base64::{engine::general_purpose::STANDARD, Engine};use hmac::{Hmac, Mac};use serde_json::{json, Value};use sha2::{Digest, Sha256};use std::sync::atomic::{AtomicU64, Ordering};use std::time::{Duration, SystemTime, UNIX_EPOCH};// SQUARE_ACCESS_TOKEN is the token; SQUARE_API_URL the API (https://connect.squareup.com when not// set; https://connect.squareupsandbox.com for the sandbox); SQUARE_VERSION an API version date.const ZERO_DECIMAL: &[&str] = &["BIF", "CLP", "DJF", "GNF", "JPY", "KMF", "KRW", "MGA", "PYG", "RWF", "UGX", "VND", "VUV", "XAF", "XOF", "XPF"];const THREE_DECIMAL: &[&str] = &["BHD", "JOD", "KWD", "OMR", "TND"];const VERSION: &str = "2024-10-17";fn setting(k: &str) -> Option<String> {    std::env::var(k).ok().filter(|v| !v.is_empty())}fn api() -> String {    setting("SQUARE_API_URL").unwrap_or_else(|| "https://connect.squareup.com".into()).trim_end_matches('/').to_string()}fn enc(s: &str) -> String {    s.bytes().map(|b| if b.is_ascii_alphanumeric() || b"-_.~".contains(&b) { (b as char).to_string() } else { format!("%{:02X}", b) }).collect()}// Square gives a list: each with a category, a code, and usually a detail and a field.fn errors_text(status: u16, v: &Value, raw: &str) -> String {    let list = v["errors"].as_array().cloned().unwrap_or_default();    if list.is_empty() {        return format!("Square {}: {}", status, raw.trim().chars().take(300).collect::<String>());    }    let parts: Vec<String> = list        .iter()        .map(|e| {            let mut t = format!("{}: {}", e["code"].as_str().unwrap_or("ERROR"), e["detail"].as_str().unwrap_or(e["category"].as_str().unwrap_or("")));            if let Some(f) = e["field"].as_str() {                t.push_str(&format!(" (field {})", f));            }            t        })        .collect();    let hint = match status {        401 => " (check SQUARE_ACCESS_TOKEN, and that it belongs to this environment)",        403 => " (the token lacks the permission this call needs)",        _ => "",    };    format!("Square {}: {}{}", status, parts.join("; "), hint)}// The body keeps its idempotency key through the retries, so a write sent twice happens once.fn call(method: &str, path: &str, body: Option<&Value>) -> Result<Value, String> {    let token = setting("SQUARE_ACCESS_TOKEN").ok_or("SQUARE_ACCESS_TOKEN is not set")?;    let url = format!("{}{}", api(), path);    let version = setting("SQUARE_VERSION").unwrap_or_else(|| VERSION.into());    let agent = ureq::AgentBuilder::new().timeout(Duration::from_secs(30)).build();    for attempt in 0..5u32 {        let req = agent.request(method, &url).set("Authorization", &format!("Bearer {}", token)).set("Square-Version", &version).set("Accept", "application/json");        let res = match body {            Some(b) => req.set("Content-Type", "application/json").send_string(&b.to_string()),            None => req.call(),        };        match res {            Ok(r) => {                let t = r.into_string().map_err(|e| e.to_string())?;                return if t.trim().is_empty() { Ok(json!({})) } else { serde_json::from_str(&t).map_err(|_| format!("Square's answer is not JSON: {}", t.chars().take(200).collect::<String>())) };            }            Err(ureq::Error::Status(429 | 500 | 502 | 503 | 504, r)) if attempt < 4 => {                let wait = r.header("Retry-After").and_then(|s| s.parse::<u64>().ok()).map_or(250u64 << attempt, |s| s * 1000);                std::thread::sleep(Duration::from_millis(wait.min(30_000)));            }            Err(ureq::Error::Status(c, r)) => {                let t = r.into_string().unwrap_or_default();                return Err(errors_text(c, &serde_json::from_str(&t).unwrap_or(Value::Null), &t));            }            Err(e) => return Err(format!("cannot reach Square at {}: {}", api(), e)),        }    }    Err("Square stayed busy through five tries".into())}static COUNTER: AtomicU64 = AtomicU64::new(0);/// A new idempotency key, a UUID in form: send the same key to make a retry of your own safe.pub fn square_new_key() -> String {    let n = COUNTER.fetch_add(1, Ordering::Relaxed);    let t = SystemTime::now().duration_since(UNIX_EPOCH).map_or(0, |d| d.as_nanos());    let seed = std::collections::hash_map::RandomState::new();    let d = Sha256::digest(format!("{}:{}:{}:{:?}", t, n, std::process::id(), seed));    let mut b: Vec<u8> = d[..16].to_vec();    b[6] = (b[6] & 0x0f) | 0x40;    b[8] = (b[8] & 0x3f) | 0x80;    let h: String = b.iter().map(|x| format!("{:02x}", x)).collect();    format!("{}-{}-{}-{}-{}", &h[..8], &h[8..12], &h[12..16], &h[16..20], &h[20..])}fn with_key(mut v: Value, key_of: &str) -> Result<Value, String> {    let k = if key_of.is_empty() { v["idempotency_key"].as_str().map(str::to_string).unwrap_or_else(square_new_key) } else { key_of.to_string() };    if k.len() > 45 {        return Err(format!("an idempotency key is at most 45 characters, not {}", k.len()));    }    v["idempotency_key"] = json!(k);    Ok(v)}/// Money as Square wants it: `square_money("19.99", "USD")` is `{ amount: 1999, currency: "USD" }`, in the currency's smallest unit (yen has none, dinars three). Takes text so no float rounding creeps in; an error for more decimals than the currency has.pub fn square_money(amount: &str, currency: &str) -> Result<serde_json::Value, String> {    let c = currency.to_uppercase();    if c.len() != 3 || !c.bytes().all(|b| b.is_ascii_uppercase()) {        return Err(format!("`{}` is not a three-letter currency code", currency));    }    let places = if ZERO_DECIMAL.contains(&c.as_str()) { 0 } else if THREE_DECIMAL.contains(&c.as_str()) { 3 } else { 2 };    let a = amount.trim();    let (whole, frac) = a.split_once('.').unwrap_or((a, ""));    if whole.is_empty() || !whole.bytes().all(|b| b.is_ascii_digit()) || !frac.bytes().all(|b| b.is_ascii_digit()) {        return Err(format!("`{}` is not an amount", amount));    }    let frac = frac.trim_end_matches('0');    if frac.len() > places {        return Err(format!("{} has {} decimals; {} has {}", amount, frac.len(), c, places));    }    let n: i64 = format!("{}{}{}", whole, frac, "0".repeat(places - frac.len())).parse().map_err(|_| format!("`{}` is too large", amount))?;    Ok(json!({ "amount": n, "currency": c }))}/// Takes a payment from `source_id` (a nonce from the Web Payments SDK, or a card on file) for `money` (from square_money). `params` adds what Square documents: `autocomplete` (false only authorizes), `location_id`, `customer_id`, `reference_id`, `note`, `idempotency_key` (one is made if not given). Gives the payment; a decline is an error naming its code.pub fn square_pay(source_id: &str, money: serde_json::Value, params: serde_json::Value) -> Result<serde_json::Value, String> {    if source_id.is_empty() {        return Err("a payment needs a source_id".into());    }    if !money["amount"].is_i64() || !money["currency"].is_string() {        return Err("money must be { amount, currency }: see square_money".into());    }    let mut b = if params.is_object() { params } else { json!({}) };    b["source_id"] = json!(source_id);    b["amount_money"] = money;    let b = with_key(b, "")?;    Ok(call("POST", "/v2/payments", Some(&b))?["payment"].clone())}/// One payment by id.pub fn square_payment(id: &str) -> Result<serde_json::Value, String> {    Ok(call("GET", &format!("/v2/payments/{}", enc(id)), None)?["payment"].clone())}/// Completes a payment taken with `autocomplete: false`.pub fn square_payment_complete(id: &str) -> Result<serde_json::Value, String> {    Ok(call("POST", &format!("/v2/payments/{}/complete", enc(id)), Some(&json!({})))?["payment"].clone())}/// Cancels a payment taken with `autocomplete: false`, before it is completed.pub fn square_payment_cancel(id: &str) -> Result<serde_json::Value, String> {    Ok(call("POST", &format!("/v2/payments/{}/cancel", enc(id)), Some(&json!({})))?["payment"].clone())}fn query_of(filter: &Value) -> String {    let mut q = vec![];    if let Some(m) = filter.as_object() {        for (k, v) in m {            let t = v.as_str().map(str::to_string).unwrap_or_else(|| v.to_string());            if !v.is_null() {                q.push(format!("{}={}", enc(k), enc(&t)));            }        }    }    q.join("&")}// GET lists: `cursor` in the query, `cursor` in the answer until the last page.fn walk_get(path: &str, filter: &Value, field: &str, max_items: i64) -> Result<Vec<Value>, String> {    let mut out = vec![];    let mut cursor: Option<String> = None;    let base_q = query_of(filter);    loop {        let mut q = base_q.clone();        if let Some(c) = &cursor {            if !q.is_empty() {                q.push('&');            }            q.push_str(&format!("cursor={}", enc(c)));        }        let url = if q.is_empty() { path.to_string() } else { format!("{}?{}", path, q) };        let v = call("GET", &url, None)?;        out.extend(v[field].as_array().cloned().unwrap_or_default());        if max_items > 0 && out.len() as i64 >= max_items {            out.truncate(max_items as usize);            return Ok(out);        }        match v["cursor"].as_str() {            Some(c) if !c.is_empty() => cursor = Some(c.to_string()),            _ => return Ok(out),        }    }}/// Payments through every page: `filter` is Square's (`begin_time`, `end_time`, `location_id`, `sort_order`, `limit`); `max_items` caps them (0: all).pub fn square_payments(filter: serde_json::Value, max_items: i64) -> Result<Vec<serde_json::Value>, String> {    walk_get("/v2/payments", &filter, "payments", max_items)}/// Refunds `money` of a payment; `reason` shows on the receipt and `idempotency_key` may be "" to make one. Gives the refund, usually PENDING at first.pub fn square_refund(payment_id: &str, money: serde_json::Value, reason: &str, idempotency_key: &str) -> Result<serde_json::Value, String> {    let mut b = json!({ "payment_id": payment_id, "amount_money": money });    if !reason.is_empty() {        b["reason"] = json!(reason);    }    let b = with_key(b, idempotency_key)?;    Ok(call("POST", "/v2/refunds", Some(&b))?["refund"].clone())}/// One refund by id, to see it leave PENDING.pub fn square_refund_get(id: &str) -> Result<serde_json::Value, String> {    Ok(call("GET", &format!("/v2/refunds/{}", enc(id)), None)?["refund"].clone())}/// Makes a customer from Square's fields (`given_name`, `family_name`, `email_address`, `phone_number`, `reference_id`...), with `idempotency_key` when you want one kept.pub fn square_customer_create(fields: serde_json::Value) -> Result<serde_json::Value, String> {    let b = with_key(if fields.is_object() { fields } else { json!({}) }, "")?;    Ok(call("POST", "/v2/customers", Some(&b))?["customer"].clone())}/// One customer by id.pub fn square_customer(id: &str) -> Result<serde_json::Value, String> {    Ok(call("GET", &format!("/v2/customers/{}", enc(id)), None)?["customer"].clone())}/// Changes a customer's fields; give `version` to be refused when someone changed it first.pub fn square_customer_update(id: &str, fields: serde_json::Value) -> Result<serde_json::Value, String> {    Ok(call("PUT", &format!("/v2/customers/{}", enc(id)), Some(&fields))?["customer"].clone())}/// Customers through every page; `max_items` caps them (0: all).pub fn square_customers(max_items: i64) -> Result<Vec<serde_json::Value>, String> {    walk_get("/v2/customers", &json!({ "limit": 100 }), "customers", max_items)}/// Customers with exactly this email address.pub fn square_customer_by_email(email: &str) -> Result<Vec<serde_json::Value>, String> {    let mut out = vec![];    let mut body = json!({ "limit": 100, "query": { "filter": { "email_address": { "exact": email } } } });    loop {        let v = call("POST", "/v2/customers/search", Some(&body))?;        out.extend(v["customers"].as_array().cloned().unwrap_or_default());        match v["cursor"].as_str() {            Some(c) if !c.is_empty() => body["cursor"] = json!(c),            _ => return Ok(out),        }    }}/// Puts any catalog object (`object` with a `type` and, for a new one, an `id` starting with `#`). Gives { object, id_mappings }, the ids Square gave in place of yours.pub fn square_catalog_upsert(object: serde_json::Value) -> Result<serde_json::Value, String> {    if !object["type"].is_string() || !object["id"].is_string() {        return Err("a catalog object needs a `type` and an `id` (a new one's starts with #)".into());    }    let b = with_key(json!({ "object": object }), "")?;    let v = call("POST", "/v2/catalog/object", Some(&b))?;    Ok(json!({ "object": v["catalog_object"], "id_mappings": v["id_mappings"] }))}/// Makes an ITEM with its variations: `variations` is a list of { name, price, currency } (price as text; Square needs at least one).pub fn square_catalog_item(name: &str, variations: Vec<serde_json::Value>) -> Result<serde_json::Value, String> {    if variations.is_empty() {        return Err("an item needs at least one variation".into());    }    let mut vars = vec![];    for (i, x) in variations.iter().enumerate() {        let vn = x["name"].as_str().ok_or("each variation needs a `name`")?;        let price = x["price"].as_str().ok_or("each variation needs a `price`, as text")?;        vars.push(json!({            "type": "ITEM_VARIATION", "id": format!("#var{}", i),            "item_variation_data": { "item_id": "#item", "name": vn, "pricing_type": "FIXED_PRICING", "price_money": square_money(price, x["currency"].as_str().unwrap_or("USD"))? },        }));    }    square_catalog_upsert(json!({ "type": "ITEM", "id": "#item", "item_data": { "name": name, "variations": vars } }))}/// Catalog objects of the `types` given ("ITEM,CATEGORY", "" for all) through every page; `max_items` caps them (0: all).pub fn square_catalog_list(types: &str, max_items: i64) -> Result<Vec<serde_json::Value>, String> {    let filter = if types.is_empty() { json!({}) } else { json!({ "types": types }) };    walk_get("/v2/catalog/list", &filter, "objects", max_items)}/// Deletes a catalog object, and its children. Gives the ids deleted.pub fn square_catalog_delete(id: &str) -> Result<serde_json::Value, String> {    Ok(call("DELETE", &format!("/v2/catalog/object/{}", enc(id)), None)?["deleted_object_ids"].clone())}fn sign(notification_url: &str, body: &str, signature_key: &str) -> String {    let mut m = Hmac::<Sha256>::new_from_slice(signature_key.as_bytes()).expect("HMAC takes any key");    m.update(notification_url.as_bytes());    m.update(body.as_bytes());    STANDARD.encode(m.finalize().into_bytes())}/// Checks a webhook: `notification_url` exactly as subscribed, `body` the raw body, `signature` the `x-square-hmacsha256-signature` header, `signature_key` the subscription's. Gives the event, or an error saying why it is refused.pub fn square_webhook(notification_url: &str, body: &str, signature: &str, signature_key: &str) -> Result<serde_json::Value, String> {    if signature.is_empty() {        return Err("no x-square-hmacsha256-signature header: this did not come from Square".into());    }    let want = sign(notification_url, body, signature_key);    if want.len() != signature.len() || want.bytes().zip(signature.bytes()).fold(0u8, |a, (x, y)| a | (x ^ y)) != 0 {        return Err("the webhook's signature does not match: a wrong signature key, a notification URL not exactly as subscribed, or a changed body".into());    }    serde_json::from_str(body).map_err(|e| format!("the webhook's body is not JSON: {}", e))}/// Signs a webhook body as Square does, for tests.pub fn square_webhook_sign(notification_url: &str, body: &str, signature_key: &str) -> String {    sign(notification_url, body, signature_key)}