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// Merchant's DB state for one particular order.
// Invariants:
// paid => claimed
// claimed => !!contractHash
// requireClaimToken => !!claimToken
// !!lastPaidSessionId => paid
interface MerchantOrderInfo {
orderId: string;
requireClaimToken: boolean;
claimToken?: string;
contractHash?: string;
claimed: boolean;
paid: boolean;
fulfillmentUrl?: string;
publicReorderUrl?: string;
lastPaidSessionId?: string;
}
// Data from the client's request to /orders/{id}
interface Req {
orderId: string;
contractHash?: string;
claimToken?: string;
sessionId?: string;
accept: "json" | "html";
}
// (Abstract) response to /orders/{id}
interface Resp {
httpStatus: string;
contentType: "json" | "html";
// Schema type of the response
responseType: string;
// Redirect "Location: " if applicable to status code
redirectLocation?: string;
// Additional details about response
response?: any;
}
// Abstracted merchant database
type MerchantOrderStore = { [orderId: string]: MerchantOrderInfo };
// Logic for /orders/{id}
function handlePublicOrdersGet(mos: MerchantOrderStore, req: Req): Resp {
const ord = mos[req.orderId];
if (!ord) {
return respNotFound(req);
}
if (!ord.claimed) {
if (ord.requireClaimToken && ord.claimToken !== req.claimToken) {
return respForbidden(req);
}
return respUnpaid(req, ord);
}
if (!ord.paid) {
const hcOk = ord.contractHash === req.contractHash;
const ctOk = ord.claimToken === req.claimToken;
if (req.contractHash && !hcOk) {
// Contract terms hash given but wrong
return respForbidden(req);
}
if (req.claimToken && ord.claimToken !== req.claimToken) {
// Claim token given but wrong
return respForbidden(req);
}
if (ord.requireClaimToken && !req.claimToken && !hcOk) {
// Client is trying to get the order status of a claimed,
// unpaid order. However, the client is not showing authentication.
//
// This can happen when the fulfillment URL includes the order ID,
// and the storefront redirects the user to the backend QR code
// page, because the order is not paid under the current session.
// This happens on bookmarking / link sharing.
if (!ord.publicReorderUrl) {
return respForbidden(req);
}
return respGoto(req, ord.publicReorderUrl);
}
return respUnpaid(req, ord);
}
// Here, we know that the order is paid for.
// But we still need the ord.claimToken, because
// the QR code page will poll until it gets a
// fulfillment URL, but we decided that the
// fulfillment URL should only be returned
// when the client is authenticated.
// (Otherwise, guessing the order ID might leak the
// fulfillment URL).
const authOk =
ord.contractHash === req.contractHash ||
(ord.requireClaimToken && ord.claimToken === req.claimToken);
if (!authOk) {
return respForbidden(req);
}
if (!!req.sessionId && req.sessionId !== ord.lastPaidSessionId) {
const alreadyPaidOrd = findAlreadyPaid(mos, req.sessionId);
if (!!alreadyPaidOrd) {
return respAlreadyPaid(req, alreadyPaidOrd);
}
return respUnpaid(req, ord);
}
return respPaid(req, ord);
}
function respNotFound(req: Req): Resp {
return {
contentType: req.accept,
httpStatus: "404 Not Found",
responseType: "TalerError",
};
}
function respForbidden(req: Req): Resp {
return {
contentType: req.accept,
httpStatus: "403 Forbidden",
responseType: "TalerError",
};
}
function respAlreadyPaid(req: Req, alreadyPaidOrd: MerchantOrderInfo): Resp {
// This could be called with an empty fulfillment URL, but that doens't
// really make sense for the client's perspective.
if (req.accept === "html") {
return {
httpStatus: "302 Found",
contentType: "html",
redirectLocation: alreadyPaidOrd.fulfillmentUrl,
responseType: "empty",
};
}
return {
httpStatus: "202 Accepted",
contentType: "json",
responseType: "StatusGotoResponse",
response: {
fulfillment_url: alreadyPaidOrd.fulfillmentUrl,
},
};
}
function respGoto(req: Req, publicReorderUrl: string): Resp {
if (req.accept === "html") {
return {
httpStatus: "302 Found",
contentType: "html",
redirectLocation: publicReorderUrl,
responseType: "empty",
};
}
return {
httpStatus: "202 Accepted",
contentType: "json",
responseType: "StatusGotoResponse",
response: {
public_reorder_url: publicReorderUrl,
},
};
}
function respUnpaid(req: Req, ord: MerchantOrderInfo): Resp {
if (req.accept === "html") {
return;
}
return {
httpStatus: "402 Payment Required",
contentType: "html",
responseType: "StatusUnpaidResponse",
response: {
// Required for repurchase detection
fulfillmentUrl: ord.fulfillmentUrl,
},
};
}
function respPaid(req: Req, ord: MerchantOrderInfo): Resp {
if (req.accept === "html") {
if (req.accept === "html") {
return {
httpStatus: "302 Found",
contentType: "html",
redirectLocation: ord.fulfillmentUrl || "<backend pay success page>",
responseType: "empty",
};
}
}
return {
httpStatus: "200 OK",
contentType: "json",
responseType: "StatusPaidResponse",
response: {
fulfillmentUrl: ord.fulfillmentUrl,
},
};
}
// Helper to find an already paid order ID.
function findAlreadyPaid(
mos: MerchantOrderStore,
sessionId: string
): MerchantOrderInfo | undefined {
for (const orderId of Object.keys(mos)) {
if (mos[orderId].lastPaidSessionId === sessionId) {
return mos[orderId];
}
}
return undefined;
}
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