[#173535710] Adult check by extracting date of birth from fiscalCode data (#687)

Author: AleDore

src/services/__tests__/bonusService.test.ts

@@ -19,6 +19,7 @@ import { User } from "../../types/user";
 import BonusService from "../bonusService";
 
 const aValidFiscalCode = "XUZTCT88A51Y311X" as FiscalCode;
+const aNotAdultFiscalCode = "DROLSS02S20H501F" as FiscalCode;
 const aValidSPIDEmail = "[email protected]" as EmailAddress;
 const aValidSpidLevel = SpidLevelEnum["https://www.spid.gov.it/SpidL2"];
 
@@ -94,7 +95,7 @@ const mockedNotAdultUser: User = {
   created_at: 1183518855,
   date_of_birth: "2020-01-01",
   family_name: "Lusso",
-  fiscal_code: aValidFiscalCode,
+  fiscal_code: aNotAdultFiscalCode,
   name: "Luca",
   session_token: "HexToKen" as SessionToken,
   spid_email: aValidSPIDEmail,
@@ -222,7 +223,7 @@ describe("BonusService#startBonusEligibilityCheck", () => {
   });
 });
 
-it("should return an error if the logged in user is not adult", async () => {
+it("should return an Unauthorized error if the logged in user is not adult", async () => {
   mockStartBonusEligibilityCheck.mockImplementation(() =>
     t.success({ status: 123 })
   );

src/services/bonusService.ts

@@ -42,8 +42,8 @@ import {
 
 import { toString } from "fp-ts/lib/function";
 
-import { fromNullable } from "fp-ts/lib/Option";
-import { isOlderThan } from "../utils/date";
+import { isSome } from "fp-ts/lib/Option";
+import { isOlderThan, toBirthDate } from "../utils/date";
 
 const readableProblem = (problem: ProblemJson) =>
   `${problem.title} (${problem.type || "no problem type specified"})`;
@@ -79,10 +79,10 @@ export default class BonusService {
   > =>
     withCatchAsInternalError(async () => {
       // check if the current logged in user can start a bonus request
+      const maybeBirthDate = toBirthDate(user.fiscal_code);
       if (
-        fromNullable(user.date_of_birth).exists(
-          _ => !isOlderThan(18)(new Date(_), new Date())
-        )
+        isSome(maybeBirthDate) &&
+        !isOlderThan(18)(maybeBirthDate.value, new Date())
       ) {
         return ResponseErrorUnauthorized(
           "Unauthorized",

src/utils/__tests__/date.test.ts

@@ -1,8 +1,14 @@
-import { isOlderThan } from "../date";
+import { isNone, isSome } from "fp-ts/lib/Option";
+import { FiscalCode } from "italia-ts-commons/lib/strings";
+import { isOlderThan, toBirthDate } from "../date";
 
 const toDate = new Date("2020-01-01");
 const olderThanValue = 18;
 
+const aFiscalCode = "DROLSS85S20H501F" as FiscalCode;
+const aWrongFiscalCode = "DROLSS85Z20H501F" as FiscalCode;
+const aDateOfBirth = new Date(1985, 10, 20);
+
 describe("Check if a birthdate is for an adult user", () => {
   it("should return true if the user is over 18 years old", () => {
     const validOlderDate = new Date("2000-01-01");
@@ -20,3 +26,21 @@ describe("Check if a birthdate is for an adult user", () => {
     ).toBeFalsy();
   });
 });
+
+describe("User utility", () => {
+  it("should extract the correct date of birth from fiscalCode", async () => {
+    const extractedDateOfBirthOrError = toBirthDate(aFiscalCode);
+    expect(isSome(extractedDateOfBirthOrError)).toBeTruthy();
+    if (isSome(extractedDateOfBirthOrError)) {
+      const birthDate = extractedDateOfBirthOrError.value;
+      expect(birthDate.getFullYear()).toEqual(aDateOfBirth.getFullYear());
+      expect(birthDate.getDay()).toEqual(aDateOfBirth.getDay());
+      expect(birthDate.getMonth()).toEqual(aDateOfBirth.getMonth());
+    }
+  });
+
+  it("should return none if fiscalCode is not recognized", async () => {
+    const extractedDateOfBirthOrError = toBirthDate(aWrongFiscalCode);
+    expect(isNone(extractedDateOfBirthOrError)).toBeTruthy();
+  });
+});

src/utils/date.ts

@@ -1,4 +1,6 @@
 import { addYears, isAfter } from "date-fns";
+import { Option, tryCatch } from "fp-ts/lib/Option";
+import { FiscalCode } from "generated/backend/FiscalCode";
 
 /**
  * Returns a comparator of two dates that returns true if
@@ -10,3 +12,64 @@ export const isOlderThan = (years: number) => (
 ) => {
   return !isAfter(addYears(dateOfBirth, years), when);
 };
+
+export const isValidDate = (d: Date) => {
+  return d instanceof Date && !isNaN(d.getTime());
+};
+
+const months: { [k: string]: number } = {
+  ["A"]: 1,
+  ["B"]: 2,
+  ["C"]: 3,
+  ["D"]: 4,
+  ["E"]: 5,
+  ["H"]: 6,
+  ["L"]: 7,
+  ["M"]: 8,
+  ["P"]: 9,
+  ["R"]: 10,
+  ["S"]: 11,
+  ["T"]: 12
+};
+
+/**
+ * Parse birth date from fiscal code
+ */
+export function toBirthDate(fiscalCode: FiscalCode): Option<Date> {
+  return tryCatch(() => {
+    const tempDay = parseInt(fiscalCode.substring(9, 11), 10);
+    if (isNaN(tempDay)) {
+      throw new Error();
+    }
+
+    const monthIndx = fiscalCode.charAt(8);
+    if (!(monthIndx in months)) {
+      throw new Error();
+    }
+
+    const month = months[fiscalCode.charAt(8)];
+
+    // female subjects have 40 added to their birth day
+    const day = tempDay - 40 > 0 ? tempDay - 40 : tempDay;
+
+    const tempYear = parseInt(fiscalCode.substring(6, 8), 10);
+    if (isNaN(tempYear)) {
+      throw new Error();
+    }
+
+    // to avoid the century date collision (01 could mean 1901 or 2001)
+    // we assume that if the birth date is grater than a century, the date
+    // refers to the new century
+    const year =
+      tempYear +
+      (new Date().getFullYear() - (1900 + tempYear) >= 100 ? 2000 : 1900);
+
+    // months are 0-index
+    const birthDay = new Date(year, month - 1, day);
+    if (!isValidDate(birthDay)) {
+      throw new Error();
+    }
+
+    return birthDay;
+  });
+}