fix: return appropriate FC error on validation failure (#157)

src/middleware/error.ts

@@ -13,7 +13,7 @@ export const errorToStatusCode = (
 ) => {
   if (error instanceof ValidationError) {
     res.status(400).json({
-      error: error.message,
+      error: error.fiatConnectError,
       data: error.validationError,
     })
   } else if (

src/routes/accounts.ts

@@ -8,6 +8,7 @@ import {
 } from '../types'
 import { siweAuthMiddleware } from '../middleware/authenticate'
 import {
+  FiatConnectError,
   deleteFiatAccountRequestParamsSchema,
   postFiatAccountRequestBodySchema,
 } from '@fiatconnect/fiatconnect-types'
@@ -27,7 +28,11 @@ export function accountsRouter({
     _res: express.Response,
     next: express.NextFunction,
   ) => {
-    validateZodSchema(req.body, postFiatAccountRequestBodySchema)
+    validateZodSchema(
+      req.body,
+      postFiatAccountRequestBodySchema,
+      FiatConnectError.InvalidSchema,
+    )
     next()
   }
 

src/routes/kyc.ts

@@ -2,6 +2,7 @@ import express from 'express'
 import { asyncRoute } from './async-route'
 import { validateZodSchema } from '../schema/'
 import {
+  FiatConnectError,
   KycRequestParams,
   KycSchemas,
   NotImplementedError,
@@ -55,7 +56,11 @@ export function kycRouter({
         _res: express.Response,
       ) => {
         // Delegate to type-specific handlers after validation provides type guards
-        validateZodSchema(req.body, kycSchemaToZodSchema[req.params.kycSchema])
+        validateZodSchema(
+          req.body,
+          kycSchemaToZodSchema[req.params.kycSchema],
+          FiatConnectError.InvalidParameters,
+        )
 
         throw new NotImplementedError('POST /kyc/:kycSchema not implemented')
       },

src/schema/index.ts

@@ -1,4 +1,4 @@
-import { ValidationError } from '../types'
+import { FiatConnectError, ValidationError } from '../types'
 
 import { z, ZodError } from 'zod'
 import { ZodType } from 'zod/lib/types'
@@ -12,6 +12,7 @@ import { ZodType } from 'zod/lib/types'
 export function validateZodSchema<T extends ZodType>(
   obj: any,
   schema: T,
+  fiatConnectError: FiatConnectError = FiatConnectError.InvalidParameters,
 ): z.infer<T> {
   try {
     return schema.parse(obj)
@@ -20,6 +21,7 @@ export function validateZodSchema<T extends ZodType>(
       throw new ValidationError(
         `Error validating object with schema ${schema.description}`,
         err.issues,
+        fiatConnectError,
       )
     }
     throw err

src/types.ts

@@ -68,9 +68,15 @@ export enum Network {
 
 export class ValidationError extends Error {
   validationError: any
-  constructor(msg: string, validationError: any) {
+  fiatConnectError: FiatConnectError
+  constructor(
+    msg: string,
+    validationError: any,
+    fiatConnectError: FiatConnectError,
+  ) {
     super(msg)
     this.validationError = validationError
+    this.fiatConnectError = fiatConnectError
   }
 }