testmempool accept more validation & switch to JSON array format

backend/src/api/bitcoin/bitcoin.routes.ts

@@ -751,13 +751,13 @@ class BitcoinRoutes {
   }
 
   private async $testTransactions(req: Request, res: Response) {
-    res.setHeader('content-type', 'text/plain');
     try {
       const rawTxs = Common.getTransactionsFromRequest(req);
       const maxfeerate = parseFloat(req.query.maxfeerate as string);
       const result = await bitcoinApi.$testMempoolAccept(rawTxs, maxfeerate);
       res.send(result);
     } catch (e: any) {
+      res.setHeader('content-type', 'text/plain');
       res.status(400).send(e.message && e.code ? 'testmempoolaccept RPC error: ' + JSON.stringify({ code: e.code, message: e.message })
         : (e.message || 'Error'));
     }

backend/src/api/common.ts

@@ -946,12 +946,16 @@ export class Common {
     return this.validateTransactionHex(matches[1].toLowerCase());
   }
 
-  static getTransactionsFromRequest(req: Request): string[] {
-    if (typeof req.body !== 'string') {
-      throw Object.assign(new Error('Non-string request body'), { code: -1 });
+  static getTransactionsFromRequest(req: Request, limit: number = 25): string[] {
+    if (!Array.isArray(req.body) || req.body.some(hex => typeof hex !== 'string')) {
+      throw Object.assign(new Error('Invalid request body (should be an array of hexadecimal strings)'), { code: -1 });
     }
 
-    const txs = req.body.split(',');
+    if (limit && req.body.length > limit) {
+      throw Object.assign(new Error('Exceeded maximum of 25 transactions'), { code: -1 });
+    }
+
+    const txs = req.body;
 
     return txs.map(rawTx => {
       // Support both upper and lower case hex

backend/src/index.ts

@@ -131,6 +131,7 @@ class Server {
       })
       .use(express.urlencoded({ extended: true }))
       .use(express.text({ type: ['text/plain', 'application/base64'] }))
+      .use(express.json())
       ;
 
     if (config.DATABASE.ENABLED && config.FIAT_PRICE.ENABLED) {