feat: convertStreamToString (#46)

CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- `convertStreamToString` function
 - pm2 metrics
 
 ## 2.5.0 - 2023-05-17

package.json

@@ -39,6 +39,7 @@
     "fastify": "^4.10.2",
     "prettier": "2.6.2",
     "rimraf": "^3.0.2",
+    "sinon": "^15.1.0",
     "typescript": "^4.7.4",
     "vite": "^3.0.4",
     "vitest": "^0.21.0"

src/fastify.ts

@@ -1,4 +1,5 @@
 import type { FastifyError, FastifyRequest, FastifyReply } from 'fastify';
+import stream from 'stream';
 
 type FastifyErrorWithStatusCode = FastifyError & {
   statusCode: NonNullable<FastifyError['statusCode']>;
@@ -253,3 +254,29 @@ export const handleInvalidXpubIndex = (reply: FastifyReply) => {
 export const handleInvalidXpubRole = (reply: FastifyReply) => {
   return handle400Custom(reply, 'Missing, out of range or malformed role.');
 };
+
+export const convertStreamToString = async (payloadStream: unknown) => {
+  const payload = await new Promise<string>((resolve, reject) => {
+    if (payloadStream instanceof stream.Readable) {
+      // receive error response from the payload stream
+      const chunks: Buffer[] = [];
+
+      payloadStream.on('data', chunk => {
+        chunks.push(chunk);
+      });
+      payloadStream.on('error', error => {
+        reject(error);
+      });
+      payloadStream.on('end', () => {
+        resolve(Buffer.concat(chunks).toString());
+      });
+    } else if (typeof payloadStream === 'string') {
+      // If payloadStream is just a string then return it
+      resolve(payloadStream);
+    } else {
+      reject(new Error(`Invalid payload type: ${typeof payload}`));
+    }
+  });
+
+  return payload;
+};

test/tests/cardano.test.ts

@@ -1,5 +1,7 @@
 import { expect, describe, test } from 'vitest';
 import * as cardanoUtils from '../../src/cardano';
+import stream from 'stream';
+import * as fastifyUtils from '../../src/fastify';
 import * as fixtures from '../fixtures/cardano';
 
 describe('cardano utils', () => {
@@ -16,3 +18,25 @@ describe('cardano utils', () => {
     });
   });
 });
+
+describe('fastify utils', () => {
+  test('returns a string from a readable stream', async () => {
+    const payload = 'hello world';
+    const payloadStream = new stream.Readable({
+      read() {
+        this.push(payload);
+        this.push(null);
+      },
+    });
+    const result = await fastifyUtils.convertStreamToString(payloadStream);
+
+    expect(result).toBe(payload);
+  });
+
+  test('returns the original string payload', async () => {
+    const payload = 'hello world';
+    const result = await fastifyUtils.convertStreamToString(payload);
+
+    expect(result).toBe(payload);
+  });
+});