# Failed to decode gzip

**URL:** <https://forum.codecrafters.io/t/failed-to-decode-gzip/13640>\
**Category:** Challenges\
**Tags:** challenge:http-server\
**Created:** [July 17, 2025, 7:06pm UTC](https://forum.codecrafters.io/t/failed-to-decode-gzip/13640 "2025-07-17T19:06:18Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![ungsophy](https://yyz1.discourse-cdn.com/flex003/user_avatar/forum.codecrafters.io/ungsophy/32/16600_2.png) [@ungsophy](https://forum.codecrafters.io/u/ungsophy)\
**Post date:** [July 17, 2025, 7:06pm UTC](https://forum.codecrafters.io/t/failed-to-decode-gzip/13640/1 "2025-07-17T19:06:18Z")

</div>

I’m stuck on Stage #CR8 “Gzip compression”

Here are my logs:

```auto
remote: [tester::#CR8] Running tests for Stage #CR8 (HTTP Compression - Gzip compression)
remote: [tester::#CR8] Running program
remote: [tester::#CR8] $ ./your_program.sh
remote: [tester::#CR8] Connected to localhost port 4221
remote: [tester::#CR8] $ curl -v http://localhost:4221/echo/apple -H "Accept-Encoding: gzip"
remote: [your_program] new connection from [::1]:50046
remote: [tester::#CR8] > GET /echo/apple HTTP/1.1
remote: [tester::#CR8] > Host: localhost:4221
remote: [tester::#CR8] > Accept-Encoding: gzip
remote: [tester::#CR8] >
remote: [tester::#CR8] Sent bytes: "GET /echo/apple HTTP/1.1\r\nHost: localhost:4221\r\nAccept-Encoding: gzip\r\n\r\n"
remote: [tester::#CR8] Received bytes: "HTTP/1.1 200 OK\r\nContent-Encoding: gzip\r\nContent-Length: 21\r\n\r\n\x1f\x8b\b\x00\x00\x00\x00\x00\x00\xffJ,(\xc8I\x05\x00\x00\x00\xff\xff"
remote: [tester::#CR8] < HTTP/1.1 200 OK
remote: [tester::#CR8] < Content-Encoding: gzip
remote: [tester::#CR8] < Content-Length: 21
remote: [tester::#CR8] <
remote: [tester::#CR8] < <Binary Content>
remote: [tester::#CR8] <
remote: [tester::#CR8] Received response with 200 status code
remote: [tester::#CR8] ✓ Content-Encoding header is present
remote: [tester::#CR8] ✓ Content-Length header is present
remote: [tester::#CR8] Failed to decode gzip: Failed to decompress data: unexpected EOF
remote: [tester::#CR8] Test failed
remote: [tester::#CR8] Terminating program
remote: [tester::#CR8] Program terminated successfully

```

And here’s a snippet of my code:

```golang
		str := strings.Replace(req.Path, "/echo/", "", 1)

		buf := bytes.NewBuffer(nil)
		zw := gzip.NewWriter(buf)
		defer zw.Close()

		_, writeErr := zw.Write([]byte(str))
		if writeErr != nil {
			panic(writeErr)
		}
		zw.Flush()

		respBuf := bytes.NewBufferString("HTTP/1.1 200 OK\r\n")
		respBuf.WriteString("Content-Encoding: gzip\r\n")
		respBuf.WriteString(fmt.Sprintf("Content-Length: %d\r\n", buf.Len()))
		respBuf.WriteString("\r\n")
		respBuf.Write(buf.Bytes())

		conn.Write(respBuf.Bytes())

```

When I use Postman to hit the endpoint, Postman is able to unzip the body and displays the content. However, when I do `curl http://localhost:4221/echo/banana -H "Accept-Encoding: gzip" | gunzip -c`, I get `gunzip: (stdin): unexpected end of file`.

Did I miss anything?

Thank you!

---

<div class="post-metadata">

**Author:** ![andy1li](https://yyz1.discourse-cdn.com/flex003/user_avatar/forum.codecrafters.io/andy1li/32/10_2.png) [@andy1li](https://forum.codecrafters.io/u/andy1li)\
**Post date:** [July 18, 2025, 9:13am UTC](https://forum.codecrafters.io/t/failed-to-decode-gzip/13640/4 "2025-07-18T09:13:22Z")

</div>

Hey @ungsophy, looks like your gzipped data is incomplete: the footer is missing.

This happens due to `defer zw.Close()`. You’ll need to explicitly call zw.Close() **before** reading from the buffer.

 ![image](https://canada1.discourse-cdn.com/flex003/uploads/codecrafters/original/2X/a/a92b30456725ee23847ce4d243e2c653dd6a0f47.png)

Let me know if you’d like further clarification!

---

<div class="post-metadata">

**Author:** ![ungsophy](https://yyz1.discourse-cdn.com/flex003/user_avatar/forum.codecrafters.io/ungsophy/32/16600_2.png) [@ungsophy](https://forum.codecrafters.io/u/ungsophy)\
**Post date:** [July 18, 2025, 9:50am UTC](https://forum.codecrafters.io/t/failed-to-decode-gzip/13640/6 "2025-07-18T09:50:05Z")

</div>

Thank you so much @andy1li. Calling `zw.Close()` before reading from the buffer fixes the issue.

---

<div class="post-metadata">

**Author:** ![system](https://canada1.discourse-cdn.com/flex003/uploads/codecrafters/original/3X/7/0/700657133935c15703e22c7c8870394f6e6dc27d.svg) [@system](https://forum.codecrafters.io/u/system)\
**Post date:** [July 23, 2025, 9:50am UTC](https://forum.codecrafters.io/t/failed-to-decode-gzip/13640/7 "2025-07-23T09:50:41Z")

</div>

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