Failed to decode gzip

Challenges
1

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

Here are my logs:

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:

		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!

4

Hey @armadillo-944, 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
image1606×1314 235 KB

Let me know if you’d like further clarification!

1 Like
6

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

1 Like