square/okhttp · error · IOException

Unexpected code

Error message

Unexpected code 

What it means

Thrown in the PostFile recipe: `if (!response.isSuccessful()) throw new IOException("Unexpected code " + response)`. It POSTs the local file README.md as text/x-markdown to GitHub's markdown/raw endpoint. If the file is missing OkHttp fails earlier (different error). This guard fires when the upload reached GitHub but the server answered non-2xx.

Solutions

1. Check response.code() and response.body().string() to read GitHub's error message.
2. Confirm the markdown/raw endpoint is still supported; use the markdown REST API (/markdown) if not.
3. Add a token header if you are being rate limited.
4. Verify the file exists and is readable before building the RequestBody.

Example fix

// before
if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);

// after
if (!response.isSuccessful()) {
  throw new IOException("markdown/raw HTTP " + response.code() + ": " + response.body().string());
}

// Verify the file exists before building the request; branch on status after.
File file = new File("README.md");
if (!file.isFile()) throw new FileNotFoundException(file.toString());
...
if (!response.isSuccessful()) { /* inspect code + body */ return; }

static boolean uploadable(Response r) { return r.isSuccessful(); }

try {
  // call
} catch (FileNotFoundException e) {
  // local file missing (fails before the status check)
} catch (IOException e) {
  // includes 'Unexpected code' (HTTP status) and transport errors
}

When it happens

Trigger: POST to https://api.github.com/markdown/raw with a markdown body returns 404 (endpoint moved/removed), 403 (rate limit), 400 (malformed markdown body), or 5xx. GitHub has changed/removed raw markdown rendering endpoints historically.

Common situations: Running from a directory with no README.md (but that fails before this line); GitHub deprecating the markdown/raw endpoint; rate limit; network/proxy rewriting the POST.

Related errors

• Unexpected code
• Unexpected code
• Unexpected code
• Unexpected code
• Unexpected code

AI-assisted analysis of square/okhttp@91a8b34c6f (2026-08-10). Data as JSON: /api/errors/e1fb5608da17ab9b. Report an issue: GitHub.

Appendix: source

Thrown at samples/guide/src/main/java/okhttp3/recipes/PostFile.java:41

import okhttp3.RequestBody;
import okhttp3.Response;

public final class PostFile {
  public static final MediaType MEDIA_TYPE_MARKDOWN
      = MediaType.get("text/x-markdown; charset=utf-8");

  private final OkHttpClient client = new OkHttpClient();

  public void run() throws Exception {
    File file = new File("README.md");

    Request request = new Request.Builder()
        .url("https://api.github.com/markdown/raw")
        .post(RequestBody.create(file, MEDIA_TYPE_MARKDOWN))
        .build();

    try (Response response = client.newCall(request).execute()) {
      if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);

      System.out.println(response.body().string());
    }
  }

  public static void main(String... args) throws Exception {
    new PostFile().run();
  }
}

View on GitHub (pinned to 91a8b34c6f)