egametang/ET · error

http request fail: {link.Substring(0,link.IndexOf('?'))}\n{e

Error message

http request fail: {link.Substring(0,link.IndexOf('?'))}\n{e}

What it means

Thrown by CoroutineHelper.HttpGet when UnityWebRequest.SendWebRequest() raises (network error, HTTP failure, timeout). The catch wraps the original exception. WARNING: the catch message itself calls link.Substring(0, link.IndexOf('?')) — if the link contains NO '?', IndexOf returns -1 and Substring(0,-1) throws ArgumentOutOfRangeException, masking the real network error with a string-processing crash. If the link has no query string, the error handler itself fails.

Source

Thrown at Packages/cn.etetet.loader/Scripts/Loader/Client/CoroutineHelper.cs:27

        // 有了这个方法，就可以直接await Unity的AsyncOperation了
        public static async ETTask GetAwaiter(this AsyncOperation asyncOperation)
        {
            ETTask task = ETTask.Create(true);
            asyncOperation.completed += _ => { task.SetResult(); };
            await task;
        }
        
        public static async ETTask<string> HttpGet(string link)
        {
            try
            {
                UnityWebRequest req = UnityWebRequest.Get(link);
                await req.SendWebRequest();
                return req.downloadHandler.text;
            }
            catch (Exception e)
            {
                throw new Exception($"http request fail: {link.Substring(0,link.IndexOf('?'))}\n{e}");
            }
        }
    }
}

View on GitHub (pinned to 5cab01f7a8)

Solutions

1. Fix the latent bug: guard the IndexOf result before Substring (use link.IndexOf('?') >= 0 ? link.Substring(0, link.IndexOf('?')) : link).
2. Validate the URL scheme/host before calling HttpGet and surface a clear error if unreachable.
3. Wrap the HttpGet call in a retry/timeout policy so transient network failures don't crash client startup.

Example fix

// before
throw new Exception($"http request fail: {link.Substring(0,link.IndexOf('?'))}\n{e}");

// after — safe truncation
int q = link.IndexOf('?');
string safeUrl = q >= 0 ? link.Substring(0, q) : link;
throw new Exception($"http request fail: {safeUrl}\n{e}");

string text;
try { text = await CoroutineHelper.HttpGet(url); }
catch (Exception e) { Log.Error($"HttpGet failed for {url}: {e.Message}"); /* fallback */ return; }

When it happens

Trigger: HttpGet is awaited and the request fails (no network, server down, DNS failure, HTTP error code). Additionally, if the link passed to HttpGet has no '?' character, the error-formatting line crashes inside the catch block with a different exception than intended.

Common situations: Backend/auth server unreachable during client startup; a URL built without a query string passed to HttpGet; a redirect or certificate error from UnityWebRequest; WebGL build hitting CORS.

Related errors

• 命令行格式错误! {error}
• http request fail: {link.Substring(0,link.IndexOf('?'))}\n{e
• 请先在cmd中运行: netsh http add urlacl url=http://*:你的address中的端口/
• RouterManager dynamic http bind failed after 10 attempts.
• btenv not found key: {key} {typeof(T).FullName}

AI-assisted analysis of egametang/ET@5cab01f7a8 (2026-08-13). Data as JSON: /api/errors/8c61fd84e9829e50. Report an issue: GitHub.