babalae/better-genshin-impact · error · InvalidDataException

图片大小超过 {MaxDownloadBytes / 1024 / 1024} MB 限制。

Error message

图片大小超过 {MaxDownloadBytes / 1024 / 1024} MB 限制。

What it means

An InvalidDataException thrown by DownloadAndSaveAsync right after the response headers are read, when the declared Content-Length header exceeds MaxDownloadBytes. This is the early, cheap size guard that fails before streaming any body bytes. It protects against oversized banner images and memory/disk abuse.

Source

Thrown at BetterGenshinImpact/Service/BannerImageService.cs:95

        using var timeoutCancellationTokenSource = new CancellationTokenSource(DownloadTimeout);
        using var linkedCancellationTokenSource = CancellationTokenSource.CreateLinkedTokenSource(
            cancellationToken,
            timeoutCancellationTokenSource.Token);
        var linkedCancellationToken = linkedCancellationTokenSource.Token;

        try
        {
            // 下载图片
            using var response = await _httpClient.GetAsync(
                uri,
                HttpCompletionOption.ResponseHeadersRead,
                linkedCancellationToken).ConfigureAwait(false);
            response.EnsureSuccessStatusCode();

            if (response.Content.Headers.ContentLength > MaxDownloadBytes)
            {
                throw new InvalidDataException($"图片大小超过 {MaxDownloadBytes / 1024 / 1024} MB 限制。");
            }

            await using (var responseStream = await response.Content
                             .ReadAsStreamAsync(linkedCancellationToken)
                             .ConfigureAwait(false))
            await using (var fileStream = new FileStream(
                             tempPath,
                             FileMode.CreateNew,
                             FileAccess.Write,
                             FileShare.None,
                             81920,
                             FileOptions.Asynchronous | FileOptions.SequentialScan))
            {
                var buffer = new byte[81920];
                long totalBytes = 0;
                int read;
                while ((read = await responseStream
                           .ReadAsync(buffer.AsMemory(), linkedCancellationToken)

View on GitHub (pinned to a7cb36712d)

Solutions

1. Use a smaller, web-optimized image (resize/compress the source to stay under the limit).
2. Pick a different URL whose Content-Length is within MaxDownloadBytes.
3. If the limit is genuinely too low for your use case, raise MaxDownloadBytes (review the trade-off first).
4. Catch InvalidDataException and tell the user the image is too large.

Example fix

null

// Issue a HEAD request first to read Content-Length without downloading the body
using var head = await _httpClient.SendAsync(new HttpRequestMessage(HttpMethod.Head, uri), ct);
if (head.Content.Headers.ContentLength > MaxDownloadBytes) { /* reject early */ }

null

try { await _banner.DownloadAndSaveAsync(url, ct); }
catch (InvalidDataException ex) { Toast.Warning(ex.Message); }

When it happens

Trigger: The server returns a response whose Content-Length header is greater than MaxDownloadBytes (the configured banner size limit). Triggered for legitimately large images or a wrong/abusive URL.

Common situations: Pointing the banner URL at a high-resolution original (tens of MB); an image host serving an uncompressed source; a misconfigured URL returning a large file; MaxDownloadBytes set lower than typical banner sizes.

Related errors

• 请输入有效的 HTTP/HTTPS 图片地址。
• 下载的图片内容为空。
• 下载内容不是有效的图片。
• 没有可用的上一步识别位置，无法执行隐式坐标操作
• milliseconds 不能小于 0

AI-assisted analysis of babalae/better-genshin-impact@a7cb36712d (2026-08-13). Data as JSON: /api/errors/5250d7719e7c6ace. Report an issue: GitHub.