OrchardCMS/OrchardCore · error · InvalidOperationException

Cannot create a stream for a directory.

Error message

Cannot create a stream for a directory.

What it means

EmbeddedDirectoryInfo represents a directory entry in the embedded file provider; directories cannot be opened as streams. CreateReadStream always throws InvalidOperationException to enforce this contract, matching IFileInfo behavior for directories.

Solutions

1. Check IFileInfo.IsDirectory before calling CreateReadStream and skip or return a 404/handle directories.
2. Verify the embedded resource path points to an actual file; print available resources via the assembly manifest.
3. If the path may be a folder, append the expected file name or resolve the specific resource.
4. Wrap in try/catch InvalidOperationException only as a last resort; prefer the IsDirectory guard.

Example fix

// before
using var stream = fileInfo.CreateReadStream();
// after
if (fileInfo.IsDirectory || !fileInfo.Exists)
{
    return Results.NotFound();
}
using var stream = fileInfo.CreateReadStream();

if (fileInfo is { Exists: true, IsDirectory: false }) { /* safe to open stream */ }

bool IsReadableFile(IFileInfo f) => f.Exists && !f.IsDirectory && f.Length >= 0;

try { using var s = fileInfo.CreateReadStream(); }
catch (InvalidOperationException) { return Results.NotFound(); }

When it happens

Trigger: Calling CreateReadStream() on an IFileInfo returned by the embedded/manifest embedded file provider when the requested path resolves to a directory (e.g. path 'MyFolder' without extension that exists as a folder in an embedded assembly), rather than a file.

Common situations: Enumerating embedded resources and blindly calling CreateReadStream on every entry, building a file-serving endpoint where the URL maps to a folder, or a path typo dropping the file name so the provider resolves the directory.

Related errors

• Error retrieving file info for
• Error creating directory
• Error deleting file
• Cannot copy file ' ' to ' '.
• Cannot get file stream of the file

AI-assisted analysis of OrchardCMS/OrchardCore@4306c0717f (2026-09-13). Data as JSON: /api/errors/e0e994bef9512602. Report an issue: GitHub.

Appendix: source

Thrown at src/OrchardCore/OrchardCore.Abstractions/Modules/FileProviders/EmbeddedDirectoryInfo.cs:54

    /// <summary>
    /// The time when the directory was last written to.
    /// </summary>
    public DateTimeOffset LastModified => DateTimeOffset.MinValue;

    /// <summary>
    /// Always true.
    /// </summary>
    public bool IsDirectory => true;

    /// <summary>
    /// Always throws an exception because read streams are not support on directories.
    /// </summary>
    /// <exception cref="InvalidOperationException">Always thrown.</exception>
    /// <returns>Never returns.</returns>
    public Stream CreateReadStream()
    {
        throw new InvalidOperationException("Cannot create a stream for a directory.");
    }
}

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