crewAIInc/crewAI · error · TypeError

{type(source).__name__} does not support async read

Error message

{type(source).__name__} does not support async read

What it means

Raised by File.aread() when the wrapped _file_source supports sync read but not async: only FilePath, FileBytes, AsyncFileStream, and FileUrl implement aread(). A FileStream (sync binary stream) does not, so calling aread() on a File backed by one raises TypeError naming the source class. This is an API-surface mismatch: use read() for sync sources.

Source

Thrown at lib/crewai-files/src/crewai_files/core/types.py:212

    @property
    def content_type(self) -> str:
        """Get the content type from the source."""
        return self._file_source.content_type

    def read(self) -> bytes:
        """Read the file content as bytes."""
        return self._file_source.read()  # type: ignore[union-attr]

    async def aread(self) -> bytes:
        """Async read the file content as bytes.

        Raises:
            TypeError: If the underlying source doesn't support async read.
        """
        source = self._file_source
        if isinstance(source, (FilePath, FileBytes, AsyncFileStream, FileUrl)):
            return await source.aread()
        raise TypeError(f"{type(source).__name__} does not support async read")

    def read_text(self, encoding: str = "utf-8") -> str:
        """Read the file content as string."""
        return self.read().decode(encoding)

    @property
    def _unpack_key(self) -> str:
        """Get the key to use when unpacking (filename stem)."""
        filename = self._file_source.filename
        if filename:
            return Path(filename).stem
        return "file"

    def keys(self) -> list[str]:
        """Return keys for dict unpacking."""
        return [self._unpack_key]

    def __getitem__(self, key: str) -> Self:

View on GitHub (pinned to 754d7323be)

Solutions

1. Use read() (optionally via asyncio.to_thread / run_in_executor) for sync FileStream-backed Files.
2. If you control construction, load the content eagerly into FileBytes so aread() works.
3. Branch on the source type or catch TypeError and fall back to the thread-offloaded sync read.

Example fix

# before
data = await file.aread()  # TypeError: FileStream does not support async read

# after
import asyncio
data = await asyncio.to_thread(file.read)

from crewai_files.core.sources import FilePath, FileBytes, AsyncFileStream, FileUrl

def supports_aread(source) -> bool:
    return isinstance(source, (FilePath, FileBytes, AsyncFileStream, FileUrl))

import asyncio
from crewai_files.core.sources import FilePath, FileBytes, AsyncFileStream, FileUrl

async def read_any(file) -> bytes:
    src = file._file_source
    if isinstance(src, (FilePath, FileBytes, AsyncFileStream, FileUrl)):
        return await file.aread()
    return await asyncio.to_thread(file.read)

try:
    data = await file.aread()
except TypeError as e:
    if "does not support async read" in str(e):
        data = await asyncio.to_thread(file.read)

When it happens

Trigger: File(source=FileStream(stream=open('x.pdf','rb'))).aread(); likewise FileBytes? no — FileBytes supports aread; concretely any File whose source is a FileStream, then calling .aread() (e.g. inside an async handler).

Common situations: Codebases that uniformly call aread() in async endpoints but receive sync FileStream objects from callers/tests; adapters that wrap sync uploads as FileStream and later get awaited.

Related errors

• Expected an async readable object with async read() method
• Cannot convert {type(v).__name__} to file source
• Expected a binary file-like object with read() and seek()
• Path traversal not allowed: {self.path}
• Symlink escapes allowed directory: {self.path}

AI-assisted analysis of crewAIInc/crewAI@754d7323be (2026-08-15). Data as JSON: /api/errors/5fddf6bb9e39efe7. Report an issue: GitHub.