Reading Files as Blobs

Daft can read files as raw bytes into DataFrames using [daft.read_blob()][daft.io.read_blob], similar to DuckDB's read_blob function. This is useful for loading non-tabular files such as images, audio, PDFs, or any other binary data into a DataFrame, with one row per file.

Basic Usage

Read files matching a path or glob pattern, where each file becomes a row:

=== "Local Files"

```python
import daft

df = daft.read_blob("/path/to/files/*.jpeg")
df.show()
```

=== "Remote Files (S3)"

```python
import daft
from daft.io import S3Config, IOConfig

io_config = IOConfig(s3=S3Config(region_name="us-west-2", anonymous=True))
df = daft.read_blob("s3://my-bucket/images/*.jpeg", io_config=io_config)
df.show()
```

=== "Remote Files (GCS)"

```python
import daft
from daft.io import GCSConfig, IOConfig

io_config = IOConfig(gcs=GCSConfig(anonymous=True))
df = daft.read_blob("gs://my-bucket/images/*.jpeg", io_config=io_config)
df.show()
```

Output Schema

The read_blob function returns a DataFrame with the following columns:

Glob Patterns

read_blob supports the same wildcards as other Daft readers:

# All .png files in a directory
df = daft.read_blob("/data/*.png")

# Recursive search
df = daft.read_blob("/data/**/*.png")

# Multiple paths
df = daft.read_blob(["/data/a.bin", "/data/b.bin"])

Error Handling

By default, a download error for any file raises immediately. Set on_error="null" to log the error and fall back to a null content value instead:

df = daft.read_blob("/data/*.bin", on_error="null")

Common Use Cases

Decoding Images

Read image files and decode them for downstream processing:

import daft
from daft.functions import decode_image

df = daft.read_blob("s3://my-bucket/images/*.jpeg", io_config=io_config)
df = df.with_column("image", decode_image(df["content"]))

Detecting File Types

Inspect magic bytes to determine the MIME type of each file:

import daft
from daft.functions import guess_mime_type

df = daft.read_blob("/data/**/*")
df = df.with_column("mime", guess_mime_type(df["content"]))

Relationship to Other APIs

read_blob is a convenience API composed of [daft.from_glob_path()][daft.from_glob_path] (which lists files with their path and size) and the [download][daft.functions.download] expression (which fetches file contents as bytes). Use those building blocks directly if you need more control, such as downloading only a filtered subset of files.