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59 lines
1.6 KiB
59 lines
1.6 KiB
5 months ago
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import base64
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import io
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from typing import Optional
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from urllib.parse import unquote
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from fsspec import AbstractFileSystem
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class DataFileSystem(AbstractFileSystem):
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"""A handy decoder for data-URLs
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Example
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-------
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>>> with fsspec.open("data:,Hello%2C%20World%21") as f:
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... print(f.read())
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b"Hello, World!"
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See https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/Data_URLs
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"""
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protocol = "data"
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def __init__(self, **kwargs):
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"""No parameters for this filesystem"""
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super().__init__(**kwargs)
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def cat_file(self, path, start=None, end=None, **kwargs):
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pref, data = path.split(",", 1)
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if pref.endswith("base64"):
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return base64.b64decode(data)[start:end]
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return unquote(data).encode()[start:end]
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def info(self, path, **kwargs):
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pref, name = path.split(",", 1)
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data = self.cat_file(path)
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mime = pref.split(":", 1)[1].split(";", 1)[0]
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return {"name": name, "size": len(data), "type": "file", "mimetype": mime}
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def _open(
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self,
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path,
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mode="rb",
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block_size=None,
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autocommit=True,
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cache_options=None,
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**kwargs,
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):
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if "r" not in mode:
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raise ValueError("Read only filesystem")
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return io.BytesIO(self.cat_file(path))
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@staticmethod
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def encode(data: bytes, mime: Optional[str] = None):
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"""Format the given data into data-URL syntax
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This version always base64 encodes, even when the data is ascii/url-safe.
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"""
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return f"data:{mime or ''};base64,{base64.b64encode(data).decode()}"
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