import os
from django.db import models
from django.utils.html import format_html
from ..utils import AttributeDict
from .base import library
from .linkcolumn import BaseLinkColumn
[docs]
@library.register
class FileColumn(BaseLinkColumn):
"""
Attempts to render `.FieldFile` (or other storage backend `.File`) as a
hyperlink.
When the file is accessible via a URL, the file is rendered as a
hyperlink. The `.basename` is used as the text, wrapped in a span::
<a href="/media/path/to/receipt.pdf" title="path/to/receipt.pdf">receipt.pdf</a>
When unable to determine the URL, a ``span`` is used instead::
<span title="path/to/receipt.pdf" class>receipt.pdf</span>
`.Column.attrs` keys ``a`` and ``span`` can be used to add additional attributes.
Arguments:
verify_exists (bool): attempt to determine if the file exists
If *verify_exists*, the HTML class ``exists`` or ``missing`` is
added to the element to indicate the integrity of the storage.
text (str or callable): Either static text, or a callable. If set, this
will be used to render the text inside the link instead of
the file's ``basename`` (default)
"""
def __init__(self, verify_exists=True, **kwargs):
self.verify_exists = verify_exists
super().__init__(**kwargs)
def get_url(self, value, record):
storage = getattr(value, "storage", None)
if not storage:
return None
return storage.url(value.name)
def text_value(self, record, value):
if self.text is None:
return os.path.basename(value.name)
return super().text_value(record, value)
[docs]
def render(self, record, value):
attrs = AttributeDict(self.attrs.get("span", {}))
classes = [c for c in attrs.get("class", "").split(" ") if c]
exists = None
storage = getattr(value, "storage", None)
if storage:
# we'll assume value is a `django.db.models.fields.files.FieldFile`
if self.verify_exists:
exists = storage.exists(value.name)
else:
if self.verify_exists and hasattr(value, "name"):
# ignore negatives, perhaps the file has a name but it doesn't
# represent a local path... better to stay neutral than give a
# false negative.
exists = os.path.exists(value.name) or exists
if exists is not None:
classes.append("exists" if exists else "missing")
attrs["title"] = value.name
attrs["class"] = " ".join(classes)
return format_html(
"<span {attrs}>{text}</span>",
attrs=attrs.as_html(),
text=self.text_value(record, value),
)
[docs]
@classmethod
def from_field(cls, field, **kwargs):
if isinstance(field, models.FileField):
return cls(**kwargs)