core.modules.file

Module Contents

Classes

DownloadUrlBone

This bone is used to inject a freshly signed download url into a FileSkel.

FileLeafSkel

Default file leaf skeleton.

FileNodeSkel

Default file node skeleton.

File

Tree module prototype.

Functions

importBlobFromViur2(dlKey, fileName)

thumbnailer(fileSkel, existingFiles, params)

cloudfunction_thumbnailer(fileSkel, existingFiles, params)

External Thumbnailer for images.

startCheckForUnreferencedBlobs()

Start searching for blob locks that have been recently freed

doCheckForUnreferencedBlobs([cursor])

startCleanupDeletedFiles()

Increase deletion counter on each blob currently not referenced and delete

doCleanupDeletedFiles([cursor])

start_delete_pending_files()

Start deletion of pending FileSkels that are older than 7 days.

Attributes

VALID_FILENAME_REGEX

GOOGLE_STORAGE_CLIENT

GOOGLE_STORAGE_BUCKET

FilePath

core.modules.file.VALID_FILENAME_REGEX
core.modules.file.GOOGLE_STORAGE_CLIENT
core.modules.file.GOOGLE_STORAGE_BUCKET
core.modules.file.FilePath
core.modules.file.importBlobFromViur2(dlKey, fileName)
core.modules.file.thumbnailer(fileSkel, existingFiles, params)
core.modules.file.cloudfunction_thumbnailer(fileSkel, existingFiles, params)

External Thumbnailer for images.

The corresponding cloudfunction can be found here . https://github.com/viur-framework/viur-cloudfunctions/tree/main/thumbnailer

You can use it like so: main.py:

from viur.core.modules.file import cloudfunction_thumbnailer

conf.file_thumbnailer_url = "https://xxxxx.cloudfunctions.net/imagerenderer"
conf.file_derivations = {"thumbnail": cloudfunction_thumbnailer}

conf.derives_pdf = {
    "thumbnail": [{"width": 1920,"sites":"1,2"}]
}

skeletons/xxx.py: .. code-block:: python

test = FileBone(derive=conf.derives_pdf)

class core.modules.file.DownloadUrlBone(*, compute=None, defaultValue=None, descr='', getEmptyValueFunc=None, indexed=True, isEmptyFunc=None, languages=None, multiple=False, params=None, readOnly=None, required=False, searchable=False, unique=None, vfunc=None, visible=True)

Bases: viur.core.bones.BaseBone

This bone is used to inject a freshly signed download url into a FileSkel.

Initializes a new Bone.

Parameters:
  • compute (Compute) –

  • defaultValue (Any) –

  • descr (str) –

  • getEmptyValueFunc (callable) –

  • indexed (bool) –

  • isEmptyFunc (callable) –

  • languages (None | list[str]) –

  • multiple (bool | MultipleConstraints) –

  • params (dict) –

  • readOnly (bool) –

  • required (bool | list[str] | tuple[str]) –

  • searchable (bool) –

  • unique (None | UniqueValue) –

  • vfunc (callable) –

  • visible (bool) –

unserialize(skel, name)

Deserialize bone data from the datastore and populate the bone with the deserialized values.

This function is the inverse of the serialize function. It converts data from the datastore into a format that can be used by the bones in the skeleton.

Parameters:
  • skel – A SkeletonInstance object containing the values to be deserialized.

  • name – The property name of the bone in its Skeleton (not the description).

Returns:

True if deserialization is successful, False otherwise.

class core.modules.file.FileLeafSkel(*args, **kwargs)

Bases: viur.core.prototypes.tree.TreeSkel

Default file leaf skeleton.

kindName = 'file'
size
dlkey
name
mimetype
weak
pending
width
height
downloadUrl
derived
pendingparententry
preProcessBlobLocks(locks)

Ensure that our dlkey is locked even if we don’t have a filebone here

classmethod refresh(skelValues)

Refresh the bones current content.

This function causes a refresh of all relational bones and their associated information.

class core.modules.file.FileNodeSkel(*args, **kwargs)

Bases: viur.core.prototypes.tree.TreeSkel

Default file node skeleton.

kindName = 'file_rootNode'
name
rootNode
class core.modules.file.File(moduleName, modulePath, *args, **kwargs)

Bases: viur.core.prototypes.tree.Tree

Tree module prototype.

It is used for hierarchical structures, either as a tree with nodes and leafs, or as a hierarchy with nodes only.

PENDING_POSTFIX = ' (pending)'
DOWNLOAD_URL_PREFIX = '/file/download/'
MAX_FILENAME_LEN = 256
leafSkelCls
nodeSkelCls
handler = 'tree.simple.file'
adminInfo
roles
default_order = 'name'
static is_valid_filename(filename)

Verifies a valid filename.

The filename should be valid on Linux, Mac OS and Windows. It should not be longer than MAX_FILENAME_LEN chars.

Rule set: https://stackoverflow.com/a/31976060/3749896 Regex test: https://regex101.com/r/iBYpoC/1

Parameters:

filename (str) –

Return type:

bool

static hmac_sign(data)
Parameters:

data (viur.core.decorators.t.Any) –

Return type:

str

static hmac_verify(data, signature)
Parameters:
  • data (viur.core.decorators.t.Any) –

  • signature (str) –

Return type:

bool

static create_download_url(dlkey, filename, derived=False, expires=datetime.timedelta(hours=1), download_filename=None)

Utility function that creates a signed download-url for the given folder/filename combination

Parameters:
  • folder – The GCS-Folder (= the download-key) for that file

  • filename (str) – The name of the file. Either the original filename or the name of a derived file.

  • derived (bool) – True, if it points to a derived file, False if it points to the original uploaded file

  • expires (viur.core.decorators.t.Optional[datetime.timedelta | int]) – None if the file is supposed to be public (which causes it to be cached on the google ede caches), otherwise a datetime.timedelta of how long that link should be valid

  • download_filename (viur.core.decorators.t.Optional[str]) – If set, browser is enforced to download this blob with the given alternate filename

  • dlkey (str) –

Returns:

The signed download-url relative to the current domain (eg /download/…)

Return type:

str

static parse_download_url(url)

Parses a file download URL in the format /file/download/xxxx?sig=yyyy into its FilePath.

If the URL cannot be parsed, the function returns None.

Parameters:

url – The file download URL to be parsed.

Returns:

A FilePath on success, None otherwise.

Return type:

viur.core.decorators.t.Optional[FilePath]

static create_src_set(file, expires=datetime.timedelta(hours=1), width=None, height=None)

Generates a string suitable for use as the srcset tag in html. This functionality provides the browser with a list of images in different sizes and allows it to choose the smallest file that will fill it’s viewport without upscaling.

Parameters:
  • file (viur.core.decorators.t.Union[viur.core.skeleton.SkeletonInstance, dict, str]) – The file skeleton (or if multiple=True a single value from it) to generate the srcset.

  • expires (viur.core.decorators.t.Optional[datetime.timedelta | int]) – None if the file is supposed to be public (which causes it to be cached on the google edecaches), otherwise it’s lifetime in seconds

  • width (viur.core.decorators.t.Optional[int]) – A list of widths that should be included in the srcset. If a given width is not available, it will be skipped.

  • height (viur.core.decorators.t.Optional[int]) – A list of heights that should be included in the srcset. If a given height is not available, it will be skipped.

Returns:

The srctag generated or an empty string if a invalid file object was supplied

Return type:

str

write(filename, content, mimetype='text/plain', width=None, height=None)

Write a file from any buffer into the file module.

Parameters:
  • filename (str) – Filename to be written.

  • content (viur.core.decorators.t.Any) – The file content to be written, as bytes-like object.

  • mimetype (str) – The file’s mimetype.

  • width (int) – Optional width information for the file.

  • height (int) – Optional height information for the file.

Returns:

Returns the key of the file object written. This can be associated e.g. with a FileBone.

Return type:

viur.core.db.Key

read(key=None, path=None)

Read a file from the Cloud Storage.

If a key and a path are provided, the key is preferred. This means that the entry in the db is searched first and if this is not found, the path is used.

Parameters:
  • key (viur.core.db.Key | int | str | None) – Key of the LeafSkel that contains the “dlkey” and the “name”.

  • path (str | None) – The path of the file in the Cloud Storage Bucket.

Returns:

Returns the file as a io.BytesIO buffer and the content-type

Return type:

tuple[io.BytesIO, str]

deleteRecursive(parentKey)

Recursively processes a delete request.

This will delete all entries which are children of nodeKey, except key nodeKey.

Parameters:

parentKey – URL-safe key of the node which children should be deleted.

getUploadURL(fileName, mimeType, size=None, node=None, authData=None, authSig=None)
Parameters:
  • fileName (str) –

  • mimeType (str) –

  • size (viur.core.decorators.t.Optional[int]) –

  • node (viur.core.decorators.t.Optional[str | viur.core.db.Key]) –

  • authData (viur.core.decorators.t.Optional[str]) –

  • authSig (viur.core.decorators.t.Optional[str]) –

download(blobKey, fileName='', download=False, sig='', *args, **kwargs)

Download a file. :param blobKey: The unique blob key of the file. :param fileName: Optional filename to provide in the header. :param download: Set header to attachment retrival, set explictly to “1” if download is wanted.

Parameters:
  • blobKey (str) –

  • fileName (str) –

  • download (bool) –

  • sig (str) –

add(skelType, node=None, *args, **kwargs)

Add a new entry with the given parent node, and render the entry, eventually with error notes on incorrect data. Data is taken by any other arguments in kwargs.

The function performs several access control checks on the requested entity before it is added.

See also

canAdd(), onAdd(), , onAdded()

Parameters:
  • skelType (viur.core.prototypes.tree.SkelType) – Defines the type of the new entry and may either be “node” or “leaf”.

  • node (viur.core.db.Key | int | str | None) – URL-safe key of the parent.

Returns:

The rendered, added object of the entry, eventually with error hints.

Raises:

viur.core.errors.NotAcceptable, when no valid skelType was provided.

Raises:

viur.core.errors.NotFound, when no valid node was found.

Raises:

viur.core.errors.Unauthorized, if the current user does not have the required permissions.

Raises:

viur.core.errors.PreconditionFailed, if the skey could not be verified.

onEdit(skelType, skel)

Hook function that is called before editing an entry.

It can be overridden for a module-specific behavior.

Parameters:
  • skelType (viur.core.prototypes.tree.SkelType) – Defines the type of the node that shall be edited.

  • skel (viur.core.skeleton.SkeletonInstance) – The Skeleton that is going to be edited.

See also

edit(), onEdited()

mark_for_deletion(dlkey)

Adds a marker to the datastore that the file specified as dlkey can be deleted.

Once the mark has been set, the data store is checked four times (default: every 4 hours) if the file is in use somewhere. If it is still in use, the mark goes away, otherwise the mark and the file are removed from the datastore. These delayed checks are necessary due to database inconsistency.

Parameters:

dlkey (str) – Unique download-key of the file that shall be marked for deletion.

Return type:

None

core.modules.file.startCheckForUnreferencedBlobs()

Start searching for blob locks that have been recently freed

core.modules.file.doCheckForUnreferencedBlobs(cursor=None)
core.modules.file.startCleanupDeletedFiles()

Increase deletion counter on each blob currently not referenced and delete it if that counter reaches maxIterCount

core.modules.file.doCleanupDeletedFiles(cursor=None)
core.modules.file.start_delete_pending_files()

Start deletion of pending FileSkels that are older than 7 days.