Flask-HashFS¶

Flask extension for HashFS, a content-addressable file management system.

What is HashFS?¶

HashFS is a content-addressable file management system. What does that mean? Simply, that HashFS manages a directory where files are saved based on the file’s hash.

Typical use cases for this kind of system are ones where:

Files are written once and never change (e.g. image storage).
It’s desirable to have no duplicate files (e.g. user uploads).
File metadata is stored elsewhere (e.g. in a database).

What is Flask-HashFS?¶

Flask-HashFS is a Flask extension that integrates HashFS into the Flask ecosystem.

Links¶

Project: https://github.com/dgilland/flask-hashfs
Documentation: http://flask-hashfs.readthedocs.org
PyPI: https://pypi.python.org/pypi/flask-hashfs/
TravisCI: https://travis-ci.org/dgilland/flask-hashfs

Quickstart¶

Install using pip:

pip install Flask-HashFS

Initialization¶

from flask import Flask
from flask_hashfs import FlaskHashFS

app = Flask(__name__)
fs = FlaskHashFS()

Configure Flask-HashFS to store files in /var/www/data/uploads and give them a route prefix at /uploads.

app.config.update({
    'HASHFS_HOST': None,
    'HASHFS_PATH_PREFIX': '/uploads',
    'HASHFS_ROOT_FOLDER': '/var/www/data/uploads',
    'HASHFS_DEPTH': 4,
    'HASHFS_WIDTH': 1,
    'HASHFS_ALGORITHM': 'sha256'
})

fs.init_app(app)

Usage¶

Use Flask-HashFS to manage files using HashFS.

with app.app_context():
    # Store readable objects or file paths
    address = fs.put(io_obj, extension='.jpg')


    # Get a file's hash address
    assert fs.get(address.id) == address
    assert fs.get(address.relpath) == address
    assert fs.get(address.abspath) == address
    assert fs.get('invalid') is None


    # Get a BufferedReader handler
    fileio = fs.open(address.id)

    # Or using the full path...
    fileio = fs.open(address.abspath)

    # Or using a path relative to fs.root
    fileio = fs.open(address.relpath)


    # Delete a file by address ID or path
    fs.delete(address.id)
    fs.delete(address.abspath)
    fs.delete(address.relpath)

For direct access to the HashFS instance, use the client attribute.

fs.client
assert isinstance(fs.client, flask_hashfs.HashFS)

Generate URLs for HashFS content.

with app.test_request_context():
    fs.url_for('relative/file/path')

For more details, please see the full documentation at http://flask-hashfs.readthedocs.org and http://hashfs.readthedocs.org.

Guide¶

Installation¶

flask-hashfs requires Python >= 2.7 or >= 3.3.

To install from PyPI:

pip install flask-hashfs

API Reference¶

The flask-hashfs module.

Flask extension for HashFS, a content-addressable file management system.

class flask_hashfs.FlaskHashFS(app=None)[source]¶

Flask extension for storing files on file system using hashfs.

Configuration values:

`HASHFS_HOST`	Host where files are served. Set if files are served from a different host than application. Defaults to `None` which uses `flask.request.host_url`.
`HASHFS_PATH_PREFIX`	URL path prefix where files are served. Defaults to `''`.
`HASHFS_ROOT_FOLDER`	Root folder to save files. Must be set.
`HASHFS_DEPTH`	Number of nested folders to use when saving files. Defaults to `4`.
`HASHFS_WIDTH`	Width of each nested subfolder. Defaults to `1`.
`HASHFS_ALGORITHM`	Hashing algorithm to use when computing content hash. Defaults to `'sha256'`.

client¶: Underlying HashFS instance.

url_for(relpath, external=True)[source]¶

Return URL for path relative to HASHFS_ROOT_FOLDER.

Parameters:	relpath (str) – Relative path to `HASHFS_ROOT_FOLDER` where file is located. external (bool) – Whether to include host in URL.
Returns:	URL for path.
Return type:	str

Note

This function builds the URL with the assumption that relpath is a valid file path. It does not check for file existence.

class flask_hashfs.HashAddress[source]¶

File address containing file’s path on disk and it’s content hash ID.

id¶: str – Hash ID (hexdigest) of file contents.

relpath¶: str – Relative path location to HashFS.root.

abspath¶: str – Absoluate path location of file on disk.

is_duplicate¶: boolean, optional – Whether the hash address created was a duplicate of a previously existing file. Can only be True after a put operation. Defaults to False.

Project Info¶

License¶

The MIT License (MIT)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Versioning¶

This project follows Semantic Versioning with the following caveats:

Only the public API (i.e. the objects imported into the flask-hashfs module) will maintain backwards compatibility between MINOR version bumps.
Objects within any other parts of the library are not guaranteed to not break between MINOR version bumps.

With that in mind, it is recommended to only use or import objects from the main module, flask-hashfs.

Changelog¶

v0.3.0 (2015-06-03)¶

Replace manual proxy access of HashFS methods with single __getattr__ method.

v0.2.0 (2015-06-02)¶

Pin hashfs dependency to >=0.3.0. (breaking change)
Rename config key HASHFS_LENGTH to HASHFS_WIDTH to be in alignment with hashfs>=0.3.0. (breaking change)

v0.1.0 (2015-06-02)¶

First release.
Add FlaskHashFS.put.
Add FlaskHashFS.get.
Add FlaskHashFS.open.
Add FlaskHashFS.delete.
Add FlaskHashFS.url_for.

Authors¶

Lead¶

Derrick Gilland, dgilland@gmail.com, dgilland@github

Contributors¶

None

Contributing¶

Contributions are welcome, and they are greatly appreciated! Every little bit helps, and credit will always be given.

You can contribute in many ways:

Types of Contributions¶

Report Bugs¶

Report bugs at https://github.com/dgilland/flask-hashfs/issues.

If you are reporting a bug, please include:

Your operating system name and version.
Any details about your local setup that might be helpful in troubleshooting.
Detailed steps to reproduce the bug.

Fix Bugs¶

Look through the GitHub issues for bugs. Anything tagged with “bug” is open to whoever wants to implement it.

Implement Features¶

Look through the GitHub issues for features. Anything tagged with “enhancement” or “help wanted” is open to whoever wants to implement it.

Write Documentation¶

Flask-HashFS could always use more documentation, whether as part of the official Flask-HashFS docs, in docstrings, or even on the web in blog posts, articles, and such.

Submit Feedback¶

The best way to send feedback is to file an issue at https://github.com/dgilland/flask-hashfs/issues.

If you are proposing a feature:

Explain in detail how it would work.
Keep the scope as narrow as possible, to make it easier to implement.
Remember that this is a volunteer-driven project, and that contributions are welcome :)

Get Started!¶

Ready to contribute? Here’s how to set up flask-hashfs for local development.

Fork the flask-hashfs repo on GitHub.

Clone your fork locally:

$ git clone git@github.com:your_name_here/flask-hashfs.git

Install your local copy into a virtualenv. Assuming you have virtualenv installed, this is how you set up your fork for local development:
```
$ cd flask-hashfs
$ make build
```
Create a branch for local development:
```
$ git checkout -b name-of-your-bugfix-or-feature
```
Now you can make your changes locally.
When you’re done making changes, check that your changes pass linting (PEP8 and pylint) and the tests, including testing other Python versions with tox:
```
$ make test-full
```
Add yourself to AUTHORS.rst.

Commit your changes and push your branch to GitHub:

$ git add .
$ git commit -m "Your detailed description of your changes."
$ git push origin name-of-your-bugfix-or-feature

Submit a pull request through the GitHub website.

Pull Request Guidelines¶

Before you submit a pull request, check that it meets these guidelines:

The pull request should include tests.
If the pull request adds functionality, the docs should be updated. Put your new functionality into a function with a docstring, and add the feature to the README.rst.
The pull request should work for Python 2.7, 3.3, and 3.4. Check https://travis-ci.org/dgilland/flask-hashfs/pull_requests and make sure that the tests pass for all supported Python versions.

Project CLI¶

Some useful CLI commands when working on the project are below. NOTE: All commands are run from the root of the project and require make.

make build¶

Run the clean and install commands.

make build

make install¶

Install Python dependencies into virtualenv located at env/.

make install

make clean¶

Remove build/test related temporary files like env/, .tox, .coverage, and __pycache__.

make clean

make test¶

Run unittests under the virtualenv’s default Python version. Does not test all support Python versions. To test all supported versions, see make test-full.

make test

make test-full¶

Run unittest and linting for all supported Python versions. NOTE: This will fail if you do not have all Python versions installed on your system. If you are on an Ubuntu based system, the Dead Snakes PPA is a good resource for easily installing multiple Python versions. If for whatever reason you’re unable to have all Python versions on your development machine, note that Travis-CI will run full integration tests on all pull requests.

make test-full

make lint¶

Run make pylint and make pep8 commands.

make lint

make pylint¶

Run pylint compliance check on code base.

make pylint

make pep8¶

Run PEP8 compliance check on code base.

make pep8

make docs¶

Build documentation to docs/_build/.

make docs