flametree 0.1.2

Opening a file tree

Here is how you open different kinds of file systems:

from flametree import file_tree

# Open a directory from the disk's file system:
root = file_tree("my_folder/")

# Open a zip archive on the disk:
root = file_tree("my_archive.zip")

# Connect to a file-like object (file handle, StringIO...) of a zip:
root = file_tree(file_like_object)

# Create a virtual 'in-memory' zip file:
root = file_tree("@memory")

# Open some data string representing a zip to read
root = file_tree(some_big_zip_data_string)

In the two first examples, if my_folder or my_archive.zip do not exist, they will be automatically created. If they do exist, it is possible to completely overwrite them with the option replace=True.

Exploring a file tree:

Once you have created the root element with one of the methods above, you can display the whole file tree with root._tree_view():

>>> print (root._tree_view())
texts/
  jokes/
    short_story1.txt
    short_story2.txt
    short_story3.txt
  todo_list.txt
figures/
  figure1.png
  figure2.png
Readme.md

The attributes of a directory like root are its files and subdirectories. For instance to access

short_story1.txt and read its content, you would write:

 print (root.texts.jokes.short_story1_png.read())

or even simpler:

.. code:: python

   root.texts.jokes.short_story1_png.print_content()

This syntactic sugar is particularly useful to explore a file tree in editors with auto-completion like IPython Notebooks. Notice that non-alphanumerical characters such as the . before png, are replaced by _ to form a valid attribute name.

Alternatively, you can access files and directories using dictionary calls:

root["texts"]["jokes"]["short_story.png"]

To iterate through the subdirectories of a directory, use the _dirs attribute:

for subdirectory in root._dirs:
    print (subdirectory._name) # Will print 'texts', 'figures'

To iterate through the files of a directory, use the _files attribute:

for f in root.figures._files:
    print (f._name) # Will print 'figure1.png', 'figure1.png'

Finally, use _all_files to iterate through all files in all directories and subdirectories. The snippet below prints the content of all .txt files in the file tree:

for f in root._all_files:
    if f._name.endswith(".txt"):
        f.print_content()

Creating files and folders

To create a new subdirectory use _dir:

root._dir("data") # create a 'data' folder at the root.

To create a new file use _file:

root._file("poem.txt") # create a 'poem.txt' file at the root.

To write content in a file, use .write:

root.poem_txt.write("Two roads diverged in a yellow wood.")

Writing to a file will append use mode a (append) by default. To overwrite the file set the write mode to "w":

root.poem_txt.write("O Captain! My Captain!", mode="w")

File and directory creation commands can be chained. Let us create folders data and day1, and write file data/day1/values.csv, all in a single line:

root._dir("data")._dir("day_1")._file("values.csv").write("1, 15, 25, 14")

Keep in mind that ._dir and ._file overwrite their target by default, which means that if you write:

root._dir("data")._file("values1.csv").write("1, 15, 25, 14")
root._dir("data")._file("values2.csv").write("1, 15, 25, 14")

The directory data will only contain values2.csv, because the second line’s _dir("data") erases the data directory and starts a new one. To avoid this, either write:

root._dir("data")._file("values1.csv").write("1, 15, 25, 14")
root.data._file("values2.csv").write("1, 15, 25, 14")

Or use replace=False in _dir:

root._dir("data")._file("values1.csv").write("1, 15, 25, 14")
root._dir("data", replace=False)._file("values2.csv").write("1, 15, 25, 14")

Other operations

You can move, copy, and delete a file with .move(folder), .copy(folder), .delete(), and a directory with ._move(folder), ._copy(folder), ._delete().

root.data.values1_csv.delete() # delete file 'values1.csv'
root.data._delete() # delete directory 'data'
# Move folder `plots` from `root/figures` to `other_root/figures`
root.figures.plots._move(other_root.figures)
# Move file `fig.png` from `root/figures` to `other_root/figures`
root.figures.fig_png.move(other_root.figures)

Special rules for ZIP archives

It it not currently possible to modify/delete a file that is already zipped into an archive (because zips are not really made for that, it would be doable but would certainly be a hack).

When creating files and folders in a zip with Flametree, the changes in the actual zip will only be performed by closing the root with root._close() (after which the root can’t be used any more). If it is an in-memory zip, root._close() returns the value of the zip content as a string (Python 2) or bytes (Python 3).

Here are a few examples:

root = file_tree("archive.zip")
root._file("new_file.txt").write("Hi there !")
root._close()

# Similar to the previous, using `with`:
with file_tree("archive.zip") as root:
    root._file("new_file.txt").write("Hi there !")

root = file_tree("@memory")
root._file("new_file.txt").write("Hi there !")
binary_data = root._close()

Using file writers from other libraries

Some libraries have file-generating methods which expect a file name or a file object to write too. You can also feed Flametree files to these functions. for instance here is how to use Weasyprint to create a PDF pdfs/report.pdf

import weasyprint
from flametree import file_tree
root = file_tree(".") # or 'archive.zip' to write in an archive.
html = weasyprint.HTML(string="<b>Hello</b> world!", base_url='.')
html.write_pdf(root._dir("pdfs")._file("test.pdf"))

And here is how you would save a Matplotlib figure in a zip archive:

import matplotlib.pyplot as plt
from flametree import file_tree
fig, ax = plt.subplots(1)
ax.plot([1, 2, 3], [3, 1, 2])
root = file_tree("archive.zip")
fig.savefig(root._dir("plots")._file("figure.png"), format="png")

That’s all folks !