Programming Project F. Directories, Databases, and Zip Files

Background

Folders, or directories, are the universal way of organizing files on general-purpose computers. Databases are the preferred method of storing data for subsequent retrieval. Files are often compressed to save space, especially when transferring them from one place to another. In this project you will use process directories and store their contents in Zip files and a relational database table. We will use the sqlite3 module that comes with Python for the SQL database portion. (Note: we will do no joins or complicated queries; we’ll just process a single table.)

Requirements

This project is divided into 3 parts, and you will write a separate, short Python script for each part.

 

Part 1

In this part you will write a script named readfiles.py that takes a directory name as a single command-line argument. The directory, Stuff contains over 1,000 files of various types occupying 56mb of disk space in itself and many subdirectories. Download the zip file Stuff.zip from the Canvas Files directory for this project and unzip it into a directory tree onto your system. The execution

 

$ python3 readfiles.py Stuff filesdb created

 

discovers all files in the associated directory subtree. It stores the information in a Sqlite3 database file named filesdb, in a table named files containing 3 fields: (ext, path, fname), which represent the file extension (.cpp, .docx, py, etc.), the full path name of the directory (only, not including the file name) the file resides in, and the name of the file (e.g., foo.cpp). Here is a sample of some of the entries in the files table:

 

('doc', '/Users/chuck/UVU/3270/Assignment8/Stuff', 'OOPSLA-Decimals.doc') 

('doc', '/Users/chuck/UVU/3270/Assignment8/Stuff', 'OOPSLA-Python.doc') 

('ppt', '/Users/chuck/UVU/3270/Assignment8/Stuff', 'XP.ppt')

('ppt', '/Users/chuck/UVU/3270/Assignment8/Stuff/ACCU', 'ACCU-Templates.ppt') 

('ppt', '/Users/chuck/UVU/3270/Assignment8/Stuff/ACCU', 'CodeQuality.ppt') 

('cpp', '/Users/chuck/UVU/3270/Assignment8/Stuff/ACCU', 'Counted.cpp')

...

 

If a file does not have an extension, use None for that field—Sqlite will then store that as a NULL in the database table. Output the result of the query “select * from files” to a text file named files-part1.txt. You will submit this file along with your source code.

 

Part 2

In this part you will write a script named gatherfiles.py that receives the name of your database file and one or more file extensions, for example

 

$ python3 gatherfiles.py filesdb cpp py

 

This script opens the database file and then does the following for each file extension appearing on the command-line:

 

1. Retrieves the file name information for all files with that extension, and forms the full pathname of that file

2. Adds the contents of that file by adding the file to a zip file using the full pathname as its name, so that the directory structure is preserved. The name of the zip file is the name of the extension followed by “.zip”, for example, cpp.zip.

3. Prints to standard output the number of files added to the zip file.

 

After executing gatherfiles.py with the command-line arguments shown above, the files cpp.zip and py.zip would be created in the current directory, and the following would be written to the console:

 

658 cpp files gathered

19 py files gathered

 

You should be able to unzip the output zip file and verify that the original directory structure is reproduced.

 

Part 3

The third script, extractfiles.py, extract from a zip file all files whose basenames i.e., (file names without any path prefix) match a regular expression, for example

 

$ python3 extractfiles.py cpp.zip ^[Cs].*

81 files extracted

 

The command above will extract all files from cpp.zip that begin with ‘C’ or ‘s’. Note that zipfile.extract uses full path information, placing extracted files in their associated directories, so you may have to execute this script in or extract the files to a directory other than the one where the original directory you’re extracting exists.

Implementation Notes

In Part 1, ignore file names that start with ‘.’ or ‘_’.

 

Submit your three scripts, output text file from Part 1, zipped output directory from Part 2, and zipped output directory from the extractfiles execution shown above together in a zip file (so you will have two zip files inside the outer zip file that you submit).

 

Don't make assumptions about what operating system your program is running on, or what the path separators (slashes) are. Use os.path.join to make your code platform-independent.

 

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