olzh2102 / basic-nodejs

Ciphering CLI Tool

CLI tool that will encode and decode a text by 3 substitution ciphers:

• Caesar cipher
• Atbash cipher
• ROT-8 as variation of ROT-13

CLI tool accepts 3 options (short alias and full name):

1. -c, --config: config for ciphers Config is a string followed by pattern {XY(-)}n, where:

• X is a cipher mark:
  • C is for Caesar cipher (with shift 1)
  • A is for Atbash cipher
  • R is for ROT-8 cipher
• Y is flag of encoding or decoding (mandatory for Caesar cipher and ROT-8 cipher and should not be passed Atbash cipher)
  • 1 is for encoding
  • 0 is for decoding

2. -i, --input: a path to input file
3. -o, --output: a path to output file

For example, config "C1-C1-R0-A" means "encode by Caesar cipher => encode by Caesar cipher => decode by ROT-8 => use Atbash"

Details:

1. Application doesn't use any 3rd party libraries
2. Config option is required and validated. In case of invalid confing human-friendly error is printed in stderr and the process should exit with non-zero status code.
3. If any option is duplicated (i.e. bash $ node my_ciphering_cli -c C1-C1-A-R0 -c C0) then human-friendly error is printed in stderr and the process should exit with non-zero status code.
4. If the input file option is missed - stdin serves as input source.
5. If the output file option is missed - stdout serves as output destination.
6. If the input and/or output file is given but doesn't exist or you can't access it (e.g. because of permissions or it's a directory) - human-friendly error is printed in stderr and the process should exit with non-zero status code.
7. If passed params are fine the output (file or stdout) contains transformed content of input (file or stdin).
8. For encoding/decoding only the English alphabet is used, all other characters kept untouched.

Usage example:

$ node my_ciphering_cli -c "C1-C1-R0-A" -i "./input.txt" -o "./output.txt"

input.txt This is secret. Message about "_" symbol!

output.txt Myxn xn nbdobm. Tbnnfzb ferlm "_" nhteru!

$ node my_ciphering_cli -c "C1-C0-A-R1-R0-A-R0-R0-C1-A" -i "./input.txt" -o "./output.txt"

input.txt This is secret. Message about "_" symbol!

output.txt Vhgw gw wkmxkv. Ckwwoik onauv "_" wqcnad!

$ node my_ciphering_cli -c "A-A-A-R1-R0-R0-R0-C1-C1-A" -i "./input.txt" -o "./output.txt"

input.txt This is secret. Message about "_" symbol!

output.txt Hvwg wg gsqfsh. Asggous opcih "_" gmapcz!

$ node my_ciphering_cli -c "C1-R1-C0-C0-A-R0-R1-R1-A-C1" -i "./input.txt" -o "./output.txt"

input.txt This is secret. Message about "_" symbol!

output.txt This is secret. Message about "_" symbol!

Testing Commands To Run:

cd my_ciphering_cli

To run tests:

npm test

To run tests with coverage:

npx jest --coverage