diff --git a/README.md b/README.md index c68f88f..2f2416d 100644 --- a/README.md +++ b/README.md @@ -4,8 +4,6 @@ - Login with your username found on your name badge and set the initial password for your account: https://git.aspp.school/user/login - You'll have to type that password many many times this week: choose wisely! - We will use the [exercise](exercise.md) in the repo for the rest of the lecture -- find a partner to do pair-programming for this lecture by finding someone with the same tarot card as you -- before starting, make yourself acquainted with the meanining and the power of the tarot cards: carefully read [this booklet](https://aspp.school/wiki/_media/tarot-runic.pdf) ## A cautionary quote @@ -15,33 +13,9 @@ — Lars Wirzenius (Linux kernel developer) -## Warm-Up -- how to start a repo from scratch? - - `git init` local method - - on an online forge (GitHub, GitLab, …): `git clone` -- how to revert mistakes? - - before commit: - - `git restore ` [discard changes in the working directory] __changes files__ - - `git restore --staged ` [unstage changes ➔ opposite of `git add `, does not modify the working directory] - - after commit: - - `git revert ` [creates a new commit, modifies the working directory] - - `git reset ` [only reset the HEAD pointer, does not modify the working directory] __rewrites history__ ➔ can not be used if you have already pushed to some remote - - `git reset --hard ` [reset HEAD and modify working directory] __rewrites history__ and __changes files__ ➔ can not be used if you have already pushed to some remote -- how to *move* the whole working directory to a specific point in history? - - `git checkout ` ➔ `DETACHED HEAD` problem, __changes__ __files__ - - interaction with branches: `git branch ` + `git switch ` -- how to copy a file from a different branch: - - `git checkout ` ➔ the file is staged automatically - - `git restore --source= `, `git push `, `git fetch `, `git merge ` -- GitHub: forks, branches and PRs: important ➔ explain fork vs. clone!!! -- strategies for keeping your fork up-to-date: your `main`, origin's and upstream's `main`, short-lived and long-lived topic branches -- a more thorough and detailed explanation can be found on the [SciPy Contributor's Guide](https://docs.scipy.org/doc/scipy/dev/gitwash/gitwash.html). This guide can be adapted to your own needs, see [gitwash](https://github.com/matthew-brett/gitwash). -- make it clear that GitHub and GitLab are just options (git≠GitHub) +… will follow after the lecture … ## Scenarios 1. [lone scientist](scenarios/scenario1.png) working alone in the cellar without Internet (local git) diff --git a/auth.py b/auth.py index 5408393..aed1472 100644 --- a/auth.py +++ b/auth.py @@ -1,88 +1,48 @@ -import getpass import json -import pathlib -import random -import string import sys +from getpass import getpass -# name of the file where we store the pw database -PWDB_FLNAME = pathlib.Path('pwdb.json') - -# list of valid characters for salt (only ASCII letters + digits + punctuation) -CHARS = string.ascii_letters + string.digits + string.punctuation - -# length of salt -SALT_LENGTH = 5 +pwdb_path = 'pwdb.json' def get_credentials(): - # get input from terminal username = input('Enter your username: ') - # get password using the appropriate module, so that typed characters are not - # echoed to the terminal - password = getpass.getpass('Enter your password: ') + password = getpass('Enter your password: ') return (username, password) -def authenticate(username, pass_text, pwdb): - # get the salt from the database - salt = pwdb[username][1] - # calculate hash and compare with stored hash - return pwhash(pass_text, salt) == pwdb[username][0] +def authenticate(username, password, pwdb): + return password == pwdb[username] def add_user(username, pwdb): - # do not try to add a username twice - if username in pwdb: - raise Exception(f'Username already exists [{username}]!') - else: - password = getpass.getpass(f'Enter password for {username}: ') - salt = get_salt() - pwdb[username] = (pwhash(password,salt), salt) + pwdb[username] = input(f'Enter password for {username}: ') return pwdb def read_pwdb(pwdb_path): - if not pwdb_path.exists(): + try: + pwdb_file = open(pwdb_path, 'rt') + pwdb = json.load(pwdb_file) + except Exception: pwdb = {} - else: - with open(pwdb_path, 'rt') as pwdb_file: - pwdb = json.load(pwdb_file) return pwdb def write_pwdb(pwdb, pwdb_path): - with open(pwdb_path, 'wt') as pwdb_file: - json.dump(pwdb, pwdb_file) + pwdb_file = open(pwdb_path, 'wt') + json.dump(pwdb, pwdb_file) -def pwhash(pass_text, salt): - # simple additive hash -> very insecure! - hash_ = 0 - full_pass_text = pass_text + salt - for idx, char in enumerate(full_pass_text): - # use idx as a multiplier, so that shuffling the characters returns a - # different hash - hash_ += (idx+1)*ord(char) - return hash_ -def get_salt(): - salt_chars = random.choices(CHARS, k=SALT_LENGTH) - return ''.join(salt_chars) - -def main(pwdb_path): - # load the password database from file +if __name__ == "__main__": + pwdb_path = 'pwdb.json' pwdb = read_pwdb(pwdb_path) - # if we are passed an argument, we want to add a new user if len(sys.argv) > 1: pwdb = add_user(sys.argv[1], pwdb) write_pwdb(pwdb, pwdb_path) - return - - # ask for credentials - username, password = get_credentials() - if username not in pwdb or not authenticate(username, password, pwdb): - print('Wrong username or password!') else: - print('Successfully authenticated!') - - return - -if __name__ == '__main__': - main(PWDB_FLNAME) + username, password = get_credentials() + if username not in pwdb: + print('Wrong username!') + else: + if authenticate(username, password, pwdb): + print('Successfully authenticated!') + else: + print('Wrong password!') diff --git a/cheatsheet.md b/cheatsheet.md deleted file mode 100644 index 813aa43..0000000 --- a/cheatsheet.md +++ /dev/null @@ -1,176 +0,0 @@ -# Git cheatsheet - -## Creating a repository -```bash -git init -``` -Creates new git repository in current directory. - -```bash -git clone () -``` -Clones the repository at the specified url. If no path is specified, the repository will -be cloned into a directory with the same name as the remote repository. - - -## Branches -```bash -git branch -``` -Lists all branches in the repository. - -```bash -git branch -``` -Creates a new branch with the given name. - -```bash -git switch -``` -Switches to the specified branch. - -```bash -git merge -``` -Merges the specified branch into the current branch. - - -## Making changes -```bash -git status -``` -Shows the status of the repository. This includes the current branch and files that have been modified. - -```bash -git diff (--staged) -``` -Shows the changes that have been made to the files in the repository. Use `--staged` to see changes that have been added to the staging area. - -```bash -git add -``` -Adds the specified file to the staging area. - -```bash -git add . -``` -Adds all files in the current directory to the staging area. - -```bash -git reset () -``` -Removes the specified file from the staging area. If no file is specified, all files are removed. - -```bash -git commit (-m "") -``` -Commits all changes in the staging area to the current branch. If the `-m` flag is omitted, a text editor will open to write a commit message. - -```bash -git commit --amend -``` -Adds the staged changes to the last commit. This can be used for fixing typos in the commit message. - - -## Undoing changes -```bash -git restore -``` -Restores the specified file to the state of the last commit. This undoes uncommitted changes. - -```bash -git revert -``` -Creates a new commit that undoes the changes of the specified commit. Use `git log` to find the hash of the commit. - -```bash -git reset --hard -``` -Resets the current branch to the specified commit. DANGER: This will remove all changes after the specified commit. Prefer `git revert`. - - -## Looking at the history -```bash -git log (--oneline) -``` -Shows all past commits on the current branch. Use `--oneline` to show a more compact view. - -```bash -git show -``` -Shows the changes of the specified commit. Use `git log` to find the has of the commit. - - -## Remote repositories -```bash -git remote add -``` -Adds a new remote repository with the specified name (e.g. `origin` or `upstream`) and url. Origin is automatically created when cloning a repository. - -```bash -git push -``` -Pushes the specified branch to the remote repository. - -```bash -git fetch -``` -Fetches changes from the remote repository. - -```bash -git pull -``` -Fetches changes from the remote repository and merges them into the current branch. - - -## Typical workflow -```bash -# 1. Fork the repository on GitHub / git.aspp.school - -# 2. Clone the repository -git clone -git remote add upstream - -# 3. Create a new branch -git branch -git switch - -# 4. Make changes to the code - -# 5. Add and commit changes -git add . -git commit -m "" - -# 6. Push changes to your fork -git push origin - -# 7. Create a pull request on GitHub / git.aspp.school - -# 8. Wait for the pull request to be reviewed and merged - -# 9. Pull changes from the remote repository -git switch main -git pull upstream main - -# 10. Delete the topic branch -git branch -d -``` - -Whenever the remote repository is updated (i.e. when a pull request is merged), you need to pull the changes into your local repository. -```bash -git switch main -git pull upstream main - -# If you have an active topic branch, you need to rebase it on top of the updated main branch -git switch -git rebase main -``` - - -## Getting help -```bash -git help -``` -Shows the manual page for the specified command (`add`, `commit`, `push`, etc.). - -Official Git documentation: https://git-scm.com/docs