CSC 321.01, Class 06: An introduction to Rails
- Notes and news
- Upcoming work
- Good things to do
- Version control systems
- Making better use of GitHub
- Other rails issues
- Mentor session Sunday and Tuesday night
- How long did Hartl 1 take?
- Observation: When things go right, it’s reasonable. But when things go wrong, it’s really hard to figure out why.
- The Friday PSA will happen in CSC 322
- Don’t forget to add yourself to the homework channel!
- Hartl 2 due Sunday at 10:30pm.
- This should take about the same amount of time as the first Hartl assignment.
- Hartl 3 due Tuesday at 10:30pm.
- The response part of this assignment will not be available until Sunday (approximately)
Good things to do (Academic/Artistic)
- Rebecca Wingo: How to Harvest History. Friday Feb. 2, 4pm, Burling
- Workshop: Saturday Feb. 3, 10-1, DLab
- Register for workshop at https://grinnell.formstack.com/forms/wingo_workshop
- Movie Sunday: I Am Not Your Negro, 4pm in the Strand
- CS table Tuesday: TBD
- CS extras Thursday: The evolution of CSC 151
Good things to do (Other)
- Indoor Track and Field Saturday at 9:30 am.
- Swimming Saturday at 1:00 pm.
- Tennis meet Sunday at 10:00 am.
- Posse Plus Retreat Reflections, Community Hour next week (Tuesday, 11am, JRC 101)
Version control systems
- Allow you to keep track of old versions of whatever you are
writing (usually code).
- Safe to make changes.
- Encouragement to describe changes.
- Ability to see changes.
- Support collaboration.
- Allows others to learn about you. (The joy of mediocre data science.)
- Good programmers use a version control system to manage the complexity of collaboration (and more).
- As you develop as a software designer, you should also develop more sophisticated ways to work with your version control system.
Making better use of Git
- Make changes
git add .
git commit . -m "asdf"
- Make sure the changes work
- Make sure the changes still work
Improvements to the workflow
- Make sure the changes work!
- Use a tool that checks for you
- Do your work in a branch so that you can have a longer series of steps
while still being able to commit.
- Empowers you to work on partial code.
- Branches are also nice for small tests.
- Add/commit individually (by name) rather than everything.
- Don’t pollute the repo.
- Don’t risk information.
- Check what files have been added or changed with
- Sam prefers that you never use anything like
git add .or
git add -Aor
git commit -a.
- Send pull requests rather than pushing the data.
- These days, Sam does a lot of
git stash saveand
git stash pop.
- I sometimes find that I need to use
git diffto recall what changes I made.
.gitignorefile tells Git not to track things.
git logis useful to get a quick list of what you did (provided you choose good log messages)
What is it?
- Segementation of three parts of a typical application.
Why do we use it?
- Components can be swapped out
- Can change the UI
- Can change the model
- Rarely change the controller
- Might provide some more security; limit the flow of data.
- With well-specified APIs, you can work on the three parts separately. (Often why we segment.)
- Should be easier to modify code.
- Makes it easier to read / understand.
How does MVC relate to the three-tier architecture?
- Both break the world up into three parts (and a similar three parts).
- But three-tier provides more limited communication between the parts.
Other Rails issues
- An MVC model for building Web applications.
- Requires/benefits from a series of magic incantations.
- “Convention over configuration”
- Which files are created
- Where it looks for data, etc.
- Naming conventions, including an important “s”
- When things go well, it’s easy.
- When you know it well, it’s easy.
- When you are a novice and things go wrong, it’s a PITA.
- Benefits from a rich plugin system.
- Normal development cycle: Develop on one machine, deploy on another.