CHIPS 3.3: HTTP and URIs

Due: 2026-09-09 11:59 PM PT

Released: 2026-09-02

Estimated difficulty: •

A short, hands-on exploration of the protocol that all SaaS runs on: HTTP.

Gradescope online assignment — no code to turn in

This CHIPS is submitted as a Gradescope online assignment: you answer the questions directly on Gradescope. You do not need to turn in any code. You may still want a private copy of the starter repo, saasbook/hw-http-intro, to work from (see Getting the Code) — the full walkthrough and setup instructions (local, Docker, or GitHub Codespaces) are in its README.md.

Goals

• Use the command-line tools curl (as a SaaS client) and nc (netcat, as a stand-in SaaS server) to experiment with HTTP.
• Understand how HTTP requests and responses are constructed, including methods, headers, status codes, and request bodies from HTML forms.
• Understand the most common HTTP status codes and what they mean.
• Understand how cookies let a stateless protocol keep track of a “session”.

What you’ll do

Work through the guided exercises in the starter repo’s README.md: issue HTTP requests against real web services and against your own fake server, observe what comes back at the protocol level, and answer the comprehension questions on Gradescope as you go — the foundation for understanding REST in the rest of the course.

Before you start

Watch Module 3 §3.1–3.2 and read the matching textbook sections. You need a shell where curl and nc are available; the starter repo’s README.md lists the supported ways to get one.

Logistics

• Getting the code: nothing to submit, but see Getting the Code below if you want your own private copy of the starter repo to work from.
• Submission: answer the questions on Gradescope (an online assignment, not a code upload) — see Submission. You may edit your answers as many times as you like before the deadline.
• Extensions: everyone automatically gets a 2-day no-penalty extension; see the extension policy.
• Collaboration: you may collaborate with your team of 4, and discuss high-level approaches with anyone. Sharing answers outside your team is academic misconduct. See the AI Use Policy below before using AI tools.

AI Use Policy

This assignment follows the course AI Policy, which will be published on this site before it is needed. Until then, the rule from the Syllabus applies: you must be able to explain everything you submit.

Getting the Code

Public starter repo: saasbook/hw-http-intro — https://github.com/saasbook/hw-http-intro

GitHub makes it challenging to have a private fork of a public repository. These steps allow you to create a private space for you own work but still update from the starter code.

Clone the starter repo, then use gh (see Local Development) to create a private copy under your own GitHub account and push the code to it. Replace YOUR_GITHUB_USERNAME with your GitHub username:

git clone https://github.com/saasbook/hw-http-intro.git
cd hw-http-intro
git remote rename origin upstream
gh repo create YOUR_GITHUB_USERNAME/hw-http-intro --private --source=. --remote=origin --push
git remote set-url --push upstream DISABLED

After this, origin is your private repo and upstream is the public starter repo. The last command disables pushing to upstream, so git push always goes to your own copy — never to the public starter repo.

Keeping your repo up to date

Your private repo is a snapshot: it does not follow the starter repo. If we fix or add something in saasbook/hw-http-intro after you copy it, you have to pull those changes in yourself. The upstream remote you set up above is how you do that:

git fetch upstream

git fetch only downloads — it changes nothing in your working copy. Review what you are about to take before merging it:

git diff --name-only HEAD upstream/main   # just the names of the files that differ
git diff --stat HEAD upstream/main       # the same list, plus how much changed in each
git diff HEAD upstream/main -- spec      # the actual changes, limited to one file or directory

Then merge the upstream changes into your branch and push them to your private repo:

git merge upstream/main
git push origin main

If you and we edited the same lines, git stops and reports a conflict: open each file it lists, keep the correct combination of both sides, delete the <<<<<<< / ======= / >>>>>>> markers, then git add those files and git commit. Ask on Ed if a merge leaves you stuck — don't start over and lose your work.

These commands assume the starter repo's default branch is main. If git branch -r shows upstream/master instead, use that name in the commands above.

View this assignment on bCourses.

Submission

This is a Gradescope online assignment: you answer the questions directly on Gradescope. There is no code to upload and no autograder to wait for. You may save and resubmit your answers as many times as you like before the deadline; only the final submission will be graded.