How to Verify If a Course Link Is Still Active

You can verify if a course link is still active by issuing HTTP HEAD or GET requests to the URL and checking for 2xx or 3xx status codes, since the cs-video-courses repository contains only static Markdown links without built-in validation.

The cs-video-courses repository by Developer-Y is a curated list of free computer science video courses hosted externally. Because the project stores only Markdown links in README.md without any backend services or automated scripts, link rot detection requires external validation tools. This guide provides concrete Python implementations to probe URLs and confirm they remain reachable.

Understanding the Repository Structure

The cs-video-courses repository has a minimal architecture consisting solely of documentation files. There is no executable code, API, or continuous integration pipeline performing health checks on the hundreds of listed URLs.

• README.md contains the entire catalogue as plain Markdown links (e.g., lines 71-78 reference the CS 10 Berkeley course). Each entry is a standard Markdown hyperlink pointing to publicly hosted video resources.
• NOTES.md provides contributor guidelines but contains no link data.
• CONTRIBUTING.md recommends verifying URLs before submitting updates, yet offers no automated tooling.

Because the repository delegates hosting to external universities and platforms like YouTube, verification must happen client-side through direct HTTP probing.

HTTP Verification Strategy

To verify if a course link is still active without downloading multi-gigabyte video files, use lightweight HTTP requests that inspect server headers rather than content payloads.

Why HEAD Requests Are Preferred

A HEAD request asks the server for status codes and metadata without transferring the response body. This is ideal for checking large video resources because:

1. Bandwidth efficiency – No video data downloads; only headers transfer.
2. Speed – Servers respond faster when omitting body content.
3. Accuracy – Status codes 200, 301, or 302 confirm the resource exists or has moved permanently.

Handling Redirects and Edge Cases

Some educational platforms block HEAD requests while permitting GET requests. When a HEAD request returns 4xx or 5xx, fall back to a GET request with stream=True to limit byte retrieval. Always enable allow_redirects=True to follow 3xx redirects to their final destinations, as many university course pages redirect to current semester URLs.

Practical Implementation

The following Python scripts use the requests library to automate link verification against the catalogue.

Single Link Verification Script

Use this function to test individual URLs from README.md:

import requests

def is_link_active(url: str) -> bool:
    """Return True if the URL responds with HTTP 2xx/3xx, otherwise False."""
    try:
        # Prefer HEAD; fall back to GET if the server rejects HEAD.

        resp = requests.head(url, allow_redirects=True, timeout=5)
        if resp.status_code >= 400:
            # Some servers reject HEAD – try a lightweight GET.

            resp = requests.get(url, stream=True, allow_redirects=True, timeout=5)
        return resp.status_code < 400
    except requests.RequestException:
        return False

# Example: verify the CS 10 course link from README.md line 71

link = "http://www.infocobuild.com/education/audio-video-courses/computer-science/cs10-spring2015-berkeley.html"
print(is_link_active(link))   # → True if still reachable

Batch Validation for the Full Catalogue

To audit every link in the repository locally, extract URLs using regular expressions and validate them in a loop:

import re
import requests
import pathlib

README = pathlib.Path("README.md")
URL_PATTERN = re.compile(r"https?://[^\s)]+")   # matches any URL in the file

def check_all_links():
    results = {}
    for line in README.read_text(encoding="utf-8").splitlines():
        for url in URL_PATTERN.findall(line):
            results[url] = is_link_active(url)
    return results

if __name__ == "__main__":
    status = check_all_links()
    for url, ok in status.items():
        print(f"{url} → {'OK' if ok else 'BROKEN'}")

Run this script against a local clone of Developer-Y/cs-video-courses to generate a complete health report.

Summary

• The cs-video-courses repository stores only static Markdown in README.md with no built-in link validation.
• HEAD requests provide the fastest method to verify if a course link is still active, with GET requests serving as a fallback.
• Valid links return 2xx (success) or 3xx (redirect) status codes; 4xx and 5xx indicate dead or failing resources.
• Automate verification using Python's requests library to parse README.md and probe URLs in batches.

Frequently Asked Questions

Does the cs-video-courses repository automatically check for broken links?

No. According to the source code analysis, the repository contains no scripts, GitHub Actions, or backend services. The README.md file holds only static Markdown links, making manual or client-side script verification necessary to detect dead links.

What HTTP status code indicates a course link is still active?

Status codes in the 2xx range (particularly 200 OK) confirm an active link. 3xx codes (301, 302) also indicate active resources that have moved, provided your HTTP client follows redirects. Any 4xx client error or 5xx server error signals a broken or unreachable link.

How do I check all links in the README.md at once?

Clone the repository and run the batch validation Python script provided above. This script uses the regular expression pattern r"https?://[^\s)+]" to extract every URL from README.md, then iterates through them calling is_link_active() to test reachability.

Why do some valid links return 4xx errors when checked?

Some educational servers reject HEAD requests for security or configuration reasons, returning 405 Method Not Allowed or similar errors. When this occurs, fall back to a GET request with stream=True to verify the link without downloading the full content. Additionally, aggressive rate-limiting by hosts may temporarily return 403 or 429 status codes.

{
  "mcpServers": {
    "instagit": {
      "command": "npx",
      "args": ["-y", "instagit@latest"]
    }
  }
}