API Doc URL Not Resolvable: Crawler Validation Issue

Hey everyone! Today, we're diving into a common challenge faced when dealing with API documentation, specifically when it comes to making sure those URLs are accessible for automated crawlers. We'll explore an interesting situation where a publiccode.yml file, despite passing local validation, stumbles during the crawling process due to an internal API documentation link. Let's break it down and see what solutions we can cook up.

The Issue: Internal API Documentation and Crawler Access

So, the core problem revolves around the accessibility of API documentation URLs. Imagine you've got a fantastic piece of software, and its API documentation is neatly packaged and deployed alongside it. This is great for users within your system's environment, but what happens when an external crawler comes knocking? This is precisely the scenario highlighted by the issue at hand, where the api.loom domain, while perfectly valid within the software's ecosystem, isn't resolvable on the broader internet.

The error message from the failing pipeline run spells it out clearly:

time="2025-11-04T16:11:24Z" level=info msg="[Swiss-Armed-Forces/Loom] BAD publiccode.yml: publiccode.yml:1:1: warning: publiccodeYmlVersion: v0.4.0 is not the latest version, use '0'. Parsing this file as v0.5.\npubliccode.yml:100:5: error: description.en.apiDocumentation: '[https://api.loom/docs](https://api.loom/docs/)' not reachable: HTTP GET failed for [https://api.loom/docs](https://api.loom/docs/): Get \"[https://api.loom/docs](https://api.loom/docs/)\": dial tcp: lookup api.loom on 168.63.129.16:53: no such host\n"

This excerpt indicates that the crawler is unable to perform an HTTP GET request to fetch the API documentation because the domain api.loom cannot be resolved. This typically means the domain isn't registered in the global DNS or isn't configured to be publicly accessible. For crawlers validating publiccode.yml files, this poses a significant hurdle.

Now, you might be wondering, "Why is this happening?" Well, when documentation is intended for internal use, it's common to host it on a domain or server that's only accessible within a specific network. This keeps things secure and controlled. However, crawlers operate from the outside, so they need a publicly accessible URL to do their job.

Why is this Important for Crawlers?

Crawlers play a vital role in automatically discovering and indexing software metadata, including API documentation. They use this information to populate catalogs, enable search functionality, and provide insights into the capabilities of different software components. If a crawler can't access your API documentation, your software might miss out on being properly listed and discovered.

The Dilemma: To Remove or Not to Remove?

Faced with this challenge, the initial reaction might be to simply remove the problematic API link. That's certainly one option, but it comes with a trade-off. Removing the link means the crawler will no longer flag an error, but it also means potential users who rely on the catalog won't have a direct path to your API documentation. So, what's the alternative?

Potential Solutions: Bridging the Accessibility Gap

Let's explore some strategies for tackling this issue without sacrificing the integrity of your publiccode.yml file or the accessibility of your API documentation.

1. Conditional API Documentation URLs

One clever approach is to use conditional URLs within your publiccode.yml. This involves providing a public-facing URL for crawlers while still allowing the internal URL to function within your software's environment. You could achieve this through environment variables or configuration settings that determine which URL to use based on the context.

For instance, you might have a setting that checks if the software is running in a development or production environment. In a development environment, the internal api.loom/docs URL would be used. In a production environment, a publicly accessible alternative, such as https://your-public-domain.com/api/docs, would be used.

This ensures that users within your system can still access the documentation as expected, while crawlers can also successfully retrieve the information they need.

2. Proxy or Redirection

Another option is to set up a proxy or redirection service. This involves creating a publicly accessible endpoint that forwards requests to your internal API documentation server. When the crawler hits the public endpoint, the proxy transparently fetches the documentation from the internal server and returns it to the crawler.

This approach can be particularly useful if you want to avoid exposing your internal infrastructure directly to the internet. It adds a layer of indirection that enhances security and control.

3. VPN or Firewall Configuration

In some cases, you might be able to configure your VPN or firewall to allow the crawler's IP address to access your internal API documentation server. This is a more direct approach, but it requires careful consideration of security implications. You'll need to ensure that only authorized crawlers are granted access and that your internal network remains protected.

4. Offer a Publicly Accessible Mirror

Consider creating a publicly accessible mirror of your API documentation. This could be a static HTML version hosted on a public server or a separate instance of your documentation platform configured for public access. You can then point the apiDocumentation URL in your publiccode.yml to this mirror.

This approach provides a dedicated public endpoint for crawlers without compromising the security or accessibility of your internal documentation. It's a clean and straightforward solution that ensures everyone gets the information they need.

5. Update the Publiccode Editor

The original issue also raises a valid point about the publiccode editor itself. It suggests that the editor should provide a warning or error message when it encounters non-internet-resolvable domains during validation. This would help developers catch potential issues early on and avoid surprises during the crawling process. Contributing to the publiccode editor project with this suggestion could benefit the entire community.

Choosing the Right Approach

The best solution for you will depend on your specific needs, infrastructure, and security requirements. Each of the methods we've discussed has its own pros and cons, so it's crucial to weigh them carefully before making a decision.

Consider factors such as:

• Security: How comfortable are you with exposing your internal documentation to the internet?
• Maintenance: How much effort will it take to maintain the solution over time?
• Complexity: How easy is it to implement the solution within your existing infrastructure?
• Scalability: Can the solution handle increased traffic from crawlers and users?

By carefully evaluating these factors, you can select the approach that best fits your situation and ensures that your API documentation is both accessible to crawlers and secure within your environment.

The Importance of Clear Communication

Regardless of the technical solution you choose, clear communication is key. Make sure to document your approach in your publiccode.yml file and any related documentation. This will help other developers understand how your API documentation is structured and how to access it. It's also a good idea to reach out to the maintainers of the crawler or catalog you're targeting to explain your approach and ensure they're able to properly index your software.

Conclusion: Making API Documentation Crawler-Friendly

Dealing with internal API documentation and crawler accessibility can be a bit of a puzzle, but it's a puzzle worth solving. By implementing the right strategies, you can ensure that your software is properly indexed and discoverable while maintaining the security and integrity of your internal systems. Remember, the goal is to strike a balance between public accessibility and private control. So, take the time to assess your needs, explore your options, and choose the solution that works best for you. Let's make our APIs discoverable, one crawl at a time!

By understanding the challenges and implementing the right solutions, you can ensure that your API documentation is accessible to crawlers, making your software more discoverable and valuable to the wider community. Remember, clear communication and careful planning are key to success. So, go forth and make your APIs shine!

Keep exploring, keep learning, and keep building awesome things!