Forum Discussion
Handling Invalid and Unsupported Video URLs in ASP.NET Web Applications
Hi everyone,
I'm exploring best practices for handling external video URLs in web applications built with ASP.NET.
When users submit video links, developers need to validate URLs, handle unsupported sources, and provide meaningful error messages without compromising application security or performance.
I'd appreciate some suggestions from experienced .NET developers:
What is the recommended approach for validating user-submitted URLs in ASP.NET?
How do you handle unsupported domains and malformed URLs?
What security measures should be considered when processing external URLs on the server?
Is it better to use asynchronous HTTP requests for validation?
How do you design clear and user-friendly error responses when a URL cannot be processed?
I'd appreciate any practical advice, examples, or documentation that could help improve the reliability and security of this workflow.
Thanks for sharing your experience!
1 Reply
Treat URL syntax validation and permission to fetch a resource as separate checks. Uri.TryCreate can parse an absolute URI, but a syntactically valid address can still target an internal service or an unsupported video provider.
Start with a small allowlist of supported providers, HTTPS and permitted ports. Compare the parsed hostname, not whether the input string contains a trusted name. Reject unsupported destinations before making any outbound request. Apply the same restrictions to redirects, and enforce outbound network controls so the server cannot reach private infrastructure through this feature.
For approved destinations, use asynchronous HttpClient calls with cancellation, a timeout and bounded response size; async improves scalability but does not make a request safe. Prefer a provider’s documented metadata API over downloading an entire video to validate it. Return separate messages for malformed input, unsupported providers and temporary retrieval failures, while logging diagnostic details privately rather than exposing raw exceptions.
