What causes "Relative URL did not contain a route path" in LykosAI/StabilityMatrix?

Pass a URL containing a route path, e.g. "/models/12345"

LykosAI/StabilityMatrix · error · InvalidOperationException

Relative URL did not contain a route path

Error message

Relative URL did not contain a route path

What it means

BuildDetailDataPath converts a relative model URL into the Next.js data path (e.g. /models/{id}.json) and throws InvalidOperationException when the resulting URL path is empty after trimming trailing slashes — meaning the relative URL had no route component.

Solutions

Pass a URL containing a route path, e.g. "/models/12345"
Strip query/fragment and rebuild from the model ID if only those parts exist
Pre-validate that the URL's path is non-empty before calling

Example fix

// before
BuildDetailDataPath("?modelVersionId=99");
// after
BuildDetailDataPath("/models/12345?modelVersionId=99");

Defensive patterns

Strategy: validation

Validate before calling

if (string.IsNullOrWhiteSpace(url) || !url.TrimStart('/').Split('?')[0].Split('#')[0].Contains('/')) throw new ArgumentException("URL has no route path");

Type guard

bool HasRoutePath(string? url) => !string.IsNullOrWhiteSpace(url) && new Uri(CivArchiveApiClient.BaseUri, url).AbsolutePath.TrimEnd('/').Length > 0;

Try / catch

try { var path = CivArchiveApiClient.BuildDetailDataPath(url); }
catch (InvalidOperationException ex) { Logger.Warn(ex, "URL {Url} has no route path", url); return null; }

Prevention

Always pass route paths like /models/{id}, not query or fragment strings
Normalize stored URLs on ingest
Reuse BuildDetailDataPath's logic to validate URLs early
Include the query string after the path, never instead of it

When it happens

Trigger: Calling BuildDetailDataPath (directly or via GetModelDetailsAsync) with a URL like "", "?query=1", or a fragment-only reference so uri.AbsolutePath resolves to "/" and trims to empty.

Common situations: Passing query-string or fragment strings instead of route paths, malformed stored URLs missing the path component, base-URI-only references.

Understand the failure class

Background: "Invalid URL" errors: why new URL(), URI.parse, and reqwest::Url reject your string — missing scheme, whitespace, and bad path format — this error's family across 39 libraries.

Related errors

AI-assisted analysis of LykosAI/StabilityMatrix@af93d6ef57 (2026-09-12). Data as JSON: /api/errors/4f95206d16fd09cd. Report an issue: GitHub.

Appendix: source

Thrown at StabilityMatrix.Core/Api/CivArchiveApiClient.cs:337

        {
            query.Add($"type={Uri.EscapeDataString(string.Join(",", filters.Types))}");
        }

        if (filters.BaseModels.Count > 0)
        {
            query.Add($"base_model={Uri.EscapeDataString(string.Join(",", filters.BaseModels))}");
        }

        return $"{NormalizeRoutePath(routePath)}.json?{string.Join("&", query)}";
    }

    public static string BuildDetailDataPath(string relativeUrl)
    {
        var uri = new Uri(BaseUri, relativeUrl);
        var path = uri.AbsolutePath.TrimEnd('/');
        if (string.IsNullOrWhiteSpace(path))
        {
            throw new InvalidOperationException("Relative URL did not contain a route path");
        }

        // Apply Next.js rewrite rules: /{platform}/models/{id}/versions/{versionId}
        // rewrites to /models/{id}?modelVersionId={versionId}&platform={platform}
        var rewriteMatch = PlatformDetailRewriteRegex().Match(path);
        if (rewriteMatch.Success)
        {
            var platform = rewriteMatch.Groups["platform"].Value;
            var modelId = rewriteMatch.Groups["modelId"].Value;
            var versionId = rewriteMatch.Groups["versionId"].Value;

            return $"/models/{modelId}.json?modelVersionId={versionId}&platform={platform}";
        }

        // Also handle /{platform}/models/{id} (without version)
        var platformModelMatch = PlatformModelRewriteRegex().Match(path);
        if (platformModelMatch.Success)
        {

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