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WebSearchService

WebSearchService wraps a caller-supplied IWebSearchProvider and adds automatic fallback query generation when a search returns no results. It does not create or dispose the provider.

Migrating from WebSearchAgent

WebSearchAgent remains available as an obsolete forwarding wrapper. Prefer WebSearchService for new code. The injected legacy constructor leaves the supplied provider caller-owned, while the parameterless legacy constructor retains its historical internally created browser provider. See the Migration from Agent APIs guide for the complete mapping.

Construction

// The caller creates and owns the provider.
using var ddg = new DuckDuckGoSearchProvider();
var search = new WebSearchService(ddg);

The constructor also accepts an optional ILogger<WebSearchService>.

Searching

var result = await search.SearchAsync(
    "weather API",
    maxResults: 10,
    ct: cancellationToken);
Parameter Default Description
query — The search query
maxResults 10 Maximum number of results to return
ct default Cancellation token

Fallback Query Strategy

When the initial query produces a failed or empty result, the service retries with generated variations:

Original query Fallback attempts (in order)
Contains API Query without API, then query + official site
Anything else Query + official site

The first fallback that yields results wins. If all attempts fail, the last SearchResult is returned unchanged — callers should still check Success.

var result = await search.SearchAsync("example API query");
// Internally: "example API query" -> "example query" -> "example API query official site"

if (!result.Success)
{
    // All attempts failed
}