/// <summary>
/// Performs a search using the query parameters specified.
/// </summary>
/// <param name="queryParameters">A Google.CustomSearch.QueryParameters that specifies the search to be performed.</param>
/// <returns>Returns an Google.CustomSearch.SearchResult containing the results of the search.</returns>
public SearchResult Search(QueryParameters queryParameters)
{
Uri requestUri = this.FormatRequest(queryParameters);
Debug.WriteLine(string.Format("Request Google : {0}", requestUri.ToString()));
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(requestUri);
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
return this.ProcessResponse(queryParameters, response);
}
/// <summary>
/// Processes the HTTP Response from Google CSE and produces a
/// Google.CustomSearch.SearchResult containing the supplied data.
/// </summary>
/// <param name="queryParameters">The parameters which were used to perform the query.</param>
/// <param name="response">The HttpWebResponse recieved from Google CSE.</param>
/// <returns>Returns a SearchResult containing the search results.</returns>
private SearchResult ProcessResponse(QueryParameters queryParameters, HttpWebResponse response)
{
if (response.StatusCode != HttpStatusCode.OK)
{
throw new WebException("The request was borked");
}
SearchResult retval = new SearchResult(queryParameters);
new ResponseParser().Parse(retval, response.GetResponseStream());
return retval;
}
/// <summary>
/// Performs an asynchronous search using the query parameters specified.
/// On completion the AsyncCallback specified as callback is notified.
/// </summary>
/// <param name="queryParameters">A Google.CustomSearch.QueryParameters that specifies the search to be performed.</param>
/// <param name="callback">A System.AsyncCallback object that will be notified when the call completes.</param>
/// <returns>Returns a System.IAsyncResult that can be used to monitor the status of the asynchronous call.</returns>
public IAsyncResult SearchAsync(QueryParameters queryParameters, AsyncCallback callback)
{
AsyncSearch caller = new AsyncSearch(this.Search);
// TODO: What should be passed as the state object? is the Filter.Label appropriate?
return caller.BeginInvoke(queryParameters, callback, queryParameters.Filter.Label);
}
/// <summary>
/// Generates the Uri to be used for the request to Google CSE.
/// </summary>
/// <param name="input">The query parameters to format in the URL.</param>
/// <returns>Returns a System.Uri to request the search results from Google CSE.</returns>
private Uri FormatRequest(QueryParameters input)
{
StringBuilder url = new StringBuilder(GOOGLE_URL);
Dictionary<string, string> queryParameters = new Dictionary<string, string>();
queryParameters.Add("cx", this.CseID);
queryParameters.Add("client", "google-csbe");
queryParameters.Add("q", input.SearchTerm);
if (null != input.SpecialQueryTerms.BackLinks)
{
// Note: You cannot specify any other query terms when using link:
queryParameters["p"] = string.Format("link:{0}", input.SpecialQueryTerms.BackLinks.ToString());
}
else
{
if (input.Filter != null)
{
queryParameters["q"] += "+more:" + input.Filter.Label;
}
foreach (string word in input.SpecialQueryTerms.InUrl)
{
queryParameters["q"] += "+inurl:" + word;
}
queryParameters.Add("num", input.Count.ToString());
queryParameters.Add("start", input.Start.ToString());
if (OutputFormat.Xml == input.Format)
{
queryParameters.Add("output", "xml");
}
else
{
queryParameters.Add("output", "xml_no_dtd");
}
// Safe search defaults to off.
if (SafeSearch.Off != input.Safe)
{
string value = "medium";
if (SafeSearch.High == input.Safe)
{
value = "high";
}
queryParameters.Add("safe", value);
}
// Auto filter defaults to true
if (!input.AutoFilter)
{
queryParameters.Add("filter", "0");
}
// Special search options.
// Exclude Query Terms
foreach (string term in input.SpecialQueryTerms.ExcludeQueryTerms)
{
queryParameters["q"] += string.Format(" -{0}", term);
}
// File type filtering
bool firstType = true;
foreach (var pair in input.FileTypes)
{
string combinator = " OR";
string type = string.Format(" filetype:{0}", pair.Key.TrimStart('.'));
if (!pair.Value)
{
type = " -" + type.TrimStart();
combinator = " AND";
// TODO: This logic is not perfect, do the terms need encapsulating in parens?
// What happens when some are ANDs and some need to be OR'd ?
}
if (!firstType) type = combinator + type;
queryParameters["q"] += type;
firstType = false;
}
// Advanced search options.
if (null != input.AdvancedSearchSite)
{
queryParameters.Add("as_sitesearch", input.AdvancedSearchSite.ToString());
}
if (null != input.AdvancedSearchSite)
{
string value = "i";
if (DomainInclusion.Exclude == input.AdvancedSearchDomainInclusion)
{
value = "e";
}
queryParameters.Add("as_dt", value);
}
if (!string.IsNullOrEmpty(input.AdvancedSearchPhraseQuery))
{
queryParameters.Add("as_epq", input.AdvancedSearchPhraseQuery);
}
if (!string.IsNullOrEmpty(input.AdvancedSearchExcludePhraseQuery))
{
queryParameters.Add("as_eq", input.AdvancedSearchExcludePhraseQuery);
}
if (null != input.AdvancedSearchRequiredLink)
{
queryParameters.Add("as_lq", input.AdvancedSearchRequiredLink.ToString());
}
// Sort options
if (input.Sort.Type != Sort.SortType.Relevance) // Sort by relevance is the Google default sort, so no need to explicitly specify the sort
{
string qs = null;
if (input.Sort.Type == Sort.SortType.Date)
{
qs = "date";
qs += (input.Sort.Direction == Sort.SortDirection.Ascending ? ":a" : ":d");
}
if (input.Sort.Type == Sort.SortType.Attribute)
{
qs = input.Sort.Attribute;
qs += (input.Sort.Direction == Sort.SortDirection.Ascending ? ":a" : ":d");
switch (input.Sort.Strength)
{
case Sort.SortStrength.Strong: qs += ":s"; break;
case Sort.SortStrength.Weak: qs += ":w"; break;
default: qs += ":h"; break;
}
}
if (!string.IsNullOrEmpty(qs))
queryParameters.Add("sort", qs);
}
}
foreach (var pair in queryParameters)
{
url.Append(pair.Key + "=" + HttpUtility.UrlEncode(pair.Value) + "&");
}
return new Uri(url.ToString().TrimEnd('&'));
}
/// <summary>
/// Initializes a new instance of the Google.CustomSearch.Facet class specifying the
/// QueryParameters that were used to generate the search to which this Facet is related.
/// </summary>
/// <param name="parameters">The QueryParameters to which this Facet is related.</param>
public Facet(QueryParameters parameters)
{
this.Parameters = parameters;
}
