/// <summary>
/// Looks up data on a given web page by searching the DOM for elements matching the configured selector
/// </summary>
/// <param name="address">Address of the web page to retrieve</param>
/// <param name="selector">Element selector to server as the basis for the query</param>
/// <returns>Returns a PageQueryResult object that contains an array of the text content for matching elements</returns>
private static async Task <PageQueryResult> getMatchingElements(string address, string selector)
{
// Setup AngleSharp to be able to load external pages
var config = AngleSharp.Configuration.Default.WithDefaultLoader();
// Load the DOM for the page at the requested address
var document = await BrowsingContext.New(config).OpenAsync(address);
// Perform the query to get all matching fragments on the site
var matchingFragments = document.QuerySelectorAll(selector);
PageQueryResult result = new PageQueryResult()
{
Results = matchingFragments.Select(m => m.TextContent).ToArray()
};
return(result);
}
public async Task <IHttpActionResult> PollWebPageContent(
[Metadata("Web Address", @"Site to poll for changes (e.g., ""https://msn.com/weather/news"")")]
string address,
[Metadata("Element Selector", @"Selector for desired content (e.g., ""li.headlines>a>h3"")")]
string selector,
[Metadata("Last result", "State data stored by the Logic App Runtime", Visibility = VisibilityType.Internal)]
string lastResult = null
)
{
PageQueryResult result = await getMatchingElements(address, selector);
var paramsForNextPoll = new
{
address = address,
selector = selector,
lastResult = result.GetHash()
};
if (null != lastResult && result.GetHash() != lastResult)
{
// 200 OK Response with result content
// Location header points to the next address to poll
// In this case, since we are triggering the event:
// TimeSpan.Zero = Poll immediately (not at pre-configured intereval).
return(ResponseMessage(Request.EventTriggered(result, TimeSpan.Zero, nameof(PollWebPageContent), paramsForNextPoll)));
}
else
{
// This code will execute under the following conditions:
// If this has never been triggered before, pass a hash of the result back to the runtime as a baseline
// If this has been run before, but the result is the same as it was the last time around
// 202 Accepted Response with no content
// Location header points to the next address to poll
// In this case, since we are not triggering the event:
// TimeSpan.Zero = Poll at pre-configured interval in Logic App
return(ResponseMessage(Request.EventWaitPoll(TimeSpan.Zero, nameof(PollWebPageContent), paramsForNextPoll)));
}
}
public PageQueryResult ExecutePageQuery(string sql, int pageIndex, int pageSize, string orderBy, IList <object> parameters)
{
if (string.IsNullOrEmpty(orderBy))
{
throw new ArgumentNullException("orderBy");
}
PageQueryResult result = new PageQueryResult(pageIndex, pageSize);
#region 查询满足条件的条目数量
string queryItemCountSql = string.Format("SELECT COUNT(*) FROM ( {0} ) T1", sql);
result.ItemCount = this.ExecuteScalar <int>(queryItemCountSql, parameters);
if (result.ItemCount == 0) // 如果满足条件的数据条目数量为零，则重置页索引为 1
{
result.PageIndex = 1;
}
else if (result.PageIndex > result.PageCount) // 如果指定的页索引大于查询直接总页数，则重置页索引为总页数
{
result.PageIndex = result.PageCount;
}
#endregion
#region 查询最终的结果集
if (parameters == null)
{
parameters = new List <object>();
}
parameters.Add((result.PageIndex - 1) * result.PageSize);
parameters.Add(result.PageSize);
string queryItemSql = string.Format("SELECT * FROM ( {0} ) T ORDER BY {1} LIMIT ?, ?", sql, orderBy);
result.Data = this.ExecuteDataTable(queryItemSql, parameters);
#endregion
return(result);
}
public async Task <IActionResult> SearchPages(string searchPattern, int start, int pageSize, string excludeId)
{
if (searchPattern == null)
{
searchPattern = "";
}
GoNorthProject project = await _projectDbAccess.GetDefaultProject();
Task <List <KirjaPage> > queryTask;
Task <int> countTask;
queryTask = _pageDbAccess.SearchPages(project.Id, searchPattern, start, pageSize, excludeId);
countTask = _pageDbAccess.SearchPagesCount(project.Id, searchPattern, excludeId);
Task.WaitAll(queryTask, countTask);
PageQueryResult queryResult = new PageQueryResult();
queryResult.Pages = queryTask.Result;
queryResult.HasMore = start + queryResult.Pages.Count < countTask.Result;
return(Ok(queryResult));
}