/// <inheritdoc />
public ICrawlerTaskManager Create()
{
var crawlerTaskMetadatas = new List <CrawlerTaskMetadata>();
// 遍历所有已经加载的 CLR 类型
_logger.LogInformation("探查后台任务类型...");
foreach (var loadedAssembly in AppDomain.CurrentDomain.GetAssemblies())
{
foreach (var t in loadedAssembly.GetTypes())
{
var annotation = t.GetCustomAttribute <CrawlerTaskAttribute>();
if (annotation == null)
{
continue;
}
if (t.GetInterface(nameof(ICrawlerTask)) == null)
{
continue;
}
// t 带有 CrawlerTaskAttribute 注解且实现了 ICrawlerTask
_logger.LogInformation("找到后台任务类型：{0}，启动间隔为 {1} 分钟", t, annotation.Interval);
var metadata = new CrawlerTaskMetadata(t, annotation);
crawlerTaskMetadatas.Add(metadata);
}
}
return(new DefaultCrawlerTaskManager(crawlerTaskMetadatas, _serviceProvider, _logger));
}
public CrawlerTaskScheduleDescriptor(int nextRunTimestamp, CrawlerTaskMetadata metadata,
IServiceProvider serviceProvider)
{
NextRunTimestamp = nextRunTimestamp;
Metadata = metadata;
TaskObject = new Lazy <ICrawlerTask>(() => Metadata.ActivateTaskObject(serviceProvider));
}