private static void ScrapePosts(Facebook fb, int lookBackDays, int maxUnscrapedPosts, bool dailyScraping, bool scrapeLikes, bool scrapeComments, UpdateOrInsertBuilder <Entity> entityUpdater)
{
log.Info("Scraping posts");
if (scrapeLikes)
{
log.Info("Scraping for likes");
}
if (scrapeComments)
{
log.Info("Scraping for comments");
}
using (var db = new FacebookDebatEntities())
{
db.Database.CommandTimeout = 0;
#region Build list of posts to be scraped for comments
log.Info("Building post-list");
var dayLimit = DateTime.Now.AddDays(-lookBackDays);
// Get unscraped posts
var posts = db.Posts.Where(x => !x.scraped).OrderBy(x => x.date).Take(maxUnscrapedPosts).ToList();
// Get posts with comments that has been made less than two days old
if (dailyScraping)
{
posts = posts.Union(db.Posts.Where(x => x.date > dayLimit)).ToList();
var latestedCommentedPosts = db.Comments.Where(x => x.date > dayLimit).GroupBy(x => x.post_id).Select(x => x.Key);
posts = posts.Union(db.Posts.Where(x => latestedCommentedPosts.Contains(x.id))).ToList();
}
#endregion
log.Info("Found " + posts.Count + " posts");
foreach (var postChunk in posts.Chunk(50))
{
var scrapedPosts = new List <Post>();
#region Scrape Comments from FB
List <Facebook.Comment> postComments = new List <Facebook.Comment>();
List <Facebook.PostLike> postLikes = new List <Facebook.PostLike>();
log.Info("Getting from " + postChunk.Count() + " post");
var fbFailed = false;
Parallel.ForEach(postChunk, (post) =>
{
if (fbFailed)
{
return;
}
try
{
var comments = Task.Run(() => scrapeComments ? fb.GetComments(post.fb_id) : new List <Facebook.Comment>());
var likes = Task.Run(() => scrapeLikes ? fb.GetLikes(post.fb_id) : new List <Facebook.PostLike>());
comments.Wait();
likes.Wait();
lock (postComments)
{
postComments.AddRange(comments.Result);
postLikes.AddRange(likes.Result);
scrapedPosts.Add(post);
}
}
catch (Exception e)
{
//fbFailed = true;
log.Warn("Being ignored by Facebook. Aborting.");
log.Warn(e.Message);
return;
}
});
#endregion
#region Update Entities
foreach (var comment in postComments)
{
entityUpdater.Process(comment.user_id, () => new Entity
{
fb_id = comment.user_id,
name = comment.user_name
});
}
foreach (var like in postLikes)
{
entityUpdater.Process(like.user_id, () => new Entity
{
fb_id = like.user_id,
name = like.user_name
});
}
entityUpdater.SyncDatabase(2000, "dbo.Entities", "id", x => new
{
id = (int?)null,
fb_id = x.fb_id,
name = x.name
});
#endregion
log.Info("Intializing post-cache");
var postTranslator = DatabaseTools.ExecuteDictionaryReader("select fb_id, id from dbo.Posts", (x) => (string)x["fb_id"], x => (int)x["id"]);
log.Info("Intializing entity-cache");
var entityTranslator = entityUpdater.GetLookup(x => x.id);
var ActivePostID = postChunk.Select(x => x.id).ToList();
#region Update comments
if (scrapeComments)
{
var commentUpdater = new UpdateOrInsertBuilder <Comment>(
AlreadyExists: db.Comments.Where(x => ActivePostID.Contains(x.post_id)),
GetKey: x => x.fb_id + "_" + x.post_id,
Updater: (dbItem, memItem) =>
{
if (dbItem.message != memItem.message)
{
dbItem.message = memItem.message;
return(true);
}
return(false);
}
);
foreach (var comment in postComments)
{
commentUpdater.Process(comment.id + "_" + comment.post_id, () => new Comment()
{
fb_id = comment.id,
message = comment.message,
post_id = postTranslator[comment.post_id],
entity_id = entityTranslator[comment.user_id],
date = comment.date,
score = Common.Classifier.Classify(comment.message)
});
}
commentUpdater.SyncDatabase(2000, "dbo.[Comments]", "id", x => new
{
id = (int?)null,
fb_id = x.fb_id,
post_id = x.post_id,
entity_id = x.entity_id,
date = x.date,
score = x.score,
scored = 1,
message = x.message,
splitted = 0,
});
}
#endregion
#region Update likes
if (scrapeLikes)
{
log.Info("Creating PostLike-UpdateOrInsertBuilder");
var likeUpdater = new UpdateOrInsertBuilder <PostLike>(
AlreadyExists: db.PostLikes.Where(x => ActivePostID.Contains(x.post_id)),
GetKey: x => x.post_id + "_" + x.entity_id,
Updater: (dbItem, memItem) => false);
log.Info("Processing PostLikes");
foreach (var like in postLikes)
{
likeUpdater.Process(postTranslator[like.post_id] + "_" + entityTranslator[like.user_id], () => new PostLike()
{
post_id = postTranslator[like.post_id],
entity_id = entityTranslator[like.user_id],
});
}
likeUpdater.SyncDatabase(10000, "dbo.[PostLikes]", "id", x => new
{
id = (int?)null,
post_id = x.post_id,
entity_id = x.entity_id,
});
}
#endregion
log.Info("Marking scraped");
Parallel.ForEach(scrapedPosts, new ParallelOptions()
{
MaxDegreeOfParallelism = 10
}, scrapedPost =>
{
if (!scrapedPost.scraped)
{
DatabaseTools.ExecuteNonQuery("UPDATE dbo.[Posts] SET scraped = 1 WHERE id = @id", new SqlParameter("id", scrapedPost.id));
}
});
}
}
}
