I'm trying to do the following Facebook Query Language query:
https://api.facebook.com/method/fql.query?query=SELECT name FROM user WHERE uid IN (SELECT actor_id FROM stream WHERE app_id = 131580206909839 AND xid = 'daily_thred_production' AND created_time > 2011-03-06 AND created_time < 2011-03-08)
The problem is that the dates aren't being recognized and I can't find any documentation on how to format FQL dates from the Facebook developer section. Any thoughts?
EDIT
I'm doing all of this from the URL with no programming language. I'm just trying to pull one-off statistics for some co-workers.
Epoch time seems to work, thanks! Only problem is that it's only displaying new users that contributed to the stream for the first time. Unfortunately I'm trying to find everyone in the stream, I'll have to look at the stream table more carefully.
Thanks Brian.
They're epoch time (Number of seconds since 00:00:00 Jan 1, 1970 UTC)
You need to convert your dates to epoch time in whatever language you're using.
EDIT: If you need an example, let me know what programming lang you're using.
Related
I'm writing a web app using Firestore that needs to be able to show "Today's Popular Posts" and I'm having trouble getting the queries right when considering users in different timezones.
The dates are stored in the DB as UTC 0, then adjusted to the current user's UTC offset in the client via Moment.js. This works correctly.
When adding a new post I use firebase.firestore.FieldValue.serverTimestamp() to store the current server timestamp in a field called timestamp, like so:
const collectionRef = db.collection('posts');
collectionRef.add({
name: "Test Post",
content: "Blah blah blah",
timestamp: firebase.firestore.FieldValue.serverTimestamp(),
likeCount: 0
});
Then on the server I have a Cloud Function that runs on create and adds another field to the document called datestamp which is the the UTC 0 timestamp, but adjusted so that the time is the beginning of the day. The function looks like this:
exports.updatePostDate = functions.firestore
.document('posts/{postID}')
.onCreate((event) => {
const db = admin.firestore();
const postRef = db.doc('post/'+event.params.postID);
const postData = event.data.data();
const startOfDay = moment(postData.timestamp).startOf('day').toDate();
return postRef.update({
datestamp: startOfDay
});
});
Storing a timestamp where the time is always the beginning of the day enables me to write a query like this for finding all posts and ordering by popularity on a given day:
const startOfDayUTC = moment.utc().startOf('day').toDate();
const postQuery = db.collection('posts')
.orderBy('likeCount', 'desc')
.orderBy('timestamp', 'desc')
.where('datestamp', '==', startOfDayUTC)
.limit(25);
The problem is, depending on the user's UTC offset, this can display posts with two different dates when parsing the post's timestamp field. So even though the query is correctly fetching all the posts where the datestamp is say, 2018-01-30T00:00:00Z, the timestamp's date might not be the same once parsed. Here's an example of two posts:
Post 2:
likeCount: 1
timestamp (UTC 0): 2018-01-30T06:41:58Z
timestamp (parsed to UTC-8): 2018-01-29T22:41:58-08:00
datestamp (UTC 0): 2018-01-30T00:00:00Z
Post 1:
likeCount: 0
timestamp (UTC 0): 2018-01-30T10:44:35Z
timestamp (parsed to UTC-8): 2018-01-30T02:44:35-08:00
datestamp (UTC 0): 2018-01-30T00:00:00Z
So you can see, while the posts have the same datestamp, after adjusting the timestamp to the local UTC, the timestamp fields can end up being on two different days.
If anyone has a solution to this I would be very grateful.
I think it is better to avoid functions in this case as you can perform compound queries now. You can simply use
query.where(date > lastMidnight).where(data < now).get().then(...)
so to speak to limit data which only belongs to one day and try to keep all your time variables in UTC 0 and just find the start point and the current time both client side and convert them to UTC0.
//get local time from midnight to now (local)
const now = new Date();
const lastMidnight = now.setHours(0,0,0,0);
//then convert those to UTC0 to pass on in your query to firestore
const lastMidNightUTC = new Date(lastMidnight + now.getTimezoneOffset() * 60000).toString();
const nowInUTC = new Date(now + now.getTimezoneOffset() * 60000).toString();
and you can get your data (remember you need to make an index or just run the query once and firebase SDK will generate a link to create the index in dev tools -> console , for you)
query.where(date > lastMidNightUTC).where(data < now).get().then(...)
I came up with a solution that I'm really not happy with... But it works!
The problem is fundamentally one post can be on more than one date, depending on the user's location. And since for this case we also want to order by a field other than timestamp we can't use a range query to select posts on a given date, because your first .orderBy must be on the field you're using a range query on (see Firestore docs).
My solution is to map localized datestamps to their corresponding UTC offset. The object contains every UTC offset as a key, and the post's datestamp in that offset's time.
An example post looks like this:
posts/{somepostid}
{
name: "Test Post",
content: "Blah blah blah",
timestamp: Mon Jan 29 2018 21:37:21 GMT-0800 (PST),
likeCount: 0,
utcDatemap: {
0: "2018-01-30,
...
-480: "2018-01-29",
...
}
}
The field utcDatemap is the the one we use in our queries now:
const now = moment();
const datestamp = now.format("YYYY-MM-DD");
const utcOffset = now.utcOffset();
const utcDatemapField = 'utcDatemap.'+utcOffset;
const postQuery = db.collection('posts')
.orderBy('likeCount', 'desc')
.orderBy('timestamp', 'desc')
.where(utcDatemapField, '==', datestamp)
.limit(25);
Now posts can show up on two different days, depending on where the user is querying from. And we can still convert the regular old timestamp to the user's local time on the client.
This is definitely not an ideal solution. For the above query I needed to create composite indexes for every single key in utcDatemap. I'm not sure what the rules of thumb are with composite indexes, but I'm thinking having 39 indexes for something simple like this is probably not great.
Additionally I checked it out using the roughSizeOfObject function from thomas-peter's answer on this post and the utcDatemap object, with all it's string datestamps clocked in at roughly 780 bytes, and it's not like 0.78kb is a lot, but you do need to be mindful of how much data you're transferring with a service like Firestore (0.78kb is a lot for a date).
I'm learning/reading up on Firestore and have Google'd to see how it deals with times, so discount my answer appropriately.
It looks as though Firestore converts times to UTC and stores them as its own Timestamp datatype. If so, then it's critical to know that this is a destructive conversion.
Though UTC is useful for comparing instants in time, it means that the wall-clock time as observed by the app user is lost forever. Some countries like the UK are in one of two timezones during the year, Daylight Savings Time and British Summer Time.
You can convert back to the user's observed time, but the problem is that the rules change over the years. You'd have to keep a record of all the different rule changes for all the timezones and countries of the world.
What was the time at the time?
The question is, what time did the user think an event happened ...at the time. This can have legal ramifications. You may need to go back through historic data to prove a person acted at a certain time as they observed it.
The solution is to capture the user's observed offset in an additional field. That way, you can always use this to convert.
Regarding the OPs problem, this seems somewhat philosophical for a web app. Does "today" mean the event, such as a post, must have happened within the user's Monday? Or just posts on today's date? Or posts within the last 24h?
An important thing to remember is that dates are the same all around the world, even when they begin and end at different instants.
What's Elvis got to do with all this?
Christmas Day is 25th everywhere. If I say something happened on Christmas Day and I'm in the USA, and then someone in Australia wants to see all the world's posts made on Christmas Day, then they need to query for posts where observedDate == 25th Dec.
Think about it. Such posts were all made on Christmas Day, even though it might have been Boxing Day for me in England at the instant that they posted.
Elvis died on 16th August. In the UK our radio stations don't all wait until it's the 16th in the timezone of the place of his death to start playing his records.
Another interesting one is whether something happened in Q1 or Q2 of a company's reporting year. Is a sale recognised as on the date at the point-of-sale in the store in New York, or in the database in LA?
The observed date is interesting.
My point is, think deeply about this and store both a normalised instant like UTC, but also the user's observed date, time and offset. Then you have all the information you'll need for the future.
Finally, consider adding observed year or week numbers, or day ordinals, H1/H2 for financial data, since it can be super useful for composing rapid queries, depending on your use-cases.
Where can I find the documentation (parameters that can be given) of the following graph url:
https://graph.facebook.com/<PAGENAME>/feed
I've been searching for hours, but I can't find them.. I'm looking for the parameter to get posts till a certain date..
What you are looking for is Time-based Pagination to navigate through results data using Unix timestamps which point to specific times in a list of data. You can use the until field which as per documentation is
A Unix timestamp or strtotime data value that points to the end of the range of time-based data.
For example, following will give you the posts of User until 10th June 2013
me/feed?until=1370840400
Upon logging into their accounts, each user has their login date and time stored to the database. What I was looking to do however is figure out the amount of days (or preferably convert into months if greater than a month) so that if a user views their profile they can see how active the band are. Also, this could benefit me in terms of keeping active profiles top of the agenda for content on the site so that it doesn't become stale from inactive users content filling up main page content.
I'm using ColdFusion so i'd be looking for a way to find for example how many days ago #lastLogin# was from #now()#. So say if the date of the last login was 23/04/2013 and todays date is 29/04/2013 it would read "Last Active, 1 day ago." However if the last login was 23/03/2013, it would read "Last Active, 1 month ago".
Anybody know how to do this? Thanks.
P.S I currently have no code from testing this as I have no idea where to start in terms of achieving this.
Use DateDiff
<cfset days = dateDiff("d", LoginDateVariable, now()) />
It's as simple as that.
P.S I currently have no code from testing this as I have no idea where
to start in terms of achieving this.
This doesn't answer your direct question but to help you know where to get started, I would strongly suggest reviewing the built in ColdFusion functions and tags that are available to you.
Tags
Tags by function
Functions
Functions by category
Also, Google searches usually land you at the docs, just add "coldfusion" to your search string. Searching google for coldfusion date functions yields very helpful answers, the first of which are a list of all ColdFusion date functions.
Dale's answer is spot on. But I would also suggest returning it as a variable with your query. Let the SQL server do the work. It's very efficient for those types of calculations. Not that CF can't do them well, too. But it's probably more appropriate for SQL to do that lifting. Especially if you're already returning the lastLogin date.
It would be similar to the CF solution:
SELECT ...., lastLogin, DATEDIFF(d, lastLogin, GETDATE()) AS LastLoginDays
FROM ....
WHERE ....
That would give you the number of days. You'd have to decide how you wanted to define a month if you wanted to break it out by month/day. That would get a bit more complex. You could write a SQL function that could be run on both dates and give you an accurate count of days/months/years since last login.
One other thing to keep in mind: Where are the dates being generated? When you insert loginDate into the database, are you doing a now() in CF before you insert it or are you doing a getDate() in SQL when you insert it? Again, I would let the database do your date logic, but you'd want to compare the two dates from the same source. For instance, if your loginDate was a database getDate() then you may not want to compare that to a CF now(). One goes by the datetime of the SQL server and the other goes by the datetime of the CF server. They could be different.
I am getting wall posts by facebook sdk
$get = $facebook->api('/me/posts', 'GET' );
or
$get = $facebook->api('/me/feed', 'GET' );
I need to save them into my own DB, and after new request, I need get posts, that I have not saved yet. But I could not find any parameters to add to get info for example last 7 days, or after post by timestamp smth.
I saw that there is FQL which has time field, but it was only in Statuses table, I need all of them, likes, shares, statuses, comments etc.
Can anyone help me?
You can add since=[time] and/or until=[time] as query strings to get a specific slice of time.
For instance, to get 7 days of posts beginning on October 1, 2012, try this:
'/me/feed?since=2012-10-01&until=2012-10-08'
Your time string can be either an ISO-8601 date string or a UNIX timestamp.
In looking at the stream table, the documentation says ..
updated_time time
The time the post was last updated, which occurs when a user comments on the post, expressed as a Unix timestamp
created_time time
The time the post was published, expressed as a Unix timestamp
However, when I execute a FQL query against the table I see
<created_time>1328136721</created_time>
<updated_time>1328136721</updated_time>
even though 700+ comments have been made on the post. Given the documentation, if a comment has been made on a post, I don't see how the 2 timestamps can ever be the same.
The bug seems the appear for status with 30+ comments, as per this bug report. It is currently marked "Assigned".