confusion about spring webflow execution key, what's the semantics behind - spring-webflow

Recently, I looked at spring 2.3 webflow booking-faces demo, I found it strange that a different flow execution key is assigned every time I click to "browse" hotel detail.
When I search the hotels and page to the 5th page of the search result, I get an URL with execution=e1s2. Then I click to browse a hotel detail, I get an URL with execution=e1s3. But when I click the "back to search" button, I found the page is directed to the first page of the search list with an execution=e1s4 URL, and the paging state is missed. However, browsing step is defined in the same flow definition with hotel search act and paging var is defined within flow scope.
My question is whether a new execution key parameter means a new flow execution? What's the semantics? If so, How can I configure to stick into an identical flow execution when I click "back to search" button.
Thanks

To be precise: the flow execution key (eg. "e1s2") indeed consists of two parts:
"e1": This part identifies the flow execution. Each time you start a new flow, a new flow execution is created. A flow execution essentially holds all state associated with the executing flow (i.e. the conversation you're having with the web application). When a flow hits an end-state, the flow execution (and all associated snapshots) will be destroyed.
"s2": This part identifies a snapshot within the flow execution. Webflow uses so-called continuation snapshots to be able to support the browser back and refresh buttons. On every request into a flow execution, webflow creates a new snapshot that allows you to continue from that point onward if needed, for instance when you use the browser back button.
See also:
https://docs.spring.io/spring-webflow/docs/current/api/org/springframework/webflow/execution/repository/support/CompositeFlowExecutionKey.html
Keep in mind that the flow execution key is not intended to be human readable or be interpreted by other software. This is essentially an internal webflow artifact.

Related

Google calendar api v3: update all future events in recurring series limited by count

My question: how do I update "this and all future" instances in a recurring event which is limited by count so that the total number of events stays consistent?
What is the problem:
Trying to modify recurring event and I follow the below guide:
https://developers.google.com/calendar/recurringevents
Basically to update all future recurring events using a target event, the doc says one need to do two calls:
update existing event to make so it ends before the target event date
create a new recurring event with the same fields except of those need changes.
That works fine until there is an event that is limited by the number of occurrences.
Let's say there is a recurring event limited by 10 occurrences and target event is 5th event.
Now I need to split the original so that the first 4 events goes to the original one (so I update COUNT from 10 to 4) and then I create a new recurring event that holds the rest 6 events (so COUNT is 6 in this case)
My first observation is that this is not how the split events are displayed in google calendar - if I test that manually, the both events still show 10 occurrences but the second one doesn't produce any extra events (I'd expect 14 events from developer perspective, yet there are 10 as any user would expect). That implies there is a different approach here? Is it?
Also if I end up counting manually the number of events, there are still issues with cases like deleting one of the events first (let's say, the 4th event) - now how do I know that I need to show 6 instances in the new one and not 7?
Those thoughts make me think there is a better approach, but I can't find any other alternatives. Any advice on that?
UPDATE
It seems like google does it differently: for example after changing a title for "this and future" events in calendar view, it doesn't seem to produce two different recurring events since if you try to delete "all" events, that will remove all of them completely (rather than deleting only one chunk, either before or after the target event)
It seems like they are creating a bunch of exceptions or maybe "recurring exception" or something to do that. Can't find any examples on how to do that as of now thought.
Can't find any good solution for this after a few days of research and while I need to move forward I ended up with a sort of "compromise" between "good enough UX for my case" and "breaking best practice".
So I ended up updating each event individually which goes against google's warning as shown below but I limited the max count by 50. This is not necessary what others want to do, but this is good enough for the real world use case in my app.
Warning: Do not modify instances individually when you want to modify
the entire recurring event, or "this and following" instances. This
creates lots of exceptions that clutter the calendar, slowing down
access and sending a high number of change notifications to users.
And if user needs to schedule more than that, the user is asked to use "end date" instead.
Again, not ideal by any means so if anyone knows how to handle that correctly or knows how google handles that, you are very welcome to share it! (meh... and I need that for outlook too now...)
UPDATE: just got an idea: as an improvement, one can edit either "all future events" or alternatively the master event + "all previous events" depending on the index of the target event. In this case one can limit the number of requests by 2 (so in case of 50 events I'll need to do 25 requests maximum)
So if user wants to change the title from "Hello" to "Goodby" and if the user picked event number 5 in the series of 50 events to change all future events, we can change the master event to "Goodby" which will change the title of all events, and then update the first 4 events to the original "Hello".
Obligatory summary of comments and chat:
Updating events:
To update specific events in a recurring event you need to update the individual instance by specifying the event instance ID.
This is just the event ID concatenated with a datetime stamp (you can see this when making an Events: instances request for your eventID; if your event ID is xxxxxxxxxxxx then an instance ID would be something like xxxxxxxxxxxx__20200603T170000Z).
Unfortunately there's no direct update-instances endpoint so to update multiple instances in one request you'd need to use batching
The API doesn't have a dedicated method for updating recurring events regardless of the recurrence type, and I presume this is the reason the documentation says to edit the previous recurring event by cutting it down and inserting a new one, as per Google's warning:
Do not modify instances individually when you want to modify the entire recurring event, or "this and following" instances. This creates lots of exceptions that clutter the calendar, slowing down access and sending a high number of change notifications to users.
Batching:
Making a batch update on event instances does keep count consistency. If you edit instances in a batch and then use the 'this and all future events' option when deleting one of the instances of the recurring event they do all get deleted as they're still a part of the recurrance. There is no new event being created in either scenario, the event instances are being changed.
If you play around with Events: instances and use Events: update to change only some instances of an event, then you can see that they all stay part of the same recurrence chain and there is no count change.
For arbitrary large counts, even if you have a recurring event with 9999999 instances, each event still has an ID which you can retrieve from Events: instances. It's stored as a single event for event use, but the IDs of the instances are the identifiers which are different.
Honestly, it's not great that you have to edit each one manually; for large counts like 9999999 it's basically infeasible because you'll have to make a batch request for each set of 100 instances you want to change, but it's the only option available via the API at the moment.
Feature Request:
You can however let Google know that this is a feature that is important for the Calendar API and that you would like to request they implement it. Google's Issue Tracker is a place for developers to report issues and make feature requests for their development services, I'd urge you to make a feature request there, the Calendar API feature request form can be found here.

GA Measurement Protocol does not fire event for just one of the views

I've setup a Zapier automation to fire an event every time a new deal is made on a 3rd party CRM. The automation triggers fine, and retrieves the GA Client ID stored in the CRM. The goal of this automation is to add the value of the deal to the client's session history. This works completely fine on a new test GA View I made as well as the original one (the one left without any filters).
However, there's one GA View which has both, anti-bot/spider setting and 3 filters set up. I tried disabling all four of them, yet the event still wasn't being fired - not in real-time, nor User Explorer. Wondering what could be the cause of this. All views are, of course, of the same property. Are there any other filters (besides the anti-bot/spider setting and view filters) or options I may have missed that are view-specific that would cause events sent by Zapier not to fire on just this one view?
Any help is appreciated!
The update of the settings, in the specific case relating to the filters, may not be immediate. If you leave the filters disabled, you can certainly check if after midnight (or after a few hours after midnight) you see that data in the reports.
This happens because after midnight the data is reprocessed again, so for that day (which has therefore become the previous one), if you have removed the filters, you should find all the data.

Google Maps - Caching - Methods

Ok! So I have spoken to a google representative about this issue, however since I am not enterprise level, he can't push me to tech support and suggested that I use the SO for answers. Here is the question...
In Google Maps Terms it states the following:
(b) No Pre-Fetching, Caching, or Storage of Content. You must not pre-fetch, cache, or store
any Content, except that you may store: (i) limited amounts of Content for the purpose of
improving the performance of your Maps API Implementation if you do so temporarily (and in
no event for more than 30 calendar days), securely, and in a manner that does not permit
use of the Content outside of the Service; and (ii) any content identifier or key that
the Maps APIs Documentation specifically permits you to store. For example, you must not
use the Content to create an independent database of "places" or other local listings
information.
This led me to originally believe that google would not allow caching of any type of information. However, then I read the following:
When to Use Client-Side Geocoding
The basic answer is "almost always." As geocoding limits are per user session, there is no risk that your application will reach a global limit as your userbase grows. Client-side geocoding will not face a quota limit unless you perform a batch of geocoding requests within a user session. Therefore, running client-side geocoding, you generally don't have to worry about your quota.
Two basic architectures for client-side geocoding exist.
Run the geocoding and display entirely in the browser. For instance, the user enters an address on your page. Your application geocodes it. Then your page uses the geocode to create a marker on the map. Or your app does some simple analysis using the geocode. No data is sent to your server. This reduces load on your server, but doesn't give you any sense of what your users are doing.
Run the geocode in the browser and then send it to the server. For instance, the user enters an address. Your application geocodes it in the browser. The app then sends the data to your server. The server responds with some data, such as nearby points of interest. This allows you to customize a response based on your own data, and also to cache the geocode if you want. This cache allows you to optimize even more. You can even query the server with the address, see if you have a recently cached geocode for it, and if you do, use that. If you don't, then return no result to the browser, and let it geocode the result and send it back to the server to for caching.
So one side says you cannot cache, the other side tells you, you should. Another solution it states is to always use clientside when you can, but then this becomes a grey area as well, because both examples state that you must have a user input data. What if the jquery read data from a div or span and then geocoded the information? The user wouldn't have actually done the geocode,but it was still done client-side? I'm trying to create a site that has a bunch of events generated by users and this site could get pretty loaded, so I am trying to determine the best practice in being able to do this. Google suggested here, so before you go and say this is "off-topic" please note, this is where they stated me to post.
Any feedback would be greatly appreciated.
The first quote does not explicitly forbid caching data at all. It is ambiguous as to how much you can cache (what number explicitly is "limited amounts"?) but it does not forbid caching.
You are allowed to cache the data if it helps improve the performance of your site as long as you retain the data for no longer than 30 days and do not make it available in any way to any other service except the service that originally retrieved the data.
Regarding user interaction - if your user explicitly enters a page with the expectation that they will be shown geocoded information I would assume that this would fulfill "user interaction".
As an example from a project I worked on last year I had it set up to do the following:
- Show markers on the map
- If the user clicked a marker they were shown a popup with data from the cache if available, otherwise a geocode would be performed and the returned information would be cached along with the date/time of the cache.
Another page of the site showed a history of these markers at 5 minute intervals throughout the day. If cached data was present (from clicking the map marker as in the previous part) this would be shown, otherwise a geocode would be performed and the data cached as before. The user clicking to run the report was (in my opinion) enough "user interaction" to not count as pre-fetching as the user had to manually select a timeframe before the report would be displayed.
A cronjob then ran every day at midnight which would go through each record with cached data over 25 days old and remove it.
As it was I was caching much less than 10% of the marker positions being shown (20+ markers being updated every minute, but the report was being run on maybe 3-5 markers each day and only geocoding data for every 5th point).

Place a Timer and Monitor and Take Certain Action Upon its expiry

I'm developing an online quiz site where the users can take tests (multiple choice). I have a requirement to put a timer on the test say if the maker of the test sets the time to 30min a timer would be placed on top of the page counting down the time, now i want to monitor the timer on the server side when it reaches to 00:00 the test would stop and the marks obtained is shown.
Solutions i have considered:
1) To use a JS plugin and upon its expiry do a location.href to some ActionResult that will end the test.
2) To create a session and clear it after the given time and before rendering each question check that session if it has expired or not.
My concern about using a javascript based solution is its robustness, i want to implement a server side solution. Please help me find the right path...
Regards.
When using the timer in the browser there is no way to verify that it is running as expected. User can disable javascript and get around your restrictions; heck they can even change your javascript. So relying solely on javascript is not an option.
The best solution is to validate postbacks on server side. You can use javascript on Client side to inform the user so that they are aware of how much time is left and server side to verify they have not gone over the time limit. If synchronization is required, then you can have the javscript ping back every so often to resynch the time.
Expanded Answer
The time of the start of the test should be on the server side. Whenever the user clicks begin test or other start buttton to begin their test. The server should note the current time - perhaps in a session or even in database.
The user should then be informed of the time remaining via javascript and expected end time. These are then updated whenever the user submits a question or perform another postback to the server.
The end time will be the fuzzy part. If the javascript does it's job correctly; you can inform the user their test has ended through this (or window.href etc). If the javascript is not worked; then the user will receive their notification whenever they next attempt to submit something to the server.
Either way, the user should clearly be informed that this is the expected end time, and how much time they have remaining on each page load.

Possibility of Ajax Response Mix-up

Suppose that I have an ASP.NET page, where a customer can select a product from a drop down list, and then with this change event, corresponding price, quantity etc. fields are changed and set to appropriate values. These values are obtained from server-side asp.net page using jquery's "$.post(....)" method. Now in the same page, there is another section, which shows live market statistics of the products. This section obtains the live market product values by making a request to the server-side asp.net page every 20 seconds interval, which is controlled using a timer.
Now suppose that this timer goes off and a request is being processed at the server. At the same time the customer selects a different product from the drop down list, which also fires another ajax request.
Is there any chance that the responses from these two different request can get mixed up? I mean the response which is intended for the live update section is considered as the response for the product catalog section? If that is the case, then before making an ajax request, how can I be sure that there is another request is being processed at the server, and if necessary, abort that request?
I don't want to use ASP.NET ajax for this situation, because it generates a lot of unnecessary script/data, which increases the page size, and the customers of this site has a bandwidth of 2-4 kbps.........................:|
It depends how the code is written. So long as you aren't using globals in your JS you should be fine.
The first example at http://www.jibbering.com/2002/4/httprequest.html uses globals (xmlhttp), don't do that. Pass variables about instead. Make use of the this keyword inside your onreadystatechange callback function.

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