I know i can call screen:get_clients() in a loop to achieve this, but I'd like to do it asynchronously.
I've tried to use manage and unmanage signals, but this doesn't cover all scenarios eg. switching tags, moving clients to other tags and minimizing clients.
There is no single signal for what you are asking, I think. So you will need to collect all the necessary signals yourself.
switching tags: That's property::selected on the tag class
moving clients to other tags: tagged and untagged signals on either clients or tags
minimizing clients: property::minimized
The same approach, connecting to lots of signals, is also done in the code in AwesomeWM. For example, here is the tasklist's code: https://github.com/awesomeWM/awesome/blob/7a759432d3100ff6870e0b2b427e3352bf17c7cc/lib/awful/widget/tasklist.lua#L641-L676
Related
I have an use case in which I need to have multiple modules loaded in the view at the same time. Thing is, each of those modules might be as simple as a component, or a complex Angular module with a router and everything. I guess you could call it a plugable framework.
The number of modules I have to show or who they are is dynamic (I'm getting them from a server).
My first idea is that it would be good for this case if the feature module's router wouldn't be a singleton with the main one and also if they wouldn't update the url completly.
Each of the feature module should be able to be launched as a stand-alone app if bootstrapped (therefore, I do need it to be able incorporate all Angular 4 features including the router).
I managed to get something working by playing with the router and with named router outlets (secondary routes) but not sure how good that is in the long run.
How should I approach this?
I am in the early stages of attacking a somewhat similar scenario. In my app, the UI is organized in panels that are designed to stand alone on smaller displays, or side by side on larger. I find this approach works well for my routes, as my app is designed to edit a complex, highly hiegraphical document with many inter-related sections. e.g. User follows link on list to open detail, new detail panel appears to right... follows link on detail to related node... etc.
The solution I'm noodling with now is attempting to use an ngrx store that interacts with the router (and router-store) to dynamically create panels based upon router data. Well, technically it does not create the panels, it only serves the data that tells a component what to create and render.
I know my situ is not exactly the same as yours, but perhaps there's something in my approach that may help you find usefull or at least thought provoking.
I am working on a project where I do not have access to page source nor can I ask client's IT team to create in-page/onload dataLayer e.g. having dataLayer before the tag. Is the idea of implementing enhanced e-commerce tracking remotely possible via dataLayer.push e.g. build dataLayer as you go?I have a very little knowledge of dataLayer.push (which I am starting to read up). Question is :
Is dataLayer.push the correct way move forward? Have anyone done this
before?
what issue I might face e.g. "add to cart" event, remove cart or
category page any working example? I still don't have a clear view of
the workflow here.
What are the downside of doing it this way beside "style/css" based
trigger might fall off during future site design update.
Thanks.
Your main problem is that you need to get the data from somewhere. Usually without a dataLayer this means DOM scraping and then assembling the scraped data into a dataLayer in a custom javascript function. Drawbacks are the same as with your stle/css based triggers:
Implementation is strongly coupled to the page layout
data might be missing, or require cleaning (if mixed with html or unrelated text)
potentially expensive in clients CPU time
custom javascript introduces new points of failure (i.e. can you test rigorously enough to guarantee that there are no side effects)
If you do workarounds around your client's ITs shortcomings remember that you own them - you will be responsible if the workarounds break, or have side effects, or need to be amended to account for new features. Make sure that you are very well compensated for that risk (and personally with the experience I have now I would not do this at all).
I think it's important to acknowledge here that the Data Layer is just one way of storing this information, and is used solely because it's possible to push data to it from the page.
If you can't write the code into the site itself, don't push information to the data layer. Just keep that information for yourself, in GTM's variables. You'll save yourself a huge headache, and a bit of computation too.
DOM scraping is a perfectly reasonable way to get hold of information, but you will run into some barriers.
You're going to have to write a lot of JavaScript to get the data you need.
Some buttons may turn out to be composed of several elements that you'll have to cover with your triggers etc.
Any changes to the site will potentially ruin your code.
Not everything is available to you, especially verification of data (checking if a purchase went through is probably no longer possible before reporting the transaction).
I am making a game. And this time trying to implement menu (-->tutorial) -> game-> scoreboard -> game over
screens.
These screens themselves are quite different in terms of structure. So i am not sure if states is a 100% correct approach here (as I understand states are good for similar layouts) From the other hand many of them has back button to return to previous state, e.g. in tutorial I will have start game and back to menu buttons, etc.
I wonder if there is a clear solution for a problem like this? Maybe there is a special library to handle such cases?
State machines (not only for visual states) are a good solution to implement the behavior of encapsulated components, such as buttons or - in your case - menu items, perhaps even some of your game logic. They can be described independently for each component, and they help to keep your interactions organized, and thus to prevent errors.
State machines are difficult to maintain, however, when you are looking at an entire application: The interactions are usually multi-dimensional (i.e. not only one component is involved, but many, and at different levels in the hierarchy), and when all the different players are taken into account, the resulting state machine will soon become very complex.
From my experience, it is best to use an event-driven approach combined with Model-View-Controller architecture for your application logic, and use state machines at the component level. I would advise to look at some of the existing Model-View-Controller frameworks for this, most notably RobotLegs, PureMVC and Parsley (though to me, Parsley seems a little less complete than the other two).
I'm working on an a pretty big project right now and am trying to implement an MVP architecture. I'm starting to run across a instances where I think JQuery or Javascript might be better suited than server-side code. I'm looking for feedback on how others are implementing client-side programming into their enterprise applications. How are you structuring the client-side code and how do you determine when to use it?
Things that can make user say "wow". For example - Populating search results while user has just typed 3-4 character of search term. Just go back in past and think about Yahoo or Hotmail which used to postback to server when you clicked on "Create Message". But when google came they just did on client side without going to server. I bet you would have said "wow" to that. At least I did.
Things that can reduce server load. For example - Adding extra data entry row in HTML table, instead of doing it through round trip, Increase/Decrease of quantity etc.
These are just some example to sight. Even to do these things properly you need to go to server but that will be behind the scene using ajax. Other than this you need to select few more jquery plugins that you will use in your project. To name some are jQuery UI, jQuery Validation, jQuery AnythingSlider etc. There are too many of them.
Http://ClearTrip.com is one site that I envy for their UX. Visit their site from mobile device and you will get further clues about their UX work. Besideds just coding you need to have a person in your team who can work on these UX aspects.
Regarding how this fits into DDD: I've just recently started my journey into DDD but one hears a lot about command/query separation in that circle. Certainly if you are doing something that hits your domain (like fetching for auto-completion or certainly if you allow partial page submission to accomplish a domain command) you have to decide how it gets there and how the domain is structured to handle it.
I think two decisions are most relevant.
First, bits entirely in the browser and even those specifically in your application layer are outside your domain and thus, though covered in the layered architecture part of the DDD discussion, do not land in the entity/value/event/service, etc. discussion. If, however, you are using AJAX to interact with your application layer and in turn need to access your domain, you need to consider again two things in my mind.
(a) Are you separating commands and queries simply using different methods on your domain? Fine if you have a relatively small demand for either queries or commands and this will not seem like "noise" in your domain API. Otherwise, you have a separate bounded context...another domain modeled just for queries that your UI needs to avoid clutter on your domain. Regardless, you are doing something like JS->AJAX handler in application layer->domain (including a domain service).
(b) Is this a command or a query? Once you have (a) figured out, this lets you know where the access will land...then use the presentation layer's use case to elaborate the domain concept and put it into your ubiquitous language.
Second, you have the DTO vs direct to domain decision. This can be a religious war gathering topic, but usually the answer is "depends." I think there are cases for using DTOs and cases for not (within the same architecture)...just search for all the discussions around the topic and apply the pattern only where it adds value; I won't try to cover details here.
Hope this provides some insight or at least conversation magnet to which others will add.
I guess this question is a little too subjective. Looks like I'm just going to grab a view books on advanced javascript and study up on the JQuery library.
Now a community wiki!
I want to make it clear first: This isn't a question in relation to server-side Javascript or running Javascript server side. This is a question regarding rendering of Javascript code (which will be executed on the client-side) from server-side code.
Having said that, take a look at below ASP.net code for example:
hlRemoveCategory.Attributes.Add("onclick", "return confirm('Are you sure you want to delete this?');")
This is prescribing the client-side onclick event on the server-side.
As oppose to writing Javascript on the client-side:
$('a[rel=remove]').bind('click', function(event) {
return confirm('Are you sure you want to delete this?');
}
Now the question I want to ask is: What is the benefit of rendering javascript from the server-side code? Or the vice-versa?
I personally prefer the second way of hooking up client-side UI/behaviour to HTML elements for the following reasons:
Server-side does what ever it needs to already, including data-validation, event delegation and etc; and
What server-side sees as an event is not necessarily the same process on the client-side. i.e., there are plenty more events on client-side (just look at custom events); and
What happens on client-side and on server-side, during an event, could be completely irrelevant and decoupled; and
What ever happens on client-side happens on client-side, there is no need for the server to know. Server should process and run what is given to them, how the process comes to life is not really up to them to decide in the event of the client-side events; and so on and so forth.
These are my thoughts obviously. I want to know what others think and if there has been any discussions on this topic.
Topics branching from this argument can reach:
Code management: is it easier to render everything from server-side?
Separation of concern: is it easier if client-side logic is separated to server-side logic?
Efficiency: which is more efficient both in terms of coding and running?
At the end of the day, I am trying to move my team to go towards the second approach. There are lot of old guys in this team who are afraid of this change. I just wish to convince them with the right facts and stats.
Let me know your thoughts.
UPDATE1: It looks like all of us who have participated in this post have common thought; Good to know that there are others who think alike. Now to go convince the guys ;) Thanks everyone.
Your second example is vastly superior to the first example. Javascript is your behaviour layer and should be separate from your semantic markup (content) and CSS (presentation). There are a number of reasons this is better architecture:
Encourages progressive enhancement. As you mentioned, the backend code should work correctly in the absence of JS. You cannot rely on your clients having JS available. This way you build it once without JS and then can enhance the experience for those with JS (e.g. by adding clientside validation as well as serverside validation so that the client can get instant feedback)
Cleaner markup. Normally reduced download size. One reusable selector in a separate JS file that can be cached and shared between pages vs. a handler on each element.
All of your JS in one re-used place. e.g. if your code was opening a popup window and you decided to change the dimensions of the window you would change it once in the code in the JS file vs. having to change it on every individual inline handler.
There are lots of other arguments and reasons but they should get you started...
Also, from your example it appears that you have a normal link in your document which can delete content. This would also be a bad practice. Anything that deletes or updates content should be done on a POST (not GET) request. So it should be the result of submitting a form. Otherwise e.g. googlebot could accidentally delete all of your content by just crawling your page (and search engine robots don't execute JS so your alert wouldn't help there)
The two biggest differences i can think of up front are:
you lose the client side caching you would get if the javascript was in a separate js file
if you need to change your javascript, you have to recompile (extrapolate this to what happens after you have released your product: if you have to recompile then you need to redistribute binaries instead of just a modified js file)
it is easier to use the VS debugger if the javascript is in a separate file; you can just set a break point in that file, if you are generating the code server side then you have to use the running documents feature, find your generated code and then add the breakpoint, and that breakpoint has to be manually added everytime you re-run your app. Following on from that, if the code is in a separate file, then you can just make your tweak to the javascript code, F5 your browser page, and keep on debugging without having to stop and restart the debugger.
It should be mentioned that sometimes you have to insert js code from the server - for example if the bulk of your code is in a separate js file and you need to insert control identities in to the page for that code to work with. Just try to avoid that situation if possible.
Looks like you already know what to do. Rendering it on the server side is a bad idea.
The simple reasoning being you're Javascript lives both on the server side pages as well as in separate Javascript files (assuming you are using Javascript at all). It can become a debugging nightmare to fix things when everything is everywhere.
Were you not using any other Javascript besides what the server side scripts generate, it would probably be fine and manageable (forget what the unobtrusive movement says).
Secondly, if you have 100 links on the page, you will be repeating that same code in 100 places. Repetition is another maintenance and debugging nightmare. You can handle all links on all pages with one event handler and one attribute. That doesn't even need a second thought.
<Rant>
It's not easy to separate HTML and Javascript, and even CSS especially if you want some AJAX or UI goodness. To have total separation we would have to move to a desktop application model where all the front-end code is generated on the client side programmatically using Javascript, and all interaction with the server gets limited to pure data exchange.
Most upstream communication (client to server) is already just data exchange, but not the downstream communications. Many server-side scripts generate HTML, merge it with data and spit it back. That is fine as long as the server stays in command of generating the HTML views. But when fancy Javascript comes onboard and starts appending rows to tables, and div's for comments by replicating the existing HTML structure exactly, then we have created two points at which the markup gets generated.
$(".comments").append($("<div>", {
"id": "123",
"class": "comment",
"html": "I would argue this is still bad practice..."
}));
Maybe this is not as big a nightmare (depending on the scale), but it can be a serious problem too. Now if we change the structure of the comments, the change needs to be done at two places - the server side script and templates where content is initially generated, and the Javascript side which dynamically adds comments after page load.
A second example is about applications that use drag and drag. If you can drag div's around the page, they would need to be taken off the regular page flow, and positioned absolutely or relatively with precise coordinates. Now since we cannot create classes beforehand for all possible coordinates (and that would be stupid to attempt), we basically inject styles directly in the element. Our HTML then looks like:
<div style="position: absolute; top: 100px; left: 250px;">..</div>
We have screwed up our beautiful semantic pages, but it had to be done.
</Rant>
Semantic, and behavioral separation aside, I would say is basically boils down to repetition. Are you repeating the code unnecessarily. Are multiple layers handling the same logic. Is it possible to shove all of it into a single layer, or cut down on all repetition.
You and the other people answering the question have already listed reasons why it is better not to having the server side code spit intrinsic event attributes into documents.
The flip side of the coin is that doing so is quick and simple (at least in the short term).
IMO, this doesn't come close to outweighing the cons of the approach, but it is a reason.
For the code in your example it doesn't really matter. The code isn't using any information that is only available at the server side, so it's just as easy to bind the event in client side code.
Sometimes you want to use some information that is available at the server side to decide whether the event should be added or not, or to create the code for the event, for example:
if (categoryCanBeDeleted) {
hlRemoveCategory.Attributes.Add(
"onclick",
"return confirm('Are you sure you want to delete the " + categoryType + "?');"
);
}
If you would do this at the client side, you have to put this information into the page somehow so that the client side code also has access to it.