I'm using Iron Router (with RouteControllers) and I'd like to know if meteor keep cache for "publishes" when page (url) change.
Example :
I want use meteor for a cooking site, so I've a section with a BIG list of recipes, and I can filter this list (by theme, preparation time, etc.). So, potentially, there will be a lot of different lists.
(This is a use case but my question can be valid for classic schema : a user visits a recipe detail page, and go away... does meteor clean cache for this subscription on server (which published the recipe datas) ?)
If I use subscriptions, does meteor keep cache when I change filter information ? And if not, how to do that without keep cache on local user database (and on server) for each request use can make ?
Sorry, I'm a beginner in meteor and it's a little confused for me. When I read documentation about meteor and publish/subscribes, I think that my app usage will increase memory excessively...
There is multiple scenarios to take into consideration:
The user closes the page and re-opens it, or refreshes.
In that case, no subscription whatsoever is natively kept.
The user changes page with a router (no reload or page closing), templates are destroyed
If the publication is done inside the router controls, it's generally cancelled (not kept) on page change. I think this is valid for both iron:router and meteorhacks:flow-router.
If the publication is done inside the template control, it is cancelled on destruction.
Else if it is done outside these pre-defined controls then the subscription is not cancelled.
You will need to adapt to these behaviours. If you want, for example, to remember the subscriptions across router pages, you will need to store them externally and control them in your own way.
afaik the cache is client-side, in minimongo. The publication on the server isn't actually used until you subscribe to it on the client. i.e.:
Meteor.publish('allRecipes',function(){
return Recipes.find();
});
Doesn't do anything by itself. A client subscription needs to refer to it.
If your collection of recipes is very large and you don't want to have a lot of network overhead to move it all to the client, then you can implement server-side search in your subscription, for example with https://atmospherejs.com/meteorhacks/search-source
Related
Let's say, hypothetically, I am working on a website which provides live score updates for sporting fixtures.
A script checks an external API for updates every few seconds. If there is a new update, the information is saved to a database, and then pushed out to the user.
When a new user accesses the website, a script queries the database and populates the page with all the information ingested so far.
I am using socket.io to push live updates. However, when someone is accessing the page for the first time, I have a couple of options:
I could use the existing socket.io infrastructure to populate the page
I could request the information when routing the user, pass it into res.render() as an argument and render the data using, for example, Pug.
In this circumstance, my instinct would be to utilise the existing socket.io infrastructure; purely because it would save me writing additional code. However, I am curious to know whether there are any other reasons for, or against, using either approach. For example, would it be more performant to render the data, initially, using one approach or the other?
I am building an ecommerce website for a project for my portfolio, and I wanted to know where the calculations should be done for the cart.
Normally I use react and I create a model folder, route folder and a controller folder but the way I was taught Angular it seems like the services acts like the routes and the actual calls to the database are done in the node server file which I am sure I could separate into a separate controller file. My question is where should the calculations for the cart be done before I send the order to the database? I thought about doing it in the cart component before the order is place or should it be done in the services or in the backend in the controller? I am just trying to figure out what is the standard
When writing an Angular app, I think it is important to adhere to the following principles that:
Components - should have a single responsibility for simple view logic only, shouldn't reach out to the server, and shouldn't do complex calculations and/or logic that is not related to the view.
Services - should have a single responsibility for (reusable/shared) and complex logic, to do outbound communication and reach out to the server, and to act as data stores (using BehaviorSubjects).
Therefore, if your calculations are needed to update the view of the cart, I would vote that these calculations need to be made at the component. If your calculations are needed to update the items or the request to be sent to the server, they need to be made at the service.
Remember, the component "shouldn't know" how the data comes to it or how it is manipulated or sent to the server. The component should only know, given any data - how to present it in the view, and shouldn't "worry about" how that data came to it. Similarly, the component shouldn't know how the data is calculated before being sent to the server, and this would fall within the responsibility of the service that works with and processes the cart data and builds the request to the server.
However, you have to always consider the security of your app, and if a malicious data modification at the client side can affect your cart. If such caculations affect the app's security - they should at least be validated at the server if not fully delegated to it.
I don't know the calculation you need exactly, but since it is an e-commerce website I assume it is simple math such as the total payment amount of checkout.
The main role of the server is communicating to the database. If a task does not involve interacting with data, you can do the calculations on the client-side. Leaving details on client-side allows you to have access to details of your formula, and reduce the communication time between client and server.
Have small app (My first Node js App), where I want add changing real-time content.
For example I have a common url which have list of content link, when user click on particular link it will open its correspondence link.
I have teacher and student role in the app so if teacher open the specific content(From the common url page) then it will automatically open that content for all student who have common url.
Please give me any Idea to implement this functionality and please tell me any plugin who have same functionality for real time content change.
One way, probably the easiest would be to use websockets, an easily manageable choice is socket.io npm package. What makes websockets different from http requests is the direction of the data flow. While http is pull based, meaning that a request has to be made to the server in order to get a response, websockets - once the connection is established - are or at least can be push based, meaning that the server could push out content without having to get a request from the client. In your situation, the teacher and the studens would all have an active websocket connection with the server. When the teacher clicked on a certain view, it would push the view’s data requirements to the students without any interaction from their side and the view would update on their screens according to the pushed data.
Look into how websockets work and try to experiment with a basic socket.io setup.
Is there any way to build a GitLab URL for a milestone or project based on its id property instead of the slug?
Context:
I have an app that I use as a GitLab web hook, and from its front end would like to link back to GitLab. I'm keeping the project and milestone ids, as they are unique, but can't find a way to link back to them. Ideally something like: http://gitlab.example.com/project/83/milestone/113 or even http://gitlab.example.com/milestone/113 would work for me (even if they do a redirect).
Examining rake routes and config/routes.rb tells me that such routes do not exist.
The only options I can see are:
store just the slugs which are also unique. Your request and memory usage will be slightly larger, but it's worth it.
make an extra API request to get the slugs. This requires 2 requests, so it is worse than having a larger request.
For new routes of form /something to be created in gitlab, something needs to be blacklisted at https://github.com/gitlabhq/gitlabhq/blob/199029b842de7c9d52b5c95bdc1cc897da8e5560/lib/gitlab/blacklist.rb, and interestingly projects is already blacklisted, but it is currently only used for project creation.
milestones however is not blacklisted: so a user could be called milestiones and that would generate ambiguity.
I would also take a close look at how GitHub organizes its API and paths, as it is likely to be optimal: is ID web access possible in GitHub?
I'm working on an app that i being built using Node and Express. All is fine, however the app is currently not asynchronous and I'd like it to be, so I'm currently investigating what would be the best way to do it.
As far as I can tell, socket.io seems to be the preferred choice to go with Node.
My question is, is socket.io's methodology the best way to move data between the server and client or is there a better, more robust way to do it? Maybe something accomplished with Node only?
PS: I think socket.io sounds really nice. Its just that I'm new to Node and though there would be a simpler way to move data back and forth.
Many thanks
EDIT:
Ok, I've seen the term "realtime" used before and was frown upon. The commenter implied that technically there is no "realtime" application, hence me choosing asynchronous, however realtime does describe what I'm after: An app that will be all ajax-like. For instance, in my app, when I need to edit a saved document (mongodb records are called documents), I need to redirect the page passing the document id as argument. I don't want that. I want all through ajax. I can achieve this with jQuery, however behind the scenes the server will still be moving through urls (I'll need to create loads of app.get('product/:id/edit', ...), app.post('/product/:id/edit'. ... and then use $.ajax to get and post stuff ) so I was wondering what's the best way to achieve this.
PS: I might be looking at this completely wrong. Like I said, I'm new to Node and for app development for that matter.
EDIT2: An example: Let's say I have a page with a table in it where I list all products. Each product will have a EDIT/DELETE button. At the moment, when I click edit, I'm redirected to another page where I can edit the product and save it, then I'm redirected to the product listing. I'd prefer to load the product into a modal window, make whatever edits I need, then update the product/listing without leaving the page.
Using $.ajax I can use the product ID, enquiry the db for that particular product, populate the field in the modal with the product details and display to the user. Then allow the user to make the changes and update the products, however the part in which I need to enquiry the db in order to populate the modal is muddy because the id needs to be passed through the url...
I don't know how to pass the id to the application unless is through app.get('/product/:id/edit', ...) then app.post('/product/:id/edit').