I am looking for a cache implementation for an Angular2 application.
For example, we have a million Movie objects stored on a server (i.e. enough that we don't want to grab them all at once). On the server, a REST endpoint is available : getMovie(String id)
Back on the client side, the cache should provide a simple way to get a movie from Angular, something like cache.getMovie(id:string): Observable<Movie>. This will hit the REST endpoint only for the first call, and store it locally for later requests.
Angular1 has angular-cache or the $cacheFactory, with LRU support and other great functionalities.
I started implementing a basic cache using a local HashMap, but that seems like a very common need.
Is there a good in-memory cache implementation for Angular2 yet?
I would use lscache and extend it providing few underlying storages: localStorage, sessionStorage, and self-implmented memoryStorage. TypeScript definitions are already available.
Related
Stack is:
Angular
Laravel
S3
nginx
I'm using S3 to store confidential resources of my users. Bucket access is set to private which means I can access files either by creating temporary (signed, dynamic) links or by using Storage::disk('s3')->get('path/to/resource') method and returning an actual file as a response.
I'm looking for a way to cache resources in user's browser. I have tried to set cache headers to resource response directly on AWS, but since I'm creating temporary urls, they are dynamic and cache is not working in that case.
Any suggestion is highly appreciated.
EDIT: One thing that makes the whole problem even more complex is that security of resources should be intact. It means that I need a way to cache resources, but in the same time I must prevent users from copy-pasting links and using them outside of the app (sharing with others via direct links).
Temporary links in terms of security are still not an ideal solution, since they can be shared (and accessed multiple times) within the period of time they are valid for (in my case it's 30 seconds).
Caching will work as-is (based on Cache-Control, et al.) as long as the URL stays the same. So, if your application uses the same signed URL for awhile, you'll be fine.
The problem comes when you want to update an expiration date or something. This of course has different querystring parameters, and is effectively a different URL. You need a different caching key, but the browser has no concept of this by default.
If it is acceptable for your security, you can create a Service Worker which uses just the base URL (without querystring) as the cache key. Then, future requests for the same object on the bucket will be able to used the cached response, regardless of other URL parameters.
I must prevent users from copy-pasting links and using them outside of the app (sharing with others via direct links).
This part of your requirement is impossible, and unrelated to caching. Once that URL is signed, it can be used by others.
You have just add one parameter in your code.
'ResponseCacheControl' => 'no-store'
Storage::disk('s3')->getAwsTemporaryUrl(Storage::disk('s3')->getDriver()->getAdapter(), trim($mNameS3), \Carbon\Carbon::now()->addMinutes(config('app.aws_bucket_temp_url_time')), ['ResponseCacheControl' => 'no-store']);
In MVC and most other service frameworks I tried, caching is done via attribute/filter, either on the controller/action or request, and can be controlled through caching profile in config file. It seems offer more flexibility and also leave the core service code cleaner.
But ServiceStack has it inside the service. Are there any reason why it's done this way?
Can I add a CacheFilterAttribute, but delegate to service instead?
ToOptimizedResultUsingCache(base.Cache,cacheKey,()=> {
// Delegate to Request/Service being decorated?
});
I searched around but couldn't find an answer. Granted, it probably won't make much difference because the ServiceStack caching via delegate method is quite clean. And you seldom change caching strategy on the fly in real world. So this is mostly out of curiosity. Thanks.
Because the caching pattern involves, checking first to see if it is cached, if not to then execute the service, populate the cache, then return the result.
A Request Filter doesn't allow you to execute the service and a Response Filter means that the Service will always execute (i.e. mitigating the usefulness of the Cache), so the alternative would require a Request + Response filter combination where the logic would be split into 2 disjointed parts. Having it inside the Service, lets you see and reason about how it works and what exactly is going on, it also allows full access to calculate the uniqueHashKey used and exactly what and when (or even if) to Cache, which is harder to control with a generic black-box caching solution.
Although we are open to 'baking-in' built-in generic caching solutions (either via an attribute or ServiceRunner / base class). Add a feature request if you'd like to see this, specifying the preferred functionality/use-case (e.g. cache based on Time / Validity / Cache against user-defined Aggregate root / etc).
After a research it seems that Meteor Sessions are reset after refreshing page or opening the website in new tab, i.e. they are not usual server-side sessions but something like global javascript variables on client-side. Some people advice to use AmplifyJS, but I'm not sure that it will work like usual session in other frameworks/languages and also it is a third party library, so is there any normal way to use sessions in Meteor, i.e. keep user-specific data on server?
At this moment I'm handling that by using custom Collections, but it is not an ideal way of doing that because it is needed to remove expired values from Collection manually, which makes additional troubles.
Yes this is correct. Despite the name Session is nothing like a cookie, but just a reactive form of a variable stored in a hashmap
To keep data persistent across tabs you need to use a Collections (as this is the only way to reactively share data across tabs) - Cookies can't work because they can't be made reactive as data needs to be sent to the server to notify the client when there is a change. There really wouldn't be another way at the moment as the publish/subscribe methods can only send down data from collections at the moment.
You can use your setup you have now with your custom collection. You can use a server side cron job to remove expired data (either with Meteor.setInterval or Tom Coleman's cron.
There is a package developed just for that: https://atmospherejs.com/u2622/persistent-session
After installation you can use the following functions to set sessions which are persistent:
//store a persistent session variable which is stored across templates
Session.setPersistent(key, value);
//same as above, but automatically deletes session data when user logs out
Session.setAuth(key, value);
I've tried the package and it works like charm.
Background: We are using grails 2.1.1. We are not using any DB as of now. We make a web service call for each response on another server.
Now the problem is, there is web service call which returns some static data in XML form and this data is usable throughout the application. The size of the xml is around 40kb. This xml contains static data like, project_list, status_type_list etc. and we have to use this in various dropdowns and menu items in different gsp pages.
So, please suggest us the best way to handle this data. So that it doesn't effect our page load time and browsing experience. And also we can easily use the data on client side.
responding to your comment on the question. I would prefer using annotation based caching over the plugin, if the requirement is as simple as you state that it is.
If the calls are being made from server-side and you want to cache the results of the parsed XML then you can do something like:
#Cacheable("staticDataCache")
def getStaticDataFromXML() {}
You can then use the above method to pull the maps, lists whatever data structure you've used to store the result and it will pull it from the cache.
and then another service method to flush the cache, which you can call frequently from a Job.
#CacheFlush("staticDataCache")
def flushStaticDataCache() {}
Use the cache plugin to cache the static xml data. And then add some policy as to when the cache should be updated... (i.e. using a job to check if the xml has changed every hour)
I'm looking at using Subsonic with a multi-tenant ASP.net web application. There are multiple DB's (one per client/instance). The user logs in with a domain suffix to their username (e.g. user#tenant1, user#tenant2).
The custom membership provider will then determine which database a user is using, and authenticate against it. All user-initiated calls in the webapp will be wrapped in a SharedDbConnectionScope call, however I have a question regarding caching subsonic items.
Basically each instance will have a few records that rarely change (search options/configurations). I would like to read these in the Application_Start event, and cache them into the ApplicationState.
In the Application_Start event, it would loop over each client database, use a SharedDbConnectionScope to connect to each DB, and create these cached records (e.g. Application('tenant1_search_obj') = subsonic_object
When a user loads the search page, it would then check what domain a user is in, and then retreive that search option from the cache.
Is this feasible? I'm just concerned that if I cache an object, when I retrieve it from the application cache it won't know what connection its using, and might possibly pull in the wrong data.
I'd like to avoid putting this in the session object if possible.
it's possible, but probably not a good idea since it doesn't scale at all - you're going to pop a new connection for every single client whether they show up or not.
Maybe your best bet is to "lazy load" the setting - first hit on the search page loads the config into the cache or Application settings and there it stays.
Other than that - to answer your question it is possible. If you're using SubSonic 3, just create a new provider on the fly using ProviderFactory.GetProvider(connectionString, "System.Data.SqlClient") and then execute your stuff against it.
For SubSonic 2 - SharedConnectionScope is what you want.