I need to create a feed based on changed documents. I figured the _changes api would be perfect in this case. Ie simply store the last sequence id client side, so we can use it to limit the results in the next call to _changes.
Currently, the application performs the following:
calls _changes with since/filter parameters
calls a show function for each id in the _changes feed
renders all changes into the customer feed
What I would like, is to be able to call a list function on the entire _changes result in a single request. This would remove the need to explicitly parse the _changes result on the client, and move that functionality to the server.
The question: is this even remotely possible?
I have been trying to implement a view, doing "almost" the same thing as _changes, but without any real luck.
This is not possible at the time, and the _changes API is different enough from regular views that it's not entirely straightforward to implement.
There is a ticket open in the CouchDB issue tracker, but it hasn't been updated in quite a while.
Related
I think I have a tough one for you guys. Or at least it's been tough for me. I've been searching for the best way to do this in Stack Overflow and everyone that has asked has been given a different response.
I have this code that is accessing an API and calling a maintenance list of all the vehicles in a fleet.
function getMaintenanceList() {
var settings = {
"url": "API URL HERE",
"method": "GET",
"timeout": 0,
"headers": {
"Authorization": "Bearer token here"
},
};
$.ajax(settings).done(function (response) {
// The response the API sends is a JSON object.
// It is an array.
var jsonMaintenance = response;
var parsedJson = JSON.stringify(jsonMaintenance);
//Left over code from when I was trying to
//pass the data directly into the other page
// I was unable to do so
//return jsonMaintenance;
//Left over code from when this was in a PHP file
//and I was posting the stringified response to the page
// for testing purpose
//I had to disable CORS in Google Chrome to test the response out
//console.log(jsonMaintenance);
//document.getElementById("main").innerHTML = parsedJson;
});
};
The code above works well. What I was attempting to do here was write the stringified response to a file. Save that file in the server. Call it from another page using JavaScript and save it as an object in JavaScript, parse it using JSON.parse(), and then pull the required information.
Here's an explanation as to why I'm trying to do it this way. When I call the maintenance list from the API, I'm getting the entire maintenance list from the API, but I need to be able to display only parts of the information from the list.
On one page, we'll call it vehicle-list.php, on it I have a list of all the vehicles in our fleet. They all have unit numbers assigned to them. When I click on a unit number on this page it'll take me to another page which has more information on the vehicle such as the VIN number, license plate, etc. we'll call this page vehicle-info.php. We're using this page for all the vehicles' information, in other words, when we click on different unit numbers on vehicle-list.php it'll always take us to vehicle-info.php. We're only updating the DOM when we go to the page.
I only want to include the information specific to each vehicle unit in the page along with the other info in the DOM. And I only want to call the info from the API once as I am limited to a certain amount of calls for that API. This is why I am attempting to do it this way.
I will say that what I originally wanted to do was get this JSON response once every 24 hours by using a function in vehicle-list.php save the reponse as a variable as seen above var jsonMaintenance = response; and then just access certain parts of the array every time a unit number is clicked. However, I have been unable to access the variable in any other page. I've written many test files attempting to call jsonMaintenance without success so I've been trying to to just save it as a text file to the server and I haven't been able to figure that out either.
After explaining all of the above. My questions are these:
How do I best manipulate this data to accomplish what I want to accomplish? What would be the best standard? Is the above code even the right way to call the data for what I'm trying to do?
There doesn't seem to be a set standard on accomplishing any of this when I search on Stack Overflow. I'd like to be as efficient as possible.
Thank you for your time.
there is a lot of ways how you pass your data through your website after getting it in from an api call, the best approach is to store these information in a database and call it back in which ever way you want, you can do that as far as you are using php, you can store it to sql or to access, if you don't want to store these information in a database like in sql or access, then best way is to store it to localStorage and call it back whenever you want.
I will show you briefly how you can do that, if you want better explanation post an example of your returned data.
to store an item in localstorage use,
localStorage.setItem('key', 'value');
to call an item back from localstorage use,
var somevar = localStorage.getItem('key')
to remove specific item from localstorage use,
localStorage.removeItem('key')
to clear all items saved to localstorage use,
localStorage.clear()
be aware storing the data to localStorage is only at the station you are using
I would do it somehow like this.
Call the maintenance list from the API with the server side language of your choice which seems to be PHP in your case. Lets say the script is called: get-list.php. This can be triggered by a cron job running get-list.php in intervals limited to the certain amount of calls that you are allowed to do for that API. Or if you are not able to create cron jobs then trigger the same get-list.php with an AJAX-call (eg jQuery.get('sld.tld/get-list.php') - in this case get-list.php have to figure out if its the right time to call the API or not).
Now that you have the data you can prepare it as you want and store it as a JSON-string in a text file or database of your choice. If I get you right you have a specific dataset for each vehicle, which have to be identified by an id (you named it "unit number") so your JSON would look kind of: {"unit1": { property1: "val1", property2: "val2" }, "unit2": { property1: "valXYZ", property2: "valABC" }} or alike.
Now when you link to vehicle-info.php from vehicle-list.php, you do it like so: ancor or similar as well. Of course you can also grab the data with AJAX, its just important to deliver vehicle-info.php the corresponding unit number (or id - better to say) and you are good to go.
vehicle-info.php now have all there is to render the page, which is the complete data set stored in text file or data base and the id (unit number) to know which part of the whole dataset to extract.
I wanted to give you this different approach because in my experience this should work out just so much better. If you are working server side (eg PHP) you have write permissions which is not the case for JavaScript-client side. And also performance is not so much of an issue. For instance its not an issue if you have heavy manipulating on the data set at the get-list.php-level. It can run for minutes and once its done it stores the ready-to-use-data making it staticly available without any further impact on performance.
Hope it helps!
If i ran into a similiar problem i would just store the data in a database of my own and call it from there, considering you are only (willing/abe/allowed) to request the data from the API very rarely but need to operate on the data quite frequently (whenever someone clicks on a specific vehice on your applicaiton) this seems like the best course of action.
So rather than querying the data on client side, I'd call it from server, store it on server and and have the client operate on that data.
I have two models to call. In the first model I include somedate like this.
this.store.query('comment',{
include : 'person,address'
});
And in the second call I include the same details that already stored in the store.
this.store.query('post',{
include : 'person,address'
});
So, the API call takes a lot of time to resolve. Is there any way I can use the first API include data in the second API call to create a relationship between those two models(person, address).
This would save a lot of time for me.
Note: Examples are testing purpose only.
You are using the query() method of Ember Data's store. It expects two arguments: the model name as first argument and the query as a second argument. Last one is directly passed to your backend as part of the request. The responsible code is quite simple: https://github.com/emberjs/data/blob/v3.10.0/addon/adapters/rest.js#L535-L560
If you are using default JSONAPIAdapter the requests executed by your method calls look like this:
this.store.query('comment', { include: 'person,address' });
=> GET /comments?include=person,address
this.store.query('post', { include: 'person,address' });
=> GET /posts?include=person,address
The API does not know from that request that the client already has some of the person and address records cached locally. Ember Data does not include that information by default. You could customize your Adapter two do it but I wouldn't recommend so - especially cause that may blow up the request size and reduce the cache hit rate by a fair amount. Also you may want to reload the locally cached records.
If you expect two have most of the related records already cached locally, you may simply not want to ask the server to include them? In that case it might be cheaper to load them afterwards in a coalesced request.
I have a page showing a large number of words. For each word I can run a non-trivial database query (left joining a few tables, for example). I would like the result of that query to be shown in a popover when I click on the word.
Running all the queries when the page is generated is not really an option as it would take a long time and be a bit wasteful.
Ideally, I would have a setup where, when clicking on the word, I somehow send a query to the server which would respond with the query result. I would then display the query result in the popover.
I am a beginner when it comes to webdev, but I imagine I am not the first person to have this use-case.
What would be the easiest way of obtaining the effect I have described above?
I am using popover.js (via Bootstrap 4). The server is written in Django, if it matters.
Since there is no code, I will explain what you need to do:
1 - Have a function on a specific URL that will receive a POST, do the query, and return the result (on a JSON)
2 - Have an Ajax post on your page that is triggered when you click on the word. That will make the request to your function (#1), and render the result on the popover.
Let me know if you need more details
I have a search function on my site that needs to search through ~2000 items (this table never changes, it will always have the same number of items) stored in MySQL. All it needs to do is search by name or 'LIKE' the name and return the id. I have thought of two approaches to this:
Query database using ajax on keyup(), this seems like it would be expensive with many people searching
Send all the data to client as a JSON file when they load the page and search through it using JavaScript to reduce the load on the database
Which approach is better? Or if you have a better approach I am open to suggestions.
Depends on what your purpose. Do you want to provide search on fly functionality while user writes its search word or would like to return the result when the user clicks search button or something? Either way, you are talking about 2000 records which is not much actually. So I think you can store all those information into an offline memory cache and you can return your results from memory. SQL is also quite optimized for queries and it also caches the results so for 2000 records it shouldn't be any problem to perform the query to DB as well.
I've developed a web application with the concept of Single Page Application but none of the modern techs and frameworks.
So I have a jQuery page that dynamically requests data to localhost - a Laravel instance that compiles the entries in the DB (within a given time interval).
So the client wants to see all the entries for last week, the app works fine. But if he wants to see the results for the whole last month... well, they're so many that the default execution time of the php ins't enough to process all the data (30 seconds). I can easily override this, of course, but then the jQuery client will loop through these arrays of objects and do stuff with them (sort, find, sum...). So I'm not even sure jQuery can handle this many data.
So my question can be broken in two:
Can laravel ->paginate() be used so the ajax request of jQuery can also chunk the data? How does this work (hopefully in a manner that doesn't force me to rewrite all the code).
How could I store large amounts of information on the client? It's only temporary but the users will hang around for a considerable amount of time on my webpage, and I don't want them to wait 5 minutes every time they press a button
Thanks.
If you want to provide an interface to a large amount of data stored in a backed, you should paginate the data. This is a standard approach, so I'm sure your client will be ok with that.
Using pagination is pretty simple - see the docs for Laravel 5.0 here: http://laravel.com/docs/5.0/pagination
In order to paginate results in the backend, you need to call paginate($perPage) on your query instead of get() in your controller, like that:
$users = User::whereIsActive(true)->paginate(15);
This will return paginated result with 15 records per page. Page number will be taken from page parameter of the request. In order to get 3rd page of users, you'll need your frontend jQuery app to send a request to URL like:
/users?page=3
I don't recommend caching data in the frontend application. The data can be changed by some other user and you won't even know about it. And with pagination, your requests should be lightweight enough to stop worrying about a request sent to fetch every page of results.
Not sure if you're subscribed to laracasts but Jeffery Way is amazing in explaining features of Laravel and I highly recommend his videos.
In short you can paginate the results, then on the view when you call the foreach on your items you can array_chunk() the results to display them how you need to. But the paginated results are going to be fetched using a query in the URL, and i'm not sure that is what you want if you're already using a lot of jQuery to keep everything on the same page.
https://laracasts.com/lessons/crazy-simple-pagination
But assuming you're already paginating the results with whatever jQuery you've already written for the json data...
You could also use a query scope to get the data you need to for the amount of time to scope to create a simple api to use with ajax. I think that's probably what you're looking for.
So here's what I would do assuming you're already doing some pagination manually with your javascript.
Create a few query scopes to filter the data for different lengths of time
Create simple routes to fetch results from URI using the query scopes
Get the json data from the route preforming an ajax requests to the URIs created
More information on Query Scopes: http://laravel.com/docs/5.1/eloquent#query-scopes