I am using SSE for my real time application. I have sort of two types of notifications I need to check on database, one type is whenever the is an update, then sent to browser(it can take 1 hour, 2 hours etc.), ant the other type is I need to take data from database every 5 seconds, so I thought would it be better to use two sse scripts for each of these my two types? or should I chec everything in one script?Wont it be very slow if I use one script only? (by the way Im using php/mysql on server side)
I wrote something on this this morning. I would use one script personally and only include the long term update conditionally in the PHP when you need it.
This should cover everything you need with a few extras.
How to send json_encode data with HTML5 SSE
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I am getting the information from the user. Then I am to sort the information (Alphanumerically), and give it back to the user again, hence not saving it to the database.
I am able to use either JavaScript (you could even count on jQuery), or PHP to do the sorting. Since the data might contain many lines, I am wondering about approaches below for the sorting:
let's say I tokenize all the lines using an array called lines
in JavaScript lines.sort();
in PHP sort($lines);
I am very keen to know if client-side or server-side would be doing this any differently, mainly in terms of speed. Also, if accuracy is important, then would they be any different at all? Please explain why.
1) jQuery sort() is speedy as it has client side load.
2) For server side sorting we need to find from whole data not only from display in current page for pagination.
For Server side sorting is best for:
Large data set
Faster initial page load
Accessibility for those not running javascript
Client side sorting is best for:
Small data set
Faster subsequent page loads
Ability to let the user sort without loading page
That makes difference between server side sorting and client side.
It would depend on the situation. Javascript means client side load. So if the client has a slow system it might take longer. But server side means you would have to get the data into php (either database or by request etc.) and after the sort back to the client.
One other thing to think about is that php is controlled. You can assure the output is the same. In Javascript it should be the same on every system. But different browsers could generate different results on sort.
I am running MySQL 5.6. I have a number of various "name" columns in the database (in various tables). These get imported every year by each customer as a CSV data dump. There are a number of places that these names are displayed throughout this website. The issue is, the names have almost no formatting (and to this point, no sanitization existed upon importation):
Phil Eaton, PHIL EATON, Phil EATON, etc.
Thus, the website sometimes look like a mess when these names are involved. There are a number of ways that I can think to do this, but none that are particularly appealing.
First, I can have a filter in Javascript. However, as I said, these names exist in a number of places throughout this (large) site. I may end up missing a page. The names do not exist already within nice "name"-classed divs/spans, etc.
Second, I could filter in PHP (the backend). This seems about as effective as doing it in Javascript. I could do it on the API, but there was still not a central method for pulling names from the database. So I could still miss an API call anyway.
Finally, the obvious "best" way is to sanitize the existing data in place for each name column. Then at the same time, immediately start sanitizing all names that get imported each time we add a customer. The issue with the first part of this is that there are hundreds of millions of rows of names in the database. Updating these could take a long amount of time and be disruptive to the clients' daily routines.
So, the most appealing way to correct this in the short-term is to invoke a function every time a column is selected. In this way I could "decorate" every name column with a formatting function so the names will appear uniform on the frontend. So ultimately, my question is: is it possible to invoke a specific function in SQL to format each row every time a specific column is selected? In other words, maybe can I call a stored procedure every time a column is selected? (Point being, I'm trying to keep the formatting in SQL to avoid the propagation of usage.)
In MySQL you can't trigger something on SELECT, but I have an idea (it's only an idea, now I don't have time to try it, sorry).
You probably can create a VIEW on this table, with the same structure, but with the stored procedure applied to the names fields, and select from this view in your PHP.
But it has two backdraw:
You have to modify all your SELECT statements in your PHPs.
The server will always call that procedure. Maybe you can store the formatted values, then check for it (cache them).
On the other hand I agree with HLGEM, I also suggest to format the data on import, because it's a very bad practice to import something you don't check into a DB (SQL Injections?). The batch tasking is also a good idea to clean up the mess.
I presume names are called frequently so invoking a sanitization function every time they are called could severely slow down your system. Further, you can't just do a simple setting to get this, you would have to change every buit of SQL code that is run that includes names.
Personally how I would handle it is to fix the imports so they put in a sanitized version for new names. It is a bad idea to directly put any data into a database without some sort of staging and clean up.
Then I would tackle the old names and fix them in batches in a nightly run that is scheduled when the fewest people are using the system. You would have to do some testing on dev to determine how big a batch you could run without interfering with other things the database is doing. The alrger the batch the sooner you would get through all the names, but even though this will take time, it is the surest method of getting the data cleaned up and over time the data will appear better to the users. If the design of your datbase allows you to identify which are the more active names (such as an is_active flag for a customer or am order in the last year), I would prioritize the update by that. Alternatively, you could clean up one client at a time starting with whichever one has noticed the problem and is driving this change.
Other answers before give some possible solutions. But, the short answer for the specific option you are asking is : No. There is no such thing called a
"Select Statement Trigger", that too for a single column, although triggers come close for this kind of expectation, but only for Insert, Update and Delete operations.
I would like to know, what's the best method to retrieve and use a large amount of dynamic data.
For example:
I have a big website with a lot of fields, which dynamically create popups. The popups are created with a Javascript template engine, which needs JSON encoded data.
Now what I can do:
Every time i request a popup, the client fetches the JSON data via AJAX
I can create a Javascript var via PHP, which stores the data for all possible popups in the HTML code
Or I can fetch the data via AJAX and cache it, in a Javascript var
So which one of these is the best one?
What are the disadvantages of them?
Or how would you attach/load the data for these popups?
BTW does anybody know why all the facebook popups are so smooth? It seems that they are created asynchronously, but they are so fast - like they were already embedded.
Pre-emptive caching.
Basically your 'pop-ups' (god knows why you have so many - there must be a better way :-D hehe) will have a pattern or logical order or whatever.
Using a combination of:
Loading the Main / Most likely to be first used pop-ups data and storing that in a var.
I would highly recommend trying to do this with JSON or similar and store data for 10-20 pop-ups together - downside is performance - have to parse whole file for 1 pop-up (but modern browsers / PCs - not much issue) - plus side number of http requests - the killer of site speed.
You COULD** start loading data for a button etc. on HOVER (as well as click) - milliseconds make prizes you know!
Finally - just ajax the data in and keep it small - the more you can strip out of the ajax call and pre-load (image sprites on page load etc. etc.) the faster your site will respond.
However without knowing:
how often the data will update
what sort of data you are sending (is it all graphs, all text etc.)
how many of these pop-ups you have
how often a new pop-up will be loaded
what device(s) you users will be using
etc.
I can only give wild stabs in the dark!
I am working on the same thing now and find a good introduction blog http://blog.mariusschulz.com/2014/02/05/passing-net-server-side-data-to-javascript, hope it can give you some suggestions.
I have a question about how to approach a certain scenario before I get halfway through it and figure out it was not the best option.
I work for a large company that has a team that creates tools for the team mates to use that aren’t official enterprise tools. We have no access to the database directly, just access to an internal server to store our files to run and be able to access the main site with javascript etc (same domain).
What I am working on is a tool that has a ton of options in it that allow you to select that I will call “data points” on a page.
There are things like “Account status, Balance, Name, Phone number, email etc” and have it save those to an excel sheet.
So you input account numbers, choose what you need and then using IE Objects it navigates to the page and scrapes data you request.
My question is as follows..
I want to make the scraping part pretty Dynamic in the way it works. I want to be able to add new datapoints on the fly.
My goal or idea is so store the regular expression needed to get the specific piece of data in the table with the “data point option”.
If I choose “Name” it knows the expression for name in the database to run again the DOM.
What would be the best way about creating that type of function in Javascript / Jquery?
I need to pass a Regex to a function, have it run against the DOM and then return the result.
I have a feeling that there will be things that require more than 1 step to get the information etc.
I am just trying to think of the best way to approach it without having to hardcode 200+ expressions into the file as the page may get updated and need to be changed.
Any ideas?
IRobotSoft scraper may be the tool you are looking for. Check this forum and see if questions are similar to what you are doing: http://irobotsoft.org/bb/YaBB.pl?board=newcomer. It is free.
What it uses is not regular expression but a language called HTQL, which may be more suitable for extracting web pages. It also supports regular expression, but not as the main language.
It organizes all your actions well with a visual interface, so you can dynamically compose actions or tasks for changing needs.
I have a Google Chart's ColumnChart in a Rails project. This is generated and populated in JavaScript, by calling a Rails controller action which renders JSON.
The chart displays a month's worth of information for a customer.
Above the chart I have next and previous arrows which allow a customer to change the month displayed on the chart. These don't have any functionality as it stands.
My question is, what is the best way to save the state of the chart, in terms of it's current month for a customer viewing the chart.
Here is how the I was thinking of doing the workflow:
One of the arrows is selected.
This event is captured in JavaScript.
Another request to the Rails action rendering JSON is performed with an additional GET parameter
passed, based on an data attribute of the arrow button (Either + or - ).
The chart is re-rendered using the new JSON response.
Would the logic around incrementing or decrementing the graphs current date be performed on the server side? With the chart's date being stored in a session array defaulting to the current date on first load?
On the other hand would it make sense to save the chart state on the client side within the JavaScript code or in cookie, then manipulate the date before it's sent to the Rails controller?
I've been developing with Rails for about 6 months and feel comfortable with it, but have only just recently started developing with JavaScript, using AJAX. My experience tying JS code together with Rails is some what limited at this point, so looking for some advice/best practices about how to approach this.
Any advice is much appreciated.
I'm going to go through a couple of options, some good, some bad.
First, what you definitely don't want to do is maintain any notion of what month you are in in cookies or any other form of persistent server-side storage. Certainly sometimes server state is necessary, but it shouldn't be used when their are easy alternatives. Part of REST (which Rails is largely built around) is trying to represent data in pure attributes rather than letting it's state be spread around like that.
From here, most solutions are probably acceptable, and opinion plays a greater role. One thing you could do is calculate a month from the +/- sign using the current month and send that to the server, which will return the information for the month requested.
I'm not a huge fan of this though, as you have to write javascript that's capable of creating valid date ranges, and most of this functionality will probably be on the server already. Just passing a +/- and the current month to the server will work as well, you'll just have to do a bit of additional routing and logic to resolve the sign on the server to a different month.
While either of these would work, my preferred solution would instead have the initial request for the month generate valid representations of the neighbouring months, and returning this to the client. Then, when you update the graph with the requested data, you also replace the forward/backward links on the graph with the ones provided by the server. This provides a nice fusion of the benefits of the prior two solutions - no additional routing on the server, and no substantive addition to the client-side code. Also, you have the added benefit of being able to grey out transitions to months where no data was collected from the client (i.e. before they were a customer and the future). Without this, you'd have to create separate logic to handle client requests for information that doesn't exist, which is extra work for you and more confusion for the customer.