Questions about "response.redirect" on Kitura - javascript

Hi guys,
I'm not familiar with web server, client and AJAX. I encountered redirect problems on Kitura.
The delete route can redirect to "/api/v1/users/list" succeeded.(I saw a message through print function)
but the browser doesn't reload data(refresh) for /api/v1/users/list.
Please following code, Thanks!
Q1-0)Do I need to perform a manual refresh for browser?
Q1-1)If I should, which side is better for that? (server side or browser side)
Q2)Do I need to do refresh action by manual, when I using AJAX delete method?
Server side method "delete"
---------------------------
...
router.delete("/api/v1/users/delete/:id" ....
_ = try? response.redirect("/api/v1/users/list", status: .seeOther)
...
Server side method "get"
------------------------
...
//list all users.
//each user have a delete button that performs AJAX delete method to "/api/v1/users/delete/:id".
router.get("/api/v1/users/list", ...
print("get /api/v1/users/list")
...

Short answers:
Q1-0: In your case, yes.
Q1-1: In your case, browser.
Q2: In your case, yes.
Longer answer:
This really depends on the architecture of your app:
Client/server: You build an API that sends/receives JSON or XML through REST endpoints. On top of that, you build a JavaScript client that uses AJAX to communicate with this API. This is what you seem to be doing. However, your AJAX requests should only send/receive JSON or XML data. Any page updating, reloading or redirecting should happen client-side.
Server-side: Here, most of the logic happens on the server. You use HTTP GET and POST to request pages and submit forms. The server then processes these requests and returns an HTML page for the browser to render. See https://github.com/svanimpe/swift-blog for an example that uses Kitura and Stencil.
Client/server is more flexible as you can build several clients (web as well as native apps) for the same API, but is also more complex, as it's a distributed architecture and usually involves multiple programming languages and some code duplication.
Server-side apps are generally easier to build for beginners as they are monolithic and involve very little non-Swift code (in your case).

Related

Locals in Javascript/JQuery like Locals in Rails?

I create a Js Application and want to have English and German locals, which i can switch via button.
Is there a way to insert locals from a extra file in a .js file, like the function t'...' in Rails ?
As far as i know there is no way to do it directly and the reason is fairly simple too, erb is executed at the server side and javascript is a client side language which means its executed in your local browser, thats why if you even try to pass a variable between the two you'll have to make a request to the server, However this problem is tackled by calling an AJAX request, this AJAX request does the same thing as sending a new request to the server however it does that without refreshing or reloading the page to it gives the users the illusion that no request was made.
a guy asks a similar question here:
http://www.quora.com/Ruby-on-Rails/Can-I-pass-a-JavaScript-variable-to-a-Rails-method
and you can learn more about AJAX here:
http://www.w3schools.com/ajax/default.asp

How should I handle many AJAX calls?

I am trying to write a plugin which will work a lot with my server. Every page load will invoke an AJAX call to my server for data, the server should return a simple string.
Now I am trying to understand what would be the best aproach for this type of program.
Should I just create an AJAX call every time I need the data or is there some method I could create an open connection (despite the change of webpages) to save on server power?
Should I somehow listen to some port or something of the sort?
Do I have other options or what should I do to do this the most efficient way?
You can use HTML5 websockets (http://www.html5rocks.com/en/tutorials/websockets/basics/)
If you use this approach, then you will need to re-think the way you program your webserver, since websockets don't follow the request-response paradigm AJAX do. Instead they use a connection to stream data so you will need to open a port on your server and listen to it, the way to do it depends on the language or framework you are using. This is fast and responsive but will only work on most modern browsers.
Other approach is using Long Polling (http://techoctave.com/c7/posts/60-simple-long-polling-example-with-javascript-and-jquery). This is used by some chat clients. It works sending an AJAX request to the server, the server receives it and keeps it waiting until the data is available and then the response is sent. Then the client makes another request, waits and repeats.
Probably you will almost never want to send simple strings to the client. It's almost always better to use XML or JSON to encode the response.
Just create a simple AJAX call and put it on each page, or save it as it's own file and put a server include on each page in the header. Simple as that!
$(document).load(function(){
$.ajax({
type: "POST",
url: "/where_your_string_is.php",
success: function(msg){
$("#stringHolder").html(msg);
}
});
});
Websockets API allows bi-directional communication, but I've just found that there's another option called HTML SSE that might be used if you only need to pull data. So if you've stumbled upon this question, consider this option as well.

Simple HTML POST without any server scripting, can be done using JS

I want to pass some textbox value strictly using POST from one html page to another...
how can this be done without using any server side language like asp.net or php
can it be done using javascript??
thnx
You can't read POST data in any way on javascript so this is not doable.
Here you can find similar questions:
http://forums.devshed.com/javascript-development-115/read-post-data-in-javascript-1172.html
http://www.sitepoint.com/forums/showthread.php?454963-Getting-GET-or-POST-variables-using-JavaScript
This reading can also be interesting: http://en.wikipedia.org/wiki/POST_%28HTTP%29
This expecially suggests why this answer (wikipedia is the source):
GET
Requests a representation of the specified resource. Requests using GET should only retrieve data and should have no other effect.
(This is also true of some other HTTP methods.)[1] The W3C has
published guidance principles on this distinction, saying, "Web
application design should be informed by the above principles, but
also by the relevant limitations."[10] See safe methods below.
POST
Submits data to be processed (e.g., from an HTML form) to the identified resource. The data is included in the body of the request.
This may result in the creation of a new resource or the updates of
existing resources or both.
POST data is added to the request. When you do a GET request the data is added to the url, and that's why you can access it through javascript (and that's why it's not parsed and you have to do it manually). Instead, POST send data directly into the http requests, which is not seen in any way by the html page (which is just a part of what is sent through the http request).
That said, only server side language will receive the full HTTP request, and definitely you can' access it by javascript.
I'm sorry but that is the real answer

How to make auto-updating (ajax) counter correctly? Or how to disable network log?

I'm trying to make auto-reload counter (for ex.: Messages [num]).
So, I just in setTimeout(); getting JSON code from test_ajax.php. I think it's not correctly..
Can I send info by server (I think not, but suddenly I something don't know..)?
Why I think that's not correctly: because when I'm looking in my chrome network log (F12 -> network tab), I see a lot of requests (to test_ajax.php), but when, I'm visiting vk.com (great example for ajax) or facebook.com, I don't see any requests while something will not change.
So, what's incorrectly in my solution (or what's bad..)?
UPD: Sorry, vk.com sending requests to q%NUM%.queue.vk.com every 25s, but until 25s last request's status is "Pending". When someone, for example, sending me a message it immediately display it. And request has parameter "wait" which equals 25. This delay in requests doing on server side.. But how?
Ajax counter can be done in easy just include below files
index.html
counter.php (ajax file)
necessary images
JS file (for jquery paging call)
download link: https://docs.google.com/open?id=0B5dn0M5-kgfDcE0tOVBPMkg2bHc
What you are looking for is called COMET (also sometimes called Reverse AJAX) techniques.
Doing what you want to do, e.g. regular polls, is one way of doing it.
A lot is actually happening on the server side; to avoid recreating new connections on every poll, some servlet containers like Jetty started to implement techniques like Continuation which basically maintain a two-way connection open.
In the Java world, with Servlet 3, you have asynchronous calls as part of the specs.

How far can I go with JavaScript?

I need to do as much as possible on the client side. In more details, I would like to use JavaScript to code an interface (which displays information to the user and which accepts and processes response from the user). I would like to use the web serve just to take a date file from there and then to send a modified data file back. In this respect I would like to know if the following is possible in JavaScript:
Can JavaScript read content of a external web page? In other words, on my local machine I run JavaScript which reads content of a given web page.
Can JavaScript process values filled in a HTML form? In other words, I use HTML and JavaScript to generate an HTML form. User is supposed to fill in the form and press a "Submit" button. Then data should be sent to the original HTML file (not to a web server). Then this data should be processed by JavaScript.
In the very end JavaScript will generate a local data-file and I want to send this file to a PHP web server. Can I do it with JavaScript?
Can I initiate an execution of a local program from JavaScript. To be more specific, the local program is written in Python.
I will appreciate any comments and answers.
It could technically, but can't in reality due to the same origin policy. This applies to both reading and writing external content. The best you can do is load an iframe with a different domain's page in it - but you can't access it programmatically. You can work around this in IE, see Andy E's answer.
Yes for the first part, mmmm not really for the second part - you can submit a form to a HTML page and read GET arguments using Javascript, but it's very limited (recommended maximum size of data around 1024 bytes). You should probably have all the intelligence on one page.
You can generate a file locally for the user to download using Downloadify. Generating a file and uploading it to a server won't be possible without user interaction. Generating data and sending it to a server as POST data should be possible, though.
This is very, very difficult. Due to security restrictions, in most browsers, it's mostly not possible without installing an extension or similar. Your best bet might be Internet Explorer's proprietary scripting languages (WScript, VBScript) in conjuction with the "security zones" model but I doubt whether the execution of local files is possible even there nowadays.
Using Internet Explorer with a local file, you can do some of what you're trying to do:
It's true that pages are limited by the same origin policy (see Pekka's link). But this can be worked around in IE using the WinHttpRequest COM interface.
As Pekka mentioned, the best you can manage is GET requests (using window.location.search). POST request variables are completely unobtainable.
You can use the COM interface for FileSystemObject to read & write local text files.
You can use the WScript.Shell interface's Exec method to execute a local program.
So just about everything you asked is attainable, if you're willing to use Internet Explorer. The COM interfaces will require explicit permission to run (a la the yellow alert bar that appears). You could also look at creating a Windows Desktop Gadget (Vista or Win 7) or a HTML Application (HTA) to achieve your goal.
Failing all that, turn your computer into a real server using XAMPP and write your pages in PHP.
see i got what you want to do
best things is do following
choose a javascript library (eg:jquery,dojo,yui etc), i use jquery.this will decrease some of your load
inspite of saving forms data in in a local file, store them in local variables process them and send them to server (for further processing like adding/updating database etc) using XMLHttp request, and when webservice returns data process that data and update dom.
i am showing you a sample
--this is dom
Name:<input type='text' id='name' />
<a href='javascript:void(0)' onClick='submit()'>Submit Form</a>
<br>
<div id='target'></div>
--this is js
function submit()
{
var _name=$('#name').val();// collect text box's data
//now validate it or do any thing you want
callWebservice(_name,_suc,_err);
//above call service fn has to be created by you where you send this data
//this function automatically do xmlHttprequest etc for you
//you have to create it ur self
}
//call this fn when data is sucessfully returned from server
function _suc(data)
{
//webservice has returned data sucessefully
//data= data from server, may be in this case= "Hello user Name"; (name = filled in input box);
//update this data in target div(manipulate dom with new data);
$('#target').html(data);
}
function _err()
{
//call this fn when error occurs on server
}
// in reality most of the work is done using json. i have shown u the basic idea of how to use js to manipulate dom and call servcies and do rest things. this way we avoid page-reloads and new data is visible to viewer
I would answer saying there's a lot you can do, but then in the comment to the OP, you say "I would like to program a group game."
And so, my answer becomes only do on the client side what you are able and willing to double check on the server side. Never Trust the Client!
And I do not want to do my job twice.
If you are going to do things on the client side, you will have to do it twice, or else be subject to rampant cheating.
We had the same question when we started our project.In the end we moved everything we could on the JS side. Here's our stack:
The backend receives and send JSON data exclusively.We use Erlang, but Python would be the same. It handles the authentication/security and the storage.
The frontend, is in HTML+CSS for visual elements and JS for the logic.A JS template engine converts the JSON into HTML. We've built PURE, but there are plenty of others available. MVC can be an overkill on the browser side, but IMO using a template engine is the least separation you can do.
The response time is amazing. Once the page and the JS/CSS are loaded(fresh or from the cache), only the data cross the network for each request.

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