How can I catch all the AJAX requests that a page makes with a Webbrowser / EmbeddedWB? BeforeNavigate2 unfortunately isn't fired for AJAX requests.
For example: requests which are made when you type in google search bar.
If the environment is under your control. you can use a custom HTTP proxy (based on Indy for example).
See: Indy's TIdHTTPProxyServer: How to filter requests?
Ajax requests can be detected based on their specific header:
How to differentiate Ajax requests from normal Http requests?
Update: this question on the Microsoft web forum has an accepted answer:
AJAX detection in WebBrowser control
If I were you, I would've injected my own script into every page after it's been loaded. This a script that captures all AJAX requests and informs the application.
Using the following code, you may capture every AJAX request made by jQuery (Haven't tried, but I don't think it works for non-jQuery AJAX requests).
$.ajaxSetup({
beforeSend: function() {
// before sending the request
},
complete: function() {
// after request completion
}
});
It's not even a code, but it can give you a clue for what you want to do.
Surely using this method, you're gonna need to somehow communicate with your application. For instance, I'd use my made up protocol and a new window command so that my Delphi component will be able to capture and parse the event.
As I said there are plenty options here and I'm just giving a clue.
Related
I just started studying Ajax and I totally have not idea what AJAX is. What is the difference between asynchronous and synchronous request? I would like to seek a very simple example demonstrating their differences.
AJAX short for Asynchronous JavaScript And XML is a programming language. It typically involves sending HTTP requests from client to server and processing the server's response, without reloading the entire page. This process is asynchronous. Comparing to synchronous request which blocks the client until operation completes, asynchronous HTTP is more efficient and user-friendly.
Take very simple example, when you are signing up on a commercial website, you can know whether your username is available or not once you finish typing the name. If the username was used already, the website will give you a reminder that your username is used on the same web page. This is the application of AJAX, so you don't need to complete the whole form and click the submit button to know that your username is not available.
AJAX uses two components for request process and display:
A browser built-in XMLHttpRequest object (to request data from a web server)
JavaScript and HTML DOM (to display or use the data)
It begins with an event occurs in a web page, such as a button is clicked. Then an XMLHttpRequest object is created by JavaScript, followed by sending a request to a web server. Once the web server receives the request, it will process it and send a response back to the web page. Then the webpage utilizes JavaScript to perform update of the web page without reloading the whole page.
AJAX stands for Asynchronous JavaScript And XML
Ajax main purpose is the loading data from the server without refreshing the web page
It's works in the background thread without interrupting UI thread
AJAX allows web pages to be updated asynchronously by exchanging data with a web server behind the scenes. This means that it is possible to update parts of a web page, without reloading the whole page.
A browser built-in XMLHttpRequest object which is used to request data from a web server
Example
when you are filling any kind of online form that time observe one thing there is option for country,state,district.
In this country drop down initially filled with data but state and district's are empty.
when you select a country like India then Asynchronous call goes to server and fetch the data of state drop down respective to selected country and so on.
when AJAX request fetching the data for the state drop down you are eligible to work with other parts of the form.
Many (probably the majority) of AJAX calls are done by a browser on a webpage and that webpage has a URL. Is it possible for a webserver to that's receiving the AJAX request to determine the URL of the webpage where the AJAX call was made? I assume there isn't a standard that requires this data in the headers, but perhaps some browsers include that info? Obviously this doesn't apply if the AJAX call was made from a phone app or other application without a URL.
Very generically (though unreliable), check incoming request headers for Referer. That should give you information about the source page.
Just keep in mind it can be spoofed, absent, etc. and shouldn't be considered bullet-proof (though it doesn't sound like you need it to be anyways).
Is it possible to write and create a JavaScript Ajax request witch cannot be catched by the Firebug plugin in Firefox?
I'm asking this because I can see on Facebook that there are no Ajax request going on, but still when I sent a message from another Account, the message box on the top will add the "1 unread message" indicator... How's even this possible to achive?
Thanks.
Firebug logs "standard" AJAX requests to the Console panel; these are requests initiated using ActiveX/XHR.
Other types of requests are happening, though - CSS loading, images, javascript, etc. These requests are logged in Firebug's Net panel. Note also that requests logged in Console also appear in Net.
JSONP is a cross-domain method of AJAX in which a <script> tag is added to the page. When the request completes, the loaded contents of the script tag are parsed as JSON. The reason this works is that you are "tricking" your browser into treating the request as a request for a javascript resource rather than an AJAX request, thus skirting cross-browser security restrictions.
Putting this all together, JSONP requests (as well as all other types of requests, listed here as well as all <iframe> requests) are logged on the Net panel rather than in the Console panel. This isn't a bug or a problem; understanding the way JSONP works it is logical that the request would only appear in Net.
When using jsonp as your data type your calls do not show up in Firebug.
will any webserver [IIS possibly] know whether a request is an AJAX request or a Normal one.
If you are using native XmlHttpRequests then there is no difference between this request and once generated by visiting a page or submitting a form. If you use jQuery to create the AJAX request then is adds a request header X-Requested-With: XMLHttpRequest. This header could be used to distinguish AJAX and non-AJAX requests.
Some (most?) frameworks can send a custom header, but, really, an ajax request is just the same as a "normal" request from the point of view of the server.
If you use curl, wget, telnet, or a program you write yourself, then the web server handles the request the same way - at the end of the day, it's all HTTP.
The easiest way for the receiving page to 'know' would be to send a query string parameter. This isn't 100% safe though.
Firebug can show you what is being sent to the server from both types of requests, try it out.
Possibly, it is not the webserver that can distinguish, but the server side code might be able to distinguish. If you are talking about ASP.NET and AJAX, then ScriptManager.IsInAsyncPostBack can be used to find whether a postback is from AJAX or not.
I want to use mootools and SqueezBox class to handle a request to a RESTful service. I don't want to use any server-side script. I am using AJAX. I send a request to the following url using GET method.
http://www.idevcenter.com/api/v1/links/links-upcoming.json
but I receive a 404 error. Is it because cross-site scripting? here is my code:
SqueezeBox.initialize({handler:'url',ajaxOptions:{method:'GET'}});
$('a.modal').addEvent('click',function(e){
new Event(e).stop();
SqueezeBox.fromElement($('a.modal'));
});
In Firebug console, sometimes 'aborted' is shown and sometimes '404'.what is wrong with that?
XMLHttpRequest is subject to the Same Origin Policy; if the document your JavaScript is running within is not from the same origin as the service you're trying to call, the call will be disallowed for security reasons.
There is now a proposed standard for cross-origin resource sharing to address this. It may be that the service you're trying to use supports it; if so, using a browser that implements CORS (recent versions of Firefox and Chrome do, as do some others) may work. IE8 supports it but requires that you do extra work.
You cannot use XMLHttpRequest (that is, ordinary "ajax") to call a service on a server that is not in your domain.
You can, however, use the JSONP trick, which takes advantage of the fact that the browser will load Javascript from other domains. However, the service has to know that you're going to do that, and it has to understand the protocol. That particular service seems perfectly willing to give me a JSON response, but it doesn't pay attention when I give it a "callback" parameter. (I've tried both "callback" and "jsonp" and the JSON blob that comes back is the same, without a function call wrapper.)