I am trying to use domain masking to simulate multi-tenant access to my application. The plan right now is to read the subdomain portion of the domain ie: demo.mydomain.com and load settings from the DB using that name.
The issue I'm having is that request.url is getting the request url - NOT the url in the browser.
So if I have http://demo.mydomain.com forwarding to http://www.mydomain.com/controllername with masking, request.url is grabbing the latter, simply because of how masking works, i assume - by putting the masked site inside of a frame.
Is it even possible to read the url in the browsers address bar? Thanks.
You probably can get the url you want, but at the client side...
So, do this:
Get the browser's url by using a javascript call, like window.location.href.
Post that url to the server-side.
Cons:
This is a javascript dependent solution, it will not work with javascript disabled.
This is ugly as hell.
Pros:
You probably do not have any other option.
Related
Similar questions have been asked about the nature of when to use POST and when to use GET in an AJAX request
Here:
What are the advantages of using a GET request over a POST request?
and here: GET vs. POST ajax requests: When and how to use either?
However, I want to make it clear that that is not exactly what I am asking. I get idempotence, sensitive data, the ability for browsers to be able to try again in the event of an error, and the ability for the browser to be able to cache query string data.
My real scenario is such that I want to prevent my users from being able to simply enter in the URL to my "Compute.cshtml" file (i.e. the file on the server that my jQuery $.ajax function posts to).
I am in a WebMatrix C#.net web-pages environment and I have tried to precede the file name with an underscore (_), but apparently an AJAX request falls under the same criteria that this underscore was designed to prevent the display of and it, of course, breaks the request.
So if I use POST I can simply use this logic:
if (!IsPost) //if this is not a post...
{
Response.Redirect("~/") //...redirect back to home page.
}
If I use GET, I suppose I can send additional data like a string containing the value "AccessGranted" and check it on the other side to see if it equals this value and redirect if not, but this could be easily duplicated through typing in the address bar (not that the data is sensitive on the other side, but...).
Anyway, I suppose I am asking if it is okay to always use POST to handle this logic or what the appropriate way to handle my situation is in regards to using GET or POST with AJAX in a WebMatrix C#.net web-pages environment.
My advice is, don't try to stop them. It's harmless.
You won't have direct links to it, so it won't really come up. (You might want your robots.txt to exclude the whole /api directory, for Google's sake).
It is data they have access to anyway (otherwise you need server-side trimming), so you can't be exposing anything dangerous or sensitive.
The advantages in using GETs for GET-like requests are many, as you linked to (caching, semantics, etc)
So what's the harm in having that url be accessible via direct browser entry? They can POST directly too, if they're crafty enough, using Fiddler "compose" for example. And having the GETs be accessible via url is useful for debugging.
EDIT: See sites like http://www.robotstxt.org/orig.html for lots of details, but a robots.txt that excluded search engines from your web services directory called /api would look like this:
User-agent: *
Disallow: /api/
Similar to IsPost, you can use IsAjax to determine whether the request was initiated by the XmlHttpRequest object in most browsers.
if(!IsAjax){
Response.Redirect("~/WhatDoYouThinkYoureDoing.cshtml");
}
It checks the request to see if it has an X-Requested-With header with the value of XmlHttpRequest, or if there is an item in the Request object with the key X-Requested-With that has a value of XmlHttpRequest.
One way to detect a direct AJAX call is to check for the presence of the http_referer header. Directly typed URLs won't generate a referrer, but you still won't be able to differentiate the call from a simple anchor link.
(Just keep in mind that some browsers don't generate the header for XHR requests.)
I am developing an iframe for use on a number of our partners websites.
Is there any way I can make sure it can only be used on those websites and not by anyone else
I was intending to add a compulsory querystring to the URL for the website.
Each partner would have a different value in the quesrystring dnd use that to look up an allowed domain
However, is there anyway to know the top level domain of the site hosting the iframe?
Presumably this is not sent in the http request for the iFrame? Or is it, I couldn’t see it?
Or do you need to send the domain from javascript?
Any advice?
However, is there anyway to know the top level domain of the site hosting the iframe?
Nothing reliable.
Presumably this is not sent in the http request for the iFrame? Or is it, I couldn’t see it?
It might be sent in the referer
Or do you need to send the domain from javascript?
If you want to fetch it from the framed page, you will be blocked by the same origin policy.
If you want to sent it from the framing page, you will be putting it in the query string and you can't trust it because it can be set to whatever the person writing the framing page likes.
There is also the X-Frame-Options header (but that has limited browser support).
The most reliable solution I can think of is:
Require the origin to be specified in the query string used to load the frame
Check the referer. If it doesn't match your white-list and is not blank, redirect to a page that is blank except for a link to your site with target="_top" and some JavaScript that top.location = "your site"
Check that the origin specified in the query string is on your whitelist, if it isn't act in the same way as a rejected step 2
Output an X-Frame-Options header that limits the framing to the specified origin
That is likely to catch enough browsers to discourage the framing site from framing your site.
You can try to check referrer which normal browser will send for IFrame requests on the page.
You also can use "x-frame-options" header covered in (How to Block Iframe call and MDN ) but not every browser will respect that (on other hand it is more reliable if browser supports it).
iframe's sanbox attribute might be helpful in controlling the various security aspects in an iframe including origins
http://www.html5rocks.com/en/tutorials/security/sandboxed-iframes/
The Architecture Journal of 2007 has a nice article about this: Secure Cross-Domain Communication in the Browser
Basically what the article suggests is:
If you have page A on domain 1 with an iframe with page B on domain 2 as its source , then having an iframe on page B to page C on domain 1, would allow you to pass information across domains
I haven't tested it, but this sounds like it could work.
Another possibility is create a file with a special filename (for instance a hash of the URL of page B on domain 2) and basic extension (like .htm) and place it in the root of domain 1. Checking whether the file exists on domain 1 cannot be done by javascript however, so it should be done with server side code.
I'm using URL redirection in my site, so in this way one url like hotels.aspx?idh=34 becomes a SEO friendly hotels-from-aruba.h.aspx.
The problem is that I need for example refer the URL to facebook recommendation button or something like from server side code and when I use the request.url method I get again "hotels.aspx?idh=34" when the URL used to access the page was "hotels-from-aruba.h.aspx."
¿How can I get from server side the SEO friendly URL?
Thanks.
Use Request.RawUrl, that will be the URL the client requested (relative of course).
I have an idea for an App that would really help me out in work but I'm not sure if it's possible.
I want to run a C# desktop application that will ask for a value. When a value is supplied, the application will open a browswer, go to a webpage and add the value into a form on an online website. The form is then submitted and a new page is loaded that contains a table of results. I then want to extract the table of results from the page source and write code to parse the result values.
It is not important that the user see's this happen in an actual browser. In other words if there's a way to do it by reading HTTP requests then thats great.
The biggest problem I have is getting the values into the form and then retrieving the page source after the form is submitted and the next page loads.
Any help really appreciated.
Thanks
Provided that you're only using this in a legal context:
Usually, web forms are sent via POST request to the web server, specifically some script that handles it. You can look at the HTML code for the form's page and find out the destination for the form (form's action).
You can then use a HttpWebRequest in C# to "pretend you are the form", sending a POST request with all the required parameters (adding them to the HTTP header).
As a result you will get the source code of the destination page as it would be sent to the browser. You can parse this.
This is definitely possible and you don't need to use an actual web browser for this. You can simply use a System.Net.WebClient to send your HTTP request and get an HTTP response.
I suggest to use wireshark (or you can use Firefox + Firebug) it allows you to see HTTP requests and responses. By looking at the HTTP traffic you can see exactly how you should pass your HTTP request and which parameters you should be setting.
You don't need to involve the browser with this. WebClient should do all that you require. You'll need to see what's actually being posted when you submit the form with the browser, and then you should be able to make a POST request using the WebClient and retrieve the resulting page as a string.
The docs for the WebClient constructor have a nice example.
See e.g. this question for some pointers on at least the data retrieval side. You're going to know a lot more about the http protocol before you're done with this...
Why would you do this through web pages if you don't even want the user to do anything?
Web pages are purely for interaction with users, if you simply want data transfer, use WCF.
#Brian using Wireshark will result in a very angry network manager, make sure you are actually allowed to use it.
I'm using a C# WebClient to post login details to a page and read the all the results.
The page I am trying to load includes flash (which, in the browser, translates into HTML). I'm guessing it's flash to avoid being picked up by search engines???
The flash I am interested in is just text (not an image/video) etc and when I "View Selection Source" in firefox I do actually see the text, within HTML, that I want to see.
(Interestingly when I view the source for the whole page I do not see the text, within HTML, that I want to see. Could this be related?)
Currently after I have posted my login details, and loaded the HTML back, I see the page which does NOT show the flash HTML (as if I had viewed source for the whole page).
Thanks in advance,
Jim
PS: I should point out that the POST is actually working, my log in is successful.
Fiddler (or similar tool) is invaluable to track down screen-scraping problems like this. Using a normal browser and with fiddler active, look at all the requests being made as you go through the login and navigation process to get to the data you want. In between, you will likely see one or more things that your code is doing differently which the server is responding to and hence showing you different HTML than a real client.
The list of stuff below (think of it as "scraping 101") is what you want to look for. Most of the stuff below is probably stuff you're already doing, but I included everything for completeness.
In order to scrape effectively, you may need to deal with one or more of the following:
cookies and/or hidden fields. when you show up at any page on a site, you'll typically get a session cookie and/or hidden form field which (in a normal browser) would be propagated back to the server on all subsequent requests. You will likely also get a persistent cookie. On many sites, if a requests shows up without a proper cookie (or form field for sites using "cookieless sessions"), the site will redirect the user to a "no cookies" UI, a login page, or another undesirable location (from the scraper app's perspective). always make sure you capture the cookies set on the initial request and faithfully send them back to the server on subsequent requests, except if one of those subsequent requests changes a cookie (in which case propagate that new cookie instead).
authentication tokens a special case of above is forms-authentication cookies or hidden fields. make sure you're capturing the login token (usually a cookie) and sending it back.
POST vs. GET this is obvious, but make sure you're using the same HTTP method that a real browser does.
form fields (esp. hidden ones!) I'm sure you're doing this already, but make sure to send all form fields that a real browser does, not just the visible fields. make sure fields are HTML-encoded properly.
HTTP headers. you already checked this, but it may make sense to check again just to make sure the (non-cookie) headers are identical. I always start with the exact same headers and then start pulling out headers one by one, and only keep the ones that cause the request to fail or return bogus data. this approach simplifies your scraping code.
redirects. These can either come from the server, or from client script (e.g. "if user doesn't have flash plug-in loaded, redirect to a non-flash page"). See WebRequest: How to find a postal code using a WebRequest against this ContentType="application/xhtml+xml, text/xml, text/html; charset=utf-8"? for a crazy example of how redirection can trip up a screen-scraper. Note that if you're using .NET for scraping, you'll need to use HttpWebRequest (not WebClient) for redirect-dependent scraping, because by default WebClient doesn't provide a way for your code to attach cookies and headers to the second (post-redirect) request. See the thread above for more details.
sub-requests (frames, ajax, flash, etc.) - often, page elements (not the main HTTP requests) will end up fetching the data you want to scrape. you'll be able to figure this out by looking which HTTP response contains the text you want, and then working backwards until you find what on the page is actually making the request for that content. A few sites do really crazy things in sub-requests, like requesting compressed or encrypted text via ajax, and then using client-side script to decrypt it. if this is the case, you'll need to do a bit more work like reverse-engineering what the client script is doing.
ordering - this one is obvious: make HTTP requests in the same order that a browser client does. that doesn't mean you need to make every request (e.g. images). Typically you only need to make the requests which return text/html content type, unless the data you want is not in the HTML and is in an ajax/flash/etc. request.
(Interestingly when I view the source for the whole page I do not see the text, within HTML, that I want to see. Could this be related?)
This usually means that the discrepancy is caused by some DOM manipulations via javascript after the page has loaded. Try turning off javascript and see what it looks like.