Keeping same session with different user-agents - c#

Is there a way to use the same session on different user-agents. I have a flash app that is generating a new session id on posting data to myHandler.ashx ( same happens on aspx ). Am i missing a trick here?

Take a look at swfupload and their implementation in ASP.Net - they use a Global.asax hack in order to keep the same session.

I have no experience from c# or anything like that, but when doing remoting using amfphp you will sometimes need to supply the session_id variable in your call manually, as the server will for some reason consider you two different users even though it's all going through the same browser.
Often, the simplest way to do this is to supply your swf with the id in a flashvar when loading it. This will require you to print the session_id in the html source, which isn't ideal, but it's not that big of a deal since it can be sniffed very easily anyway.

It appears as though it is common to pass the session id through flash vars. I have not done this myself, but a quick Google search with these keys seems to find some promising hits: keep session data flash

Related

Securly Passing variable values from one page to another page

When passing variable from one page to another
To avoid the user messing around with the URL parameter Values
Is it best to ...
1) pass the variable via session
2) pass the variable in the URL along with a signature
As long as you're passing in a signature, it wouldn't matter where are you passing the values because you will always check for the signature integrity
What I would do is pass everything (including the signature) in the session. Just to keep the URL clean. But that's up to you and your particular use case.
If you use the session, the user cannot control the contents of the values.
Also, if you have view state encryption enabled, you could use the view state. The advantage of the view state is that it's localized to a single page. This means that when the user has two tabs open of your website, the variables are localized to the specific tabs.
See http://www.codeproject.com/KB/viewstate/AccessViewState.aspx for how to access view state from another page.
Depends on your use case. Session IS in most cases safer. If someone can compromise your server to get your session data, then you have different things to worry about. It would be bad though if you store session data in a place where other people can see it ;-).
URL signature could theoretically be brute-forced. Since the parameters are probably short and they may be sometimes predictable it may give someone who knows about encryption some point of attack. This is not trivial though. But if security is top option for you then I'd not allow this data to leave your server.
If you are really worried user going crazy and stripping down params, then you can go with Session states, however you may lose history, i.e Back Forward buttons.
The second option looks good but if user is stripping things you can't be sure that the param even existed.
So a mix of both looks good.

Fastest way to code up hitting a URL

I need to login to a site, then hit a certain URL about a thousand times (with different params, of course).
The URL is something this:
http://www.foo.com/bar.asp?id=x ' where x is the ID
Of course if I simply hit the URL without being logged, it will fail.
I am not very familiar with this type of work, but I would imagine that whatever the method I choose, it would have to support cookies.
I was thinking that I could create a winform app with a browser control and somehow drive it, but that seems like a massive overkill.
Is there a better way?
If you are determined to do it in your code itself then i dont think any thing is stopping you from doing that.
HttpRequest and HttpResponse classes has pretty much everything you need to do that.
Moreover if you are concerned about cookies then you could always store received cookies in a database or file and send them with every subsequent request.
If you want to know the structure of the Http Request like a GET request then look here.
Also you can make your request look like a Request from browser by specifying the Proper Request Headers...(However it doesn't work every time)
And all this can be done even in a console app
You may want to look into WCAT if you are mainly interested in how your server performs under load.
Using Python or PHP, you can use the libcURL library, I believe they both have bindings for these languages. If not, just use the urllib2 module (for Python).

Are Querystrings in .NET Good Practice?

I'm developing a web app that has a database backend. In the past I'm done stuff like:
http://page.com/view.aspx?userid=123 to view user 123's profile; using a querystring.
Is it considered good practice to use a querystring? Is there something else I should be doing?
I'm using C# 4.0 and ASP.net.
Your question isn't really a .NET question... it is a concern that every web framework and web developer deals with in some way.
Most agree that for the main user facing portion of your website you should avoid long query strings in favor of a url structure that makes "sense" to the website visitor. Try to use a logical hierarchy that when the visitor reads it there is a good chance they can deduce where they are on the site. Click around StackOverflow in a few areas and see what they have done with the url's. You usually have a pretty good idea what you're looking at and where you are.
A couple of other heads up... Although a lot of database lookups are done with the primary key it's also a good idea to provide a user friendly name of the resource in your url instead of just the primary key. You see StackOverflow doing that in the current address where they're doing the lookup with the primary key "3544483" but also including an SEO/user friendly url paramenter "are-querystrings-in-net-good-practice." If someone emailed you that link you'd have a pretty good idea of what you're about to open up.
I'm not really sure how WebForms handles Url Routing but if you're struggling to grasp the concepts go through the MVC NerdDinner tutorial. They cover some basic url routing in there that could help.
Query String are perfectly fine if you're sure to lock down what people are meant to view.. You should be checking for a valid value (number, not null, etc..) and if your application has security, whether a Visitor has permission to view User 1245's profile..
You could look into Session & ViewState, but QueryString seems to be what you're after.
If possible, I think this practice should be avoided especially if you're passing auto-incrementing ids in plain text. In my opinion, you're almost teasing the user to manipute the querystring value and see if they can get access to someone else's profile. Even with appropriate security measures in place (validating the request on the server-side before rendering the page), I would still recommend encrypting the querystring param in this particular case.
I think using query strings is perfectly fine, but there's a case to be made for hackable URLs, in that they are more understandable to advanced users and are SEO-friendly. For example, I happen think http://www.example.com/user/view/1234 looks more intuitive than http://www.example.com/view.aspx?user=1234.
And you don't have to alter your application to use pretty URLs if you're using IIS 7.0. The URL Rewrite Module and a few rewriting rules should be enough.
To answer clearly at your question: yes it't a good pratice. In fact it's an expected behavior of a web site.
I'm totaly agree with ShaderOp and you should use a url rewritter to get an nice loocking url. In fact I'm assuming that you will put a bit of validation to avoid someone manipulating the url and access to data they don't desserve.
Query string are ok, but don´t compromise security with them.
If the profile you are accessing is the current logged in user, there´s no need to send in the uid. Just go to /profile and load the current logged in user information.
if you are looking at other member profile, i recommend to just go with it´s 'username', an encrypted id or a Guid.
Exposing user ids to clients are generally not a good idea.

ASP.NET URL remapping &redirection - Best Practice needed

This is the scenario: I have a list of about 5000 URLs which have already been published to various customers. Now, all of these URLs' location has changed on my server side. The server is still the same though. This is a ASP.NET website with .NET3.5/C#.
My requirement is : Though the customers use the older source URL they should be redirected to the new URL without any perceived change or intermediate redirection message etc.
I am trying to make sense of the whole scenario:
Where would I put the actual mapping of Old URL to New URL -- in a database or some config. file or is there a better option?
How would I actual implement a redirect:
Should I write a method with Server.Transfer ot Response.Redirect?
And is there a best practice to it like - placing the actual re-routing in HTTPModules..or is it Application_BeginRequest?
I am looking to achieve with a best-practice compliant methodology and very low performance degradation, if any.
If your application already uses a database then I'd use that. Make the old URL the primary key and lookups should be very fast. I'd personally wrap the whole thing in .NET classes that abstracts it and allow you to create a Dictionary<string,string> of all the URLs which can be loaded into memory from the DB and cached. This will be even faster.
Definitely DON'T use Server.Transfer. Instead you should do a 301 Permanently Moved redirect. This will let search engines know to use the new URL. If you were using NET 4.0 you could use the HttpResponse.RedirectPermanent method. However, in earlier versions you have to set the headers yourself - but this is trivial.
Keep the data in a database, but load into ASP.NET cache to reduce access time.
You definitely want to use HTTPModules. It's the accepted practice, and having recently tried to do it inside Global.asax, I can tell you that unless you want to do only the simplest kind of stuff (i.e. "~/mypage.aspx/3" <-> "~/mypage.aspx?param1=3) it's much more complicated and buggy than it seems.
In fact, I regret even trying to roll my own URL rewriting solution. It's just not worth it if you want something you can depend on. Scott Guthrie has a very good blog post on the subject, and he recommends UrlRewriter.net or UrlRewriting.net as a couple of free, open-source URL rewriting solutions.
Good luck.

Hold global data for an ASP.net webpage

I am currently working on a large-scale website, that is very dynamic, and so needs to store a large volume of information in memory on a near-permanent basis (things like configuration settings for the checkout, or the tree used to implement the menu structure).
This information is not session-specific, it is consistent for every thread using the website.
What is the best way to hold this data globally within ASP, so it can be accessed when needed, instead of re-loaded on each use?
Any AppSettings in web.config are automatically cached (i.e., they aren't read from the XML every time you need to use them).
You could also manually manipulate the cache yourself.
Edit: Better links...
Add items to the cache
Retrieve items from the cache
Caching Application Data
It's not precisely clear whether your information is session specific or not...if it is, then use the ASP Session object. Given your description of the scale, you probably want to look at storing the state in Sql Server:
http://support.microsoft.com/kb/317604
That's the 101 approach. If you're looking for something a little beefier, then check out memcached (that's pronounced Mem-Cache-Dee):
http://www.danga.com/memcached/
That's the system that apps like Facebook and Twitter use.
Good luck!
Using ASP.NET caching feature is a good option I think. In addition to John's answer, you can use Microsoft's Patterns & Practices team's Caching Application Block.
This is a good video exploring the different ways to can retain application state.
http://www.asp.net/learn/3.5-videos/video-11.aspx
It brushes on the Application object which is global for the whole application, for all users and shows you how to create a hit counter (obviously instead of storing an integer you could store objects). If you need to make changes, you do need to use a lock for concurrency, and I'm not sure how it handles LARGE amounts of data because I've never had to keep that much there.
I usually keep things like that in the Application object.
If the pages are dependent upon one another and they post to one another, you could use the page's request object. Probably not the answer you're looking for, but definitely one of the smallest in memory to use.
I have run into the same situation in the past and found an interface to be the most scalable solution. Application cache may be the answer today, but will it scale to meet your needs?
If you need to scale up, you may find cookies, or some type of temp database storage to be the trick. Simply add a new method to your interface, and set the interface to choose the "mode" from web.config.

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