I want to create an html page inside a asp.net page using c# and then request that html page. The flow is, I'll be creating a request that will give me a response with some values. Those values will be stored in hidden fields in the html page I'm creating on the fly and then requesting. I figure it would be something like below but I'm not sure if it would work, I've also received some "Thread Aborting" errors. So, does anyone know the proper way to do this or at least direct me to a nice article or something?
StringBuilder builder = new StringBuilder();
builder.Append("<html><head></head>");
builder.Append("<body onload=\"document.aButton.submit();\">");
builder.Append("<input type=\"hidden\" name=\"something\" value=\"" + aValue + "\">");
HttpContext.Current...Response.Write(builder.ToString());
... end response
This is a very common request and is almost never a good idea. What are you trying to do?
That said: you write out a file with a temporary name and redirect to that file. Later you have to figure out when it's safe to delete the file.
Edit That method points out one of the problems: you have to do your own garbage collection, deciding how long files must be kept around and deleting them appropriately.
Related
The problem here is the middle of the line (HTML).
The chain:
I have WinForm program that uses awesomium (alternative to native webBrowser) to view Html page that has a part of asp.net page in it's iframe.
The problem:
The problem is that I need to pass value to asp.net page, it is easily achieved without middle of the chain (Html iframe) by sending hashed and crypted querystring.
How it works:
WinForm do some thing, then use few-step-crypt to code all the needed values into 1 string.
Then it should send this string to asp.net page through the iframe (and that's the problem, it is easy to receive query string in asp.net page, but firstly I need to receive it in Html and send to asp.net).
Acceptable answers:
1) Probably the most easily one - using JavaScript. I have heard it is possible to be done in that way.
How I imagine this - I send query string from WinForm to Html page as http:\\HtmlPage.html?AspNet.aspx?CryptedString
Then Html receive it with JavaScript and put querystring "AspNet.aspx?CryptedString" into iframe's "src=http:\\" resulting in "src=http:\\AspNet.aspx?CryptedString"
And then I easily get it in asp.net page.
2) Somehow create >>>VIRTUAL<<<(NOTE: Virtual, I don't want querystring to be saved on the HDD, even don't suggest) asp.net or html page with iframe source taken directly from WinForm string.
Probably that is possible with awesomium, but I'm new to it and don't know how to (if it is possible ofc).
3) Some web service with which I can communicate between asp.net and WinForm through the existing HTML iframe.
4) Another way that replace one of 3 previous, that doesn't save "values" in querystring/else on HDD nor is visible for the user, doesn't use asp.net page's server to create iframe-page on it. On HTML page's server HTML is only allowed, PhP isn't.
5) If you don't know any of 4 above - suggest free PhP hosting without ads (if such exists, what I highly doubt).
Priority:
The best one would be #3, then #2, then #1, then #5 (#4 is excluded as it is unknown).
And in the end:
Thanks in advance for your help.
P.S.Currently at work, so I'll check/try all answers later on and will report tomorrow if any suits my needs. Thanks again.
Answering my own question. I have found 2 ways that can do what I did want.
The first one:
Creating a RAM file System.IO.MemoryStream or another method (google c# create a file in ram).
The second one:
Creating a hidden+encrypted+system+custom-readable-only-by-program-crypt file somewhere in the far away folder via File.SetAttributes Method and System.IO.StreamWriter/Reader or System.IO.FileStream or System.IO.TextWriter, etc. depending on what it should be.
Once this file was used for needs delete it + delete on exit + delete on start using
if (File.Exists(path)
{
File.Delete(path);
}
(Need more reputation to post few links -_-, and I don't want to post only part of them, either all or no at all, so use google if you'll need anything from here).
If you'll need to store "Small temp file" and not for a long time use first one, if "Heavy" use second one, unless you badly need to use RAM for it.
I want to allow my users to "bulk export" an archive of selected resources, i.e., http://.../resource/1, resource/2, resource/4, ... ,
My thought was "render the HTML of each page to a string and use java.util.zip to create a multifile archive."
My problem then became "how to get the HTML of a page so that I can loop over them?"
I cannot figure out a way to get a JstlView to render to a String, nor can I see a way to set the ServletOutputStream to be a ZipOutputStream.
My last thought is to actually GET the HTML of each of the resources via HTTP. I imagine that will be easy enough to code, but it seems pretty byzantine. Is there a better way? (Perhaps something with RequestDispatcher.forward()? )
Use a SwallowingHttpServletResponse from DWR (or a PageResponseWrapper from Sitemesh) as a parameter to RequestDispatcher.include() and then get the output from that response object.
See my response (no pun intended) to this question.
i use such code
string.Format("<img src='{0}'><br>", u.Avatar);
u.Avatar-it's like '/img/path/pic.jpg'
but in this site i can upload new image instead old pic.jpg. so picture new, but name is old. and browser show OLD picture (cache). if i put random number like /img/path/pic.jpg?123 then works fine, but i need it only ufter upload, not always. how can i solve this?
string imgUrl = _
string.Format("<img src='{0}?{1}'><br>", _
u.Avatar, _
FunctionThatLookupFileSystemForItsLastModified(u.Avatar).Ticks.ToString());
Instead of linking to the images directly, consider setting up a generic HTTP handler to serve the images.
MSDN: HTTP Handlers and HTTP Modules Overview
Stack Overflow: How to use output caching on .ashx handler
Append DateTime.Now.Ticks to the image url:
string imgUrl =
string.Format("<img src='{0}?{1}'><br>", u.Avatar,DateTime.Now.Ticks);
EDIT: I don' think this best practice are even a practice I would use. This is just a suggestion given the limited information given in case the Random implementation isn't truly Random.
Read your post again,,, sorry for general answer.
To workaround it do following
On Application_Start create a Dictionary with uploaded images save it on Application object, set it to null. Once you upload an image add it to this Dictionary. Wrap every place avatars appear on your website with function that evaluates image in Dictionary if found return imagename.jpg?randomnumber and then delete it from a Dictionary else return just an imagename.jpg.
This is going to be heavy because you will need to check each image in Dictionary but this will do exactly what you need.
You can set cache dependancy using the System.Web.Caching.CacheDependency namespace.
This can set the dependancy on the file uploaded, and will release the cache for that file automatically when the file changes.
There are lots of articles and stuff on MSDN and other places so I will not go into details on all that level of detail.
You can do inserts, deletes and other management of cache using the tools available.
(and this does not require you to change the file names or tack on stuff - it knows by the file system that the file changed)
I think it's possible with jQuery, but any ASP.NET serverside code is good for my situation too.
With jQuery I can load a page to for example a div, and filter the div for <title> tag, but I think for heavy pages, it is not good to first read all of the content and then read the title tag..
or maybe it has a very simple solution? anyways I couldnt find anything about that from internet.
thanks
okay thanks to cjjer and Boo, I've just read more about regex and finally the code below is working for me.
Dim qq As New System.Net.WebClient
Dim theuri As New Uri(TextBox1.Text)
Dim res As String = qq.DownloadString(theuri)
Dim re As Regex = New Regex("<title\b[^>]*>(.*?)</title>", RegexOptions.Singleline)
Dim ma As Match = re.Match(res)
If Not ma Is Nothing And ma.Success Then
Response.Write(ma.Groups(1).Value.ToString())
Else
Response.Write("error")
End If
but anyways, the problem remains, this code is downloading the whole page and seeking through it, which one heavy websites it took more than 2 or 3 secconds to complete, but seems it is the only way as far as I know :|
Is there any suggestions to refine this code?
cjjer almost got it right.
First, change the regex to: <title>(?<Content>.*?)?</title>
Second, you need to create a match object first (just in case your URI does not have a title).
Match tMatch = new RegEx(#"<title>(?<Content>.*?)?</title>").Match(new System.Net.WebClient().DownloadString(url));
if ((null != tMatch) && (tMatch.IsSuccess)) {
// yay.
title = tMatch.Groups("Content").value;
}
Titles usually appear within the first few hundred bytes, so you could try a range request for the first 1KiB or so, try parsing that (with an error-correcting parser, since some closing tags will be missing) and if that fails fall back to loading the whole page.
It would be security risk for you to load any other web page into yours, just for title read... You should do this with server side scripting (asp.net, php, ...) and just output the title to your web page. Thing of some kind of caching because it is seamless to fetch titles on every request.
There is no simple clean way to retrieve an external page's title. You could do it server side using a WebClient and parsing the response.
However it may be worth reviewing the requirement, is it really necessary, how much extra traffic and latency is it going to generate. Consider also that you could be generating load on the external site which is unaware all you want is a title, the page creation may be quite expensive.
string title=Regex.Match(new System.Net.WebClient().DownloadString(url),(#"<title>(.*?)</title>"))[0].Groups[1].ToString();
try.i am not sure.
I am not sure whether all servers support this.
See, if this helps
char[] data = new char[299];
System.Net.HttpWebRequest wr =(HttpWebRequest)WebRequest.Create("http://www.yahoo.com");
wr.AddRange("bytes", 0, 299);
HttpWebResponse wre = (HttpWebResponse)wr.GetResponse();
StreamReader sr = new StreamReader(wre.GetResponseStream());
sr.Read(data, 0, 299);
Console.WriteLine((data));
sr.Close();
EDIT: Try checking with some network monitoring tool to find out what is the text that servers send out. I used fiddler to see the output & wrote it to console.
EDIT2: I am assuming the title to be in the beginning of the page.
I am doing an e-commerce solution in ASP.NET which uses PayPal's Website Payments Standard service. Together with that I use a service they offer (Payment Data Transfer) that sends you back order information after a user has completed a payment. The final thing I need to do is to parse the POST request from them and persist the info in it. The HTTP request's content is in this form :
SUCCESS
first_name=Jane+Doe
last_name=Smith
payment_status=Completed
payer_email=janedoesmith%40hotmail.com
payment_gross=3.99
mc_currency=USD
custom=For+the+purchase+of+the+rare+book+Green+Eggs+%26+Ham
Basically I want to parse this information and do something meaningful, like send it through e-mail or save it in DB. My question is what is the right approach to do parsing raw HTTP data in ASP.NET, not how the parsing itself is done.
Something like this placed in your onload event.
if (Request.RequestType == "POST")
{
using (StreamReader sr = new StreamReader(Request.InputStream))
{
if (sr.ReadLine() == "SUCCESS")
{
/* Do your parsing here */
}
}
}
Mind you that they might want some special sort of response to (ie; not your full webpage), so you might do something like this after you're done parsing.
Response.Clear();
Response.ContentType = "text/plain";
Response.Write("Thanks!");
Response.End();
Update: this should be done in a Generic Handler (.ashx) file in order to avoid a great deal of overhead from the page model. Check out this article for more information about .ashx files
Use an IHttpHandler and avoid the Page model overhead (which you don't need), but use Request.Form to get the values so you don't have to parse name value pairs yourself. Just pretend you're in PHP or Classic ASP (or ASP.NET MVC, for that matter). ;)
I'd strongly recommend saving each request to some file.
This way, you can always go back to the actual contents of it later. You can thank me later, when you find that hostile-endian, koi-8 encoded, [...], whatever it was that stumped your parser...
Well if the incoming data is in a standard form encoded POST format, then using the Request.Form array will give you all the data in a nice to handle manner.
If not then I can't see any way other than using Request.InputStream.
If I'm reading your question right, I think you're looking for the InputStream property on the Request object. Keep in mind that this is a firehose stream, so you can't reset it.