My asp.net 2.0 web site generates text files. Sometimes these files can get quite large. Under most cases the files are presented to the user, and approved without modification. However there are times when the end-user has to make changes to these files and submit the changed version back to the system.
Currently, when a file needs to be changed, I load the text into a textbox control, and I rewrite the file on postback. However I'm running into problems with OutOfMemory exceptions, invalid viewstate, etc.... These problems only occur when the file generated is large.
I beginning to think that I need another strategy for editing these files, but I'm at a loss as to which direction to take. Is there an ACTIVEX control that would serve me better? Should I abandon server side controls for this interaction and just deal with plain vanilla http posts?
Thanks in advance.
I am not sure about an activeX control, but you could use Silverlight. Thsi would allow you to stream the file to th Silverlight control, and then it could be edited on the clints machine, and when they are done, the chnages are sent back and stored by the server.
However, you will need to have .Net 3.5 on the server and make some changes to the web.config inorder to build against the 3.5 framework. If this is not acceptable, but you like the idea of doing stuff on the client side, you can also try using flash.
One suggestion to consider would be an ajax call to a pagemethod that way you could just post the text file to the server without posting the whole page and the associated viewstate.
Can you break up the text files into sections and allow the users to submit changes one section at a time?
Related
I've read through some of the questions here and my understanding is that this is true. Could someone confirm that visitors to an ASP.NET website can actually download the aspx files in their original format? Just like with the css files, etc. Thanks.
Clarification: Please be patient with me. I am newbie and just want to make sure I understand. I know that using Dreamweaver, a person can just download almost all the source files from a website. At least that what could be done some years ago with many websites. He would just change a few text contents and have a similar website like the original with all the original design, images, etc.
So if he can do the same with an asp.net site: downloading all the files, he can look at the aspx file and see what the code does. I am not talking about him executing the page and do the view source command. This file would naturally be processed by the server and doesn't expose source code.
This is one of the reasons why code behind is recommended because the code can be compiled and the source is not uploaded to the site. Only the dll is uploaded and minimum logic is exposed through the aspx file.
No, they can't. The ASPX page contains server-side code that is executed, well, by the server, and ends up containing plain HTML that the client browser can understand.
When IIS receives a GET request for an ASPX page, the ASP.NET handler kicks in and returns the processed HTML. So unless IIS is misconfigured, that is not possible.
No. Visitors cannot see your business logic.
If that were the case the markup asp:TextBox wont get rendered as input type='text'
Also, if that were the case we would be seeing code snippets of sites written using scripting languages like PHP or Classic ASP
in newbie's term:
No, the server won't give you ASPX and code behind files, these are files that don't mean anything to the end-user/visitor/browsers. These codes are processed on the server, and what you get is only a bunch of HTML code, javascripts, css, images, etc. which browsers can render.
If you try to "download" (by accessing them through your browser) .ASPX, .CS, and WEB.CONFIG files to see the actual source code, well you simply can't.
I am trying to use aspx pages as an email templates. There will likely be a bunch of objects on the page which will be used as replacements in the html. Because it's an aspx page I'll be able to use databinding, repeaters, etc. At run time, I want to be able to instantiate the aspx page from its path, pass in a bunch of properties, and then get the rendered result of the page and email it. This seems pretty straightforward from a asp.net website (maybe using BuildManager or Server.Execute.) However, I want to be able to use the same templates via a console application by just loading up a page object from its filepath. Is this possible?
You could host your own webserver. Like the Cassini webserver.
In my own application (a Windows-based Desktop-CMS), I include a web server, too (non-Cassini). It works very well, also it does not serve ASP.NET but plain, HTML.
As I did some research back then, I first wanted to use the Cassini, too, but at some point, I found out that too much user privileges were required to run it successfully; this may not be an issue to you, but keeping this in mind and try to run it early with the permissions of the later user, might be a good idea.
I need to add a file upload function to an ASP.NET website and would like to be able to read a small portion of the file on the server while it's still uploading. A peek or preview type function so I can determine contents and give some feedback to the user while it is still uploading (we're talking about large files here). Is there any way to do this? I'm thinking worst case of writing a custom control which uploads only a fixed number of bytes of the file once chosen and then under the covers starts another upload of the full file. Not totally sure even this is possible, but I'm looking for a more elegant solution anyway... Thanks!
It sounds like you want to avoid the "white screen of death" during large file uploads. If so, you might want to look into Telerik's RadUpload control , which provides a progress bar during upload.
If you want to roll your own, I'd decompile their trial copy for ideas. I've peeked at their source in this way, and they accomplish the progress bar through a combination of a custom HttpModule and HttpHandler along with their control. The handler routes the file in a streamed fashion while the module provides "percent complete" information--or the other way round; it's been a few years since I looked at it.
Edit:
Actually, I'm trying to do server-side processing as the file is still being uploaded. I want to import user data via HTTP, but want to present the user with preview/options of how we'll process their data while the file is still uploading (column definitions, etc.). No matter what, we'll take the file as is, so the upload doesn't need to be interrupted. Given that I actually want interaction during the upload based on reading a relatively small portion of the file as it is being uploaded, would you still recommend the same approach?
Well... it'd be very difficult to do, and it might not work cross-browser, but it could be done with this approach.
Since it's entirely possible to work with the incoming file as a stream as I mentioned, you could have your intial processing update some state as part of that stream processing. If you don't process as a stream, you have to wait for the full file upload before you can do anything with it.
The problem is this: during the file upload, you cannot have any more HTML-based interaction. The post must continue unabated or the upload will fail. The control I linked only works at all because most browsers allow javascript to continue to execute and update page DOM during the post.
So in order to make this work, you have to update some standardized state server-side during your file processing in the HttpModule, which is transmitted back to the client via XmlHttpRequest calls handled by the HttpHandler. You have to use pure javascript/DOM to update the UI for the user.
So, as I said, it's complex and likely to be buggy cross-browser, but it could theoretically be done.
There are alernatives that might be more stable, but might not necessarily be feasible: you could build an ActiveX control or a Click-Once .NET application that pre-processes the file before upload, and maybe even asynchronously transfers the file while the user continues browsing. Some users may not like that option, and I don't know the particulars of your deployment scenario, but it's an option.
There is an HTTP HEAD method but not PEEK.
HEAD will give you information and headers about the file.
Of course you can make a special request handler that does anything you want. You don't have to work with static resources, you can dynamically create any response you want.
Is there a way to share the session between ASP3 And ASP.NET?
Thanks
Despite all of Microsoft's best efforts to make ASP and ASP.NET coexist effortlessly, one area remains a stumbling block... session state. Fortunately the advantages of ASP.NET's upgraded session state management far outweigh the inconvenience of not being able to pass "Classic" session information to .NET. Unfortunately there is no simple solution; the most I can offer is an easy to implement workaround.
In trying to find a suitable resolution, I've come across two good options that are worth mentioning. The first involves parsing the session information out to hidden form fields on a "Classic" intermediate page and then submitting the page to a .NET intermediate page that loads the form fields into the session state. This is a good, simple solution, however it doesn't work both ways. In .NET you cannot specify the page that you submit to. Each page has to PostBack to itself.
The second option is probably closer to an actual solution than to a workaround. Billy Yuen at Microsoft has developed an effective solution. The code is elegant, the integration appears to be seamless, but I couldn't get it to work on my system (remember I said that there was no simple solution, not that there was no solution at all). If this solution works for you, great! You won't need my code and you'll be happily passing session information from "Classic" to .NET like it's going out of vogue, thanks for stopping by.
Ok, if you're still reading let me briefly describe the workaround I've created. It requires a database, but it is not important which type of database (though the code is written for SQL Server). When a page (source page) wants to redirect to another page (destination page) that uses a different version of ASP, it calls an intermediate page. The source intermediate page takes each session variable and adds it to the database along with a Globally Unique ID (GUID). Since "Classic" and .NET use different SessionID formats it is not possible to use SessionID, hence the use of a GUID. The source intermediate page then passes the GUID to the destination intermediate page through a Querystring variable. The destination intermediate page retrieves the session information from the database, cleans up after itself, and then redirects to the destination page. It's similar to the first workaround, but supports transferring state in both directions.
Code Usage
Installation
Run the SQL Query in "ASPSessionState.sql" on the database which will hold the temporary Session information.
Copy the .asp and .aspx.* (SessionTransfer.aspx and SessionTransfer.aspx.cs) files to a folder on your website.
Update connection object information in the "SessionTransfer.asp" and "SessionTransfer.aspx.cs" files. It is located in three places in each file (sorry about not consolidating the connection info).
Compile the aspx files.
The .asp and .aspx.* files must all reside in the same folder to work.
Usage
For use in a Hyperlink (Anchor Tag) or a Response.Redirect, set the destination URL to be one of the following:
From a ASP "Classic" page:
SessionTransfer.asp?dir=2aspx&url=<asp_dotnet_url>
From an ASP.NET page:
SessionTransfer.aspx?dir=2asp&url=<asp_classic_url>
The code will transfer the Session information and Redirect the user to the url specified by or .
Download
You can download the code from here: session_transfer.zip (4.6 KB).
Could take a look at NSession it allows sharing session state between Classic ASP and ASP.Net using State server. Pretty easy to setup just configure App to use State Server for session and register a couple of dll files.
I am trying to find out how to upload a file from a web user to a server using an ASP page. The displayed page has an Input tag of type "File" like this:
<input type="file" name="uploadfile">
And a submit button that passes the Form info to another .ASP page. This page must take the path it gets from the Input control and use it to somehow save the file to the server.
I keep thinking there must be a common way to do this, since I see this kind of thing on a number of websites, but how is it done? Is there some sort of server object that can be called for it?
This script will help you.
Also, you may google for "asp upload file" - there are tons of results.
If you are doing any serious uploading or have a commercial product you really need to use a COM component in classic asp. Check out SA-FileUp. It has been the defacto standard for this since like forever.
If your hosting service doesn't allow you to install components, you may also want to look at this script:
http://chris.brimson-read.com.au/index.php?option=com_content&view=article&id=6&Itemid=7
I've seen a wide variety of upload scripts floating around, and they ... vary ... in quality. I've not used the script in the selected answer, but its worth trying a few different options.
I can recommend SA-FileUp and Dundas Upload. They both are easy to install and have good tutorials on how to implement.