Save javascript variable to text file in server

Question

I've spent the better half of the past 4 work days trying to find a solution to this issue, but as a newbie coder, I'm yet to find a solution.

Basically I'm interning in this company, and they tasked me with translating a .NET app (C#) from doing its reading and writing of a webpage from a .dll to a .xml. The page is still opened from the dll, yet all the settings-saving will be done on the .xml, located at ./config.xml. I got it to write the file from the C# end, but when it comes to in-browser, client-side saving, I'm getting some issues. The page looks like this

In the previously mentioned DLL, that is hosted using IIS, I can both use C# to program server-side stuff and html through the use of a C# variable from a proprietary method that is used to render the webpage.

Every checkbox and dropdown (and its content) is dynamically given an HTML ID taking into consideration the divider it lies in and the number of the item, for example "general1", "misc3". To do that, I used XElement to create the base XML, which is read using C# and plugged into the html, and several javascript scripts to read what checkboxes are checked and what values the dropdowns own.

I'm having issues with the saving part, as this is a webpage meant to be opened on a mobile phone and needs to save the xml file onto the server. I've coded it so that, at the end of the page, there's a debug section so I can see the variables and their values, and update the webpage according to the item's contents (basically a way for me to study how getelementbyid and innerhtml work in JS). I then process the webpage data, and print out to a

what the .xml file would look like, as I stored it on a javascript variable. My major issue is finding out how to save that javascript variable into a file. I've read around that I could use php and VB, but I have no clue 1- how to code those and 2- if I can even implement that in this scenario. I've also looked around some javascript ways of doing this, but it often involves the user specifying where to save it LOCALLY, instead of somewhere hardcoded on the server. Any help will be incredibly thanked, as I managed to even baffle my higher-ups, so no one here found a solution yet

TL;DR: Got a client-side variable in javascript from an aspx, need to save it locally through javascript to a hardcoded location, maybe using php if you can get me to wrap my head around how it even works

Answer 1

Well, first this this idea that some ".dll" is loading the page or data?

No, you have code behind. It has some referneced assembly and library, and the code behin for that page calls that code. In fact ALL pages work this way.

You have plain jane code behind - if the user enters data on that page, then VERY little reason exists as to why the code behind is not then able to freely use + consume the values and data in those controls. VERY strange this issue is not dealt with.

I mean, have js pass some value to a method in that code behind and save that data or whatever? Sure. (not clear why some class or object structure is not being used here).

I mean, if you want to pass some text to the server, then you can do this:

markup:

        <asp:Button ID="Button2" runat="server" Text="Button" ClientIDMode="Static"/>
        <asp:HiddenField ID="HiddenField1" runat="server" ClientIDMode="Static"/>

        <script>
            function myfuntest() {
                var sometext = "Hello, this is fun"
                $('#HiddenField1').val(sometext)
                $('#button2').click()
            }
        </script>

So in the js code, we shove a value/text into that hidden field. Click the button.

The code behind will now look like this:

protected void Button2_Click(object sender, EventArgs e)
{
Debug.Print("script passed value = " + HiddenField1.Value);
}

So, above now is code behind, and we passed that value.

The PROBLEM here is that you attempting to pass xml. And passing xml is NOT safe when using controls on the form. (you have to turn off validation)

As noted, again: VERY confusing why the value(s) of the controls on that page are NOT picked up by the code behind.

However, if you wanted to, then yes, you can pass a value to code behind.

And you don't even need say a button and hidden field. Just using a jQuery post (ajax call).

So, our code will look like this:

      <script>

            function test1() {  

                var strXML = '<?xml version="1.0" encoding="utf - 8"?><test>Some text</test></xml>'
        
                $.ajax({
                    type: "POST",
                    url: 'SaveXML.aspx/Test',
                    data: JSON.stringify({sXML : strXML }),
                        contentType: "application/json",  
                        datatype: "json"    
                    });  
                }  

        </script>

So I just shoved some xml into a var. But my spider sense VERY VERY much thinks a large detail here about that xml strucutre - and having a class server side that de-serlizes that xml is at play here - or should be used.

but, regardless, the above ajax call and web method will work. So on that web page, we can now have a public function called Test, with one paratmers called xXML.

The code behind stub can thus look like this:

[WebMethod()]
public static void Test(string sXML)
{
Debug.Print("web method - value data = " + sXML);

string strOutFile;
strOutFile = HttpContext.Current.Server.MapPath("/Content/test.xml");

File.WriteAllText(strOutFile, sXML);
}

So the above would write out the passed xml data from the client side, and the xml data you passed would be written out to a file on the web server under the web server folder called "Content" with a file name of test.xml

So it only a wee bit few lines of code. But I think overall, there is no doubt additonal details here, and it not quite at a all clear why the data is being gathered up in to some xml, and then sent to the server. If that data is a "group" of data rendered by asp.net controls, then the repeating data can be directly used for a "for each" and seen, used, and grabbed by code behind in place of a whole bunch of client side code that builds up the xml.

And it also not clear in regards to save the file - you ping pong and alternate the context between saving a file on disk - do you mean client side, or server side? I had to guess - since you can't save such files client side.

But above does show how to pass a simple var to the server side code behind in that web page, and then write out what you passed to a file on disk.