从HTML / Javascript发送大型String数据到背后的代码

Question

Our application has some hidden fields like any other asp.net application. Here we are using hidden fields to store HTML of an image, which is considerably large. We use the value(large HTML string) of hidden field in our C# code for further processing.

We tend to create 4 instances of our application and we have doubts over load balancing of azure cloud service. We assign values to these hidden fields in midway of our application process through javascript. As this processing is done on client side there are no issues here. But since azure has multiple instances so if want to access these hidden fields on server side (ie in our C#), accessing these hidden fields directly would create any problem due to load balancing if the instance changes ?

Note: Our page does not postback while accessing these hidden fields on the server side.

We are not clear when does the instance change, if our page does not postback then will the request go the same instance ? Is this guaranteed. Also if the page does postback then does the response goes to the same instance of the calling request instance.

We need suggestions or the correct way of accessing these hidden fields on the server side. These hidden fields are very important to us; using the cache/session settings of azure will become very costly for us since the data is very large. It would be very helpful if the suggestion would be for cost free implementation. As we are already running on a tight budget.

//25Oct 2013

We have a large string of data, which is majorly made up of HTML obtained from Bing Map, we have taken the HTML of the Bing map using the Jquery Selector of our Bing Map div element, we want this HTML string to be sent to the code behind. We have this string on our javascript but when we do ajax call to the code behind it fails.

We even tried to send it in body via a POST method, but this fails again.

 var string = formData; // so long text
        var xhr = new XMLHttpRequest();
        var body = "string=" + encodeURIComponent(string);
        xhr.open("POST", "index.aspx/getString", true);
        xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
        xhr.setRequestHeader("Content-Length", body.length);
        xhr.setRequestHeader("Connection", "close");
        xhr.send(body);

As Rick suggested, we had already tried blob but the problem is with sending the string from javascript to code behind. We are really stuck on the dead end here.

Answer 1

You indicated that caching would be costly for you. While it is true that using the Cache Service would incur some costs, have you considered co-located in-role caching as an alternative? Perhaps you have enough extra resources on your existing instances to support your needs. There is a link to some capacity planning in the link I've provided above if you choose to take this route.

--- 10/24/2013 ---

If I'm understanding your latest description correctly, you are generating some HTML on the client that you want to upload to your web app on Azure. In the web app, you're using that HTML to generate a PDF that I assume the client would later receive. If this is your scenario, then you could just upload the HTML and store it as a blob? This way any instance of the web app can reference it from blob storage rather than stuffing it into hidden fields.

In your web app, you can use HttpPostedFile to receive the file from the client and save it to a blob. Note: You may need to adjust the max. size allowed for the post since it defaults to 4MB and you indicated your data could be up to 5MB.

I'm trying to help you but your question is just not that clear. Even the title is misleading given the context of the discussion. If this doesn't help, then you may want to edit your question.