Passing a very long URL to a HTTPServletRequest

Question

I want to pass a long series of request parameters (over 2000 characters in total) from one .jsp to another (via a URL), and make it seem to the receiving HTTPServletRequest as if it received the request parameters normally.

I cannot simply pass the URL normally as IE11 is truncating the URL at about 2000 characters (see What is the maximum length of a URL in different browsers?) so I need to have some kind of workaround.

It is trivial to save the url in the ClientSession with a key in one .jsp

public String addValue(String aString) {
    String key=""+UUID.randomUUID();
    mapValues.put(key, aString);
    return key;
}

and then retrieve it in the other .jsp

public String getValue(String key) {
        return mapValues.get(key);
}

However the other .jsp needs a HTTPServletRequest and not a string

I.e. I need to be able to do

public MyPosition(HttpServletRequest request) {
        this.id= (String)request.getParameter("ID");

Is there anyway of doing this by converting the retrieved url to a HTTPServletRequest?

I know that I could rewrite MyPosition to take a string and extract the data from there directly, but I would much rather not touch the very lengthy, legacy code.

If I could do setParameter on the request, then this would be a solution. But such an option is not available (see HttpServletRequest - SetParameter)

Are you passing the values from *.jsp to another *.jsp? Or to a servlet? — Roshana Pitigala, Jun 06 '18 at 14:39
You want to pass the request which comes to the 1.jsp to 2.jsp by adding some more parameters.. right? — Roshana Pitigala, Jun 06 '18 at 14:44
@RoshanaPitigala: that is definitely one possible direction of solving the problem, but it is not necessarily the only direction... Thanks! — gordon613, Jun 06 '18 at 14:52
what about storing the url somewhere and then giving that a unique identifier... then use the unique identifier to retrieve the url you assigned to it? (sending the unique identifier in the url instead of the whole url) — Jonathan Laliberte, Jun 06 '18 at 15:13
@JonathanLaliberte that is exactly what I am doing and describe above! The question is what I do with the URL after I have retrieved it. It is a `string` and I need a `HTTPServletRequest`! — gordon613, Jun 06 '18 at 15:27
my bad, missed that part. I don't understand why you can't just save the url as a session attribute? Why do you need `HTTPServletRequest` ? — Jonathan Laliberte, Jun 06 '18 at 15:30
@JonathanLaliberte. I am trying to solve the problem without adapting my old existing legacy code. If I have to, then I will! I attempted to explain this above in the penultimate paragraph... Thanks! — gordon613, Jun 07 '18 at 09:56

score 1 · Answer 1 · answered Jun 06 '18 at 14:56

1

The only way to modify an HttpServletRequest is to wrap it.

answered Jun 06 '18 at 14:56

dimplex

494
5
9

score 1 · Answer 2 · answered Jun 08 '18 at 22:29

1

It sounds like you want to make a standard POST request instead of what sounds like a GET request.

answered Jun 08 '18 at 22:29

Deadron

5,135
1
16
27

In what way would this help? Would it bypass the 2000 character limitation? – gordon613 Jun 10 '18 at 10:25
Post bodies are not subjected to url length restrictions. You can pass a body of arbitrary length – Deadron Jun 11 '18 at 04:12

score 0 · Accepted Answer · answered Jun 27 '18 at 16:29

I tried both @dimplex's and @Deadron's solutions, which I think should both work, but didn't manage to implement either in the short time frame I had available.

I ended up replacing the HTTPServletRequest request parameter in the MyPosition function with String urlKey and adding the following line inside the function

RequestStr request=new RequestStr(cSession,urlKey);

now my existing code did not need to be changed at all, and request.getParameter("paramName") would call my function below.

public class RequestStr {
    String url = "";

    public RequestStr(ClientSession cSession, String urlKey) {
        super();
        this.url = cSession.getValue(urlKey);
    }

    public String getParameter(String aParam) {
        int i = url.indexOf("?" + aParam + "=");
        if (i == -1) {
            i = url.indexOf("&" + aParam + "=");
        }
        if (i == -1) {
            return null;
        } else {

            int j = url.indexOf("&", i + 1);
            if (j == -1) {
                return url.substring(i + aParam.length() + 2);
            } else {
                return url.substring(i + aParam.length() + 2, j);
            }
        }
    }

}

So all I needed to do was to save the very long URL in the session in a map with key urlKey and then in the request just passed this urlKey, and then I could retrieve the long URL via the urlKey and then decode it via my RequestStr class

You need to make sure you call URLDecoder.decode on the query string params or you may have strings containing percent encoded values. Refer to https://stackoverflow.com/questions/13592236/parse-a-uri-string-into-name-value-collection — Deadron, Jun 27 '18 at 18:10

Passing a very long URL to a HTTPServletRequest

3 Answers3