How to pass a “url with parameters” as a url parameter in GWT

gwturl-encoding

I am calling a servlet from GWT client code using RequestBuilder.

In the request (a POST) I am passing some request data

builder.sendRequest(postData, new RequestCallback()….

In the postData I have a url parameter called "returnToUrl"

This "returnToUrl" has url parameters, and would be like this

returnToUrl = "http://my.server/add?pn=a&pd=b";

When I pass it to the servlet, the second (and later) parameters (pd=b in my example) get interpreted as request parameters for the servlet, not as part of the returnToUrl parameter, and hence get lost….

It is being URL encoded, but of course that doesn't change the '?' and '&' characters.

Any help much appreciated!

Best Answer

You need to encode your data in GWT.

Take a look at the URL class to do this: http://google-web-toolkit.googlecode.com/svn/javadoc/2.4/com/google/gwt/http/client/URL.html

escpecially at encodeQueryString which basically has the same behaviour as encodeURIComponent in javascript.

Related Solutions

Is a colon `:` safe for friendly-URL use

I recently wrote a URL encoder, so this is pretty fresh in my mind.

http://site/gwturl#user:45/comments

All the characters in the fragment part (user:45/comments) are perfectly legal for RFC 3986 URIs.

The relevant parts of the ABNF:

fragment      = *( pchar / "/" / "?" )
pchar         = unreserved / pct-encoded / sub-delims / ":" / "@"
unreserved    = ALPHA / DIGIT / "-" / "." / "_" / "~"
pct-encoded   = "%" HEXDIG HEXDIG
sub-delims    = "!" / "$" / "&" / "'" / "(" / ")"
                 / "*" / "+" / "," / ";" / "="

Apart from these restrictions, the fragment part has no defined structure beyond the one your application gives it. The scheme, http, only says that you don't send this part to the server.

EDIT:

D'oh!

Despite my assertions about the URI spec, irreputable provides the correct answer when he points out that the HTML 4 spec restricts element names/identifiers.

Note that identifier rules are changing in HTML 5. URI restrictions will still apply (at time of writing, there are some unresolved issues around HTML 5's use of URIs).

Javascript – How to properly send URL parameters containing commas using AngularJS

As you've described the API, there is no way to reliably pass values containing commas.

Suppose you want to pass the items ["one","two","three,four"] as a list.

If you pass the strings as-is, the API will see (after the normal server-side URL decoding)
```
one,two,three,four
```
which makes the three,four indistinguishable from two separate items.
If you pass the strings URL-encoded, the entire parameter will be double-encoded, and the API will see (again, after URL decoding)
```
one,two,three%2Cfour
```
Now the parameters are distinguishable, but this requires support from the API to URL-decode each item separately.
Suppose you pass the strings like one,two,"three,four", i.e. items containing commas are quoted. The API can decode the parameters correctly, but it needs to support a more complex syntax (quoted strings) instead of simply splitting by commas...

...and so on. The bottom line is that without additional support from the API, I don't think there is anything you can do client-side to trick it into decoding strings containing commas correctly. There are many tweaks that the API developer can make, e.g.

Accepting some escape sequence for commas within list items which is unescaped server-side.
Accepting each item in a separate URL parameter.
Accepting JSON-encoded body via POST.

You will need to ask the API developer to do something.

Best Answer

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Javascript – How to properly send URL parameters containing commas using AngularJS

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