Encode a URL Containing a JSONArray

Question

I've got an android application that I'm attempting to use to pass some data to a webservice using HTTPGet. If I just construct the string using the JSONArray.toString() method, I end up with a URL that looks something like the following:

http://xxx.xx.xxx.xx/api?method=upload&args[deviceID]=123456789&args[data]=["{element1=93295352, element2=235235, element3=3523523}","{element1=93295352, element2=235235, element3=3523523}"]

This doesn't work because of the spaces and quotation marks in the URL. If I attampt to do something like the following:

JSONArray ja = new JSONArray();

// Add Data to JSONArray

String s = ja.toString();

// Add array to StringBuilder url

HTTPGet httpget = new HTTPGet(UrlEncoder.encode(url.toString()));

I get an error thrown because the entire URL gets encoded and ends up like this:

http%3A%2F%2Fxxx.xx.xxx.xx%2Fapi%3Fmethod%3Dupload%26args%5BdeviceID%5D%3D123456879%26args%5Bdata%5D%3D%5B%22%7Belement1%3D915156028000%2C+element2%3D1651651%2C+element3%3D489461%7D%22%2C%22

Obviously, this isn't what I'm looking for, and there's got to be a better solution than searching/replacing all the necessary characters in the JSONArray portion of that url, though I suppose doing it that way wouldn't be a huge hassle since I'm only worried about quotation and space characters.

Note that manually pasting this into my browser returned the results I expect:

http://xxx.xx.xxx.xx/api?method=upload&args[deviceID]=123456789&args[data]=[%22{element1=915156028000,%20element2=0.0,%20element3=2.297444}%22,%22{element1=915156055000,%20element2=0.0,%20element3=2.2974419999999998}%22]

Solution

You need to URL encode just the query argument value; for example

JSONArray ja = new JSONArray();

// Add Data to JSONArray

String s = UrlEncoder.encode(ja.toString());

// Add string to StringBuilder url

HTTPGet httpget = new HTTPGet(url.toString());

The other thing that you need to be aware of is that there are practical limits on the length of a URL. These limits vary from one implementation to another (browser, server, proxy, HTTP client library, etc). In some cases, it is as low as 2k bytes, IIRC.

FOLLOW UP

If I want to do the same thing using POST instead, do I end up having to encode the data in the same manner?

It depends.

• If you sent the arguments as URL query arguments with a POST, the same encoding rules and limits would apply. For the record, the URL encoding rules are part of the URL and URI specs.
• If instead you sent the arguments as POST data using the "application/x-www-form-urlencoded" content type, the encoding rules are a bit different; see the HTML spec. (The main difference is that this encoding encodes spaces as + characters.)
• You could also encode the POST data in some other way, provided that the HTTP client and server both understood the encoding and content type.

Of course, one of the advantages of using POST data is that there is typically no limit on the size of the arguments you can send.

Comments

[wtollett]

Thanks. Yeah, I ran into the limit. If I want to do the same thing using POST instead, do I end up having to encode the data in the same manner?