Newbie Question on GWT/JSON

[Ian]

I am new to the Web application world; I am trying to encapsulate my
set of data in a JSONObject, convert to string, and send it (async
POST) to a PHP page using GWT's RequestBuilder. GWT's tutorial
discusses the trip from the server back to the client and not the
other way around where I am unclear about.

Do I need to set the header? Currently I set it to:
builder.setHeader("Content-Type", "application/x-www-form-
urlencoded");

However, this works fine as long as am sending
key1=value1&key2=values where I can retrieve variable via $_POST
['key1'] or $_POST['key2']

But I am not sure how to send a JSON string where it can be retrieved
in a php page. I have tried sending myvar=MyJsonString but cannot
retrieve in my php page. How should $_POST reference the JSON object?

Any clarification would be much appreciated.

Thanks,

Ian

[Ian]

For those who might be facing a similar problem and others who might
be interested in my previous question I have come up with an answer.
First my disclaimer: the solution below may not be the proper one but
it does work. Now on to the solution:

On the GWT Client Side:

JSONObject jObject = new JSONObject();
jObject .put("propA", new JSONString("valA"));
jObject .put(...

RequestBuilder builder = new RequestBuilder(RequestBuilder.POST,
YOUR_PHP_URL);
builder.sendRequest(jObject.toString(), new YourReponseHandler());

Note that there is no setHeader.

On the PHP side:

Get the raw data instead of $_POST
$jsonReq = file_get_contents("php://input");

Decode the json request
$request = json_decode($jsonReq);

Cheers,
Ian

[Reinier Zwitserloot]

Whatever possessed you to send the "application/x-www-form-
urlencoded" as mime type?

JSON is nothing like form-encoded. That's like sending your HTML as
"image/jpeg" just for kicks. Don't do that.

JSON's mimetype is "application/json" (see [1] below). If you want to
be nice, you should actually set that in the header (as follows:
Content-type: application/json; encoding=UTF-8 - note that JSON is
defined to be UTF-8 encoded, so you're just clarifying there, you
can't pick your own encoding).

And, yes, of course, in PHP you would have to get the entire request
body, instead of letting PHP try to parse it as form data. Possibly
PHP is presuming that the data IS form encoded when there is no header
at all. Is file_get_contents("php://input"); really the only feasible
way to get the entire body in PHP?

Oh, PHP. Every single time someone posts a code snippet written in
PHP, my aesthetic sense blows its brains out in sheer despair. And
this one is up there, which is really saying something. I think its a
conspiracy by the zend folks to make the inner child of developers
worldwide die a little inside every time they come in contact with it.
Sadistic bastards.

[Ian Petersen]

On Sun, Jan 4, 2009 at 11:31 PM, Reinier Zwitserloot <rein...@gmail.com> wrote:
> JSON's mimetype is "application/json" (see [1] below).

You missed the [1] below part and my interest is piqued. Is
application/json an officially accepted MIME type?

> Oh, PHP. Every single time someone posts a code snippet written in
> PHP, my aesthetic sense blows its brains out in sheer despair. And
> this one is up there, which is really saying something. I think its a
> conspiracy by the zend folks to make the inner child of developers
> worldwide die a little inside every time they come in contact with it.
> Sadistic bastards.

Too bad the truth can be so inflammatory....

Ian

[rakesh wagh]

You probably got your answer by now. Think this way. JSON string is
like any other string. The transport mechanism does not have to know
weather it is json or text or number or binary or otherwise. With that
said, you can use forms with get or post(knowing the advantages
drawback of each will help you select the right mechanism) and simply
posting it to your php page. In your php page, read the request
parameters as if they were any other parameters.

As a matter of fact you can even append the json string as part of
your target page url with a variable name and expect the json string
(with a hyperlink click) to reach its destination as expected.

Good luck!
Rakesh Wagh

[martykube]

On Jan 4, 2:32 am, Reinier Zwitserloot <reini...@gmail.com> wrote:
> Whatever possessed you to send the "application/x-www-form-
> urlencoded" as mime type?

> at all. Is file_get_contents("php://input"); really the only feasible
> way to get the entire body in PHP?

file_get_contents("php://input") is not the only way, but it is the
recommended way.

>
> Oh, PHP. Every single time someone posts a code snippet written in
> PHP, my aesthetic sense blows its brains out in sheer despair. And
> this one is up there, which is really saying something. I think its a
> conspiracy by the zend folks to make the inner child of developers
> worldwide die a little inside every time they come in contact with it.
> Sadistic bastards.
>

I'm using the same setup as Ian - GWT + JSON + PHP. This is my first
contact with PHP. After years of working on the bloated stack that is
JEE I've found PHP to be a breath of fresh air. Sure, the aesthetics
are low, but the productivity is high.

Marty

[Reinier Zwitserloot]

Whoops, forgot my footnote:

[1] http://www.ietf.org/rfc/rfc4627.txt

I don't know if that makes it official. I believe the official entity
that vets mime types is IANA, but on their site I couldn't quickly get
to an official list of recognized mime types. Still, if Doug Crockford
says the type is application/json, and almost everyone uses that,
that's the standard. That's how the internet works; standards bodies
can wax rhapsodic about whatever they fancy, but if no one does it,
it's not something you should be doing either, regardless of whether
or not its the 'official standard', so, there you have it.

Oh, and martykube: Be careful that your soul doesn't waft out the
window that is giving you that fresh air. As a general rule, if PHP is
a good fit for you, grails, rails, or django are usually an even
better fit.