consume REST service with totalcross

Question

I would like to know how to consume a REST service using totalcross.

I made an example following what is in the documentation, I am using Httpstream.

String url = enderecoWS + servico;
HttpStream hs = new HttpStream(new URI(url));
byte[] buf = new byte[hs.contentLength];
hs.readBytes(buf, 0, hs.contentLength);
String str = new String(buf);

Put in line byte[] buf = new byte[hs.contentLength], the value of contentLength is -1 and generates

Exception: class java.lang.NegativeArraySizeException.

I made a change to the code above by changing hs.contentLength for hs.readLine().length(), this way I can catch the return, but from a part of the string.

Another thing, in case I have the following situation:

• Group Class
• Subgroup class

Where the Subgroup class has a group object. When using the JSONFactory thus:

Subgrupo[] subgrupoArray = JSONFactory.parse(str, Subgrupo[].class);

Makes a mistake:

java.lang.IllegalAccessException: Can not call newInstance() on the Class for java.lang.Class

Answer 1

I would like to know how to consume a REST service using totalcross.

[...]

Put in line "byte[] buf = new byte[hs.contentLength]", the value of contentLength is -1 and generates

In the service definition, the server does not necessarily need to send the content size. To handle these situations, Totalcross uses the contentLength == -1

We wrapped to treat this in the best possible way, including treating the part of receiving a compressed response (gzip or deflate). Wrapper is found in Totalcross utilities (class Httpconn).

Another thing, in case I have the following situation:

Class Group Class Subgroup

Where the Subgroup class has a group object, when using Jsonfactory, thus:

Subgrupo[] subgrupoArray = JSONFactory.parse(str, Subgrupo[].class);

To the JSONFactory, you are passing the array class. You should pass Subgrupo[] subgrupoArray = JSONFactory.parse(str, Subgrupo.class);

If Subgrupo is not a shallow object, I recommend using the Jsonsimple API for that purpose. The JSONFactory.parse can only interpret correctly if the parsed object has no subobjects. So, if Subgrupo have as tribute an object of type OutraClasse, there will be a fault in the parser.

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EDIT

At Totalcross, we port the repository of JSON Simple into the SDK, so much so that we have a lightweight JSON compiler (SAX-like). To parse a JSON with this framework, you need to create a ContentHandler. In the original JSON Simple repository itself examples of this. We also have an example of this within an example repository.

Answer 2

Alessandro,

In Totalcross’s github there is an example of how to use the API for REST calls. https://github.com/TotalCross/tcrest

Try running the example and see if it meets what you need =)

Another important thing is that you download the latest version of the SDK on www.totalcross.com always has API updates/fixes