[Developers] Java and mql write service

[Bryan Cheung]

Hi Christian,

I've had better luck using the Jakarta Commons HTTPClient library(http://hc.apache.org/httpclient-3.x/ 
).

In pseudo-code, you can login using the PostMethod:
private static final String LOGIN_PATH = "/api/account/login";
private static final String WRITE_PATH = "/api/service/mqlwrite";
private String freebaseUrl;  // sandbox or www
PostMethod method = new PostMethod(freebaseUrl);
method.setPath(LOGIN_PATH);
method.setRequestBody(requestBody);  // the request body
int responseCode = client.executeMethod(method);  // execute method

The client object will store your cookie credentials and you can then  
reuse the client to execute a write:

method.setPath(WRITE_PATH);
method.setRequestHeader("X-Metaweb-Request", "true");
method.setRequestHeader("Content-type", "application/x-www-form- 
urlencoded");
method.setRequestBody(requestBody);  // the request body
int responseCode = client.executeMethod(method);

Once upon a time, I wrote a FreebaseClient using HTTPClient and JSON  
in Java (http://json.org/java/).  If you're interested, I can send you  
or anyone else some code samples.

Bryan



On Feb 18, 2008, at 7:07 PM, Christian Hirsch wrote:

> Hi All,
>
> I am trying to access the write API using Java, but somehow I always  
> get an error.
> Sending read and login requests works just fine, however when I'm  
> sending write requests I'm always getting '400 bad request'. I'm not  
> very familiar with http requests in java... could there be something  
> wrong with the request header? or the credentials? - maybe someone  
> has some working example code?
>
> this is the code I'm using:
>
> query = "{\"create\":\"unless_exists\",\"id\":null,\"type\":\"/ 
> common/topic\", \"name\":\"test_xy\"}";
> String envelope = "{\"qname\":{\"query\":" +query+ "}}";
> String data = URLEncoder.encode(envelope, "UTF-8");
>
> URL url = new URL("http://sandbox.freebase.com/api/service/mqlwrite");
> URLConnection conn = url.openConnection();
> conn.setDoInput(true);
> conn.setDoOutput(true);
>
> String credentials = "metaweb-user=..."; // value of the Set-Cookie  
> from the login response
> conn.setRequestProperty("Cookie", credentials);
> conn.setRequestProperty("X-Metaweb-Request", "True");
> conn.setRequestProperty("Content-type", "application/x-www-form- 
> urlencoded");
>
> OutputStreamWriter wr = new  
> OutputStreamWriter(conn.getOutputStream());
> wr.write(data);
> wr.flush();
>
> BufferedReader rd = new BufferedReader(new  
> InputStreamReader(conn.getInputStream()));
> //write the response to a JSON object...
> wr.close();
> rd.close();
>
>
> Thanks,
> Christian
> _______________________________________________
> Developers mailing list
> Developers at freebase.com
> http://lists.freebase.com/mailman/listinfo/developers

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.freebase.com/pipermail/developers/attachments/20080218/d669246f/attachment-0001.htm