-
An application in StackMob. If you don't have any, you need to create an application.
-
Custom code with 2 parameters uploaded into your app. If you don't know how, follow this instruction to quickly get your custom code up and running.
- None in particular, but see our Custom Code API docs for more details.
There are two different ways to parse the parameters that get passed in to your custom code methods. One is for GET and DELETE requests, and the other one is for POST and PUT requests.
In this tutorial, you will see how to handle these two cases.
If you use stackmob-custom-code-example project, all you need to do is add a class for your custom code.
Say you want to have a custom code method called set_high_score that accepts two parameters, i.e. username and score.
Your java class should look similar to the code below.
package com.stackmob.example;
import com.stackmob.core.customcode.CustomCodeMethod;
import com.stackmob.core.rest.ProcessedAPIRequest;
import com.stackmob.core.rest.ResponseToProcess;
import com.stackmob.sdkapi.SDKServiceProvider;
import java.lang.Exception;
import java.lang.String;
import java.lang.StringBuilder;
import java.net.HttpURLConnection;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
public class SetHighScore implements CustomCodeMethod {
/**
* Name our custom code method
*/
@Override
public String getMethodName() {
return "set_high_score";
}
/**
* Specify parameters for our custom code method
*/
@Override
public List<String> getParams() {
return new ArrayList<String>() {{
add("username");
add("score");
}};
}
@Override
public ResponseToProcess execute(ProcessedAPIRequest request, SDKServiceProvider serviceProvider) {
// this logger can be used to log any activity and you can view the log at https://dashboard.stackmob.com/api/app/logs
// LoggerService logger = serviceProvider.getLoggerService(SetHighScore.class);
Map<String, Object> map = new HashMap<String, Object>();
String verb = request.getVerb().toString();
StringBuilder sb = new StringBuilder(verb + " => ");
// this where we handle the special case for `POST` and `PUT` request
if (verb.equalsIgnoreCase("post") || verb.equalsIgnoreCase("put")) {
if (!request.getBody().isEmpty()) {
try {
JSONObject jsonObj = new JSONObject(request.getBody());
sb.append( "username: %s | score: %s".format(jsonObj.getString("username"), jsonObj.getString("score")) );
} catch (JSONException e) {
sb.append("Caught JSON Exception");
e.printStackTrace();
}
} else sb.append("Request body is empty");
} else sb.append( "username: %s | score: %s".format(request.getParams().get("username"), request.getParams().get("score")) );
map.put("message", sb.toString());
map.put("verb", verb);
return new ResponseToProcess(HttpURLConnection.HTTP_OK, map);
}
}When you do mvn package, you might get an error about org.json. To solve this, you just need to add a dependency for that in pom.xml like this:
<dependency>
<groupId>org.json</groupId>
<artifactId>json</artifactId>
<version>20090211</version>
</dependency>Your scala class should look similar to the code below.
package com.stackmob.example
import com.stackmob.core.customcode.CustomCodeMethod
import com.stackmob.sdkapi.SDKServiceProvider
import com.stackmob.core.rest.{ResponseToProcess, ProcessedAPIRequest}
import java.util.{List => JList}
import java.net.HttpURLConnection
import scala.collection.JavaConverters._
import util.parsing.json.JSON
class SetHighScore extends CustomCodeMethod {
/**
* Name our custom code method
*/
override def getMethodName: String = "set_high_score"
/**
* Specify parameters for our custom code method
*/
override def getParams: JList[String] = List[String]("username", "score").asJava
override def execute(request: ProcessedAPIRequest, serviceProvider: SDKServiceProvider): ResponseToProcess = {
// this logger can be used to log any activity and you can view the log at https://dashboard.stackmob.com/api/app/logs
// val logger = serviceProvider.getLoggerService(classOf[SetHighScore])
val verb = request.getVerb.toString
val sb = new StringBuilder(verb + " => ")
// this where we handle the special case for `POST` and `PUT` request
if (verb.equalsIgnoreCase("post") || verb.equalsIgnoreCase("put")) {
if (!request.getBody.isEmpty) {
JSON.parseFull(request.getBody).map(json => {
json match {
case x: Map[String,Any] =>
x.get("username").map(obj => sb.append("username: ").append(obj.toString))
x.get("score").map(obj => sb.append(" | score: ").append(obj.toString))
case y: List[Any] =>
sb.append(y.toString)
case _ =>
sb.append("unknown data type received")
}
})
}
} else sb.append( "username: %s | score: %s".format(request.getParams.get("username"), request.getParams.get("score")) )
new ResponseToProcess(HttpURLConnection.HTTP_OK, Map("verb" -> verb, "message" -> sb.toString).asJava)
}
}