code_contributions.md

Sample code

This section contains code snippets (most of them contributed by external developers) that can be used as examples for programming with Orion Context Broker in different technologies. Note that Orion Context Broker evolves with time so it could happen that the code examples get obsolete in some moment (the publication date is provides as reference).

Java

Thanks to Kurento (http://www.kurento.org) a Java library that shows how to access to Orion Context Broker: https://github.com/KurentoLegacy/kmf-orion-connector/tree/develop (published June 2014).

Thanks to Alejandro Villamarin (published around October 2013):

   import com.sun.jersey.api.client.Client;
   import com.sun.jersey.api.client.ClientResponse;
   import com.sun.jersey.api.client.WebResource;

   //Test the Orion Broker, query for Room
   String urlString = "http://orion.lab.fiware.org:1026/v1/queryContext";
   String XML = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>" + 
        "<queryContextRequest>" + 
        "<entityIdList>" + 
        "<entityId type=\"Room\" isPattern=\"true\">" + 
        "<id>Room.*</id>" + 
        "</entityId>" +
        "</entityIdList>" + 
        "<attributeList>" + 
        "<attribute>temperature</attribute>" + 
        "</attributeList>" + 
        "</queryContextRequest>";      
   try {     
      Client client = Client.create();
      WebResource webResource = client.resource(urlString);
      ClientResponse response = webResource.type("application/xml").header("X-Auth-Token", "your_auth_token").post(ClientResponse.class, XML);
   
      if (response.getStatus() != 200) {
         System.err.println(response.getEntity(String.class));
    throw new RuntimeException("Failed : HTTP error code : " + response.getStatus());
      }
   
      System.out.println("Output from Server .... \n");
      String output = response.getEntity(String.class);
      System.out.println(output);
   
   } 
   catch (Exception e) {
      System.err.println("Failed. Reason is " + e.getMessage());
   }

JavaScript

Using JQuery AJAX, thanks to Marco Vereda Manchego (original post) (published around October 2013):

 function capture_sensor_data(){  
 var contentTypeRequest = $.ajax({  
      url: 'http://orion.lab.fiware.org:1026/v1/queryContext',  
      data: '<?xml version="1.0" encoding="UTF-8"?>  
                <queryContextRequest>  
                     <entityIdList>  
                          <entityId type = "Sensor" isPattern="true">  
                               <id>urn:smartsantander:testbed:.*</id>   
                          </entityId>   
                     </entityIdList>   
                     <attributeList>   
                          <attribute>Latitud</attribute>  
                          <attribute>Longitud</attribute>  
                     </attributeList>       
                </queryContextRequest>  ',  
      type: 'POST',  
      dataType: 'xml',  
      contentType: 'application/xml',  
      headers: { 'X-Auth-Token' :   
           'you_auth_token'}  
      });  
      contentTypeRequest.done(function(xml){   
           var latitud = new Array();  
           var longitud = new Array();  
           var i = 0;       
           var len = $(xml).find("contextAttribute").children().size();  
           $(xml).find('contextAttribute').each(function(){  
                     if (  $(this).find('type').text() == "urn:x-ogc:def:phenomenon:IDAS:1.0:latitude"  
                           && $(this).find('contextValue').text() != "" )  
                     {   
                          latitud[i] = $(this).find('contextValue').text(); i=i+1;  
                     }  
                     if ($(this).find('type').text() == "urn:x-ogc:def:phenomenon:IDAS:1.0:longitude"  
                            && $(this).find('contextValue').text() != ""       )  
                     {   
                          longitud[i] = $(this).find('contextValue').text();   
                     }  
                                                                  });  
           for (var j=0; j<i; j++){                 
                console.log("DEBUG :" + latitud[j] + "," + longitud[j]);                 
           }                      
      });                 
      contentTypeRequest.fail(function(jqXHR, textStatus){     
           console.log( "DEBUG :  Ajax request failed... (" + textStatus + ' - ' + jqXHR.responseText + ")." );  
      });  
      contentTypeRequest.always(function(jqXHR, textStatus){       });  
 }

Arduino

Thanks to Enrique Hernandez Zurita, using Orion 0.11.0 and 0.12.0 (published around June 2014):

#include <SPI.h>
#include <WiFi.h>
#include <WString.h>
char ssid[] = "SSID"; 
char pass[] = "CONTRASEÑA";    
          
int status = WL_IDLE_STATUS;
IPAddress server(130,206,82,115);
WiFiClient client;
String line="";
int value=0;
int led=9;

void setup() {
  
    pinMode(led,OUTPUT);
    Serial.begin(9600); 
    while (!Serial) {  ;
    }
    if (WiFi.status() == WL_NO_SHIELD) {

    Serial.println("WiFi shield not present"); 
    while(true);
    } 
    while (status != WL_CONNECTED) { 
    Serial.print("Attempting to connect to SSID: ");
    Serial.println(ssid); 
    status = WiFi.begin(ssid, pass);
    delay(5000); 
    } 
    Serial.println("Connected to wifi");
    Serial.println("\nStarting connection to server..."); 
    
    if (client.connect(server, 1026)) {
    Serial.println("connected to server");
    client.println("POST /NGSI10/queryContext HTTP/1.1");
    client.println("Host: 130.206.82.115:1026");
    client.println("User-Agent: Arduino/1.1");
    client.println("Connection: close");
    client.println("Content-Type: application/xml");
    client.print("Content-Length: ");
    client.println("227");
    client.println();
    client.println("<?xml version=\"1.0\" encoding=\"UFT-8\"?>");
    client.println("<queryContextRequest>");
    client.println("<entityIdList>");
    client.println("<entityId type=\"UPCT:ACTUATOR\" isPattern=\"false\">");
    client.println("<id>UPCT:ACTUATOR:1</id>");
    client.println("</entityId>");
    client.println("</entityIdList>");
    client.println("<attributeList/>");
    client.println("</queryContextRequest>");
    client.println();
    
    Serial.println("XML Sent");
    
    }else{Serial.println("Impossible to connect");}
}

void loop() {
    if(value=1){digitalWrite(led, HIGH);}
  
    while (client.available()) {
    char c = client.read();
    Serial.write(c);
    line=line + c;
        if(c==10){
        value=searchValue(line,value);
        line="";
        }
     }
  
     if (!client.connected()) {
     Serial.println();
     Serial.println("disconnecting from server.");
     Serial.println(value);
     client.stop();
     while(true);
     }
}


int searchValue(String s,int i) {
  int beginning,ending;
  String val;
  beginning=s.indexOf('>');
  ending=s.indexOf('<', beginning+1);
    if(s.startsWith("contextValue",s.indexOf('<')+1)){
    val =s.substring(beginning+1,ending);
    return val.toInt();
    }else{return i;}
}