GatewayScript code examples

apim.getvariable('request');

Example two returns the header named myheader:

apim.getvariable('request.headers.myheader');

Example three shows how to set, add, or clear a context variable, in this case a message header:

apim.setvariable('message.headers.name', value, action)

where

• name is the name of the message header that you want to set, add, or clear.
• value is the string value that you want to set the variable to. This can be a literal value, or another variable. For example, to set your named variable to the value of the Content-Type header in a request, you would specify the value as request.headers.content-type. This property is only required when set or add is specified as the action.
• action is the action that you want to apply to the variable. Valid options are:
  • set
  • add
  • clear
  If no option is set, the default option of set is applied.

var json = apim.getvariable('request.body');

Example two returns a synchronous read of the current message into the variable that is called xml:

var xml = apim.getvariable('message.body');

var data = apim.getvariable('request.body');

// if a nodelist was returned and the type is 13 (BLOB/Binary Node), convert it
// to a Buffer, which can then be converted to a string
if ((data.item && data.length > 0 && data.item(0).nodeType === 13)) {
  data = data.item(0).toBuffer().toString();
}

// if the string really is XML or JSON, then now add code to parse it with
// the appropriate XML or JSON parse function
      .
      .
      .

apim.readInput(callback(err,input) {});
apim.readInputAsJSON(callback(err,json) {});
apim.readInputAsXML(callback(err,nodelist) {});
apim.readInputAsBuffer(callback(err,buffer) {});

The following is an example of how to use the apim.readInputAsJSON() callback function to get data into a variable that is called json:

apim.readInputAsJSON(function (error, json) {
if (error)
{
// handle error
}
else
{
// the json parameter will contain the json data that has been read
// process the json object in some way and write to the output context
if (json.test=='true') 
{
// if json data contains a variable called test that is set to true, then also add some test data
json.data = 'This is my test data'
}
session.output.write(json); 
// write to the output context
}
});

The following example shows how, in the catch block of an API assembly, you can obtain the details of the current caught exception. A possible use would be to create a custom error response using the details of the caught exception.

let exception = apim.getError();

The function returns a JSON object; for example:

{
  "name": "OperationError",
  "message": "This is a thrown Operation Error",
  "policyTitle": "Throw Operation Error",
  "status": {
    "code": "500",
    "reason": "Internal Server Error"
  }
}

The following example shows how to write data into the output, in this case the JSON data '{ "status": "created" }', by using the session.output.write variable:

session.output.write('{ "status": "created" }');

The session.output.write variable is a standard GatewayScript method that writes data to the output context. For more information, see Contexts and sessions.

Use the following function to set the format of the content that is written to the session.output variable:

apim.output('application/type');

For example, if you were creating a policy that called:

session.output.write('<test>this is some xml data</test>');

the policy would write XML data to the output context. You would need to configure the policy to also call

apim.output('application/xml');

to tell the system that the output is XML. It can cause issues in the processing of the policy if the actual output context format, and the format that is specified in apim.output, are different.