com.softwareag.is.interceptor

Interface HttpInterceptorIFC

public interface HttpInterceptorIFC

This class defines a set of contracts that any HttpInterceptor must implement.

Integration Server provides a framework for creating and registering an HTTP interceptor. An HTTP interceptor intercepts all received HTTP requests and outbound HTTP responses. Integration Server makes the raw HTTP request and response, including the HTTP header information, accessible to the HTTP interceptor. In the case of HTTP requests, the HTTP interceptor intercepts a received HTTP request before Integration server performs any processing. For an outbound HTTP response, the HTTP interceptor intercepts an HTTP response after Integration Server creates the HTTP response but before Integration Server sends the response to the requesting client.

An HTTP interceptor is comprised of:

• A preProcess method that gets called for every HTTP request received by Integration Server. The preProcess method has access to the raw HTTP request data, including the headers and a clone of the request body, The preProcess method is called before Integration Sever has done any processing, such as engaging a content handler. However, Integration Server authenticates the client before calling the preProcess method. The preProcess method can stop normal processing for the HTTP request by throwing an exception, specifically a HTTPInterceptorException. The exception contains the HTTP status code and message that Integration Server will use in its response to the requestor.
• A postProcess method that gets called for every HTTP response that Integration Server sends. Before Integration Server writes the HTTP response to the connection, the postProcess method receives a clone of the response body along with response status code, status message, and headers.

An HTTP interceptor can be useful if there is some logic, such as an auditing requirement, that you want executed for every request and response. By placing the logic in in the interceptor, you ensure that Integration Server executes the logic for every HTTP request and response. For example, you can use an HTTP interceptor to write all HTTP requests and responses to a data lake or perform some kind of logging.

Keep the following information in mind when creating an HTTP interceptor:

• You can register only one HTTP interceptor per Integration Server
• The class that contains the HTTP interceptor must implement the com.softwareag.is.interceptor.HTTPInterceptorIFC interface and provide implementations of both methods in the class -- preProcess and postProcess.
• Using an HTTP interceptor delays processing of a request. Any logic the preProcess method executes to determine whether or not to continue with request processing needs to be done synchronously. However, if the preProcess method includes logic that can be done asynchronously by spawning off another thread, regular processing can proceed as quickly as possible.
• Using an HTTP interceptor delays sending of the response.
• An HTTP interceptor cannot modify the content of the HTTP request or response. For an HTTP request, Integration Server passes the HTTP interceptor a byte array representation of the input stream. When the HTTP interceptor completes execution, as long as the interceptor does not throw an HTTPInterceptorException to reject the HTTP request, normal Integration Server processing continues with the original input stream.

Following are the general steps to take when creating an HTTP interceptor.

1. Create a Java Class that implements the HTTPInterceptorIFC interface. Build the implementation into a class file that goes into a jar file.
2. Place the jar file in one of these locations to ensure that the class appears on the Integration Server classpath.
   • Software AG_directory\IntegrationServer\instances\\lib\jars\custom
   • Software AG_directory\IntegrationServer\lib\jars\custom
   • Software AG_directory\IntegrationServer\instances\\packages\\code\jars\static
3. Set the following server configuration properties in Integration Server.
   • watt.server.http.interceptor.enabled
   • watt.server.http.interceptor.impl
   • watt.server.http.interceptor.preprocess.sizeLimit
   For more information about these properties, refer to the webMethods Integration Server Administrator’s Guide.
4. Restart Integration Server.

Method Summary

Modifier and Type	Method and Description
void	postProcess(int responseCode, java.lang.String responseMessage, java.util.Map<java.lang.String,java.lang.String> headers, byte[] bytes, java.lang.String correlationID) Receives HTTP Response data after all processing has been done, but before the response is sent back to the client.
void	preProcess(java.lang.String requestURL, java.lang.String requestType, java.lang.String httpVersion, java.util.Map headers, byte[] streamBytes, java.lang.String correlationID) Receives HTTP request data before any processing has been done on the Integration Server.

Method Detail

preProcess

void preProcess(java.lang.String requestURL,
                java.lang.String requestType,
                java.lang.String httpVersion,
                java.util.Map headers,
                byte[] streamBytes,
                java.lang.String correlationID)
         throws HttpInterceptorException

Receives HTTP request data before any processing has been done on the Integration Server. Throws HttpInterceptorException if processing should be interrupted.

Parameters:

requestURL - The URL used by the client for this HTTP request, including the query if present.

requestType - The HTTP method used. Possible values are GET, PUT, POST, PATCH, and DELETE.

httpVersion - The HTTP version of the request.

headers - A map of the fields in the request transport header, where key names represent header field names and values represent the header field values.

streamBytes - The body of the HTTP request represented as a byte array.

correlationID - An id assigned to this request that can be used to correlate this request to a specific response when it comes back through the HTTP Interceptor.

Throws:

HttpInterceptorException - - Thrown by preProcess method to interrupt Integration Server processing of this request.

postProcess

void postProcess(int responseCode,
                 java.lang.String responseMessage,
                 java.util.Map<java.lang.String,java.lang.String> headers,
                 byte[] bytes,
                 java.lang.String correlationID)

Receives HTTP Response data after all processing has been done, but before the response is sent back to the client.

Parameters:

responseCode - HTTP status code of the response.

responseMessage - HTTP status message of the response.

headers - A map of the fields in the response transport header, where key names represent header field names and values represent the header field values.

bytes - The body of the HTTP response represented as a byte array.

correlationID - An id assigned to the original preprocess request that can be used to correlate this postProcess response back to a specific request that came through the HTTP Interceptor.