Retrieve Attribute from HTTP Header


The Retrieve from HTTP Header attribute retrieval filter can be used to retrieve the value of an HTTP header and set it to a message attribute. For example, this filter can retrieve an X.509 certificate from a USER_CERT HTTP header, and set it to the authentication.cert message attribute. This certificate can then be used by the filter's successors. The following HTTP request shows an example of such a header:

 POST /services/getEmployee HTTP/1.1
 Host: localhost:8095
 Content-Length: 21
 SOAPAction: HelloService

You can also retrieve a value from a named query string parameter and set this to the specified message attribute. The following example shows a request URL that contains a query string:

In the above example, the query string is first=john&last=smith. As is clear from the example, query strings consist of attribute name-value pairs. Each name-value pair is separated by the & character.


The following fields are available on the Retrieve from HTTP Header filter configuration screen:


Enter an appropriate name for this filter.

HTTP Header Name:

Enter the name of the HTTP header contains the value that we want to set to the message attribute.

Base64 Decode:

Check this box if the extracted value should be Base64 decoded before it is set to the message attribute.

Use Query String Parameters:

Select this setting if the API Gateway should attempt to extract the HTTP Header Name from the query string parameters instead of from the HTTP headers.

Attribute ID:

Finally, select the attribute used to store the value extracted from the request.