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HTTP and JMS Headers

Use header functions to get details about headers that you pass when you invoke a process. You can get details about process headers and message event headers.

Use header functions to get information that is only available in the header that you pass when you invoke a process. Examples include dates, JSON Web Tokens, and security IDs.

You can assign the header value to a field and, optionally, perform XQuery operations on the value.

The following image shows the header functions available under the

Request Context

section of the Expression Editor:

To understand how each function works, consider a process invoked with the following headers and values:

Header	Value
accept-language	en-US;q=0.9
client-ip	192.0.2.1
accept	text/xml
postman-token	0023-a5dfd-8vdg3-n2b3
CustomHeader	This is a custom header
ExecutionDate	Wed, July 25 2018 06:25:24 GMT

You can use the following header functions on their own, or along with other functions:

Get All Header Values: Use the
getAllHeaders
function to get a list of all headers and their values.; For example, if you use the following expression, you get a specific output:; Expression:
fn:getAllHeaders(); Output:
<headers> <header name="accept-language">en-US;q=0.9</header> <header name="client-ip">192.0.2.1</header> <header name="accept">text/xml</header> <header name="postman-token">0023-a5dfd-8vdg3-n2b3</header> <header name="CustomHeader">This is a custom header</header> <header name="ExecutionDate">Wed, July 25 2018 06:25:24 GMT</header> </headers>

Get Date Headers: Use the
getDateHeader
function to get the value of a Date header. The function returns data in the dateTime type.; You can use other Date and Time functions to parse the value.; For example, if you use the following expression, you get a specific output:; Expression:
fn:year-from-dateTime(request:getDateHeader("ExecutionDate"); Output:; 2018

Get a Specific Header Value: Use the
getHeader
function to get the value of a specific header.; For example, if you use the following expression, you get a specific output:; Expression:
request:getHeader("accept"); Output:; text/xml

Get a list of Headers Names: Use the
getHeaderNames
function to get a sequence of header names without values.; For example, if you use the following expression, you get a specific output:; Expression:
request:getHeaderNames(); Output:
accept-language,client-ip,accept,postman-token,CustomHeader,ExecutionDate

Get a Header value or 'Default': Use the
getHeaderOrDefault
to get a header value if the header exists, or some default value if the header does not exist.; To use this function, you must give the header name and a default value as expression parameters.; Let the default value be
Not Available
.; For example, if you use the following expression, you get a valid output:; Expression:
concat ("The header I want is", request:getHeaderOrDefault("postman-token","Not Avaialble" ); Output:
The header I want is 0023-a5dfd-8vdg3-n2b3; If you use the following expression, you get a Not Available output:; Expression:
concat ("The header I want is", request:getHeaderOrDefault("special-token","Not Avaialble" ); Output:
The header I want is Not Available; This is because the request does not contain a header with the name
special-token
.

Check if a Specific Header Exists: Use the
headerExists
function to check if a header with a specific name exists.; You get either
True
or
False
in the output.; For example, if you use the following expression, you get a specific output:; Expression:
request:headerExists("CustomHeader"); Output:
True

Headers from Message Events

If a process has message events, you can use any header functions to get headers from the message events. To do this, you must add the case-sensitive message event name as an expression parameter.

For example, if you pass a header with the name

CustomHeader

to the message event receive step, use the following expression to get the value of

CustomHeader

from the message event

ME1