Passing Headers in InvokeHTTP

InvokeHTTP lets you send any custom HTTP header, either hard-coded or built from attributes using Expression Language. If the header isn’t showing up in your outbound request, it’s almost always because of one of these configuration issues.

Static header

1. Open the processor

2. Add a new property

3. Set the property name to the exact header name

4. Set the value to the literal value you want sent

Example:

Property Name: X-Client
Value: clockspring-ui

This sends X-Client: clockspring-ui.

Dynamic header with Expression Language

Same process, but use EL to build the value from FlowFile attributes.

Example:

Property Name: X-Customer-ID
Value: ${customerId}

If customerId exists, the header is populated.
If not, the header ends up empty.

More examples:

• X-Env: ${env}

• X-Region: ${region}

• X-Trace: ${uuid()}

• X-Date: ${now():format("yyyy-MM-dd")}

Things to know

• Header names must match exactly. Case differences can matter depending on the target API.

• Headers are not automatically created from attributes. Every header must be explicitly added.

• Missing or invalid EL resolves to an empty header value.

• The built-in Authorization configuration is separate and should be used instead of manually creating Authorization headers.

Example config

You want to send three headers:

InvokeHTTP will include all three in the outbound request.