The Content Modifier Lab · Nest Labs

What you will learn

One step, three destinations

Write headers, properties and the body — and know which one to reach for.
Pull fields out of an XML payload with XPath, then build a new JSON body from them.
Externalize a value so the same iFlow moves DEV → QA → PROD without opening the editor.
Read the Trace pane like a debugger — the habit that makes every later lab faster.

What you are building

Three Content Modifiers, one round trip

There is no receiver system in this lab. An HTTPS sender with no receiver returns the final body straight back to the caller — so whatever your last Content Modifier writes is what you see in Postman. Every mistake is visible in one second.

SenderHTTPSOrder XML arrives

→

Content ModifierCM_SetContextConstants · timestamp

→

Content ModifierCM_ReadOrderXPath out of payload

→

Content ModifierCM_BuildAckNew JSON body

→

EndReplyBody back to caller

The one idea behind all of it. A CPI message carries three separate things: headers (travel out to the receiver), properties (live only inside the flow), and the body (the payload). The Content Modifier is the one step that writes all three — one tab each.

Before you start

What you need on the bench

Prerequisites
Item	Why
An SAP BTP / CPI trial tenant	To create the package, iFlow and deploy it. A free trial is enough.
The role `ESBMessaging.send`	Assigned to your test user, or the endpoint answers 401.
Postman (or any HTTP client)	To POST the test payload and read the response.
~90 minutes	Deploy and test after every task — that habit is half the lab.

Set up the sandbox

10 minNot graded — but nothing works without it

In Design → Integration Content, create a package Training_ContentModifier_XX.
Add an integration flow named Order_Enrichment_CM.
Connect the sender to Start, pick the HTTPS adapter, address /order-enrich-XX, Authorization User Role with ESBMessaging.send.
Do not add a receiver. Set Log Level to Trace. Save, then Deploy.

Check yourselfPOST the sample payload with Basic auth and Content-Type: application/xml. You should get HTTP 200 and your own XML echoed back. A 401 means the role is missing; a 404 means the flow is not started.

Stamp the message with constants

Tab: Message Header10 min15 marks

Learn the simplest thing a Content Modifier does — write a fixed value that was never in the payload — and learn how to see that it worked.

Drop a Content Modifier between Start and End. Rename it CM_SetContext.
Open its Message Header tab and add these three entries.

CM_SetContext · Message Header
Name	Source Type	Source Value
SourceSystem	Constant	WEBSHOP
InterfaceId	Constant	INT-0042
ProcessedBy	Constant	your full name

Verify · learn this once, use it all labSave, deploy, send the payload. Open Monitor → Message Processing, the newest log, the Trace tab. Select CM_SetContext and switch the pane between Header, Property and Payload. All three headers must be listed.

Deliverable. A screenshot of the Trace header pane showing all three names and values.

Keep working values out of the headers

Tab: Exchange Property15 min20 marks

Learn the header-versus-property decision, and write your first value calculated at runtime instead of typed by hand.

CM_SetContext · Exchange Property
Name	Source Type	Source Value
ProcessingStatus	Constant	ACCEPTED
ReceivedAt	Expression	${date:now:yyyy-MM-dd'T'HH:mm:ss}

Write it down · 5 of 20 marks. In two sentences: why does ReceivedAt belong in a property rather than a header? Say what happens to each when the message leaves through a receiver adapter.

Pull values out of the payload with XPath

Tab: Exchange Property20 min25 marks

Learn the Content Modifier's most-used trick: lifting fields out of an XML body so you can use them later without touching the payload again.

CM_ReadOrder · Exchange Property
Name	Type	Data Type	XPath
OrderNumber	XPath	java.lang.String	/Order/Header/OrderNumber
CustomerId	XPath	java.lang.String	/Order/Header/CustomerId
Currency	XPath	java.lang.String	/Order/Header/Currency

VerifyTrace → CM_ReadOrder → Property pane shows real values. Empty values almost always mean a wrong path or a missing Data Type — not a broken tenant.

Replace the payload with your acknowledgement

Tab: Message Body20 min25 marks

Write a completely new body out of values you collected earlier — and see that the Message Body tab replaces the payload rather than editing it.

CM_BuildAck · Message Body

{
  "acknowledgement": {
    "orderNumber": "${property.OrderNumber}",
    "customerId":  "${property.CustomerId}",
    "sourceSystem":"${header.SourceSystem}",
    "receivedAt":  "${property.ReceivedAt}",
    "status":      "${property.ProcessingStatus}"
  }
}

VerifyThe Postman response is now JSON, not your order XML, every field filled in. A field that comes back literally as ${property.OrderNumber} means a misspelled name, or the value was stored as a header instead of a property.

Make one value configurable without editing the flow

Externalize15 min15 marks

Externalized parameters — the reason real projects move the same iFlow from DEV to QA to PROD without opening the editor.

Two things beginners expect and don't find. There is no "External Parameter" in the Source Type list — externalizing is the Externalize link at the top-right of the step. And the Source Value there holds the parameter name, not the value — it comes back as {{EnvName}}.

VerifyChange EnvName from DEV to QA via Configure only — never reopening the editor — and the same flow answers "environment": "QA".

Read this before you get stuck

Where beginners lose an hour

BODY

The Message Body tab is a replacement, not an edit.
Whatever you type becomes the entire payload. Only adding a header? Stay out of that tab.

ORDER

XPath reads the body as it is right now.
Once a Content Modifier replaced the XML with JSON, every later XPath returns nothing. Read first, rewrite last.

SCOPE

${header.X} will not find a property.
Mixing the two prefixes is the most common beginner bug — the placeholder survives into the output as literal text.

TRACE

No Trace, no debugging.
Trace records only while Log Level is Trace and keeps data about ten minutes.

Self-check

Before you submit

01A value must reach the receiver system. Header or property?

Header. Properties exist only inside the flow and are dropped at the boundary; headers are handed to the receiver adapter.

02Your acknowledgement comes back containing literal ${property.Currency}. Two likely causes?

Either the name doesn't match exactly (case included), or the value was written on the Message Header tab while you read it as a property.

03What does an externalized value buy you that a plain constant does not?

It changes from the Configure screen — per tenant, per deployment — without opening the flow. One artifact serves DEV, QA and PROD.

Hand-in

Submission checklist

Tick these off as you go — this page remembers your ticks.

Exported iFlow (.zip) or a screenshot of the full canvas Trace screenshot from Task 1 showing the three headers Trace from Task 3 showing the XPath properties with real values The final JSON response from Postman, pasted as text Two responses from Task 5 — one DEV, one QA

Resources

Everything for this lab

Test payload · use this exact XML for every task

<Order>
  <Header>
    <OrderNumber>SO-100234</OrderNumber>
    <CustomerId>CUST-8891</CustomerId>
    <Currency>EUR</Currency>
  </Header>
</Order>

SAP Help — search "Define Content Modifier" for the official field reference.

Discussion

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Nest Labs · SAP Cloud IntegrationBeginner · ~90 min