Integrating Electronic Data Interchange (EDI) can feel like navigating a complex maze, especially when you're starting out.
I recently embarked on an assignment from my mentors to convert internal data into an EDIFACT file and securely transfer it via SFTP using webMethods Integration Server.
It was a journey of high stakes, hidden errors, and a 48-hour delay that taught me the most important lesson in integration: The Pipeline is King.
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Chapter 1: The Starting Line – Building Without a Map
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From Manual Architect to EDI Expert From Manual Architect to EDI Expert😅
The initial stage of this project was a massive hurdle that forced me to level up quickly.
In the flurry of onboarding and the high volume of documentation shared by my mentors, I initially overlooked the specific EDIFACT order specifications.
Without that "north star" guide, I found myself facing a blank canvas with only an SNF file in hand.
Instead of waiting, I dove into the deep end. I took on the role of an Architect before I ever wrote a line of code. This involved:
Reverse-Engineering the SNF: I analyzed the raw file structure to understand the data relationships.
Manual Schema Creation: I built the entire EDI Dictionary and Flat File Schema from scratch, manually defining every segment and element based on my own structural analysis.
The Hard Way is the Best Way: While the specs were eventually found, this manual "reverse-engineering" phase proved to be a blessing in disguise. It gave me a granular understanding of the EDIFACT conversion process that I never would have gained by simply following a document.
It was a classic "developer's lesson": sometimes the documents we miss lead us to the insights we need most. Once I finally aligned my custom-built schema with the official specs, the mapping became a precision exercise rather than a guessing game.
Chapter 2: The 48-Hour Roadblock – The ffData Trap
My first major struggle came when I tried to use pub.client.sftp:get to retrieve a file from the SFTP server. I kept hitting a wall with a frustrating error: "Pipeline input parameter ffData cannot be null."
My screenshot of the "ffData cannot be null" error in the console, with the confused expression.
I was convinced the two sftp:get services I was testing in my flow were somehow confusing the pipeline, leading to data loss.
I spent nearly 48 hours of intense debugging and stress trying to figure out why the ffData input was coming up empty. It turns out, the issue wasn't the services themselves, but a fundamental misunderstanding of the pipeline flow and mapping.
I wasn't correctly linking the contentStream from the sftp:get output to the subsequent service that needed ffData. A simple detail, overlooked, leading to days of delay 🙄🤭.
Lesson Learned: A single missing or incorrect mapping line in the pipeline can lead to days of delay. Success relies entirely on a deep understanding of the Pipeline and the structured data format you’ve built.
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Chapter 3: The Core Challenge – Converting Data to EDI**
Once I overcame the ffData roadblock, the next major step was transforming my internal DATA structure into a standard EDIFACT string. I chose wm.b2b.edi:convertToString for this, mapping my custom DATA document directly to the Values input.
![My screenshot of the "correct data mapping for convertToString"]
As shown in my mapping screen, I had to ensure the complex hierarchy I built—containing SenderID, ReceiverID, and the detailed HEADER and ITEM loops—was correctly linked so the service could iterate through the data.
The Struggle with Delimiters:
A subtle but critical point here was the configuration of the service parameters. I had to manually enter the EDItemplate path (e.g., WMEDIFACT.V97A:ORDERS) and the EDI delimiters:
Segment_terminator: '
Field_separator: +
Subfield_separator: :
If these weren't precisely entered in the properties, the convertToString service would either fail with a technical exception or, worse, produce an empty string that would lead to a 0-byte file on the SFTP server. This was the moment where my self-built schema and dictionary had to precisely align with the EDIFACT standard expectations.
The Proof of Success: Validating the Output
To ensure the transformation worked, I monitored the pipeline results. Seeing the DemoStatus update to "SUCCESS" and witnessing the structured data successfully populate the Values document was a massive win after the initial mapping struggles.
![Screenshot of the successful Results screen showing populated EDI Values]
My screenshot of the "correct data mapping for convertToString" (with the green checkmark visual from our previous discussion).
The Struggle with Delimiters: A subtle but critical point here was ensuring the EDItemplate path (e.g., WMEDIFACT.V97A:ORDERS) and the EDI delimiters (Segment_terminator as ', Field_separator as +, Subfield_separator as :) were manually entered correctly. If these weren't precise, the convertToString service would either fail or produce an empty string, leading to an empty file later. This was a place where my self-built schema and dictionary had to precisely match the service's expectations.
Chapter 4: The Translation Layer – Why stringToBytes?
After convertToString successfully produced my human-readable EDI string, the next step was pub.string:stringToBytes.
During my demo, I was asked: "Why did you use the stringToBytes service instead of converting directly to bytes?"
The answer is about control, validation, and protocol requirements.
SFTP servers primarily deal in binary data streams, not plain text.
While some webMethods services might attempt an implicit conversion, using stringToBytes provides explicit control over the encoding (e.g., UTF-8) and ensures data integrity.
- The Matter of Validation Because I built the Dictionary and Schema manually from an SNF file without a specification, I needed a "safety check".
Using convertToString first allowed me to verify the EDI segments (like UNB, UNH, and BGM) were structured perfectly while they were still in a readable text format.
If I had converted directly to bytes, any mapping error would have been hidden inside a binary "blob" that is impossible for a human to read during debugging.
- The Protocol Requirement
While we see "text" when we open a file,
SFTP servers move binary data streams.
The pub.client.sftp:put service specifically requires a contentStream or bytes object to execute the transfer.
By using stringToBytes, I explicitly controlled the encoding (like UTF-8) to ensure that the special characters in the EDIFACT message wouldn't be corrupted during the move from the Integration Server to the remote host.
![My mapping of the string output to the bytes input for final SFTP preparation]
The Final Result: "Sweet Success"
As you can see in my final Results screen, this logic worked perfectly.
The contentStream is populated with a byte array ([B@211340e2).
My DemoStatus confirms: "SUCCESS: EDI File Generated and Sent to SFTP Server".
Before wrapping up this journey, I want to give a heartfelt thank‑you to my mentors Jason, Canes Jhon, and Susan for their guidance, patience, and steady support throughout this entire adventure.
**Stay tuned **a new blog is coming soon,and the next chapter is going to be even more exciting 🚀✨
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