Overview

When a FileClassified event is received from the Service Bus, the document-splitter service downloads the original PDF and its classification result, splits the PDF into separate files per classified form, uploads each split to blob storage, saves a manifest, and publishes a FileSplitFile event per output file for downstream processing.

Flow

Service Bus (FileClassified)
        │
        ▼
ClassifiedFileHandler
  1. Download classification JSON from blob (classifiedOutputUrl)
  2. Download original PDF from blob (internalUrl)
  3. For each form in classification → split PDF by page range(s)
  4. Upload each split PDF to blob storage (splits/<clientAppId>/splitFiles/)
  5. Save manifest JSON to blob (splits/<clientAppId>/splitResults/)
  6. Publish FileSplitFileEvent per split file → Service Bus

Key Components

Events

Input – FileClassifiedEvent

{
  clientApplicationId: string;
  internalUrl: string;           // blob URL of the original PDF
  classifiedOutputUrl: string;   // blob URL of the classification JSON
  fileId: string;
  timestamp: Date;
}

Output – FileSplitFileEvent (one per split file)

{
  clientApplicationId: string;
  internalUrl: string;           // blob URL of the split PDF
  fileLocationUrl: string;
  timestamp: Date;
}

Error – ProblemEvent

Published when processing fails. Returns 404 if the blob is not found, 500 for all other errors.

Blob Storage Layout

splits/
  <clientApplicationId>/
    splitFiles/
      <timestamp>_<baseName>_pg<start>-<end>_<formType>.pdf
    splitResults/
      <timestamp>_<baseName>_splitResult.json   ← manifest

Manifest Schema

{
  "clientApplicationId": "...",
  "fileId": "...",
  "parentFileBlobUrl": "...",
  "classificationUrl": "...",
  "timestamp": "...",
  "totalSplitFiles": 3,
  "splitFiles": [
    { "fileName": "...", "formType": "...", "formIndex": 0, "pageStart": 1, "pageEnd": 3, "blobUrl": "..." }
  ]
}

Edge Cases

• No forms in classification → skipped with a warning, no split produced.
• Form with no valid page range → skipped with a warning.
• Multiple page ranges per form → one split file produced per range (concurrent upload).
• Any processing error → ProblemEvent published; error is rethrown for Service Bus dead-lettering.

Limitations

• File Type Supported only PDF.

TO-BE: Future Changes

Overview

The direct blob upload from document-splitter will be replaced by delegating file storage to the file-intake service. Document-splitter will call file-intake’s upload endpoint for each split file, and file-intake is responsible for storing the blob and generating a FileId. Document-splitter then publishes the split file event (including the FileId) to the Service Bus.

Updated Flow

Service Bus (FileClassified)
        │
        ▼
Document-Splitter (ClassifiedFileHandler)
  1. Download classification JSON from blob (classifiedOutputUrl)
  2. Download original PDF from blob (internalUrl)
  3. For each form in classification → split PDF by page range(s)
  4. POST each split file to file-intake upload endpoint
       └─ file-intake stores the child blob + creates FileId
       └─ file-intake returns { fileId, internalUrl, hashValue }
  5. Save manifest JSON to blob (splits/<clientAppId>/splitResults/)
  6. Publish FileSplitFileEvent per split file → split-file topic
       └─ message includes FileId returned from file-intake

Current Implementation and To-Be

Updated Output Event – FileSplitFileEvent

Current

{
  clientApplicationId: string;
  internalUrl: string;
  fileLocationUrl: string;
  timestamp: Date;
}

To-Be

{
  clientApplicationId: string;
  fileId: string;                // returned by file-intake after upload
  internalUrl: string;
  fileLocationUrl: string;
  timestamp: Date;
}

file-intake Integration

• Endpoint: POST /files/child/upload (file-intake service, NEW Endpoint)
• Request: multipart or binary body containing the split PDF buffer
• Response: { fileId: string, internalUrl: string, hashValue: string }
• One HTTP call is made per split file; document-splitter awaits the response before publishing the event.
• If the file-intake call fails, a ProblemEvent is published and the error is rethrown (same error handling as today).