Letter & Correspondence Generation

DocuDesk provides an API for generating personalized correspondence — letters, notifications, decisions — by combining a stored Twig template with data resolved from one or more OpenRegister objects. Output formats include PDF, DOCX, HTML, and email.

Overview

The correspondence pipeline:

1. Fetch template — Load a stored template by UUID via TemplateService
2. Resolve data — Fetch recipient and case data from OpenRegister objects
3. Render — Render the Twig template with the merged data context
4. Produce output — Convert to the requested format (PDF, DOCX, HTML, email)
5. Log — Record the generated correspondence in an OpenRegister log register

For batches larger than 10 recipients, the work is offloaded to a BatchCorrespondenceJob Nextcloud background job so the HTTP request returns immediately with a job ID.

API Endpoints

Generate Single Correspondence

POST /apps/docudesk/api/correspondence/generate

Generates a single correspondence document for one or more data references and returns the rendered output inline.

Request body (JSON):

Field	Type	Required	Description
templateId	string	Yes	UUID of the stored template to use
dataRefs	array	Yes	Array of OpenRegister references { register, schema, id }
options	object		Generation options (see below)

options fields:

Field	Type	Default	Description
format	string	pdf	Output format: pdf, docx, html, email
huisstijlId	string		UUID of a huisstijl/branding object to apply
caseReference	string		Case or dossier reference for the correspondence log
recipientType	string		Recipient category label for logging
userId	string		Nextcloud user ID to attribute the generation to

Response:

{
  "content": "<base64 or HTML string>",
  "format": "pdf",
  "warnings": [],
  "registerEntry": { "id": "...", "status": "logged" }
}

---

Generate Batch Correspondence

POST /apps/docudesk/api/correspondence/generate/batch

Generates correspondence for multiple recipients. Batches of more than 10 recipients are processed asynchronously and a job ID is returned immediately.

Request body (JSON):

Field	Type	Required	Description
templateId	string	Yes	UUID of the stored template
recipients	array	Yes	Array of dataRefs sets — one entry per recipient
options	object		Same options as single generate

Synchronous response (≤ 10 recipients):

{
  "results": [
    { "recipientIndex": 0, "content": "...", "format": "pdf", "warnings": [] }
  ]
}

Asynchronous response (> 10 recipients):

{
  "jobId": "job-uuid",
  "status": "queued",
  "message": "Batch queued for background processing"
}

---

Get Job Status

GET /apps/docudesk/api/correspondence/jobs/{jobId}

Returns the current status of a batch background job.

Response:

{
  "jobId": "job-uuid",
  "status": "completed",
  "processedCount": 25,
  "totalCount": 25,
  "errors": []
}

---

Data Resolution

DataResolverService resolves referenced OpenRegister objects into a merged data context:

• Accepts an array of { register, schema, id } references
• Resolves nested object references up to 3 levels deep
• Merges all resolved objects into a single flat Twig context
• Uses a per-request in-memory cache to avoid duplicate lookups

Example dataRefs:

[
  { "register": "woo-register", "schema": "person", "id": "person-uuid" },
  { "register": "cases-register", "schema": "case", "id": "case-uuid" }
]

Output Formats

Format	Description
pdf	PDF/A-3b via mPDF with embedded fonts (default)
docx	Microsoft Word document via PhpOffice/PhpWord
html	Rendered HTML string
email	Sends the rendered content as an email (requires SMTP)

Background Processing

When a batch request exceeds 10 recipients, CorrespondenceService schedules a BatchCorrespondenceJob via IJobList. The job runs in the next Nextcloud cron cycle and stores progress in the cache under the returned job ID.

Services

CorrespondenceService

Main orchestration service.

Method	Description
generate()	Generate a single correspondence document
generateBatch()	Generate correspondence for multiple recipients
getJobStatus()	Retrieve background job status by job ID
storeJobStatus()	Persist job status to the cache

DataResolverService

Resolves OpenRegister object data for use as Twig context.

Method	Description
resolve()	Resolve one or more data references to a merged array

BatchCorrespondenceJob

Nextcloud QueuedJob for large batch correspondence processing.

Dependencies

Dependency	Purpose
TemplateService	Load stored templates by UUID
DataResolverService	Resolve OpenRegister objects to Twig data
TemplateRenderer	Twig sandboxed rendering
PdfService	PDF/A-3b generation
IJobList	Schedule background jobs for large batches