frappe-core-files

Use when handling file uploads, attachments, private/public file access, or S3 storage configuration. Prevents broken file URLs, permission leaks on private files, and failed uploads from incorrect MI

SKILL.md

GitHub

Frappe File Management

Quick Reference

Action Method Notes
Save file from bytes save_file(fname, content, dt, dn) Returns File doc
Save file from URL save_url(file_url, fname, dt, dn) Creates File doc from URL
Read file content frappe.get_file(fname) Returns [filename, content]
Get file path get_file_path(file_name) Resolves to absolute path
Upload via HTTP POST /api/method/upload_file Multipart form upload
Delete file frappe.delete_doc("File", name) Removes doc + filesystem file
Attach print frappe.attach_print(dt, dn, print_format) Returns {"fname", "fcontent"}
Get cached doc frappe.get_cached_doc("File", name) Read-only, cached

Decision Tree

What file operation do you need?
│
├─ Upload a file from user input?
│  ├─ Via web form → Attach field type (auto-handles upload)
│  └─ Via API → POST /api/method/upload_file
│
├─ Create a file programmatically?
│  ├─ From bytes/content → save_file(fname, content, dt, dn)
│  ├─ From external URL → save_url(file_url, fname, dt, dn)
│  └─ Full control → frappe.get_doc({"doctype": "File", ...}).insert()
│
├─ Read file content?
│  ├─ By filename → frappe.get_file(fname)
│  └─ By File doc → file_doc.get_content()
│
├─ Public or private?
│  ├─ Public (anyone with link) → is_private=0, URL: /files/fname
│  └─ Private (permission-based) → is_private=1, URL: /private/files/fname
│
└─ Generate PDF attachment?
   └─ frappe.attach_print(doctype, name, print_format)

File DocType: Core Fields

Field Type Description
file_name Data Filename without path
file_url Data URL path (e.g., /files/report.pdf)
file_type Data Extension (PDF, PNG, DOCX, etc.)
is_private Check 0 = public, 1 = private
is_folder Check True for folder entries
folder Link → File Parent folder
attached_to_doctype Link → DocType Parent document type
attached_to_name Data Parent document name
attached_to_field Data Field name on parent
content_hash Data SHA-256 for deduplication
file_size Int Size in bytes

File URL Patterns

Type URL Pattern Filesystem Path
Public /files/{filename} {site}/public/files/{filename}
Private /private/files/{filename} {site}/private/files/{filename}
Remote https://... Not stored locally
API /api/method/{path} Generated dynamically

Valid URL prefixes: http://, https://, /api/method/, /files/, /private/files/.

ALWAYS use /private/files/ for sensitive documents. Public files are accessible to anyone with the URL, including unauthenticated users.


Permission Model

Frappe files use a three-tier permission model:

  1. Administrator — unrestricted access to all files
  2. Public files (is_private=0) — readable by anyone with the URL (no authentication required for read)
  3. Private files (is_private=1) — access requires:
    • User is the file owner, OR
    • User has explicit share on the file, OR
    • User has read permission on the attached_to_doctype/attached_to_name document

NEVER store sensitive data as public files. ALWAYS set is_private=1 for documents containing personal data, financial records, or confidential information.


Programmatic File Operations

Save File from Content

from frappe.utils.file_manager import save_file

# Save a generated CSV
csv_content = "Name,Amount\nACME,1000\nGlobex,2000"
file_doc = save_file(
    fname="report.csv",
    content=csv_content.encode("utf-8"),
    dt="Sales Invoice",           # attach to this DocType
    dn="SINV-00001",              # attach to this document
    folder="Home/Attachments",    # optional folder
    is_private=1,                 # private file
)
# file_doc.file_url → "/private/files/report.csv"

Save File from URL

from frappe.utils.file_manager import save_url

file_doc = save_url(
    file_url="https://example.com/logo.png",
    filename="company-logo.png",
    dt="Company",
    dn="My Company",
    folder="Home",
    is_private=0,
)

Read File Content

# By filename
filename, content = frappe.get_file("report.csv")

# By File document
file_doc = frappe.get_doc("File", {"file_name": "report.csv"})
content_bytes = file_doc.get_content()

Create File Document Directly

file_doc = frappe.get_doc({
    "doctype": "File",
    "file_name": "generated-report.pdf",
    "attached_to_doctype": "Sales Invoice",
    "attached_to_name": "SINV-00001",
    "is_private": 1,
    "content": pdf_bytes,  # raw bytes — written to disk on insert
}).insert(ignore_permissions=True)

Generate and Attach PDF

# Create PDF attachment dict (for use with sendmail)
pdf_attachment = frappe.attach_print(
    "Sales Invoice",
    "SINV-00001",
    print_format="Standard",
)
# Returns: {"fname": "Sales Invoice - SINV-00001.pdf", "fcontent": <bytes>}

# Save PDF as file attachment
from frappe.utils.file_manager import save_file

pdf = frappe.get_print("Sales Invoice", "SINV-00001", print_format="Standard", as_pdf=True)
save_file("invoice.pdf", pdf, "Sales Invoice", "SINV-00001", is_private=1)

File Upload via REST API

# Upload file attached to a document
curl -X POST https://site.example.com/api/method/upload_file \
  -H "Authorization: token api_key:api_secret" \
  -F "file=@/path/to/document.pdf" \
  -F "doctype=Sales Invoice" \
  -F "docname=SINV-00001" \
  -F "is_private=1"

Response:

{
  "message": {
    "name": "FILE-00001",
    "file_name": "document.pdf",
    "file_url": "/private/files/document.pdf",
    "is_private": 1
  }
}

File Size and Extension Limits

Default max file size: 10 MB per attachment.

Override in site_config.json:

{
  "max_file_size": 20971520
}

Max attachments per document: Set via Customize Form → Max Attachments field on the DocType.

Check file size programmatically:

from frappe.utils.file_manager import check_max_file_size
check_max_file_size(content)  # raises MaxFileSizeReachedError if too large

Attach Field Types

Field Type Stores UI
Attach Single file URL File picker + upload button
Attach Image Single image URL Image preview + upload

Both store the file_url string in the field value. The File DocType record is created separately with attached_to_field set.


S3 / Cloud Storage Integration

Frappe supports custom file storage via the delete_file_data_content hook and custom upload handlers.

S3 via frappe-s3-attachment or similar app

# In hooks.py of custom app
delete_file_data_content = "my_app.storage.delete_from_s3"

ALWAYS test file deletion when using custom storage backends — the default delete_file_from_filesystem only handles local files.

Configuration Pattern

# site_config.json for S3-compatible storage
{
  "s3_bucket": "my-frappe-files",
  "s3_region": "eu-west-1",
  "s3_access_key": "AKIA...",
  "s3_secret_key": "...",
}

Version Differences

Feature v14 v15 v16
File DocType Available Available Available
content_hash dedup Available Available Available
Image optimization Manual Auto (1920x1080, 85%) Auto
Import/Export Zip Not available Available Available

See Also