/frappe-impl-whitelisted

name: frappe-impl-whitelisted
description: >
  Use when building API endpoints with @frappe.whitelist() in Frappe.
  Covers endpoint design, permission patterns, error handling, client
  integration, file uploads, background jobs, rate limiting, REST API
  testing, and migration from Server Scripts to whitelisted methods.
  Prevents permission bypasses, SQL injection, and data exposure.
  Keywords: how to create API, build REST endpoint, frappe.call,, create API endpoint, call from frontend, custom API, REST endpoint, how to call python from JS.
  frappe.whitelist, API permission, guest API, secure endpoint,
  rate limiting, curl testing, frm.call.
license: MIT
compatibility: "Claude Code, Claude.ai Projects, Claude API. Frappe v14-v16."
metadata:
  author: OpenAEC-Foundation
  version: "2.0"

Frappe Whitelisted Methods Implementation Workflow

Step-by-step workflows for building API endpoints. For decorator syntax, see `frappe-syntax-whitelisted`.

**Version**: v14/v15/v16 (version-specific features noted)

---

Master Decision: What Type of Endpoint?

WHAT ARE YOU BUILDING?
│
├─► Public API (no login required)?
│   └─► allow_guest=True + STRICT input validation + rate limiting
│
├─► Authenticated API for logged-in users?
│   └─► Default @frappe.whitelist() + document permission checks
│
├─► Admin-only API?
│   └─► frappe.only_for("System Manager")
│
├─► Document-specific method (called from form)?
│   └─► Controller method + frm.call() from JS
│
├─► Standalone utility API?
│   └─► Separate api.py + frappe.call() from JS
│
├─► External webhook receiver?
│   └─► allow_guest=True + signature verification
│
└─► Background job trigger?
    └─► Authenticated API that calls frappe.enqueue()

---

Workflow 1: Design the Endpoint

Step 1: Choose Location

WHERE SHOULD THE CODE LIVE?
│
├─► Related to a DocType, called from its form?
│   └─► doctype/xxx/xxx.py (controller method)
│       Client: frm.call('method_name', args)
│
├─► Related to a DocType, standalone?
│   └─► doctype/xxx/xxx_api.py or myapp/api/module.py
│       Client: frappe.call('myapp.api.module.method')
│
├─► General app utility?
│   └─► myapp/api.py (small app) or myapp/api/module.py (large app)
│
└─► External integration?
    └─► myapp/integrations/service_name.py

Step 2: Choose Permission Model

WHO CAN CALL THIS API?
│
├─► Anyone (public) → allow_guest=True
│   ⚠️ MUST validate ALL input, sanitize for XSS, rate limit
│
├─► Any logged-in user → Default (no allow_guest)
│   Still check document permissions per record!
│
├─► Specific role(s) → frappe.only_for("Role")
│
└─► Document-level → frappe.has_permission(doctype, ptype, doc)

Step 3: Choose HTTP Method

WHAT DOES THE API DO?
│
├─► Read-only → methods=["GET"]
├─► Creates/modifies data → methods=["POST"]
└─► Both or default → omit methods parameter (all allowed)

---

Workflow 2: Implement an Authenticated API

Step-by-Step

**Step 1: Create the function**

# myapp/api.py
import frappe
from frappe import _

@frappe.whitelist()
def get_customer_balance(customer):
    """Get outstanding balance for a customer."""
    # 1. Permission check
    if not frappe.has_permission("Customer", "read", customer):
        frappe.throw(_("Not permitted"), frappe.PermissionError)

    # 2. Validate input
    if not customer or not frappe.db.exists("Customer", customer):
        frappe.throw(_("Customer not found"), frappe.DoesNotExistError)

    # 3. Fetch and return
    balance = frappe.db.sql("""
        SELECT COALESCE(SUM(outstanding_amount), 0)
        FROM `tabSales Invoice`
        WHERE customer = %s AND docstatus = 1
    """, customer)[0][0]

    return {"customer": customer, "balance": balance}

**Step 2: Call from Client Script**

frappe.call({
    method: 'myapp.api.get_customer_balance',
    args: { customer: 'CUST-00001' },
    callback(r) {
        if (r.message) console.log(r.message.balance);
    }
});

**Step 3: Test with curl**

# Authenticate first
curl -X POST https://site.com/api/method/login \
  -d 'usr=admin&pwd=password'

# Call the API
curl -X POST https://site.com/api/method/myapp.api.get_customer_balance \
  -H "Content-Type: application/json" \
  -d '{"customer": "CUST-00001"}' \
  --cookie cookies.txt

# Or use token auth
curl -X POST https://site.com/api/method/myapp.api.get_customer_balance \
  -H "Authorization: token api_key:api_secret" \
  -H "Content-Type: application/json" \
  -d '{"customer": "CUST-00001"}'

---

Workflow 3: Implement a Public (Guest) API

Step-by-Step

**Step 1: Create with strict validation**

@frappe.whitelist(allow_guest=True, methods=["POST"])
def submit_inquiry(name, email, phone=None, message=None):
    """Public contact form — strict validation required."""
    # 1. Validate required fields
    if not all([name, email]):
        frappe.throw(_("Name and email are required"))

    # 2. Validate email format
    if not frappe.utils.validate_email_address(email):
        frappe.throw(_("Invalid email address"))

    # 3. Sanitize ALL input
    name = frappe.utils.strip_html(name)[:100]
    email = email.strip().lower()[:200]
    phone = frappe.utils.strip_html(phone)[:20] if phone else None
    message = frappe.utils.strip_html(message)[:2000] if message else None

    # 4. Create record with ignore_permissions
    lead = frappe.get_doc({
        "doctype": "Lead",
        "lead_name": name, "email_id": email,
        "phone": phone, "notes": message, "source": "Website"
    })
    lead.insert(ignore_permissions=True)

    return {"success": True, "message": _("Thank you")}

**Step 2: Add rate limiting (v15+)**

from frappe.rate_limiter import rate_limit

@frappe.whitelist(allow_guest=True, methods=["POST"])
@rate_limit(limit=5, seconds=60)  # 5 calls per minute
def submit_inquiry(name, email, phone=None, message=None):
    ...

Critical Rules for Guest APIs

• **ALWAYS** validate a