Frappe_Claude_Skill_Package frappe-syntax-jinja

install
source · Clone the upstream repo
git clone https://github.com/OpenAEC-Foundation/Frappe_Claude_Skill_Package
Claude Code · Install into ~/.claude/skills/
T=$(mktemp -d) && git clone --depth=1 https://github.com/OpenAEC-Foundation/Frappe_Claude_Skill_Package "$T" && mkdir -p ~/.claude/skills && cp -r "$T/skills/source/syntax/frappe-syntax-jinja" ~/.claude/skills/openaec-foundation-frappe-claude-skill-package-frappe-syntax-jinja && rm -rf "$T"
manifest: skills/source/syntax/frappe-syntax-jinja/SKILL.md
source content

Frappe Jinja Templates Syntax

Deterministic Jinja reference for Print Formats, Email Templates, Notification Templates, and Portal Pages in Frappe v14/v15/v16.


When to Use This Skill

USE when:

  • Creating or modifying Print Formats (Jinja-based)
  • Writing Email Templates with dynamic fields
  • Building Portal Pages (
    www/*.html
    ) with Python controllers
  • Writing Notification Templates (system/email/SMS)
  • Registering custom Jinja methods or filters via
    hooks.py

DO NOT USE for:

  • Report Print Formats — they use JavaScript templating (
    {%= %}
    ), NOT Jinja
  • Client Scripts — see
    frappe-syntax-clientscripts
  • Server Scripts — see
    frappe-syntax-serverscripts

Decision Tree: Which Template Type?

Need a printable document?
├─ YES → Is it for a Query/Script Report?
│        ├─ YES → Use JS Template ({%= %}), NOT Jinja
│        └─ NO  → Use Jinja Print Format
└─ NO  → Is it for email?
         ├─ YES → Is it triggered by workflow/notification?
         │        ├─ YES → Notification Template (Jinja)
         │        └─ NO  → Email Template (Jinja)
         └─ NO  → Is it a web page?
                  ├─ YES → Portal Page (www/*.html + .py controller)
                  └─ NO  → frappe.render_template() for ad-hoc rendering

Quick Reference: Jinja Syntax

SyntaxPurposeExample
{{ }}
Output expression
{{ doc.name }}
{% %}
Control statement
{% if doc.status == "Paid" %}
{# #}
Comment
{# This is a comment #}
{{ _("text") }}
Translation
{{ _("Invoice") }}
{{ val | filter }}
Filter
{{ name | default("N/A") }}

CRITICAL: Jinja vs JS Template Syntax

AspectJinja (Print Formats)JS Template (Report Print Formats)
Output
{{ expression }}
{%= expression %}
Code block
{% statement %}
{% js_code %}
LanguagePythonJavaScript
Context
doc
,
frappe
data
,
filters

NEVER use Jinja syntax in Report Print Formats. NEVER use

{%= %}
in standard Print Formats.


Context Objects by Template Type

Print Formats

ObjectDescription
doc
The document being printed (full Document object)
frappe
Frappe module (whitelisted methods only)
frappe.utils
Utility functions
_()
Translation function
doc.items
,
doc.taxes
Child table accessors (by fieldname)

Email Templates

ObjectDescription
doc
The linked document (when triggered from a DocType)
frappe
Frappe module (limited)
_()
Translation function

Notification Templates

ObjectDescription
doc
The document that triggered the notification
frappe
Frappe module
_()
Translation function

Portal Pages (www/*.html)

ObjectDescription
frappe
Frappe module
frappe.session.user
Current authenticated user
frappe.form_dict
Query parameters from URL
frappe.lang
Current language code
Custom contextSet via
get_context(context)
in
.py
controller

Full details:

references/context-objects.md


Essential Methods (Whitelisted in Jinja)

Formatting: ALWAYS Use for Display

{# ALWAYS use get_formatted() for fields in Print Formats #}
{{ doc.get_formatted("posting_date") }}
{{ doc.get_formatted("grand_total") }}

{# Child table rows — ALWAYS pass parent doc for currency context #}
{% for row in doc.items %}
    {{ row.get_formatted("rate", doc) }}
    {{ row.get_formatted("amount", doc) }}
{% endfor %}

{# General formatting with explicit fieldtype #}
{{ frappe.format(value, {'fieldtype': 'Currency'}) }}
{{ frappe.format_date(doc.posting_date) }}

Document Retrieval

{# Full document — use only when multiple fields needed #}
{% set customer = frappe.get_doc("Customer", doc.customer) %}

{# Single field — ALWAYS prefer over get_doc for one field #}
{% set abbr = frappe.db.get_value("Company", doc.company, "abbr") %}

{# List of records (no permission check) #}
{% set tasks = frappe.get_all("Task",
    filters={"status": "Open"},
    fields=["title", "due_date"],
    order_by="due_date asc",
    page_length=10) %}

{# List with permission check (portal pages) #}
{% set orders = frappe.get_list("Sales Order",
    filters={"customer": doc.customer},
    fields=["name", "grand_total"]) %}

Translation: REQUIRED for All User-Facing Strings

<h1>{{ _("Invoice") }}</h1>
<p>{{ _("Total: {0}").format(doc.get_formatted("grand_total")) }}</p>

System & Session

{{ frappe.get_url() }}
{{ frappe.get_fullname() }}
{{ frappe.get_fullname(doc.owner) }}
{{ frappe.db.get_single_value("System Settings", "time_zone") }}
{% if frappe.session.user != "Guest" %}...{% endif %}

Full method reference:

references/methods-reference.md


Control Structures

Conditionals

{% if doc.status == "Paid" %}
    <span class="paid">{{ _("Paid") }}</span>
{% elif doc.status == "Overdue" %}
    <span class="overdue">{{ _("Overdue") }}</span>
{% else %}
    <span>{{ doc.status }}</span>
{% endif %}

Loops with Child Tables

{% for item in doc.items %}
<tr>
    <td>{{ loop.index }}</td>
    <td>{{ item.item_name }}</td>
    <td>{{ item.get_formatted("amount", doc) }}</td>
</tr>
{% else %}
<tr><td colspan="3">{{ _("No items") }}</td></tr>
{% endfor %}

Loop Variables

VariableDescription
loop.index
1-indexed position
loop.index0
0-indexed position
loop.first
True
on first iteration
loop.last
True
on last iteration
loop.length
Total number of items

Variables

{% set total = 0 %}
{% set name = doc.customer_name | default("Unknown") %}

Filters

FilterExampleNotes
default
{{ val | default("N/A") }}
ALWAYS use for optional fields
length
{{ items | length }}
Count items
join
{{ names | join(", ") }}
Join list to string
truncate
{{ text | truncate(100) }}
Truncate with ellipsis
escape
{{ input | escape }}
HTML-escape (default behavior)
safe
{{ html | safe }}
Render raw HTML — NEVER for user input
round
{{ num | round(2) }}
Round number
lower
/
upper
{{ text | upper }}
Case conversion

Full filter reference:

references/filters-reference.md


Custom Jinja Methods & Filters via hooks.py

hooks.py Registration

# hooks.py
jenv = {
    "methods": [
        "myapp.jinja.methods"       # Module with callable functions
    ],
    "filters": [
        "myapp.jinja.filters"       # Module with filter functions
    ]
}

Custom Method

# myapp/jinja/methods.py
import frappe

def get_company_logo(company):
    """Returns company logo URL. Called as get_company_logo() in Jinja."""
    return frappe.db.get_value("Company", company, "company_logo") or ""
<img src="{{ get_company_logo(doc.company) }}" alt="Logo">

Custom Filter

# myapp/jinja/filters.py
def nl2br(text):
    """Convert newlines to <br> tags. Used as {{ text | nl2br }}."""
    return (text or "").replace("\n", "<br>")
{{ doc.notes | nl2br | safe }}

Details:

references/methods.md


Print Format Patterns

Minimal Print Format Template

<style>
    .print-header { background: #f5f5f5; padding: 15px; }
    .item-table { width: 100%; border-collapse: collapse; }
    .item-table th, .item-table td { border: 1px solid #ddd; padding: 8px; }
    .text-right { text-align: right; }
</style>

<div class="print-header">
    <h1>{{ doc.select_print_heading or _("Invoice") }}</h1>
    <p>{{ doc.name }} — {{ doc.get_formatted("posting_date") }}</p>
</div>

<table class="item-table">
    <thead>
        <tr>
            <th>#</th>
            <th>{{ _("Item") }}</th>
            <th class="text-right">{{ _("Qty") }}</th>
            <th class="text-right">{{ _("Amount") }}</th>
        </tr>
    </thead>
    <tbody>
        {% for row in doc.items %}
        <tr>
            <td>{{ loop.index }}</td>
            <td>{{ row.item_name }}</td>
            <td class="text-right">{{ row.qty }}</td>
            <td class="text-right">{{ row.get_formatted("amount", doc) }}</td>
        </tr>
        {% endfor %}
    </tbody>
</table>

<p><strong>{{ _("Grand Total") }}: {{ doc.get_formatted("grand_total") }}</strong></p>

Page Breaks

/* v14/v15 (wkhtmltopdf) */
.page-break { page-break-before: always; }

/* v16 (Chrome PDF) — ALWAYS prefer break-* in v16 */
.page-break { break-before: page; }

Full examples:

references/examples.md
| Patterns:
references/patterns.md


V16: Chrome PDF Rendering

Aspectv14/v15 (wkhtmltopdf)v16 (Chrome)
CSS SupportLimited CSS3Full modern CSS
Flexbox/GridPartialFull support
Page breaks
page-break-*
break-*
preferred
FontsSystem fonts onlyWeb fonts supported

V16 Configuration

// site_config.json
{
    "pdf_engine": "chrome",
    "chrome_path": "/usr/bin/chromium"
}

Portal Page Pattern

www/projects/index.html

{% extends "templates/web.html" %}
{% block title %}{{ _("Projects") }}{% endblock %}

{% block page_content %}
<h1>{{ _("Projects") }}</h1>
{% for project in projects %}
    <h3>{{ project.title }}</h3>
    <p>{{ project.description | default("") | truncate(150) }}</p>
{% else %}
    <p>{{ _("No projects found.") }}</p>
{% endfor %}
{% endblock %}

www/projects/index.py

import frappe

def get_context(context):
    context.title = "Projects"
    context.no_cache = True
    context.projects = frappe.get_all("Project",
        filters={"is_public": 1},
        fields=["name", "title", "description"],
        order_by="creation desc")
    return context

Full structure:

references/structure.md
| Templates:
references/templates.md


Critical Rules

ALWAYS

  1. Use
    _()
    for ALL user-facing strings
  2. Use
    get_formatted()
    for currency, date, and numeric fields
  3. Use
    default()
    filter for optional/nullable fields
  4. Pass parent
    doc
    to child row
    get_formatted("field", doc)
  5. Use
    frappe.db.get_value()
    when you need only one field
  6. Keep calculations in Python controllers, not Jinja templates

NEVER

  1. Execute database queries inside loops (N+1 problem)
  2. Use
    | safe
    on user-supplied input (XSS vulnerability)
  3. Use Jinja syntax in Report Print Formats (they require JS
    {%= %}
    )
  4. Use
    frappe.get_doc()
    when
    frappe.db.get_value()
    suffices
  5. Hardcode strings without
    _()
    translation wrapper
  6. Disable
    safe_render
    without security review

Anti-patterns with fixes:

references/anti-patterns.md


Reference Files

FileContents
references/syntax.md
Jinja syntax reference (tags, filters, tests, loops)
references/methods.md
Custom Jinja methods/filters via hooks
references/context-objects.md
Available objects per template type
references/filters-reference.md
All standard and custom Frappe filters
references/methods-reference.md
All frappe.* methods available in Jinja
references/examples.md
Complete Print Format, Email, Portal examples
references/anti-patterns.md
Common mistakes and correct alternatives
references/templates.md
Template structure patterns
references/patterns.md
Conditional rendering, loops, child tables
references/structure.md
File structure for template types

See Also

  • frappe-syntax-hooks
    — jenv configuration in hooks.py
  • frappe-impl-printformat
    — Print Format implementation patterns
  • frappe-errors-serverscripts
    — Server-side error handling