transform-template

Template transform (minijinja)

Last modified: 2026-04-27

Demonstrates the template transform. A static action emits a JSON document describing an order; the template transform parses that JSON as the input context and renders a minijinja template producing a human-readable plaintext receipt. A response_modifier rewrites Content-Type to text/plain; charset=utf-8. The origin is reached on 127.0.0.1:8080 via the tmpl.local Host header.

Run

sbproxy serve -f sb.yml

Try it

# Upstream body (what the static action emits internally):
# {
#   "order_id": "ORD-1042",
#   "customer": "Ada Lovelace",
#   "items": [
#     {"name":"Analytical Engine","qty":1,"price":9999.0},
#     {"name":"Punch Cards (1000-pack)","qty":3,"price":14.5}
#   ],
#   "total": 10042.5
# }

# Client response after the template transform
$ curl -i -H 'Host: tmpl.local' http://127.0.0.1:8080/
HTTP/1.1 200 OK
content-type: text/plain; charset=utf-8

Order ORD-1042 for Ada Lovelace
----
1 x Analytical Engine @ $9999
3 x Punch Cards (1000-pack) @ $14.5
----
Total: $10042.5

# Same response served as plain text - useful for receipts, email bodies, logs
$ curl -s -H 'Host: tmpl.local' http://127.0.0.1:8080/
Order ORD-1042 for Ada Lovelace
----
1 x Analytical Engine @ $9999
3 x Punch Cards (1000-pack) @ $14.5
----
Total: $10042.5

What this exercises

• template transform - minijinja rendering with the upstream JSON as the context
• minijinja control flow ({%- for item in items %}) and variable interpolation
• response_modifiers rewriting Content-Type to text/plain; charset=utf-8
• static action - inline JSON body so the example runs offline

See also

• docs/features.md - full feature reference
• docs/configuration.md - configuration schema