get (purchaseOrder)

get fetches a single purchase order by _id with the full depth-2 projection — including related snapshots like requester, product, process, stepApprovals, and budgetLine. It's the detail view behind any PO card: click a row in gets and load it here. Every authenticated role can call it.

note

Package import The tutorial source imports the framework as "lesan" — in this repo that alias maps to the local framework source (deno.json → ../../src/mod.ts). In your own app import from @hemedani/lesan (npm/Bun) or jsr:@hemedani/lesan (Deno). @lib and @model are the tutorial's aliases for utils/ and models/.

The validator (get.val.ts)

Only _id plus the activeRoleId mixin. get is a depth-2 selectStruct("purchaseOrder", 2) — deeper than the list acts so the detail view can pull in related documents.

import { object, objectIdValidation } from "lesan";
import { selectStruct } from "../../../mod.ts";
import { activeRoleMixin } from "@lib";

export const getValidator = () => {
  return object({
    set: object({
      ...activeRoleMixin,
      _id: objectIdValidation,
    }),
    get: selectStruct("purchaseOrder", 2),
  });
};

The implementation (get.fn.ts)

A single findOne with filters: { _id: new ObjectId(_id) }. If nothing is found it throws purchase order not found; otherwise it returns the document shaped by the requested get projection.

import { type ActFn, ObjectId } from "lesan";
import { purchaseOrder } from "../../../mod.ts";
import { throwError } from "@lib";

export const getFn: ActFn = async (body) => {
  const {
    set: { _id },
    get,
  } = body.details;

  const foundedPO = await purchaseOrder.findOne({
    filters: { _id: new ObjectId(_id as string) },
    projection: get,
  });

  !foundedPO && throwError("purchase order not found");
  return foundedPO;
};

In the workflow

get sits between gets and the actions. From here you branch: submit a Draft, cancel a pending one, or view the history and step approvals of an in-flight order.

Links: overview, purchaseOrder model, po-gets, po-get-history.

Run it

curl -X POST http://localhost:1380/lesan \
  -H "Content-Type: application/json" \
  -H "token: $TOKEN" \
  -d '{
    "model": "purchaseOrder",
    "act": "get",
    "details": {
      "set": {
        "activeRoleId": "ghost-role",
        "_id": "<poId>"
      },
      "get": {
        "_id": 1,
        "title": 1,
        "status": 1,
        "currentStep": 1,
        "estimatedAmount": 1,
        "process": { "_id": 1, "name": 1 },
        "requester": { "_id": 1, "first_name": 1, "last_name": 1 }
      }
    }
  }'

Errors & fixes

Error	Meaning	Fix
purchase order not found	No PO with that _id	Double-check the id (use gets to find a real one)
_id invalid	objectIdValidation rejected the value	Pass a 24-char hex ObjectId

Shared auth-chain errors apply; all roles are allowed.