Inventory Clearing Price API

Overview

This endpoint exposes two computational operations via a single POST route.

• action="calculatePrice" → returns the Profit-Equalizing Price (aka “special price”).
• action="calculateExtraProfit" → given an offer price, returns the incremental profit over the profit-equalizing price.

Endpoint

All requests and responses are JSON. Include Content-Type: application/json.

Request Schema

Common

Action: calculatePrice

Action: calculateExtraProfit

Response Schema

Success

{
  "profitEqualizingPrice": number
}

{
  "extraProfit": number
}

Errors

{"error":"Invalid JSON input."}

{"error":"Please enter valid numerical values for all fields."}

{"error":"Inventory and Deal Volume cannot be zero."}

{"error":"Missing or invalid values for calculation."}

{"error":"Invalid action."}

{"error":"Only POST method is supported."}

Business Logic & Formulas

Interpretation: specialPrice is the per-unit price that makes total profit indifferent between clearing the deal now (with scrap of remainder) and proceeding with expected lifetime sales.

Examples

1) Compute Profit-Equalizing Price

POST https://www.promptbox.cn/api/inventory.php
Content-Type: application/json

{
  "action": "calculatePrice",
  "inventory": 12000,
  "lifetimeVolume": 7000,
  "avgPrice": 31.5,
  "dealVolume": 7500,
  "dieCost": 12.8,
  "finalCost": 22.4
}

HTTP/1.1 200 OK
Content-Type: application/json

{
  "profitEqualizingPrice": 19.437
}

curl

curl -sS -X POST https://www.promptbox.cn/api/inventory.php \
  -H "Content-Type: application/json" \
  -d '{
    "action":"calculatePrice",
    "inventory":12000,
    "lifetimeVolume":7000,
    "avgPrice":31.5,
    "dealVolume":7500,
    "dieCost":12.8,
    "finalCost":22.4
  }'

JavaScript (fetch)

await fetch("https://www.promptbox.cn/api/inventory.php",{
  method:"POST",
  headers:{ "Content-Type":"application/json" },
  body: JSON.stringify({
    action:"calculatePrice",
    inventory:12000,
    lifetimeVolume:7000,
    avgPrice:31.5,
    dealVolume:7500,
    dieCost:12.8,
    finalCost:22.4
  })
}).then(r=>r.json());

Python (requests)

import requests
payload = {
  "action":"calculatePrice",
  "inventory":12000,
  "lifetimeVolume":7000,
  "avgPrice":31.5,
  "dealVolume":7500,
  "dieCost":12.8,
  "finalCost":22.4
}
r = requests.post("https://www.promptbox.cn/api/inventory.php", json=payload)
print(r.json())

2) Compute Extra Profit for an Offer

POST https://www.promptbox.cn/api/inventory.php
Content-Type: application/json

{
  "action": "calculateExtraProfit",
  "globalSpecialPrice": 19.437,
  "dealVolume": 7500,
  "offerPrice": 20.25
}

HTTP/1.1 200 OK
Content-Type: application/json

{
  "extraProfit": 6097.50
}

curl

curl -sS -X POST https://www.promptbox.cn/api/inventory.php \
  -H "Content-Type: application/json" \
  -d '{
    "action":"calculateExtraProfit",
    "globalSpecialPrice":19.437,
    "dealVolume":7500,
    "offerPrice":20.25
  }'

Validation Rules & Edge Cases

• All numeric fields must be valid numbers (integers or decimals). Non-numeric → 400.
• inventory and dealVolume must be non-zero for calculatePrice → else 400.
• Negative values are accepted mathematically but usually not meaningful; validate upstream if business rules disallow.
• Rounding: price → 3 decimals; extra profit → 2 decimals.
• HTTP method must be POST; others → 405.

Security, Headers & CORS

• Send Content-Type: application/json.
• Over HTTPS only (https:// scheme shown in examples).
• If calling from browsers on other origins, ensure server sets Access-Control-Allow-Origin appropriately.

Performance & Limits

• Each request is O(1) compute—latency is dominated by network.
• No explicit rate limit is enforced in the sample implementation; add one at proxy/API gateway if needed.
• Idempotent for identical inputs (pure calculation).

Change Log