# Request Security (/developers/pinets/architecture/specifics/request-security)



## Request Security Architecture [#request-security-architecture]

`request.security` is the most complex function in PineTS as it involves creating and managing secondary execution contexts.

## Context Hierarchy [#context-hierarchy]

PineTS creates a strictly **Two-Level Hierarchy** to prevent infinite recursion.

1. **Primary Context**: The main script execution.
2. **Secondary Context**: Created by `request.security` to run the same script on a different timeframe/symbol.

**Guard**: Secondary contexts have `isSecondaryContext = true`. If `request.security` is called inside a secondary context, it returns the expression directly instead of creating a tertiary context.

## Caching Strategy [#caching-strategy]

Since creating a `PineTS` instance and running a script is expensive, secondary contexts are aggressively cached.

### Cache Key [#cache-key]

The cache key is composite:

```typescript
key = `${symbol}_${timeframe}_${expressionID}`;
```

* `expressionID`: The unique ID (`p0`, `p1`...) of the expression parameter passed to `security`. This is why `request.param()` returns `[val, name]`.

## Data Flow [#data-flow]

1. **User calls `request.security(..., expression)`**.
2. **Primary Context**:
   * Checks cache.
   * If miss: Creates `new PineTS(...)` for target timeframe.
   * Sets `isSecondaryContext = true`.
   * Runs the script.
   * Stores result in cache.
   * Extracts result aligned to primary timeframe.
3. **Secondary Context**:
   * Runs the same script.
   * When it encounters `request.security`:
   * Checks `isSecondaryContext`.
   * Returns `expression` directly.
   * This effectively "unwraps" the security call inside the secondary context, allowing the script to calculate the expression natively in that timeframe.