Ticruz
102 lines
2.3 KiB
Markdown
102 lines
2.3 KiB
Markdown
# Feed Compiler
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The `FeedCompiler` class is responsible for transforming feed definitions into executable relay requests. It handles the complex task of converting various feed types into optimized filters and relay selections.
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## Overview
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```typescript
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class FeedCompiler {
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constructor(readonly options: FeedOptions)
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canCompile(feed: Feed): boolean
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compile(feed: Feed): Promise<RequestItem[]>
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}
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```
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## Feed Compilation Process
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The compiler transforms feed definitions into `RequestItem[]`, where each item contains:
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```typescript
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type RequestItem = {
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relays?: string[] // Specific relays to query
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filters?: Filter[] // Nostr filters to apply
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}
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```
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## Examples
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### Basic Feed Compilation
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```typescript
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const compiler = new FeedCompiler(options)
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// Simple author feed
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const feed = [FeedType.Author, "pubkey1", "pubkey2"]
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const requests = await compiler.compile(feed)
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// => [{ filters: [{ authors: ["pubkey1", "pubkey2"] }] }]
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```
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### Complex Feed Compilation
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```typescript
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// Complex feed with multiple operations
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const feed = [
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FeedType.Intersection,
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[FeedType.Kind, 1],
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[
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FeedType.Union,
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[FeedType.Scope, Scope.Follows],
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[FeedType.List, { addresses: ["trending"] }]
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]
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]
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const requests = await compiler.compile(feed)
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// Compiles to optimized filters for relay queries
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```
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### DVM Integration
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```typescript
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const feed = [
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FeedType.DVM,
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{
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kind: 5300,
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mappings: [
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["p", [FeedType.Author]],
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["t", [FeedType.Tag, "#t"]]
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]
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}
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]
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const requests = await compiler.compile(feed)
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// Queries DVM and compiles resulting tags into feeds
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```
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## Implementation Notes
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### Optimization Strategies
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1. **Filter Merging**: Similar filters are combined when possible
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```typescript
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// Before: [{ authors: ["a"] }, { authors: ["b"] }]
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// After: [{ authors: ["a", "b"] }]
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```
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2. **Relay Grouping**: Requests are grouped by relay where possible
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```typescript
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// Filters are organized by relay to minimize connections
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filtersByRelay: Map<string, Filter[]>
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```
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3. **Deduplication**: Duplicate values are removed using `uniq`
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```typescript
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uniq(scopes.flatMap(this.options.getPubkeysForScope))
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```
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### Error Handling
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The compiler includes various safety checks:
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```typescript
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canCompile(feed: Feed): boolean {
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// Checks if feed type is supported
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// Recursively checks sub-feeds
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}
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```
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