v2: Implement Network Handling (HTTP Metadata, Conditional Requests, Request Config)

[mmcdole]

Overview

Implement comprehensive network handling for ParseURL including HTTP response metadata, conditional requests, and request configuration using the RequestOptions sub-struct from #244.

Tasks

Request Configuration

• [ ] Use RequestOptions from ParseOptions for HTTP configuration:
  • [ ] Apply custom Client if provided
  • [ ] Set Timeout on HTTP client
  • [ ] Set UserAgent header
  • [ ] Apply AuthConfig for basic auth

Conditional Requests

• [ ] Implement conditional request support:
  • [ ] Send If-None-Match header when IfNoneMatch is set in RequestOptions
  • [ ] Send If-Modified-Since header when IfModifiedSince is set
  • [ ] Return ErrNotModified for 304 responses
  • [ ] Handle 304 responses gracefully

Response Metadata

• [ ] Add ResponseMetadata struct to gofeed.Feed:

  type ResponseMetadata struct {
      StatusCode int
      ETag string
      LastModified time.Time
      CacheControl struct {
          MaxAge *time.Duration
          MustRevalidate bool
          NoCache bool
          NoStore bool
      }
      RetryAfter *time.Time
      Expires *time.Time
  }
  

• [ ] Parse and populate HTTP headers:

  • [ ] ETag response header
  • [ ] Last-Modified header (parse HTTP date)
  • [ ] Cache-Control directives (max-age, must-revalidate, no-cache, no-store)
  • [ ] Retry-After header (both HTTP-date and delay-seconds formats)
  • [ ] Expires header

Testing & Documentation

• [ ] Add comprehensive tests for all network functionality
• [ ] Document usage patterns for:
  • Conditional requests to reduce bandwidth
  • Cache control interpretation
  • Retry-After handling for rate limiting

Benefits

• Enable proper HTTP caching strategies
• Support conditional requests to reduce unnecessary fetches
• Provide scheduling hints from HTTP headers
• Better HTTP client configuration support

Related Issues

• #111 (HTTP ETag, Last-Modified, conditional requests)
• #165 (Proxy/custom HTTP client support)
• #228 (Scheduling hints)
• #244 (ParseOptions implementation)

Parent Issue

• #241 (RFC: gofeed v2)