Search/node-request-text.go

//go:build experimental
// +build experimental

package main

import (
	"bytes"
	"encoding/binary"
	"fmt"
	"time"
)

var textResultsChan = make(chan []TextSearchResult)

// Try other nodes is not defined for every type
func tryOtherNodesForTextSearch(query, safe, lang string, page int) []TextSearchResult {
	for _, nodeTarget := range sockets {
		results, err := sendTextSearchRequestToNode(nodeTarget, query, safe, lang, page)
		if err != nil {
			printWarn("Error contacting node %s: %v", nodeTarget, err)
			continue
		}
		if len(results) > 0 {
			return results
		}
	}
	return nil
}

func sendTextSearchRequestToNode(target, query, safe, lang string, page int) ([]TextSearchResult, error) {
	payload, err := encodeSearchTextParams(query, safe, lang, page)
	if err != nil {
		return nil, fmt.Errorf("encode error: %v", err)
	}

	msg := Message{
		ID:      generateMessageID(), // assume function returns uint32
		Type:    MsgTypeSearchTextRequest,
		Content: payload,
		Target:  target,
	}

	err = sendMessage(msg)
	if err != nil {
		return nil, fmt.Errorf("failed to send search request to node %s: %v", target, err)
	}

	select {
	case res := <-textResultsChan:
		return res, nil
	case <-time.After(20 * time.Second):
		return nil, fmt.Errorf("timeout waiting for results from node %s", target)
	}
}

func handleTextResultsMessage(msg Message) {
	results, err := decodeTextResults([]byte(msg.Content))
	if err != nil {
		printWarn("Error decoding text results: %v", err)
		return
	}
	printDebug("Received text results: %+v", results)

	go func() {
		textResultsChan <- results
	}()
}

func encodeTextResults(results []TextSearchResult) ([]byte, error) {
	buf := new(bytes.Buffer)

	if err := binary.Write(buf, binary.BigEndian, uint16(len(results))); err != nil {
		return nil, err
	}

	for _, r := range results {
		if err := writeString(buf, r.URL); err != nil {
			return nil, err
		}
		if err := writeString(buf, r.Header); err != nil {
			return nil, err
		}
		if err := writeString(buf, r.Description); err != nil {
			return nil, err
		}
		if err := writeString(buf, r.Source); err != nil {
			return nil, err
		}
	}

	return buf.Bytes(), nil
}

func decodeTextResults(data []byte) ([]TextSearchResult, error) {
	buf := bytes.NewReader(data)

	var count uint16
	if err := binary.Read(buf, binary.BigEndian, &count); err != nil {
		return nil, err
	}

	results := make([]TextSearchResult, 0, count)
	for i := 0; i < int(count); i++ {
		url, err := readString(buf)
		if err != nil {
			return nil, err
		}
		header, err := readString(buf)
		if err != nil {
			return nil, err
		}
		description, err := readString(buf)
		if err != nil {
			return nil, err
		}
		source, err := readString(buf)
		if err != nil {
			return nil, err
		}
		results = append(results, TextSearchResult{
			URL:         url,
			Header:      header,
			Description: description,
			Source:      source,
		})
	}
	return results, nil
}