Files
hadrian/proxychain/responsemodifers/generate_readable_outline.go
2023-11-30 15:50:02 -06:00

85 lines
2.9 KiB
Go

package responsemodifers
import (
"embed"
"fmt"
"html/template"
"io"
"ladder/proxychain"
"log"
"github.com/go-shiori/dom"
"github.com/markusmobius/go-trafilatura"
)
//go:embed generate_readable_outline.html
var templateFS embed.FS
// GenerateReadableOutline creates an reader-friendly distilled representation of the article.
// This is a reliable way of bypassing soft-paywalled articles, where the content is hidden, but still present in the DOM.
func GenerateReadableOutline() proxychain.ResponseModification {
// get template only once, and resuse for subsequent calls
f := "generate_readable_outline.html"
tmpl, err := template.ParseFS(templateFS, f)
if err != nil {
panic(fmt.Errorf("tx.GenerateReadableOutline Error: %s not found", f))
}
return func(chain *proxychain.ProxyChain) error {
// ===========================================================
// 1. extract dom contents using reading mode algo
// ===========================================================
opts := trafilatura.Options{
IncludeImages: true,
IncludeLinks: true,
//FavorPrecision: true,
FallbackCandidates: nil, // TODO: https://github.com/markusmobius/go-trafilatura/blob/main/examples/chained/main.go
// implement fallbacks from "github.com/markusmobius/go-domdistiller" and "github.com/go-shiori/go-readability"
OriginalURL: chain.Request.URL,
}
result, err := trafilatura.Extract(chain.Response.Body, opts)
if err != nil {
return err
}
doc := trafilatura.CreateReadableDocument(result)
distilledHTML := dom.OuterHTML(doc)
// ============================================================================
// 2. render generate_readable_outline.html template using metadata from step 1
// ============================================================================
data := map[string]interface{}{
"Success": true,
"Params": chain.Request.URL,
//"Title": result.Metadata.Title, // todo: modify CreateReadableDocument so we don't have <h1> titles duplicated?
"Date": result.Metadata.Date.String(),
"Author": result.Metadata.Author,
"Body": distilledHTML,
}
// ============================================================================
// 3. queue sending the response back to the client by replacing the response body
// (the response body will be read as a stream in proxychain.Execute() later on.)
// ============================================================================
pr, pw := io.Pipe() // pipe io.writer contents into io.reader
// Use a goroutine for writing to the pipe so we don't deadlock the request
go func() {
defer pw.Close()
err := tmpl.Execute(pw, data) // <- render template
if err != nil {
log.Printf("WARN: GenerateReadableOutline template rendering error: %s\n", err)
}
}()
chain.Context.Set("content-type", "text/html")
chain.Response.Body = pr // <- replace reponse body reader with our new reader from pipe
return nil
}
}